JP2024136471A - Light-adjusting sheet, light-adjusting device, and method for manufacturing light-adjusting sheet - Google Patents

Abstract

To provide a light control sheet, a light control device, and a method for manufacturing a light control sheet which can improve responsibility under low temperature environment.SOLUTION: A light control sheet has a light control layer 31 positioned between a first transparent electrode layer 34 and a second transparent electrode layer 35, wherein the light control layer 31 includes an ionizing radiation curable resin layer 31P partitioning a gap 31D, and a liquid crystal composition 31LC filling the gap 31D, an acryloyl group and a methacryloyl group are functional groups, an acrylic compound having three of more functional groups and a double bond equivalent of 150 g/eq or less is a first acrylic compound, and a percentage content of the first acrylic compound constituting the ionizing radiation curable resin layer is 2 mass% or more and 50 mass% or less of the ionizing radiation curable resin layer.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a light-adjusting sheet in which a liquid crystal composition is filled into the gaps defined by an ionizing radiation cured resin layer, a light-adjusting device including the light-adjusting sheet, and a method for manufacturing the light-adjusting sheet.

The light-controlling sheet comprises a light-controlling layer between transparent electrode films. The light-controlling layer comprises an ionizing radiation cured resin layer that defines a plurality of voids, and a liquid crystal composition that fills the voids. Changing the voltage between the transparent electrode films changes the alignment state of the liquid crystal compound. Changing the alignment state of the liquid crystal compound changes the degree of scattering at the interface between the ionizing radiation cured resin layer and the liquid crystal composition, thereby changing the degree of transparency of the light-controlling sheet.

The time it takes for the transparency of the light-adjusting sheet to respond to a change in voltage between the transparent electrode films depends on the environmental temperature in which the light-adjusting sheet is installed. The lower the environmental temperature at which the transparency of the light-adjusting sheet can respond to a change in voltage, the more suitable the light-adjusting sheet is for use in a low-temperature environment. An example of a configuration for lowering the application temperature of the light-adjusting sheet is to add a viscosity-reducing agent to the liquid crystal composition so as to reduce the viscosity of the liquid crystal composition in a low-temperature environment (see, for example, Patent Documents 1 and 2).

JP 2022-148343 A JP 2022-098845 A

On the other hand, the addition of a viscosity reducing agent reduces the content of the ionizing radiation cured resin layer or the content of the liquid crystal compound in the light control layer. The reduction in the content reduces the interface between the ionizing radiation cured resin layer and the liquid crystal composition, which reduces the degree of scattering in the light control sheet, so there is a limit to the viscosity reduction that can be achieved by adding a viscosity reducing agent. Thus, the above-mentioned light control sheet is required to have a new configuration that can improve responsiveness in low-temperature environments.

The light-adjusting sheet for solving the above problem includes a first transparent electrode layer, a second transparent electrode layer, and a light-adjusting layer located between the first transparent electrode layer and the second transparent electrode layer, and changes the haze of the light-adjusting layer by changing the voltage applied between the first transparent electrode layer and the second transparent electrode layer. The light-adjusting layer includes an ionizing radiation cured resin layer that defines a gap, and a liquid crystal composition that fills the gap. The liquid crystal composition does not include a viscosity reducing agent, and the first acrylic compound is an acrylic compound that has three or more functional groups, an acryloyl group, and a methacryloyl group, and has a double bond equivalent of 150 g/eq or less, and the content of the first acrylic compound that constitutes the ionizing radiation cured resin layer is 2% by mass or more and 50% by mass or less of the ionizing radiation cured resin layer. The second acrylic compound is a monofunctional alkyl acrylate containing a saturated alkyl group having 2 to 12 carbon atoms, a monofunctional alkoxyalkyl acrylate containing a saturated alkoxyalkyl group having 2 to 12 carbon atoms, a monofunctional alkyl methacrylate containing a saturated alkyl group having 2 to 12 carbon atoms, and a monofunctional alkoxyalkyl methacrylate containing a saturated alkoxyalkyl group having 2 to 12 carbon atoms, and the content of the second acrylic compound constituting the ionizing radiation cured resin layer is 35% by mass to 85% by mass of the ionizing radiation cured resin layer. The third acrylic compound is an acrylic compound having 1 to 3 functional groups and a polyethylene oxide chain and a double bond equivalent of 300 g/eq to 700 g/eq, and the content of the third acrylic compound constituting the ionizing radiation cured resin layer is 5% by mass to 20% by mass of the ionizing radiation cured resin layer.

A light-adjusting sheet for solving the above problem comprises a first transparent electrode layer, a second transparent electrode layer, and a light-adjusting layer located between the first transparent electrode layer and the second transparent electrode layer, and changes the haze of the light-adjusting layer by changing the voltage applied between the first transparent electrode layer and the second transparent electrode layer. The light-adjusting layer comprises an ionizing radiation cured resin layer that defines a gap, and a liquid crystal composition that fills the gap. The first acrylic compound is an acrylic compound having three or more of the functional groups, an acryloyl group, and a methacryloyl group, and a double bond equivalent of 150 g/eq or less. The content of the first acrylic compound constituting the ionizing radiation cured resin layer is 2% by mass or more and 50% by mass or less of the ionizing radiation cured resin layer. The second acrylic compound is a monofunctional alkyl acrylate containing a saturated alkyl group having 2 to 12 carbon atoms, a monofunctional alkoxyalkyl acrylate containing a saturated alkoxyalkyl group having 2 to 12 carbon atoms, a monofunctional alkyl methacrylate containing a saturated alkyl group having 2 to 12 carbon atoms, and a monofunctional alkoxyalkyl methacrylate containing a saturated alkoxyalkyl group having 2 to 12 carbon atoms, and the content of the second acrylic compound constituting the ionizing radiation cured resin layer is 35% by mass to 85% by mass of the ionizing radiation cured resin layer. The third acrylic compound is an acrylic compound having 1 to 3 functional groups and a polyethylene oxide chain and a double bond equivalent of 300 g/eq to 700 g/eq, and the content of the third acrylic compound constituting the ionizing radiation cured resin layer relative to the content of the first acrylic compound constituting the ionizing radiation cured resin layer is 0.25 or more.

The light control device for solving the above problem includes the above light control sheet and a drive unit that applies a voltage to the light control sheet.
A method for producing a light-controlling sheet for solving the above problems includes forming a coating layer containing an ionizing radiation curable composition and a liquid crystal composition between a first transparent electrode layer and a second transparent electrode layer, and forming a light-controlling layer between the first transparent electrode layer and the second transparent electrode layer by irradiating the coating layer with ionizing radiation, the light-controlling layer comprising an ionizing radiation curable resin layer that defines a gap between the first transparent electrode layer and the second transparent electrode layer, and the liquid crystal composition that fills the gap. This method for producing a light-controlling sheet changes the haze of the light-controlling layer by changing the voltage applied between the first transparent electrode layer and the second transparent electrode layer, wherein the functional groups are an acryloyl group and a methacryloyl group, the first acrylic compound is an acrylic compound that has three or more of the functional groups and has a double bond equivalent of 150 g/eq or less, and the content of the first acrylic compound that constitutes the ionizing radiation curable composition is 2% by mass or more and 50% by mass or less of the ionizing radiation curable composition. The second acrylic compound is a monofunctional alkyl acrylate containing a saturated alkyl group having 2 to 12 carbon atoms, a monofunctional alkoxyalkyl acrylate containing a saturated alkoxyalkyl group having 2 to 12 carbon atoms, a monofunctional alkyl methacrylate containing a saturated alkyl group having 2 to 12 carbon atoms, and a monofunctional alkoxyalkyl methacrylate containing a saturated alkoxyalkyl group having 2 to 12 carbon atoms, and the content of the second acrylic compound constituting the ionizing radiation cured resin layer is 35% by mass to 85% by mass of the ionizing radiation cured resin layer.The third acrylic compound is an acrylic compound having 1 to 3 functional groups and a polyethylene oxide chain and having a double bond equivalent of 300 g/eq to 700 g/eq, and the content of the third acrylic compound constituting the ionizing radiation cured resin layer is 5% by mass to 20% by mass of the ionizing radiation cured resin layer.

A method for manufacturing a light-adjusting sheet for solving the above problems includes forming a coating layer containing an ionizing radiation curable composition and a liquid crystal composition between a first transparent electrode layer and a second transparent electrode layer, and forming a light-adjusting layer between the first transparent electrode layer and the second transparent electrode layer by irradiating the coating layer with ionizing radiation, the light-adjusting layer comprising an ionizing radiation curable resin layer that defines a gap and the liquid crystal composition that fills the gap. The method for manufacturing a light-adjusting sheet changes the haze of the light-adjusting layer by changing the voltage applied between the first transparent electrode layer and the second transparent electrode layer, in which an acryloyl group and a methacryloyl group are functional groups, an acrylic compound having three or more of the functional groups and a double bond equivalent of 150 g/eq or less is the first acrylic compound, and the content of the first acrylic compound constituting the ionizing radiation curable composition is 2% by mass or more and 50% by mass or less of the ionizing radiation curable composition. The second acrylic compound is a monofunctional alkyl acrylate containing a saturated alkyl group having 2 to 12 carbon atoms, a monofunctional alkoxyalkyl acrylate containing a saturated alkoxyalkyl group having 2 to 12 carbon atoms, a monofunctional alkyl methacrylate containing a saturated alkyl group having 2 to 12 carbon atoms, and a monofunctional alkoxyalkyl methacrylate containing a saturated alkoxyalkyl group having 2 to 12 carbon atoms, and the content of the second acrylic compound constituting the ionizing radiation cured resin layer is 35% by mass to 85% by mass of the ionizing radiation cured resin layer. The third acrylic compound is an acrylic compound having 1 to 3 functional groups and a polyethylene oxide chain and a double bond equivalent of 300 g/eq to 700 g/eq, and the content of the third acrylic compound constituting the ionizing radiation cured resin layer relative to the content of the first acrylic compound constituting the ionizing radiation cured resin layer is 0.25 or more.

Phase separation between the cured product of the ionizing radiation curable composition and the liquid crystal composition causes unreacted ionizing radiation curable compound, by-products such as water resulting from the curing reaction of the ionizing radiation curable compound, and low molecular weight compounds such as the solvent of the ionizing radiation curable composition to remain in the liquid crystal composition. The degree to which the viscosity of the ionizing radiation curable compound, by-products such as water, and low molecular weight compounds such as the solvent increases with decreasing temperature is greater in low temperature environments such as cold regions than the degree to which the viscosity of the liquid crystal compound increases with decreasing temperature.

According to each of the above configurations, the first acrylic compound having three or more of the functional groups and a double bond equivalent of 150 g/eq or less constitutes 2% by mass or more of the ionizing radiation curable resin layer. Therefore, the cured product of the ionizing radiation curable composition becomes dense during the process of phase separation between the cured product of the ionizing radiation curable composition and the liquid crystal composition. As a result, low molecular weight compounds are prevented from remaining in the liquid crystal composition. Furthermore, the prevention of low molecular weight compounds remaining in the liquid crystal composition prevents the liquid crystal composition from thickening in a low temperature environment.

The content of the second acrylic compound is 35% by mass or more and 85% by mass or less of the ionizing radiation cured resin layer. The content of the third acrylic compound, which has 1 to 3 functional groups and a polyethylene oxide chain and has a double bond equivalent of 300 g/eq or more and 700 g/eq or less, is 5% by mass or more and 20% by mass or less of the ionizing radiation cured resin layer. Therefore, while the ionizing radiation cured resin layer suppresses low molecular weight compounds from remaining in the liquid crystal compound, a decrease in peel strength within the light control sheet is also suppressed.

In the above light-adjusting sheet, the number of functional groups in the first acrylic compound may be 3 or more and 5 or less, the content of the first acrylic compound constituting the ionizing radiation cured resin layer may be 30% by mass or less of the ionizing radiation cured resin layer, and the content of the second acrylic compound constituting the ionizing radiation cured resin layer may be 55% by mass or more of the ionizing radiation cured resin layer.

In the light controlling sheet, the content of polyethylene oxide chains constituting the ionizing radiation cured resin layer may be 2% by mass or more and 20% by mass or less of the ionizing radiation cured resin layer.
In the above light controlling sheet, the first acrylic compound may be a pentaerythritol compound, the second acrylic compound may be isobornyl acrylate, and the third acrylic compound may be an alkoxypolyethylene glycol compound.

In the above light-adjusting sheet, the first acrylic compound may be a trimethylolpropane compound, the second acrylic compound may be isobornyl acrylate, and the third acrylic compound may be a polyethyleneoxyside-modified trimethylolpropane compound.

In the above light controlling sheet, the liquid crystal composition may not contain a viscosity reducing agent.
The light-adjusting sheet may further include a first alignment layer sandwiched between the first transparent electrode layer and the light-adjusting layer, and a second alignment layer sandwiched between the second transparent electrode layer and the light-adjusting layer.

In the above light-adjusting sheet, the first alignment layer and the second alignment layer may each contain at least one polymer selected from the group consisting of a polyimide precursor and a polyimide.

In the above light-adjusting sheet, the weight of the liquid crystal composition relative to the total weight of the ionizing radiation cured resin layer and the liquid crystal composition may be 20% by mass or more and 70% by mass or less.

The light control sheet, light control device, and light control sheet manufacturing method disclosed herein can improve responsiveness in low temperature environments.

FIG. 1 is a configuration diagram of a light control device. FIG. 2 is an enlarged cross-sectional view of the light controlling sheet. FIG. 3 shows the content of acrylic compounds and the evaluation results in the test examples. FIG. 4 shows the content of acrylic compounds and the evaluation results in the test examples. FIG. 5 shows the first acrylic compound dependence on low temperature response. FIG. 6 shows the dependence of peel strength on the first acrylic compound. FIG. 7 shows the dependency of peel strength on the acrylic blend ratio. FIG. 8 shows the dependence of haze after heat treatment on the first acrylic compound. FIG. 9 shows the dependence of the haze after heat treatment on the acrylic blend ratio. FIG. 10 shows the dependence of the evaluation results on the first acrylic compound and on the EO modification.

[Light control device 10]
As shown in FIG. 1 , the light control device 10 includes a light control sheet 11 and a drive unit 12 .
The light control device 10 may be used as a partition device that divides a space. The light control sheet 11 itself may be a partition member that divides a space, or a light control adhesive body in which the light control sheet 11 is mounted on a transparent member may be a partition member that divides a space. The partition member may be a window glass or a partition. The window glass may be mounted on a moving body such as a vehicle or an airplane, or may be installed in a building such as an office building or a public facility. The partition may be disposed in a space inside a vehicle, or may be disposed in an indoor space.

The light control device 10 may be used as a screen for displaying an image. The light control sheet 11 itself may be the screen, or a light control adhesive body in which the light control sheet 11 is mounted on a transparent member may be the screen. The screen may be a front screen that uses reflected light for the image, or a rear screen that uses transmitted light for the image.

The light-adjusting adhesive may have one light-adjusting sheet 11 mounted on one transparent member, or may have multiple light-adjusting sheets 11 mounted on one transparent member. The light-adjusting adhesive may have the light-adjusting sheet 11 sandwiched between two transparent substrates. The light-adjusting sheet 11 is flexible. The light-adjusting adhesive may or may not be flexible. The light-adjusting adhesive may have a flat shape or a curved shape.

The driving type of the light-adjusting sheet 11 may be a reverse type. The driving unit 12 supplies a voltage signal to the reverse type light-adjusting sheet 11. The reverse type light-adjusting sheet 11 changes from transparent to opaque in response to the input of a voltage signal. The reverse type light-adjusting sheet 11 remains opaque during the period in which the voltage signal is input. The reverse type light-adjusting sheet 11 returns from opaque to transparent in response to the cessation of the supply of the voltage signal.

The driving type of the light-adjusting sheet 11 may be a normal type. The driving unit 12 supplies a voltage signal to the normal type light-adjusting sheet 11. The normal type light-adjusting sheet 11 changes from opaque to transparent in response to the input of a voltage signal. The normal type light-adjusting sheet 11 remains transparent during the period in which the voltage signal is input. The normal type light-adjusting sheet 11 returns from transparent to opaque in response to the cessation of the supply of the voltage signal.

The light-adjusting sheet 11 achieves its opacity by scattering transmitted light through the light-adjusting sheet 11. The opaque light-adjusting sheet 11 has a lower parallel light transmittance than the transparent light-adjusting sheet 11. The opaque light-adjusting sheet 11 has a higher haze than the transparent light-adjusting sheet 11. The color of the opaque light-adjusting sheet 11 may be achromatic or chromatic. The color of the transparent light-adjusting sheet 11 may be achromatic or chromatic.

[Light-adjusting sheet 11]
The following mainly describes the configuration and function of the reverse-type light controlling sheet 11. The configuration of the normal-type light controlling sheet 11 that differs from the reverse-type light controlling sheet 11 is described, and the configuration of the normal-type light controlling sheet 11 that overlaps with the reverse-type light controlling sheet 11 is omitted.

The light-controlling sheet 11 includes a light-controlling layer 31 , a first alignment layer 32 , a second alignment layer 33 , a first transparent electrode layer 34 , a second transparent electrode layer 35 , a first transparent support layer 36 , and a second transparent support layer 37 .
The light control layer 31 is located between the first alignment layer 32 and the second alignment layer 33. A first surface 31F of the light control layer 31 contacts the first alignment layer 32. A second surface 31S of the light control layer 31 contacts the second alignment layer 33. The first alignment layer 32 is located between the light control layer 31 and the first transparent electrode layer 34, and contacts both the light control layer 31 and the first transparent electrode layer 34. The second alignment layer 33 is located between the light control layer 31 and the second transparent electrode layer 35, and contacts both the light control layer 31 and the second transparent electrode layer 35.

The first transparent electrode layer 34 is connected to the driving unit 12 through the first connection terminal 22A and the first wiring 23A. The first transparent electrode layer 34 is located between the first alignment layer 32 and the first transparent support layer 36, and is in contact with the first alignment layer 32 and the first transparent support layer 36.

The second transparent electrode layer 35 is connected to the driving unit 12 through the second connection terminal 22B and the second wiring 23B. The second transparent electrode layer 35 is located between the second alignment layer 33 and the second transparent support layer 37, and is in contact with the second alignment layer 33 and the second transparent support layer 37.

The first transparent electrode layer 34 and the second transparent electrode layer 35 are visually recognized as colorless and transparent, or colored and transparent. The materials constituting the first transparent electrode layer 34 and the second transparent electrode layer 35 are conductive inorganic oxides, metals, or conductive organic polymer compounds. An example of the conductive inorganic oxide is any one selected from the group consisting of indium tin oxide, fluorine-doped tin oxide, tin oxide, and zinc oxide. The metal is gold or silver nanowires. An example of the conductive organic polymer compound is any one selected from the group consisting of carbon nanotubes and poly(3,4-ethylenedioxythiophene). An example of the thickness of the first transparent electrode layer 34 and the second transparent electrode layer 35 is 5 nm or more and 200 nm or less.

The first transparent support layer 36 and the second transparent support layer 37 are visually recognized as colorless and transparent, or colored and transparent. The materials constituting the first transparent support layer 36 and the second transparent support layer 37 are organic polymer compounds or inorganic polymer compounds. An example of an organic polymer compound is any one selected from the group consisting of polyester, polyacrylate, polycarbonate, and polyolefin. An example of an inorganic polymer compound is any one selected from the group consisting of silicon oxide, silicon oxynitride, and silicon nitride. An example of the thickness of the first transparent support layer 36 and the second transparent support layer 37 is 20 μm or more and 400 μm or less, respectively.

The driving unit 12 is separately connected to the first transparent electrode layer 34 and the second transparent electrode layer 35. The driving unit 12 applies a voltage between the first transparent electrode layer 34 and the second transparent electrode layer 35 by supplying a voltage signal. The driving unit 12 changes the voltage between the first transparent electrode layer 34 and the second transparent electrode layer 35 by stopping the supply of the voltage signal. Supplying and stopping the supply of the voltage signal changes the orientation state of the liquid crystal compound LCM. The driving unit 12 reversibly switches the light control sheet 11 from transparent to opaque by changing the orientation state of the liquid crystal compound LCM.

When the driving unit 12 stops supplying the voltage signal, the orientation state of the liquid crystal compound LCM follows the orientation regulation force of the first orientation layer 32 and the second orientation layer 33. The orientation state of the liquid crystal compound LCM according to the orientation regulation force allows visible light to pass through the light control layer 31. This makes the light control sheet 11 transparent. When the driving unit 12 is supplying a voltage signal, the liquid crystal compound LCM is subjected to the action of an electric field against the orientation regulation force. The orientation state of the liquid crystal compound LCM according to the action of the electric field scatters visible light in the light control layer 31. This makes the light control sheet 11 opaque.

The light-adjusting sheet 11 may have another functional layer between the first transparent electrode layer 34 and the first transparent support layer 36. The light-adjusting sheet 11 may have another functional layer between the second transparent electrode layer 35 and the second transparent support layer 37. The other functional layer may be a gas barrier layer that suppresses the transmission of oxygen and moisture toward the light-adjusting layer 31, or an ultraviolet barrier layer that suppresses the transmission of ultraviolet light rays other than a specific wavelength toward the light-adjusting layer 31. The other functional layer may be a hard coat layer that mechanically protects the light-adjusting sheet 11, or an adhesive layer that increases the adhesion between layers in the light-adjusting sheet 11.

[Light control layer 31]
As shown in FIG. 2, the light control layer 31 includes a liquid crystal composition 31LC, spacers SP, and an ionizing radiation cured resin layer 31P.

The liquid crystal composition 31LC includes a liquid crystal compound LCM. The liquid crystal composition 31LC may contain additives such as a dichroic dye DP, a defoamer, an antioxidant, a weathering agent, and a solvent. Examples of weathering agents are ultraviolet absorbers and light stabilizers. The liquid crystal composition 31LC does not contain a viscosity reducing agent that reduces the viscosity of the liquid crystal composition 31LC below that of the liquid crystal compound LCM. The viscosity reducing agent is an adipate ester such as dibutyl adipate, bis(2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, and bis(2-butoxyethyl) adipate. The viscosity reducing agent is at least one selected from the group consisting of an adipate ester, diethyl malonate, di-n-butyl phthalate, bis(2-ethylhexyl) phthalate, tris(2-ethylhexyl) trimellitate, tributyl o-acetylcitrate, and methyl benzoate. The viscosity reducing agent is at least one selected from the group consisting of tripropyl phosphate, tributyl phosphate, and tripentyl phosphate. If further improvement in responsiveness in a low-temperature environment is required, the liquid crystal composition 31LC may contain a viscosity reducing agent.

The dielectric constant of the liquid crystal compound LCM in the long axis direction may be greater than the dielectric constant of the liquid crystal compound LCM in the short axis direction, and may have a positive dielectric anisotropy. The dielectric constant of the liquid crystal compound LCM in the long axis direction may be less than the dielectric constant of the liquid crystal compound LCM in the short axis direction, and may have a negative dielectric anisotropy. The dielectric anisotropy of the liquid crystal compound LCM is appropriately selected based on the driving type of the light control sheet 11.

The liquid crystal compound LCM is at least one selected from the group consisting of Schiff base type, azo type, azoxy type, biphenyl type, terphenyl type, benzoic acid ester type, tolan type, pyrimidine type, pyridazine type, cyclohexane carboxylate type, phenylcyclohexane type, biphenylcyclohexane type, dicyanobenzene type, naphthalene type, and dioxane type. The liquid crystal compound LCM is one type of liquid crystal compound LCM or a combination of two or more types of liquid crystal compounds LCM.

An example of the structure of the liquid crystal compound LCM is represented by the following formula 1.
R ¹¹ -A ¹¹ -Z ¹¹ -A ¹² -Z ¹² -A ¹³ -Z ¹³ -A ¹⁴ -R ¹² ...Formula 1
R ¹¹ in formula 1 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. One or two or more non-adjacent methylene bonds contained in the alkyl group of R ¹¹ can be replaced with any one selected from the group consisting of an oxygen atom, an ethylene bond, an ester bond, and a diether bond. R ¹² in formula 1 is a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group, or an alkyl group having 1 to 15 carbon atoms. One or two or more non-adjacent methylene bonds contained in the alkyl group of R ¹² in formula 1 can be replaced with any one selected from the group consisting of an oxygen atom, an ethylene bond, an ester bond, and a diether bond.

A ¹¹ , A ¹² , A ¹³ , and A ¹⁴ in formula 1 each independently represent a 1,4-phenylene group or a 2,6-naphthylene group. One or more hydrogen atoms in the 1,4-phenylene group or the 2,6-naphthylene group can be substituted with a fluorine atom, a chlorine atom, a trifluoromethyl group, or a trifluoromethoxy group. A ¹¹ , A ¹² , A ¹³ , and A ¹⁴ in formula 1 each independently may represent a 1,4-cyclohexylene group, a 3,6-cyclohexenylene group, a 1,3-dioxane-2,5-diyl group, or a pyridine-2,5-diyl group. A ¹³ and A ¹⁴ in formula 1 each independently may represent a single bond. Z ¹¹ , Z ¹² and Z ¹³ in formula 1 each independently represent any one bond selected from the group consisting of a single bond, an ester bond, a diether bond, an ethylene bond, a fluoroethylene bond and a carbonyl bond.

The dichroic dye DP is driven by a guest-host system with the liquid crystal compound LCM as a host, and exhibits color. The dichroic dye DP is at least one selected from the group consisting of polyiodine, azo compounds, anthraquinone compounds, naphthoquinone compounds, azomethine compounds, tetrazine compounds, quinophthalone compounds, merocyanine compounds, perylene compounds, and dioxazine compounds. The dichroic dye DP is one type of compound or a combination of two or more types of compounds. When it is required to increase the light resistance and the dichroic ratio, the dichroic dye DP is at least one selected from the group consisting of azo compounds and anthraquinone compounds, and more preferably an azo compound.

The spacers SP are dispersed throughout the ionization radiation cured resin layer 31P. The spacers SP determine the thickness of the light-adjusting layer 31 based on the particle size of the spacers SP. An example of the thickness of the light-adjusting layer 31 is 5 μm or more and 100 μm or less. The spacers SP make the thickness of the light-adjusting layer 31 uniform. The spacers SP may be bead spacers or photospacers formed by exposing and developing a photoresist. The spacers SP may be colorless and transparent, or colored and transparent. When the liquid crystal composition 31LC contains a dichroic dye DP, it is preferable that the color of the spacers SP is the same color as the color exhibited by the dichroic dye DP.

[Ionizing radiation curing resin layer 31P]
The ionizing radiation curable resin layer 31P is a cured product of an ionizing radiation curable composition. The ionizing radiation may be ultraviolet rays or electron beams. The ionizing radiation curable composition may be an ultraviolet ray curable composition. The lower limit of the content of the ionizing radiation curable resin layer 31P relative to the total amount of the ionizing radiation curable resin layer 31P and the liquid crystal composition 31LC is 20% by mass, and a more preferable lower limit of the content is The value is 30% by mass. If the content of the ionizing radiation cured resin layer 31P is 20% by mass or more, a high transmittance is easily obtained when transparent. The upper limit of the content of the ionizing radiation cured resin layer 31P in the ionizing radiation cured resin layer 31 is 70% by mass, and a more preferable upper limit of the content is 60% by mass. If the composition is opaque, a high haze is easily obtained.

The lower limit and upper limit of the content of the ionizing radiation cured resin layer 31P are within a range in which the liquid crystal particles of the liquid crystal composition 31LC phase separate from the polymer of the ionizing radiation cured resin layer 31LC during the polymerization process of the ionizing radiation cured resin layer 31LC. When it is necessary to increase the mechanical strength of the ionizing radiation cured resin layer 31P, it is preferable that the lower limit of the content of the ionizing radiation cured resin layer 31P is high. When it is necessary to reduce the driving voltage of the liquid crystal compound LCM, it is preferable that the upper limit of the content of the ionizing radiation cured resin layer 31P is low. The lower limit of the content of the ionizing radiation cured resin layer 31P relative to the total amount of the ionizing radiation cured resin layer 31P and the liquid crystal composition 31LC may be 20% by mass or more and 70% by mass or less, or 30% by mass or more and 70% by mass or less. The lower limit of the content of the ionizing radiation cured resin layer 31P relative to the total amount of the ionizing radiation cured resin layer 31P and the liquid crystal composition 31LC may be 20% by mass or more and 60% by mass or less, or 30% by mass or more and 60% by mass or less.

The ionizing radiation cured resin layer 31P defines a void 31D in the light control layer 31. The liquid crystal composition 31LC is filled in the void 31D. The void 31D may be isolated from other voids 31D adjacent to the void 31D, or may be connected to other adjacent voids 31D. There are two or more sizes of the void 31D. The shape of the void 31D is spherical, ellipsoidal, or amorphous. The diameter of the sphere circumscribing the void 31D may be 0.4 μm or more, or 1 μm or more. The diameter of the sphere circumscribing the void 31D may be 20 μm or less, or 10 μm or less. The diameter of the sphere circumscribing the void 31D is, for example, 1 μm or more and 10 μm or less.

The voids 31D may be unevenly distributed in the ionization radiation cured resin layer 31P, or may be uniformly dispersed in the ionization radiation cured resin layer 31P. The voids 31D may be unevenly distributed in a range 31H1 closer to the first alignment layer 32 than the center in the thickness direction of the ionization radiation cured resin layer 31P, so that the voids 31D are more numerous in the area closer to the first alignment layer 32. The voids 31D may be unevenly distributed in a range 31H2 closer to the second alignment layer 33 than the center in the thickness direction of the ionization radiation cured resin layer 31P, so that the voids 31D are more numerous in the area closer to the second alignment layer 33. The ionization radiation cured resin layer 31P may have a portion in the center in the thickness direction of the ionization radiation cured resin layer 31P where no voids 31D exist, and may have voids 31D between the portion and the first alignment layer 32. The ionizing radiation cured resin layer 31P may have a portion in the center in the thickness direction of the ionizing radiation cured resin layer 31P where no void 31D exists, and may have a void 31D between that portion and the second alignment layer 33.

The voids 31D are formed by phase separation between the cured product of the ionizing radiation curable composition and the liquid crystal composition 31LC. The area 31H1 of the ionizing radiation curable resin layer 31P that is closer to the first alignment layer 32 than the center in the thickness direction is the area where irradiation with ionizing radiation begins, and is the area where voids 31D begin to form. The area 31H2 of the ionizing radiation curable resin layer 31P that is closer to the second alignment layer 33 than the center in the thickness direction is also the area where irradiation with ionizing radiation begins, and is the area where voids 31D begin to form.

The range 31H1 of the ionization radiation cured resin layer 31P that is closer to the first alignment layer 32 than the center in the thickness direction is also a region where low molecular weight impurities begin to diffuse from the first alignment layer 32. The range 31H2 of the ionization radiation cured resin layer 31P that is closer to the second alignment layer 33 than the center in the thickness direction is also a region where low molecular weight impurities begin to diffuse from the second alignment layer 33. For this reason, a configuration in which the voids 31D are unevenly distributed in the range 31H1 close to the first alignment layer 32, i.e., a configuration in which the liquid crystal composition 31LC is unevenly distributed in the range 31H1 close to the first alignment layer 32, strongly requires the diffusion of low molecular weight impurities. Also, a configuration in which the voids 31D are unevenly distributed in the range 31H2 close to the second alignment layer 33, i.e., a configuration in which the liquid crystal composition 31LC is unevenly distributed in the range 31H2 close to the second alignment layer 33, strongly requires the diffusion of low molecular weight impurities.

Phase separation between the cured product of the ionizing radiation curable composition and the liquid crystal composition 31LC causes unreacted ionizing radiation curable compounds, by-products such as water resulting from the curing reaction of the ionizing radiation curable compounds, and low molecular weight compounds such as the solvent of the ionizing radiation curable composition to remain in the liquid crystal composition 31LC. The degree to which the viscosity of the ionizing radiation curable compounds, by-products such as water, and low molecular weight compounds such as the solvent increases with decreasing temperature is greater in low temperature environments such as cold regions than the degree to which the liquid crystal compound LCM increases with decreasing temperature. Making the cured product of the ionizing radiation curable composition dense during the process of phase separation between the cured product of the ionizing radiation curable composition and the liquid crystal composition 31LC suppresses low molecular weight compounds from remaining in the liquid crystal composition 31LC. Suppressing the remaining low molecular weight compounds in the liquid crystal composition 31LC suppresses the increase in viscosity of the liquid crystal composition 31LC in low temperature environments.

The type of retention of the liquid crystal composition 31LC by the ionizing radiation cured resin layer 31P is any one selected from the group consisting of a polymer dispersion type, a polymer network type, and a capsule type. The polymer dispersion type light control layer 31 has an ionizing radiation cured resin layer 31P that divides a large number of isolated voids 31D. The polymer dispersion type light control layer 31 retains the liquid crystal composition 31LC in the voids 31D dispersed in the ionizing radiation cured resin layer 31P. The polymer network type light control layer 31 has an ionizing radiation cured resin layer 31P that has three-dimensional mesh-like voids 31D. The polymer network type light control layer 31 retains the liquid crystal composition 31LC in the interconnected mesh-like voids 31D. The capsule type light control layer 31 retains the liquid crystal composition 31LC in the capsule-like voids 31D dispersed in the ionizing radiation cured resin layer 31P.

The ionizing radiation curable resin layer 31P is formed by applying a photochromic coating liquid containing an ionizing radiation curable composition and a liquid crystal composition 31LC, and irradiating the coating layer with ionizing radiation. The photochromic coating liquid contains a polymerization initiator for initiating polymerization of the ionizing radiation curable composition. The ionizing radiation curable resin layer 31P contains a polymerization initiator that initiates polymerization. The polymerization initiator is at least one selected from the group consisting of a diketone compound, an acetophenone compound, a benzoin compound, a benzophenone compound, and a thioxanthone compound. The polymerization initiator may be one type of compound or a combination of two or more types of compounds. An example of the polymerization initiator is any one selected from the group consisting of benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and cyclohexyl phenyl ketone.

[First Acrylic Compound]
The ionizing radiation curable composition contains a first acrylic compound. The first acrylic compound has three or more functional groups and a double bond equivalent of 150 g/eq or less. The functional groups are an acryloyl group and a methacryloyl group. The double bond equivalent is a value obtained by dividing the molecular weight of the first acrylic compound by the number of functional groups. The number of functional groups is the sum of the number of acryloyl groups and the number of methacryloyl groups contained in the first acrylic compound. The first acrylic compound may be contained in the electron beam curable compound as a monomer. The first acrylic compound may be contained in the electron beam curable compound as a component of a urethane acrylate such as a urethane prepolymer. When the first acrylic compound is a component of a urethane acrylate, the double bond equivalent is determined based on the skeleton structure of the first acrylic compound in the urethane acrylate.

Examples of the first acrylic compound include a pentaerythritol compound, a trimethylolpropane compound, and a glycol compound. The pentaerythritol compound is pentaerythritol diacrylate, pentaerythritol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, pentaerythritol ethoxytetraacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol ethoxytetraacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, and trispentaerythritol octaacrylate. The trimethylolpropane compounds are trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane ethoxy triacrylate, ditrimethylolpropane tetraacrylate, and ditrimethylolpropane tetramethacrylate. The glycol compounds are glycerin diacrylate, glycerin triacrylate, glycerin trimethacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, and 1,6-hexanediol diacrylate. An example of a prepolymer containing the first acrylic compound is pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer.

The ionizing radiation curable composition may contain a radical curing assistant. The ionizing radiation curable resin layer 31P may contain a radical curing assistant. The radical curing assistant enhances the polymerizability of the acrylic compound. The polymerization of the acrylic compound is terminated by generating a peroxide radical. An example of the radical curing assistant contains a thiol group. The thiol group of the radical curing assistant promotes the polymerization of the acrylic compound by donating hydrogen to the peroxide radical. An example of the radical curing assistant may be a primary multifunctional thiol compound or a secondary multifunctional thiol compound. An example of a primary multifunctional thiol compound is pentaerythritol tetrakis (3-mercaptopropionate) or tetraethylene glycol bis (3-mercaptopropionate). An example of a secondary multifunctional thiol compound is pentaerythritol tetrakis (3-mercaptobutyrate).

[Second Acrylic Compound]
The ionizing radiation curable composition contains a second acrylic compound. The second acrylic compound is a monofunctional alkyl acrylate, a monofunctional alkyl methacrylate, a monofunctional alkoxyalkyl acrylate, and a monofunctional alkoxyalkyl methacrylate. The monofunctional alkyl acrylate and the monofunctional alkyl methacrylate each contain a saturated alkyl group having 2 to 12 carbon atoms. The monofunctional alkoxyalkyl acrylate and the monofunctional alkoxyalkyl methacrylate each contain a saturated alkoxyalkyl group having 2 to 12 carbon atoms. The saturated alkyl group may be a linear alkyl group, a branched alkyl group, a monocyclic alkyl group, or a polycyclic alkyl group. The saturated alkoxyalkyl group may be a linear alkoxyalkyl group or a branched alkoxyalkyl group.

Examples of the second acrylic compound are ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, hexyl acrylate, 2-ethylbutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, methoxyethyl methacrylate, octyl acrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylbutyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, lauryl methacrylate, cyclohexyl acrylate, cyclopentyl acrylate, dicyclopentanyl acrylate, norbornyl acrylate, norbornyl methacrylate, isobornyl acrylate, and isobornyl methacrylate.

[Tertiary Acrylic Compound]
The ionizing radiation curable composition contains a third acrylic compound. The third acrylic compound has one or more and three or less functional groups and a polyethylene oxide chain, and has a double bond equivalent of 300 g/eq or more and 700 g/eq or less. The functional groups are an acryloyl group and a methacryloyl group. The double bond equivalent is a value obtained by dividing the molecular weight of the third acrylic compound by the number of functional groups. The number of functional groups is the total of the number of acryloyl groups and the number of methacryloyl groups contained in the third acrylic compound. The third acrylic compound may be contained in the electron beam curable compound as a monomer. The third acrylic compound may be contained in the electron beam curable compound as a component of a urethane acrylate such as a urethane prepolymer.

An example of the third acrylic compound may be a polyethylene glycol compound, an alkoxypolyethylene glycol compound, or a polyethylene oxyside modified trimethylolpropane compound (EO modified trimethylolpropane compound). An example of the third acrylic compound is polyethylene glycol acrylate, polyethylene glycol methacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol acrylate, polypropylene glycol methacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, methoxypolyethylene glycol acrylate, methoxypolypropylene glycol acrylate, EO modified trimethylolpropane triacrylate, EO modified trimethylolpropane trimethacrylate, EO modified ditrimethylolpropane tetraacrylate, EO modified ditrimethylolpropane tetramethacrylate.

[Acrylic compound content]
The ionizing radiation curable composition satisfies the following conditions 1, 2, and 3 simultaneously. Alternatively, the ionizing radiation curable composition satisfies the following conditions 1, 2, and 4 simultaneously. The ionizing radiation curable composition may simultaneously satisfy the following conditions 1A, 2A, and 3. The ionizing radiation curable composition may simultaneously satisfy the following conditions 1A, 2A, and 4. Furthermore, the ionizing radiation curable composition may simultaneously satisfy the following conditions 1B, 2B, and 3. The ionizing radiation curable composition may simultaneously satisfy the following conditions 1B, 2B, and 4. Furthermore, the ionizing radiation curable composition may satisfy the following condition 5 or the following condition 6.

[Condition 1] The content of the first acrylic compound is 2% by mass or more and 50% by mass or less.
[Condition 1A] The content of the first acrylic compound is 2% by mass or more and 40% by mass or less.
[Condition 1B] The content of the first acrylic compound is 2% by mass or more and 30% by mass or less.

[Condition 2] The content of the second acrylic compound is 35% by mass or more and 85% by mass or less.
[Condition 2A] The content of the second acrylic compound is 45% by mass or more and 85% by mass or less.
[Condition 2B] The content of the second acrylic compound is 55% by mass or more and 85% by mass or less.

[Condition 3] The content of the third acrylic compound is 5% by mass or more and 20% by mass or less.
[Condition 4] The acrylic compounding ratio is 0.25 or more.
[Condition 4A] The acrylic compounding ratio is 0.25 or more and 2.0 or less.

[Condition 5] The number of functional groups of the first acrylic compound is 3 or more and 5 or less, and the content of the first acrylic compound is 30 mass % or less.
[Condition 6] The content of polyethylene oxide chains is 2% by mass or more and 20% by mass or less.

The content of the first acrylic compound is the ratio of the weight of the first acrylic compound to the total weight of the ionizing radiation curable composition for forming the ionizing radiation curable resin layer 31P. The total weight of the ionizing radiation curable composition is the sum of the weight of the first acrylic compound, the weight of the radical curing assistant, the weight of the second acrylic compound, and the weight of the third acrylic compound.

The content of the second acrylic compound is the ratio of the weight of the second acrylic compound to the total weight of the ionizing radiation curable composition for forming the ionizing radiation curable resin layer 31P.
The content of the third acrylic compound is the ratio of the weight of the third acrylic compound to the total weight of the ionizing radiation curable composition for forming the ionizing radiation curable resin layer 31P.

The content of the polyethylene oxide chain is the ratio of the weight of the polyethylene oxide chain to the total weight of the ionizing radiation curable composition for forming the ionizing radiation curable resin layer 31P.
The acrylic compounding ratio is the content of the third acrylic compound relative to the content of the first acrylic compound.

[First alignment layer 32, second alignment layer 33]
The first alignment layer 32 and the second alignment layer 33 each regulate the alignment direction of the liquid crystal compound LCM. The first alignment layer 32 and the second alignment layer 33 each appear as colorless and transparent or colored and transparent. The first alignment layer 32 and the second alignment layer 33 may be vertical alignment films or horizontal alignment films.

The material constituting the first alignment layer 32 and the second alignment layer 33 is an organic polymer compound or an inorganic oxide. An example of the organic polymer compound is any one selected from the group consisting of polyimide, polyamide, and polyvinyl alcohol. An example of the inorganic oxide is any one selected from the group consisting of silicon oxide, zirconium oxide, and silicone. The material constituting the first alignment layer 32 and the second alignment layer 33 contains an organic polymer compound or a low molecular weight impurity for generating an inorganic oxide. An example of the low molecular weight impurity may be a polyimide precursor such as polyamic acid used to generate polyimide, or water generated by imidization of polyamic acid. An example of the thickness of the first alignment layer 32 and the second alignment layer 33 is 20 nm or more and 500 nm or less, respectively.

When the first alignment layer 32 and the second alignment layer 33 are each vertical alignment films, the first alignment layer 32 and the second alignment layer 33 each apply an alignment control force to the liquid crystal compound LCM so as to align the long axis direction of the liquid crystal compound LCM with the thickness direction of the dimming layer 31. As a result, the first alignment layer 32 and the second alignment layer 33 transmit visible light to the dimming layer 31 during the period when the supply of the voltage signal is stopped.

When the first alignment layer 32 and the second alignment layer 33 are each a horizontal alignment film, the light control sheet 11 includes a polarizing layer. The first alignment layer 32 and the second alignment layer 33 apply an alignment control force to the liquid crystal compound LCM so that the long axis direction of the liquid crystal compound LCM is parallel to the extension direction of the transmission axis of the polarizing layer. As a result, the first alignment layer 32 and the second alignment layer 33 transmit visible light through the polarizing layer to the light control layer 31 during the period when the supply of the voltage signal is stopped.

When the first alignment layer 32 and the second alignment layer 33 are each a horizontal alignment film, the light control sheet 11 has polarizing layers arranged in crossed Nicols. The first alignment layer 32 applies an alignment control force to the liquid crystal compound LCM so that the long axis direction of the liquid crystal compound LCM is parallel to the extension direction of the transmission axis of one polarizing layer. The second alignment layer 33 applies an alignment control force to the liquid crystal compound LCM so that the long axis direction of the liquid crystal compound LCM is parallel to the extension direction of the transmission axis of the other polarizing layer. In other words, the first alignment layer 32 and the second alignment layer 33 apply a twisted alignment control force to the liquid crystal compound LCM. As a result, the first alignment layer 32 and the second alignment layer 33 transmit visible light through the polarizing layer to the light control layer 31 during the period when the supply of the voltage signal is stopped.

In addition, when the first alignment layer 32 and the second alignment layer 33 are each a horizontal alignment film, the light control sheet 11 includes two polarizing layers having mutually parallel transmission axes. The first alignment layer 32 and the second alignment layer 33 apply an alignment control force to the liquid crystal compound LCM so that the long axis direction of the liquid crystal compound LCM intersects at 45° with the extension direction of the transmission axis of the polarizing layer. As a result, the first alignment layer 32 and the second alignment layer 33 suppress the transmission of visible light through the polarizing layer to the light control layer 31 during the period when the supply of the voltage signal is stopped. The voltage applied between the first transparent electrode layer 34 and the second transparent electrode layer 35 gives the liquid crystal compound LCM a vertical alignment against the alignment control force, and transmits visible light through the polarizing layer to the light control layer 31.

The light-adjusting sheet 11 may be configured so that the first alignment layer 32 and the second alignment layer 33 are omitted. The light-adjusting layer 31 of the light-adjusting sheet 11 from which the first alignment layer 32 and the second alignment layer 33 are omitted may be in contact with the first transparent electrode layer 34 or may be in contact with the second transparent electrode layer 35.

[Method of manufacturing light controlling sheet 11]
The method for producing the light-adjusting sheet 11 includes forming a light-adjusting coating layer containing an ionizing radiation curable composition and a liquid crystal composition 31LC between a first transparent electrode layer 34 and a second transparent electrode layer 35. The method for producing the light-adjusting sheet 11 includes forming a light-adjusting layer 31 between the first transparent electrode layer 34 and the second transparent electrode layer 35 by irradiating the light-adjusting coating layer with ionizing radiation.

When the light-adjusting sheet 11 includes a first alignment layer 32 and a second alignment layer 33, the manufacturing method of the light-adjusting sheet 11 includes forming the first alignment layer 32 on the first transparent electrode layer 34, and forming the second alignment layer 33 on the second transparent electrode layer 35. The first alignment layer 32 is formed by applying an alignment coating liquid to the first transparent electrode layer 34 laminated on the first transparent support layer 36, and heating the alignment coating layer. The second alignment layer 33 is formed by applying an alignment coating liquid to the second transparent electrode layer 35 laminated on the second transparent support layer 37, and heating the alignment coating layer.

The manufacturing method of the light-adjusting sheet 11 includes forming a light-adjusting coating layer containing an ionizing radiation curable composition and a liquid crystal composition 31LC between the first alignment layer 32 and the second alignment layer 33. The light-adjusting coating layer is formed by applying a light-adjusting coating liquid to the first alignment layer 32 supported by the first transparent support layer 36. The light-adjusting coating layer is sandwiched between the first alignment layer 32 supported by the first transparent support layer 36 and the second alignment layer 33 supported by the second transparent support layer 37. In addition, when the light-adjusting sheet 11 does not include the first alignment layer 32 and the second alignment layer 33, the light-adjusting coating layer is formed by applying a light-adjusting coating liquid to the first transparent electrode layer 34 supported by the first transparent support layer 36. The light-adjusting coating layer is sandwiched between the first transparent electrode layer 34 supported by the first transparent support layer 36 and the second transparent electrode layer 35 supported by the second transparent support layer 37.

The manufacturing method of the light-adjusting sheet 11 includes irradiating the light-adjusting coating layer with ionizing radiation to form a light-adjusting layer 31 between a first transparent electrode layer 34 and a second transparent electrode layer 35, the light-adjusting layer 31 including an ionizing radiation-cured resin layer 31P that defines a gap 31D and a liquid crystal composition 31LC that fills the gap 31D. The light-adjusting coating layer may be irradiated with ionizing radiation from the first transparent support layer 36 toward the light-adjusting coating layer, or from the second transparent support layer 37 toward the light-adjusting coating layer, or a combination of these.

The ionizing radiation curable composition irradiated with ionizing radiation initiates polymerization and phase-separates the liquid crystal particles of the liquid crystal composition 31LC from the polymer. Phase separation of the liquid crystal particles of the liquid crystal composition 31LC proceeds through polymerization of the ionizing radiation curable composition and diffusion of the liquid crystal composition 31LC. The polymerization rate of the ionizing radiation curable composition varies depending on the intensity of the ionizing radiation irradiated to the ionizing radiation curable composition. The diffusion rate of the liquid crystal composition 31LC varies depending on the processing temperature during polymerization of the ionizing radiation curable composition. In the phase separation of the liquid crystal composition 31LC, the intensity of the ionizing radiation irradiated to the ionizing radiation curable composition is set so that the size of the liquid crystal particles is the desired size, that is, so that the size of the voids 31D is the desired size. In addition, in the phase separation of the liquid crystal composition 31LC, heating may be performed to promote diffusion of the liquid crystal composition 31LC.

When it is required to reduce the size of the voids 31D, it is preferable to increase the intensity of the ionizing radiation irradiated to the ionizing radiation curable composition and proceed with the polymerization at a low temperature to suppress the diffusion of the liquid crystal composition 31LC. When it is required to increase the size of the voids 31D, it is preferable to decrease the intensity of the ionizing radiation irradiated to the ionizing radiation curable composition and proceed with the polymerization at a high temperature to promote the diffusion of the liquid crystal composition 31LC.

[Test Example]
The light-adjusting sheets 11 of each test example are shown below. The light-adjusting sheets 11 of each test example have vertical alignment films as the first alignment layer 32 and the second alignment layer 33. The driving format of each test example is reverse type. The light-adjusting sheets 11 of test examples 1 to 13 were obtained using different ionizing radiation curable compositions and in the same manner except for the ionizing radiation curable composition. The light-adjusting sheets 11 of test examples 14 to 17 were obtained using different ionizing radiation curable compositions and liquid crystal composition 31LC and in the same manner except for the ionizing radiation curable composition and liquid crystal composition 31LC.

First, the constituent materials of the first transparent electrode layer 34, the second transparent electrode layer 35, the first transparent support layer 36, and the second transparent support layer 37 are shown below.
First transparent electrode layer 34: indium tin oxide having a thickness of 30 nm Second transparent electrode layer 35: indium tin oxide having a thickness of 30 nm First transparent support layer 36: polyethylene terephthalate film having a thickness of 125 μm Second transparent support layer 37: polyethylene terephthalate film having a thickness of 125 μm [First alignment layer 32, second alignment layer 33]
Next, the constituent materials and forming methods of the first alignment layer 32 and the second alignment layer 33 will be described below.

First, polyamic acid was produced in a solvent from diamines shown in the following raw materials B1 and B2 and carboxylic anhydrides shown in the following raw materials C1 and C2. At this time, 10 parts by weight of raw material B1, 8 parts by weight of raw material B2, and 4 parts by weight of raw material C2 were reacted in 75 parts by weight of the first solvent while heating to 80°C for 5 hours. Next, 16 parts by weight of raw material C1 and 38 parts by weight of the first solvent were added and reacted for 6 hours while heating to 40°C. This resulted in a polyamic acid solution with a resin solid content concentration of 25% by mass. Next, an alignment layer coating liquid was obtained from the polyamic acid solution with a resin solid content concentration of 25% by mass, the first solvent, and the second solvent. At this time, 12 parts by weight of the polyamic acid solution, 27 parts by weight of the first solvent, and 36 parts by weight of the second solvent were mixed and stirred for 24 hours while heating to 50°C.

Next, the alignment coating liquid was applied to the first transparent electrode layer 34 using a bar coater and heated to 150°C for 4 minutes. This resulted in a first alignment layer 32 with a thickness of 100 nm and mainly composed of polyimide. Similarly, the alignment coating liquid was applied to the second transparent electrode layer 35 using a bar coater and heated to 150°C for 4 minutes. This resulted in a second alignment layer 33 with a thickness of 100 nm and mainly composed of polyimide.

[Orientation coating fluid raw material]
B1: 4,4'-diaminodiphenylmethane (Tokyo Chemical Industry Co., Ltd.)
B2: 3,5-diaminobenzoic acid (Tokyo Chemical Industry Co., Ltd.)
C1: 1,2,3,4-cyclobutanetetracarboxylic dianhydride (Tokyo Chemical Industry Co., Ltd.)
C2: 3-(carboxymethyl)-1,2,4-cyclopentanetricarboxylic acid 1,4:2,3-dianhydride (Tokyo Chemical Industry Co., Ltd.)
First solvent: N-ethyl-2-pyrrolidone Second solvent: Butyl cellosolve [light-controlling layer 31]
Next, the constituent materials and formation method of the light-controlling layer 31 are shown below. The constituent materials of the ionizing radiation curable compositions of Test Examples 1 to 17 and the evaluation results of the light-controlling sheet 11 are shown in FIG. 3 and FIG. 4. The dependence of the responsiveness of the light-controlling sheet 11 of Test Examples 1 to 13 in a low-temperature environment on the first acrylic compound is shown in FIG. 5. The dependence of the peel strength of the light-controlling sheet 11 of Test Examples 1 to 13 on the first acrylic compound is shown in FIG. 6. The dependence of the peel strength of the light-controlling sheet 11 of Test Examples 1 to 9 on the acrylic compounding ratio is shown in FIG. 7. The dependence of the haze after heat treatment of the light-controlling sheet 11 of Test Examples 1 to 13 on the first acrylic compound is shown in FIG. 8. The dependence of the haze after heat treatment of the light-controlling sheet 11 of Test Examples 1 to 9 on the acrylic compounding ratio is shown in FIG. The evaluation results of the light-controlling sheet 11 of Test Examples 1 to 13 are shown in terms of the content of the first acrylic compound and the EO modification dependence.

First, a light-adjusting coating liquid was produced using the following liquid crystal compound LCM, spacer SP, polymerization initiator, and ionizing radiation curable composition. The ionizing radiation curable composition was a mixture of compounds selected from the following compounds 1 to 9. In this case, for the light-adjusting layer coating liquid of test examples 1 to 13, 50 parts by weight of the liquid crystal compound LCM, 1 part by weight of the polymerization initiator, and 1 part by weight of the spacer SP were mixed with 48 parts by weight of the ionizing radiation curable composition. For the light-adjusting layer coating liquid of test examples 14 to 15, 50 parts by weight of the liquid crystal compound LCM, 1 part by weight of the polymerization initiator, 0.25 parts by weight or more and 1 part by weight or less of the viscosity reducing agent, and 1 part by weight of the spacer SP were mixed with 47 parts by weight or more and 47.75 parts by weight or less of the ionizing radiation curable composition.

Next, a photochromic coating liquid was applied to the first alignment layer 32 using a bar coater, and the second alignment layer 33 was placed on top of the photochromic coating layer to form a photochromic coating layer sandwiched between the first alignment layer 32 and the second alignment layer 33. Next, ultraviolet light was irradiated from the first transparent support layer 36 toward the photochromic coating layer, and ultraviolet light was irradiated from the second transparent support layer 37 toward the photochromic coating layer. This resulted in a photochromic layer 31 with a thickness of 10 μm.

[Light-adjusting coating fluid raw materials]
Liquid crystal compound LCM: Fluorine-based nematic mixed liquid crystal (product name: MLC-6608, refractive index anisotropy Δn=0.20 (manufactured by Merck Ltd.))
Spacer SP: PMMA spherical with a diameter of 10 μm (manufactured by Sekisui Plastics Co., Ltd.)
Polymerization initiator: 1-hydroxycyclohexyl phenyl ketone (manufactured by IGM Resins B.V.)
Viscosity reducer: diisodecyl adipate (Tokyo Chemical Industry Co., Ltd.)
[Ionizing radiation curable composition]
Compound 1 is pentaerythritol tetrakis(3-mercaptobutyrate) (product name: Karenz MT PE-1 (manufactured by Showa Denko K.K.)) Compound 1 is a radical curing auxiliary.

Compound 2 is a monofunctional acrylic compound, and is methoxypolyethylene glycol acrylate (product name: AM-130G (manufactured by Shin-Nakamura Chemical Co., Ltd.)). The double bond equivalent of compound 2 is 658 g/eq. Compound 2 contains a polyethylene oxide chain between the acrylate group and the methoxy group. The polyethylene oxide chain has ethylene oxide as a repeating unit. The number of repeats in the polyethylene oxide chain of compound 2 is 13. Compound 2 is an example of a third acrylic compound.

Compound 3 is a monofunctional acrylic compound, and is isobornyl acrylate (product name: IBXA (manufactured by Osaka Organic Chemical Industry Ltd.)). The double bond equivalent of compound 3 is 208 g/eq. Compound 3 is an example of a second acrylic compound.

Compound 4 is a bifunctional acrylic compound, and is ethoxy polyethylene glycol acrylate (product name: Light Acrylate 14EGA (manufactured by Kyoeisha Chemical Co., Ltd.)). The double bond equivalent of compound 4 is 371 g/eq. Compound 4 is an example of a third acrylic compound containing a polyethylene oxide chain.

Compound 5 is a trifunctional acrylic compound, and is polyethylene oxide modified trimethylolpropane triacrylate (product name: AT-20E (manufactured by Shin-Nakamura Chemical Co., Ltd.)). The double bond equivalent of compound 5 is 392 g/eq. Compound 5 is an example of a tertiary acrylic compound containing a polyethylene oxide chain.

Compound 6 is a trifunctional acrylic compound, trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.). The double bond equivalent of compound 6 is 99 g/eq. Compound 6 is an example of a first acrylic compound.

Compound 7 is a tetrafunctional acrylic compound, pentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.). The double bond equivalent of compound 7 is 88 g/eq. Compound 7 is an example of a first acrylic compound.

Compound 8 is a hexafunctional acrylic compound, pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer (product name: 306I (manufactured by Kyoeisha Chemical Co., Ltd.)). The double bond equivalent of compound 8 is 136 g/eq. Compound 8 is a urethane prepolymer of the first acrylic compound.

Compound 9 is a hexafunctional acrylic compound, dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.). The double bond equivalent of compound 9 is 96 g/eq. Compound 9 is an example of a first acrylic compound.

[Formulation]
As shown in Fig. 3, the ionizing radiation curable composition of Test Example 1 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 36 parts by weight of Compound 3 (second acrylic compound), 5 parts by weight of Compound 4 (third acrylic compound), and 5 parts by weight of Compound 7 (first acrylic compound). The content of the first acrylic compound in Test Example 1 is 10% by mass. The content of the polyethylene oxide chain in Test Example 1 is 9% by mass. The content of the second acrylic compound in Test Example 1 is 75% by mass. The content of the third acrylic compound in Test Example 1 is 10% by mass.

The ionizing radiation curable composition of Test Example 2 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 27 parts by weight of Compound 3 (second acrylic compound), 5 parts by weight of Compound 4 (third acrylic compound), and 14 parts by weight of Compound 7 (first acrylic compound). The content of the first acrylic compound in Test Example 2 is 29% by weight. The content of the polyethylene oxide chain in Test Example 2 is 9% by weight. The content of the second acrylic compound in Test Example 2 is 56% by weight. The content of the third acrylic compound in Test Example 2 is 10% by weight.

The ionizing radiation curable composition of Test Example 3 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 18 parts by weight of Compound 3 (second acrylic compound), 5 parts by weight of Compound 4 (third acrylic compound), and 23 parts by weight of Compound 7 (first acrylic compound). The content of the first acrylic compound in Test Example 3 is 48% by weight. The content of the polyethylene oxide chain in Test Example 3 is 9% by weight. The content of the second acrylic compound in Test Example 3 is 38% by weight. The content of the third acrylic compound in Test Example 3 is 10% by weight.

The ionizing radiation curable composition of Test Example 4 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 16 parts by weight of Compound 3 (second acrylic compound), 5 parts by weight of Compound 4 (third acrylic compound), and 25 parts by weight of Compound 7 (first acrylic compound). The content of the first acrylic compound in Test Example 4 is 52% by weight. The content of the polyethylene oxide chain in Test Example 4 is 9% by weight. The content of the second acrylic compound in Test Example 4 is 33% by weight. The content of the third acrylic compound in Test Example 4 is 10% by weight.

The ionizing radiation curable composition of Test Example 5 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 40 parts by weight of Compound 3 (second acrylic compound), 5 parts by weight of Compound 4 (third acrylic compound), and 1 part by weight of Compound 7 (first acrylic compound). The content of the first acrylic compound in Test Example 5 is 2% by mass. The content of the polyethylene oxide chain in Test Example 5 is 9% by mass. The content of the second acrylic compound in Test Example 5 is 83% by mass. The content of the third acrylic compound in Test Example 5 is 10% by mass.

The ionizing radiation curable composition of Test Example 6 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 38 parts by weight of Compound 3 (second acrylic compound), 5 parts by weight of Compound 4 (third acrylic compound), and 3 parts by weight of Compound 8 (first acrylic compound). The content of the first acrylic compound in Test Example 6 is 6% by mass. The content of the polyethylene oxide chain in Test Example 6 is 9% by mass. The content of the second acrylic compound in Test Example 6 is 79% by mass. The content of the third acrylic compound in Test Example 6 is 10% by mass.

The ionizing radiation curable composition of Test Example 7 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 3 parts by weight of Compound 2 (third acrylic compound), 36 parts by weight of Compound 3 (second acrylic compound), and 7 parts by weight of Compound 9 (first acrylic compound). The content of the first acrylic compound in Test Example 7 is 15% by weight. The content of the polyethylene oxide chain in Test Example 7 is 5% by weight. The content of the second acrylic compound in Test Example 7 is 75% by weight. The content of the third acrylic compound in Test Example 7 is 6% by weight.

The ionizing radiation curable composition of Test Example 8 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 28 parts by weight of Compound 3 (second acrylic compound), 8 parts by weight of Compound 5 (third acrylic compound), and 10 parts by weight of Compound 6 (first acrylic compound). The content of the first acrylic compound in Test Example 8 is 21% by weight. The content of the polyethylene oxide chain in Test Example 8 is 13% by weight. The content of the second acrylic compound in Test Example 8 is 58% by weight. The content of the third acrylic compound in Test Example 8 is 17% by weight.

The ionizing radiation curable composition of Test Example 9 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 36 parts by weight of Compound 3 (second acrylic compound), and 10 parts by weight of Compound 7 (first acrylic compound). The content of the first acrylic compound in Test Example 9 is 21% by weight. The content of the polyethylene oxide chain in Test Example 9 is 0% by weight. The content of the second acrylic compound in Test Example 9 is 75% by weight. The content of the third acrylic compound in Test Example 9 is 0% by weight.

As shown in FIG. 4, the ionizing radiation curable composition of Test Example 11 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 43 parts by weight of Compound 3 (second acrylic compound), and 3 parts by weight of Compound 4 (third acrylic compound). The content of the first acrylic compound in Test Example 11 is 0% by mass. The content of the polyethylene oxide chain in Test Example 11 is 5% by mass. The content of the second acrylic compound in Test Example 11 is 90% by mass. The content of the third acrylic compound in Test Example 11 is 6% by mass.

The ionizing radiation curable composition of Test Example 12 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 36 parts by weight of Compound 3 (second acrylic compound), and 10 parts by weight of Compound 4 (third acrylic compound). The content of the first acrylic compound in Test Example 12 is 0% by weight. The content of the polyethylene oxide chain in Test Example 12 is 16% by weight. The content of the second acrylic compound in Test Example 12 is 75% by weight. The content of the third acrylic compound in Test Example 12 is 21% by weight.

The ionizing radiation curable composition of Test Example 13 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 26 parts by weight of Compound 3 (second acrylic compound), and 20 parts by weight of Compound 4 (third acrylic compound). The content of the first acrylic compound in Test Example 13 is 0% by weight. The content of the polyethylene oxide chain in Test Example 13 is 31% by weight. The content of the second acrylic compound in Test Example 13 is 54% by weight. The content of the third acrylic compound in Test Example 13 is 42% by weight.

The ionizing radiation curable composition of Test Example 14 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 3 parts by weight of Compound 2 (third acrylic compound), 35.75 parts by weight of Compound 3 (second acrylic compound), and 7 parts by weight of Compound 9 (first acrylic compound). The light-adjusting coating liquid of Test Example 14 contains 0.25 parts by weight of a viscosity reducer in the light-adjusting coating liquid. The content of the first acrylic compound in Test Example 14 is 15% by mass. The content of the polyethylene oxide chain in Test Example 14 is 5% by mass. The content of the second acrylic compound in Test Example 14 is 75% by mass. The content of the third acrylic compound in Test Example 14 is 6% by mass. The content of the viscosity reducer in the liquid crystal composition 31LC of Test Example 14 is 0.5% by mass.

The ionizing radiation curable composition of Test Example 15 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 3 parts by weight of Compound 2 (third acrylic compound), 35.5 parts by weight of Compound 3 (second acrylic compound), and 7 parts by weight of Compound 9 (first acrylic compound). The light-adjusting coating liquid of Test Example 15 contains 0.5 parts by weight of a viscosity reducer in the light-adjusting coating liquid. The content of the first acrylic compound in Test Example 15 is 15% by mass. The content of the polyethylene oxide chain in Test Example 15 is 5% by mass. The content of the second acrylic compound in Test Example 15 is 75% by mass. The content of the third acrylic compound in Test Example 15 is 6% by mass. The content of the viscosity reducer in the liquid crystal composition 31LC of Test Example 15 is 1.0% by mass.

The ionizing radiation curable composition of Test Example 16 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 3 parts by weight of Compound 2 (third acrylic compound), 35.25 parts by weight of Compound 3 (second acrylic compound), and 7 parts by weight of Compound 9 (first acrylic compound). The light-adjusting coating liquid of Test Example 16 contains 0.75 parts by weight of a viscosity reducer in the light-adjusting coating liquid. The content of the first acrylic compound in Test Example 16 is 15% by mass. The content of the polyethylene oxide chain in Test Example 16 is 5% by mass. The content of the second acrylic compound in Test Example 16 is 75% by mass. The content of the third acrylic compound in Test Example 16 is 6% by mass. The content of the viscosity reducer in the liquid crystal composition 31LC of Test Example 16 is 1.5% by mass.

The ionizing radiation curable composition of Test Example 17 is a mixture of 2 parts by weight of Compound 1 (radical curing assistant), 3 parts by weight of Compound 2 (third acrylic compound), 35.0 parts by weight of Compound 3 (second acrylic compound), and 7 parts by weight of Compound 9 (first acrylic compound). The light-adjusting coating liquid of Test Example 17 contains 1 part by weight of a viscosity reducer. The content of the first acrylic compound in Test Example 17 is 15% by mass. The content of the polyethylene oxide chain in Test Example 17 is 5% by mass. The content of the second acrylic compound in Test Example 17 is 75% by mass. The content of the third acrylic compound in Test Example 17 is 6% by mass. The content of the viscosity reducer in the liquid crystal composition 31LC of Test Example 17 is 2.0% by mass.

[Evaluation method]
(i) Responsiveness Evaluation The light-adjusting sheet 11 of each test example was placed in a room temperature environment at 23° C., and an AC signal of 100 V was supplied to the light-adjusting sheet 11 of each test example to confirm that the light-adjusting sheet 11 of each test example changed from transparent to opaque. Next, the supply of the AC signal was stopped to confirm that the light-adjusting sheet 11 changed from opaque to transparent. At this time, the haze was measured using a method conforming to JIS K 7136:2000, and the time from when the supply of the AC signal was stopped until the haze of the light-adjusting sheet 11 stabilized was measured as the responsiveness in a room temperature environment.

The light-adjusting sheet 11 of each test example was placed in a low-temperature environment with a temperature of -23°C, and a 100V AC signal was supplied to the light-adjusting sheet 11 of each test example to confirm that the light-adjusting sheet 11 of each test example changed from transparent to opaque. Next, the supply of the AC signal was stopped to confirm that the light-adjusting sheet 11 changed from opaque to transparent. At this time, the time from when the supply of the AC signal was stopped until the haze of the light-adjusting sheet 11 stabilized was measured as the responsiveness in a low-temperature environment, as in the evaluation of responsiveness in a normal temperature environment.

(ii) Peel Strength Evaluation A rectangular test piece having a width of 25 mm was cut out from the light control sheet 11 of each test example, and the peel strength before heat treatment was measured at a peel angle of 180° using a method conforming to JIS Z-0237: 2009. At this time, the first transparent support layer 36 of the test piece was fixed to a test plate, and the second transparent support layer 37 of the test piece was peeled off at 180° to the test plate.

(iii) Haze Evaluation After Heat Treatment The light-adjusting sheet 11 of each test example was placed in an oven at 130° C. for 30 minutes to subject the light-adjusting sheet 11 of each test example to a heat treatment. Next, an AC signal of 100 V was supplied to the light-adjusting sheet 11 of each test example to measurement of the haze when transparent after the heat treatment.

[Evaluation Results]
3, the light-adjusting sheets 11 of Test Examples 1 to 9 had a response time of 1 second in a room temperature environment. The light-adjusting sheets 11 of Test Examples 1 to 9 had a response time of 1 second or more and 2 seconds or less in a low temperature environment.

As shown in Figure 4, the light-adjusting sheets 11 of test examples 11 to 13 showed a response time of 1 second in a room temperature environment. In contrast, the light-adjusting sheets 11 of test examples 11 to 13 showed a response time of 8 to 10 seconds in a low-temperature environment, which was significantly longer than the response time in a room temperature environment. The light-adjusting sheets 11 of test examples 14 to 17, which contained a viscosity-reducing agent, showed a response time of 1 second in a room temperature environment. Furthermore, the light-adjusting sheets 11 of test examples 14 to 17 showed a response time of 1 second in a low-temperature environment, which was equal to the response time in a room temperature environment.

Comparing Test Example 5 with Test Examples 11 to 13, it is found that by having the content of the first acrylic compound be 2 mass% or more, i.e., by satisfying the lower limit of [Condition 1], the response time in a low-temperature environment is shortened. Comparing Test Examples 1 to 5 with Test Examples 11 to 13, it is found that by having the content of the first acrylic compound be 2 mass% or more and 52 mass% or less, the response time in a low-temperature environment is almost stable.

In addition, from the trend of the response time of the light-adjusting sheet 11 in Test Examples 11 to 13, an increase in the content of the third acrylic compound gradually shortens the response time in a low-temperature environment. However, from a comparison between Test Example 5 and Test Examples 11 to 13, an increase in the content of the first acrylic compound from 0% by mass to 2% by mass shortens the response time in a low-temperature environment to a greater extent than an increase in the content of the third acrylic compound from 6% by mass to 42% by mass. From the effect of the content of the first acrylic compound and a comparison between Test Examples 5 to 8 and Test Example 9, even if the content of the third acrylic compound is 0% by mass, by satisfying the lower limit of [Condition 1], the response time in a low-temperature environment is shortened to approximately the same extent as in a room temperature environment.

As shown in FIG. 5, the response time in a low-temperature environment is rapidly shortened by changing the content of the first acrylic compound from 0% by mass to 2% by mass. Furthermore, when the content of the first acrylic compound is in the range of 2% by mass or more and 52% by mass or less, the response time in a low-temperature environment is stabilized to approximately the same level as in a room temperature environment. In this way, when the light-controlling sheet 11 satisfies the lower limit of [Condition 1], the cured product of the ionizing radiation curable composition is made dense during the phase separation process of the light-controlling layer 31, and low molecular weight compounds are prevented from remaining in the liquid crystal composition 31LC. Thus, the response time in a low-temperature environment is shortened to approximately the same level as in a room temperature environment.

(ii) Peel strength Returning to Fig. 3, a peel strength of 0.20 N/25 mm or more was observed in the light-adjusting sheets 11 of Test Examples 1, 2, and 5 to 8. A peel strength of 0.10 N or more was observed in the light-adjusting sheets 11 of Test Examples 3 and 9. In contrast, a peel strength of less than 0.10 N/25 mm was observed in the light-adjusting sheet 11 of Test Example 4.

As shown in Figure 4, the light-adjusting sheets 11 of test examples 11 and 12 had a peel strength of 0.10 N/25 mm or more. In contrast, the light-adjusting sheet 11 of test example 13 had a peel strength of less than 0.10 N/25 mm. The light-adjusting sheets 11 of test examples 14 and 15, which contained a viscosity-reducing agent, had a peel strength of 0.10 N/25 mm or more. In contrast, the light-adjusting sheets 11 of test examples 16 and 17 had peel strengths of less than 0.10 N/25 mm.

Comparing Test Example 3 and Test Example 4, decreasing the content of the first acrylic compound from 52% by mass to 48% by mass increases the peel strength to 0.10 N/25 mm or more. Comparing Test Example 2 and Test Example 3, decreasing the content of the first acrylic compound from 48% by mass to 29% by mass sharply increases the peel strength.

From a comparison between Test Example 7 and Test Example 9, increasing the content of the third acrylic compound to 5% by mass or more also sharply increases the peel strength. Also, from a comparison between Test Example 7 and Test Example 9, a content of the polyethylene oxide chain of 2% by mass or more and 20% by mass or less, i.e., satisfying [Condition 6], also sharply increases the peel strength.

Thus, from a comparison of Test Examples 1, 2, and 5 with Test Examples 3 and 4, and a comparison of Test Examples 7 and 8 with Test Example 9, it can be seen that the peel strength is increased when the content of the first acrylic compound is 50% by mass or less and the content of the third acrylic compound is 5% by mass or more and 20% by mass or less. Also, the peel strength is further increased when the content of the first acrylic compound is 40% by mass or less and the content of the third acrylic compound is 5% by mass or more and 20% by mass or less. And the peel strength is still further increased when the content of the first acrylic compound is 30% by mass or less and the content of the third acrylic compound is 5% by mass or more and 20% by mass or less.

That is, the peel strength is increased when the content of the first acrylic compound satisfies the upper limit of [Condition 1] and the content of the third acrylic compound satisfies [Condition 3]. In this case, the evaluation results of Test Examples 1 to 3, 5, 7, and 8 show that the effectiveness of improving the peel strength is increased when the content of the second acrylic compound is 35% by mass or more and 85% by mass or less, i.e., satisfies [Condition 2].

In addition, the peel strength is further increased when the content of the first acrylic compound satisfies the upper limit of [Condition 1A] and the content of the third acrylic compound satisfies [Condition 3]. In this case, the evaluation results of Test Examples 1, 2, 5, 7, and 8 show that the effectiveness of improving the peel strength is increased when the content of the second acrylic compound is 45% by mass or more and 85% by mass or less, i.e., satisfies [Condition 2A].

The peel strength is further increased when the content of the first acrylic compound satisfies the upper limit of [Condition 1B] and the content of the third acrylic compound satisfies [Condition 3]. In this case, the evaluation results of Test Examples 1, 2, 5, 7, and 8 show that the effectiveness of improving the peel strength is increased when the content of the second acrylic compound is 55% by mass or more and 85% by mass or less, i.e., satisfies [Condition 2B].

In addition, from the results of the peel strength of Test Examples 1, 2, 5, and 6, it is clear that the number of functional groups of the first acrylic compound is 3 to 5, and the content of the first acrylic compound is 30 mass% or less, i.e., satisfying [Condition 5], enhances the effectiveness of obtaining a peel strength of 0.2 N/25 mm or more.

In addition, from the tendency of the peel strength in the light-adjusting sheet 11 of the test examples 11 to 13, increasing the content of the third acrylic compound to more than 20 mass% reduces the peel strength. In addition, from the comparison between the test examples 7 and 14, decreasing the content of the viscosity reducing agent to less than 0.25 mass% sharply increases the peel strength. From the comparison between the test examples 7 and 14, making the content of the viscosity reducing agent 0.13 mass% or less stabilizes a high peel strength. Not including a viscosity reducing agent in the liquid crystal composition 31LC further stabilizes a higher peel strength. From the tendency of the peel strength in the light-adjusting sheet 11 of the test examples 14 to 17, increasing the content of the viscosity reducing agent from 0.25 mass% further reduces the peel strength. In this way, when it is required to increase the peel strength, the viscosity reducing agent is preferably 0.50 mass% or less, more preferably 0.25 mass% or less, and even more preferably not included in the liquid crystal composition 31LC.

As shown in FIG. 6, when the content of the third acrylic compound is in the range of 5% by mass or more and 20% by mass or less, the peel strength increases sharply as the content of the first acrylic compound decreases from 50% by mass. Also, when the content of the first acrylic compound is in the range of 40% by mass or less, the peel strength is stabilized at a high level of 0.2 N/25 mm or more. In this way, when the light-adjusting sheet 11 satisfies [Condition 1] to [Condition 3], the densification of the cured product of the ionizing radiation curable composition is prevented from excessively increasing the rigidity, and the peel strength is steeply increased to 0.10 N/25 mm or more. And when the light-adjusting sheet 11 satisfies [Condition 1A], [Condition 2A], and [Condition 3], the peel strength is stabilized at a high level of 0.20 N/25 mm or more.

As shown in FIG. 7, the peel strength increases sharply as the acrylic compounding ratio increases from 0 to 0.25. Furthermore, when the acrylic compounding ratio is in the range of 0.25 or more, the peel strength is stabilized at a high level of 0.20 N/25 mm or more. In this way, the light-adjusting sheet 11 satisfying [Condition 1], [Condition 2], and [Condition 4] also prevents the densification of the cured product of the ionizing radiation curable composition from excessively increasing rigidity, stabilizing the peel strength at a high level of 0.20 N/25 mm or more.

(iii) Haze after Heat Treatment Returning to FIG. 3, in the light controlling sheets 11 of Test Examples 1 to 9, a low haze of 5% or less was observed when the sheets were transparent before the heat treatment.

In the light-adjusting sheets 11 of test examples 1 to 4 and 6 to 9, a low haze of 10% or less was observed when transparent after heat treatment. In the light-adjusting sheets 11 of test examples 3, 4, 8, and 9, an even lower haze of 6% or less was observed when transparent after heat treatment. In the light-adjusting sheets 11 of test examples 1 to 4 and 6 to 9, a low increase in haze of 5% or less was observed due to heat treatment.

In contrast, in the light-adjusting sheet 11 of Test Example 5, a high haze of 14% was observed when transparent after heat treatment. In the light-adjusting sheet 11 of Test Example 5, a 9% increase in haze was observed due to heat treatment.

Returning to Figure 4, the light-adjusting sheets 11 of test examples 11 to 13 had a low haze of 4% or less when transparent before heat treatment. On the other hand, the light-adjusting sheets 11 of test examples 11 to 13 had a high haze of 11% or more when transparent after heat treatment. The light-adjusting sheets 11 of test examples 11 to 13 showed an increase in haze of 7% or more due to heat treatment. It should be noted that the light-adjusting sheets 11 of test examples 14 to 17 had a low haze of 5% or less when transparent before heat treatment. The light-adjusting sheets 11 of test examples 14 to 17 had a low haze of 10% or more when transparent after heat treatment.

Comparison of Test Example 6 with Test Examples 5 and 11 reveals that increasing the content of the first acrylic compound from 0% by mass to 5% by mass or more sharply suppresses an increase in haze after heat treatment.
Comparing Test Examples 1 to 4 and 6 with Test Example 5, when the content of the first acrylic compound is 5% by mass or more and 50% by mass or less, the increase in haze after heat treatment is stably suppressed.

In this case, by setting the content of the second acrylic compound to 30% by mass or more and 80% by mass or less, the effectiveness of suppressing the increase in haze and improving the peel strength is increased. The content of the third acrylic compound is 5% by mass or more and 20% by mass or less. In addition, a comparison of Test Examples 6 to 8 with Test Example 9 shows that by setting the content of polyethylene oxide chains to 2% by mass or more and 20% by mass or less, i.e., satisfying [Condition 6], the peel strength is increased to 0.11 N/25 mm or more.

Comparing Test Examples 1 to 3, 6 with Test Examples 4 and 5, it was found that a content of the first acrylic compound of 5% by mass or more and 40% by mass or less suppresses an increase in haze after heat treatment and increases the peel strength to 0.10 N/25 mm or more. In this case, a content of the second acrylic compound of 40% by mass or more and 80% by mass or less increases the effectiveness of suppressing an increase in haze and improving the peel strength. The content of the third acrylic compound is 5% by mass or more and 20% by mass or less. The content of the polyethylene oxide chain may be 2% by mass or more and 20% by mass or less.

Comparing Test Examples 1, 2, and 6 with Test Examples 3 to 5, the content of the first acrylic compound is 5% by mass or more and 30% by mass or less, which suppresses the increase in haze after heat treatment and further increases the peel strength to 0.20 N/25 mm or more. In other words, by satisfying [Condition 5], in which the number of functional groups of the first acrylic compound is 3 to 5 and the content is 30% by mass or less, both the heat resistance and peel strength of the light-adjusting sheet 11 become very good. In this case, the content of the second acrylic compound is 50% by mass or more and 80% by mass or less, which further increases the effectiveness of suppressing the increase in haze and improving the peel strength. The content of the third acrylic compound is 5% by mass or more and 20% by mass or less. The content of the polyethylene oxide chain may be 2% by mass or more and 20% by mass or less.

Based on the tendency of the haze after heat treatment in the light-controlling sheets 11 of Test Examples 11 to 13, increasing the content of the third acrylic compound gradually reduces the haze after heat treatment. However, a comparison between Test Example 6 and Test Example 11 shows that increasing the content of the first acrylic compound from 0% by mass to 6% by mass effectively reduces the haze after heat treatment to the same extent as increasing the content of the third acrylic compound from 6% by mass to 42% by mass.

Comparing Test Example 7 with Test Examples 14 to 17, changing the viscosity reducing agent content within the range of 0% by mass to 1% by mass suppresses the increase in haze after heat treatment to the same extent. If improved responsiveness in low-temperature environments, improved peel strength, and low haze after heat treatment are required for the light-adjusting sheet 11, the viscosity reducing agent content is preferably 0.50% by mass or less. If improved responsiveness in low-temperature environments, stable high peel strength, and low haze after heat treatment are required, the viscosity reducing agent content is preferably less than 0.25% by mass, and more preferably 0.13% by mass or less.

In this case, the decrease in peel strength due to the inclusion of a viscosity reducer may be suppressed if [Condition 1A], [Condition 2A], and [Condition 3] are satisfied and the content of the first acrylic compound is 5% by mass or more. Also, the decrease in peel strength due to the inclusion of a viscosity reducer may be suppressed if [Condition 1B], [Condition 2B], and [Condition 3] are satisfied and the content of the first acrylic compound is 5% by mass or more.

On the other hand, when [Condition 1] to [Condition 3] are satisfied, but at least one of [Condition 1B] and [Condition 2B] is not satisfied, and high stabilization of peel strength is required, it is preferable that no viscosity reducing agent is included in liquid crystal composition 31LC. When [Condition 1], [Condition 2], and [Condition 4] are satisfied, but at least one of [Condition 1B] and [Condition 2B] is not satisfied, and high stabilization of peel strength is required, it is also preferable that no viscosity reducing agent is included in liquid crystal composition 31LC.

As shown in FIG. 8, by changing the content of the first acrylic compound from 0% by mass to 5% by mass, the increase in haze after heat treatment is suppressed sharply. Furthermore, the change in haze with respect to the change in the content of the first acrylic compound is gradual when the content of the first acrylic compound is 5% by mass or more. In this way, a content of the first acrylic compound of 5% by mass or more provides the light-control sheet 11 with stable and good heat resistance.

As shown in FIG. 9, as the acrylic blend ratio increases from 0 to 5, the haze after heat treatment gradually increases from 5% to 14%. When the acrylic blend ratio is in the range of 0.25 to 2.0, the haze after heat treatment remains between 5% and 9%. In this way, when the light-adjusting sheet 11 satisfies [Condition 1], [Condition 2], and [Condition 4A], it exhibits good haze after heat treatment.

The open circles in Figure 10 indicate the levels at which (i) a response time in a low-temperature environment of 2 seconds or less, (ii) a peel strength of 0.2 N/25 mm or more, and (iii) a haze after heat treatment of 9% or less can be achieved. In other words, the open circles in Figure 10 indicate test examples 1, 2, and 6 to 8, which indicate the levels at which good response and good peel strength can be achieved in a low-temperature environment, and good transparency can be obtained when heating is involved in the manufacturing and mounting processes.

The black triangles in Figure 10 indicate the level at which (i) the response in a low-temperature environment is 2 seconds or less, (ii) the peel strength is less than 0.2 N/25 mm, and (iii) the haze after heat treatment is 9% or less. In other words, the black triangles in Figure 10 indicate test examples 3, 4, and 9, which show good response in a low-temperature environment and provide good transparency when heating is involved in manufacturing and mounting, but are at a level at which good peel strength cannot be obtained.

The open squares in Figure 10 indicate the level at which (i) the response in a low-temperature environment is 2 seconds or less, (ii) the peel strength is 0.2 N/25 mm or more, and (iii) the haze after heat treatment is 10% or more. In other words, the open squares in Figure 10 indicate Test Example 5, which shows a good response and good peel strength in a low-temperature environment, but does not show a good level of transparency when heating is involved in the manufacturing or mounting process.

The black circles in Figure 10 indicate the levels at which (i) a response in a low-temperature environment of 10 seconds, (ii) a peel strength of 0.2 N/25 mm or more, and (iii) a haze after heat treatment of 10% or more were achieved. In other words, the black circles in Figure 10 indicate test example 11, which indicates a level at which good peel strength was achieved but good response was not achieved in a low-temperature environment and good transparency was not achieved when heating was involved in the manufacturing or mounting process.

The black diamonds in Figure 10 indicate levels where (i) the response in a low-temperature environment is 8 or 9 seconds, (ii) the peel strength is less than 0.2 N/25 mm, and (iii) the haze after heat treatment is 10% or more. In other words, the black diamonds in Figure 10 indicate test examples 12 and 13, which are levels where good response in a low-temperature environment, good peel strength, and good transparency cannot be obtained when heating is involved in the manufacturing or mounting process.

As shown in FIG. 10, a comparison of the open circles and squares with the filled circles and diamonds shows that a content of the first acrylic compound of 2% by mass or more provides good responsiveness in a low-temperature environment. A comparison of the open squares, filled circles, and diamonds with the open circles shows that a content of the first acrylic compound of 5% by mass or more provides good responsiveness in a low-temperature environment and also provides good haze when transparent after heat treatment. A comparison of the filled circles, diamonds, and triangles with the open circles and squares shows that satisfying conditions 1A, 2A, and 3, or satisfying conditions 1A, 2A, and 3, provides good responsiveness in a low-temperature environment and good peel strength.

[First alignment layer 32, second alignment layer 33, viscosity reducing agent]
The mounting technique for the light-adjusting sheet 11 described above requires the light-adjusting sheet 11 to have heat resistance. In the mounting technique using the intermediate film method, the light-adjusting sheet 11 is sandwiched between glass substrates and the glass substrates are heated for lamination. The films sandwiching the light-adjusting layer 31 generate low-molecular-weight impurities from the films in a high-temperature environment such as during lamination. Since the low-molecular-weight impurities diffused into the light-adjusting layer 31 deteriorate the electrical properties of the liquid crystal compound LCM, the surface treatment layers of the films sandwiching the light-adjusting layer 31 have a barrier function that suppresses contact between the low-molecular-weight impurities and the liquid crystal compound LCM.

The use of a flexible substrate such as the first transparent support layer 36 or the second transparent support layer 37 enables the production of the light control sheet 11 by roll-to-roll. On the other hand, the use of a substrate that is easily deformed in a high-temperature environment limits the formation conditions of the light control sheet 11 to a low-temperature environment to avoid a high-temperature environment. When alignment of the liquid crystal compound LCM is required during the period when the supply of the voltage signal is stopped, as in the case of the reverse-type light control sheet 11, the light control sheet 11 includes a first alignment layer 32 or a second alignment layer 33. The first alignment layer 32 or the second alignment layer 33, which applies an alignment control force to the liquid crystal compound LCM, is arranged to be in contact with the light control layer 31, regardless of the presence or absence of the above-mentioned surface treatment layer.

The first alignment layer 32 and the second alignment layer 33, which are limited in formation conditions under a low-temperature environment, contain low-molecular-weight impurities such as unreacted substances such as polyamic acid and residual solvents. The mounting technology of the light-controlling sheet 11, which requires heating, causes by-products and residual solvents generated from unreacted substances to diffuse from the first alignment layer 32 and the second alignment layer 33 arranged in contact with the light-controlling layer 31 to the light-controlling layer 31. The low-molecular-weight impurities such as unreacted substances diffused into the light-controlling layer 31 weaken the effect of the alignment control force of the first alignment layer 32 and the second alignment layer 33 through the ionizing radiation curable resin layer 31P, thereby increasing the haze of the light-controlling sheet 11 when transparent. In this regard, the configuration for making the cured product of the ionizing radiation curable composition dense in the process of phase separation between the cured product of the ionizing radiation curable composition and the liquid crystal composition 31LC includes a configuration for suppressing the thermal diffusion of low-molecular-weight impurities into the liquid crystal composition 31LC through the ionizing radiation curable resin layer 31P.

The degree to which viscosity reducing agents such as adipates and phosphates increase the viscosity due to a decrease in temperature is smaller in low-temperature environments such as cold regions than the degree to which the liquid crystal compound LCM increases the viscosity due to a decrease in temperature. On the other hand, the viscosity reducing agent in the liquid crystal composition 31LC reaching the interface between the light-adjusting layer 31 and other layers reduces the peel strength of the light-adjusting layer 31 against other layers. Making the cured product of the ionizing radiation curable composition dense during the process of phase separation between the cured product of the ionizing radiation curable composition and the liquid crystal composition 31LC suppresses the remaining of low-molecular-weight compounds in the liquid crystal composition 31LC. And the configuration for making the cured product of the ionizing radiation curable composition dense to the extent that the low-molecular-weight compounds do not reduce the peel strength includes a configuration for suppressing the diffusion of the viscosity reducing agent to the interface between the light-adjusting layer 31 and other layers.

According to the above embodiment, the following effects can be obtained.
(1) The ionizing radiation curable resin layer 31P satisfying the conditions 1, 2, and 3, or the conditions 1, 2, and 4, densifies the cured product of the ionizing radiation curable composition during the phase separation process of the light control layer 31, and suppresses low molecular weight compounds from remaining in the liquid crystal composition 31LC. As a result, the ionizing radiation curable resin layer 31P improves the responsiveness in a low temperature environment.

(2) The ionizing radiation cured resin layer 31P that satisfies conditions 1A, 2A, and 3, or conditions 1A, 2A, and 4, increases the peel strength within the light control sheet 11 while preventing the low molecular weight compound from reaching the liquid crystal compound LCM.

(3) The ionizing radiation cured resin layer 31P that satisfies conditions 1B, 2B, and 3, or conditions 1B, 2B, and 4, significantly increases the peel strength within the light control sheet 11 while preventing the low molecular weight compound from reaching the liquid crystal compound LCM.

(4) The content of the first acrylic compound may be 5% by mass or more and 50% by mass or less, the content of the second acrylic compound may be 30% by mass or more and 80% by mass or less, and the content of the third acrylic compound may be 5% by mass or more and 20% by mass or less. This allows the ionizing radiation cured resin layer 31P to prevent low molecular weight impurities contained in the first alignment layer 32 and the second alignment layer 33 from reaching the liquid crystal compound LCM. As a result, the heat resistance of the optical properties of the light control sheet 11 is improved.

(5) The content of the first acrylic compound may be 5% by mass or more and 40% by mass or less, the content of the second acrylic compound may be 40% by mass or more and 80% by mass or less, and the content of the third acrylic compound may be 5% by mass or more and 20% by mass or less. The acrylic compounding ratio may be 0.25 or more and 2.0 or less. As a result, the ionizing radiation cured resin layer 31P has an effect similar to that of (1) above, and while improving the heat resistance of the optical properties of the light-adjusting sheet 11, it also improves the peel strength within the sheet of the light-adjusting sheet 11.

(6) The content of the first acrylic compound may be 5% by mass or more and 30% by mass or less, the content of the second acrylic compound may be 50% by mass or more and 80% by mass or less, and the content of the third acrylic compound may be 5% by mass or more and 20% by mass or less. The acrylic compounding ratio may be 0.25 or more and 2.0 or less. As a result, the ionizing radiation cured resin layer 31P has an effect similar to that of (2) above, and while improving the heat resistance of the optical properties of the light-adjusting sheet 11, it also significantly increases the peel strength within the sheet of the light-adjusting sheet 11.

(7) In addition to the above (4) to (6), when the light-adjusting sheet 11 includes a first alignment layer 32 and a second alignment layer 33, it becomes possible to provide a reverse-type light-adjusting sheet 11 with improved responsiveness in low-temperature environments.

(8) The ionizing radiation cured resin layer 31P satisfies conditions 1A, 2A, and 3, or conditions 1A, 2A, and 4, and the liquid crystal composition 31LC may contain 0.25% by mass or less of a viscosity reducing agent. This enhances the effectiveness of improving the responsiveness of the light control sheet 11 in a low-temperature environment and suppresses a decrease in peel strength.

(9) The ionizing radiation cured resin layer 31P satisfies conditions 1B, 2B, and 3, or conditions 1B, 2B, and 4, and the liquid crystal composition 31LC does not need to contain a viscosity reducing agent. This enhances the effectiveness of improving the responsiveness of the light control sheet 11 in a low-temperature environment and significantly suppresses the decrease in peel strength.

LCM...liquid crystal compound 10...light control device 11...light control sheet 12...driver 31...light control layer 31P...ionizing radiation curing resin layer 31LC...liquid crystal composition 31D...void 32...first alignment layer 33...second alignment layer 34...First transparent electrode layer 35...Second transparent electrode layer 36...First transparent support layer 37...Second transparent support layer

Claims (14)

A first transparent electrode layer;
A second transparent electrode layer;
a light control layer located between the first transparent electrode layer and the second transparent electrode layer,
A light-controlling sheet that changes the haze of the light-controlling layer by changing a voltage applied between the first transparent electrode layer and the second transparent electrode layer,
The light-controlling layer is
an ionizing radiation cured resin layer defining a gap;
A liquid crystal composition filled in the gap,
The acryloyl group and the methacryloyl group are functional groups,
the first acrylic compound is an acrylic compound having three or more of the functional groups and a double bond equivalent of 150 g/eq or less;
the content of the first acrylic compound constituting the ionizing radiation cured resin layer is 2% by mass or more and 50% by mass or less of the ionizing radiation cured resin layer,
the second acrylic compound is a monofunctional alkyl acrylate containing a saturated alkyl group having from 2 to 12 carbon atoms, a monofunctional alkoxyalkyl acrylate containing a saturated alkoxyalkyl group having from 2 to 12 carbon atoms, a monofunctional alkyl methacrylate containing a saturated alkyl group having from 2 to 12 carbon atoms, or a monofunctional alkoxyalkyl methacrylate containing a saturated alkoxyalkyl group having from 2 to 12 carbon atoms;
the content of the second acrylic compound constituting the ionizing radiation cured resin layer is 35% by mass or more and 85% by mass or less of the ionizing radiation cured resin layer,
the third acrylic compound is an acrylic compound having one or more and three or less of the functional groups and a polyethylene oxide chain, and having a double bond equivalent of 300 g/eq or more and 700 g/eq or less;
The light-controlling sheet, characterized in that the content of the third acrylic compound constituting the ionizing radiation cured resin layer is 5% by mass or more and 20% by mass or less of the ionizing radiation cured resin layer. A first transparent electrode layer;
A second transparent electrode layer;
a light control layer located between the first transparent electrode layer and the second transparent electrode layer,
A light-controlling sheet that changes the haze of the light-controlling layer by changing a voltage applied between the first transparent electrode layer and the second transparent electrode layer,
The light-controlling layer is
an ionizing radiation cured resin layer defining a gap;
A liquid crystal composition filled in the gap,
The acryloyl group and the methacryloyl group are functional groups,
the first acrylic compound is an acrylic compound having three or more of the functional groups and a double bond equivalent of 150 g/eq or less;
the content of the first acrylic compound constituting the ionizing radiation cured resin layer is 2% by mass or more and 50% by mass or less of the ionizing radiation cured resin layer,
the second acrylic compound is a monofunctional alkyl acrylate containing a saturated alkyl group having from 2 to 12 carbon atoms, a monofunctional alkoxyalkyl acrylate containing a saturated alkoxyalkyl group having from 2 to 12 carbon atoms, a monofunctional alkyl methacrylate containing a saturated alkyl group having from 2 to 12 carbon atoms, or a monofunctional alkoxyalkyl methacrylate containing a saturated alkoxyalkyl group having from 2 to 12 carbon atoms;
the content of the second acrylic compound constituting the ionizing radiation cured resin layer is 35% by mass or more and 85% by mass or less of the ionizing radiation cured resin layer,
the third acrylic compound is an acrylic compound having one or more and three or less of the functional groups and a polyethylene oxide chain, and having a double bond equivalent of 300 g/eq or more and 700 g/eq or less;
A light-adjusting sheet, characterized in that a content ratio of the third acrylic compound constituting the ionizing radiation cured resin layer relative to a content ratio of the first acrylic compound constituting the ionizing radiation cured resin layer is 0.25 or more. a first alignment layer sandwiched between the first transparent electrode layer and the light control layer;
The light-controlling sheet according to claim 1 or 2, further comprising a second alignment layer sandwiched between the second transparent electrode layer and the light-controlling layer. The light controlling sheet according to claim 1 or 2, wherein the liquid crystal composition does not contain a viscosity reducing agent. the number of the functional groups in the first acrylic compound is 3 or more and 5 or less,
the content of the first acrylic compound constituting the ionizing radiation cured resin layer is 30% by mass or less of the ionizing radiation cured resin layer,
The light-controlling sheet according to claim 1 or 2, wherein the content of the second acrylic compound constituting the ionizing radiation cured resin layer is 55% by mass or more of the ionizing radiation cured resin layer. The light-controlling sheet according to claim 1 or 2, wherein the content of polyethylene oxide chains constituting the ionizing radiation cured resin layer is 2% by mass or more and 20% by mass or less of the ionizing radiation cured resin layer. the first acrylic compound is a pentaerythritol compound;
the second acrylic compound is isobornyl acrylate;
The light controlling sheet according to claim 1 or 2, wherein the third acrylic compound is an alkoxypolyethylene glycol compound. the first acrylic compound is a trimethylolpropane compound;
the second acrylic compound is isobornyl acrylate;
The light-controlling sheet according to claim 1 or 2, wherein the third acrylic compound is a polyethyleneoxyside-modified trimethylolpropane compound. The light control sheet according to claim 3 , wherein the first alignment layer and the second alignment layer each contain at least one polymer selected from the group consisting of a polyimide precursor and a polyimide. The light-controlling sheet according to claim 1 , wherein a weight of the liquid crystal composition is 20% by mass or more and 70% by mass or less with respect to a total weight of the ionizing radiation cured resin layer and the liquid crystal composition. A light-adjusting sheet,
A light-adjusting device comprising: a driving unit that applies a voltage to the light-adjusting sheet;
The light control sheet is
A first transparent electrode layer;
A second transparent electrode layer;
a light control layer located between the first transparent electrode layer and the second transparent electrode layer,
changing the haze of the light control layer by changing the voltage applied between the first transparent electrode layer and the second transparent electrode layer;
The light-controlling layer is
an ionizing radiation cured resin layer defining a gap;
A liquid crystal composition filled in the gap,
The acryloyl group and the methacryloyl group are functional groups,
the first acrylic compound is an acrylic compound having three or more of the functional groups and a double bond equivalent of 150 g/eq or less;
the content of the first acrylic compound constituting the ionizing radiation cured resin layer is 2% by mass or more and 50% by mass or less of the ionizing radiation cured resin layer,
the second acrylic compound is a monofunctional alkyl acrylate containing a saturated alkyl group having from 2 to 12 carbon atoms, a monofunctional alkoxyalkyl acrylate containing a saturated alkoxyalkyl group having from 2 to 12 carbon atoms, a monofunctional alkyl methacrylate containing a saturated alkyl group having from 2 to 12 carbon atoms, or a monofunctional alkoxyalkyl methacrylate containing a saturated alkoxyalkyl group having from 2 to 12 carbon atoms;
the content of the second acrylic compound constituting the ionizing radiation cured resin layer is 35% by mass or more and 85% by mass or less of the ionizing radiation cured resin layer,
the third acrylic compound is an acrylic compound having one or more and three or less of the functional groups and a polyethylene oxide chain, and having a double bond equivalent of 300 g/eq or more and 700 g/eq or less;
A light control device, characterized in that a content of the third acrylic compound constituting the ionizing radiation cured resin layer is 5% by mass or more and 20% by mass or less of the ionizing radiation cured resin layer. A light-adjusting sheet,
A light-adjusting device comprising: a driving unit that applies a voltage to the light-adjusting sheet;
The light control sheet is
A first transparent electrode layer;
A second transparent electrode layer;
a light control layer located between the first transparent electrode layer and the second transparent electrode layer,
changing the haze of the light control layer by changing the voltage applied between the first transparent electrode layer and the second transparent electrode layer;
The light-controlling layer is
an ionizing radiation cured resin layer defining a gap;
A liquid crystal composition filled in the gap,
The acryloyl group and the methacryloyl group are functional groups,
the first acrylic compound is an acrylic compound having three or more of the functional groups and a double bond equivalent of 150 g/eq or less;
the content of the first acrylic compound constituting the ionizing radiation cured resin layer is 2% by mass or more and 50% by mass or less of the ionizing radiation cured resin layer,
the second acrylic compound is a monofunctional alkyl acrylate containing a saturated alkyl group having from 2 to 12 carbon atoms, a monofunctional alkoxyalkyl acrylate containing a saturated alkoxyalkyl group having from 2 to 12 carbon atoms, a monofunctional alkyl methacrylate containing a saturated alkyl group having from 2 to 12 carbon atoms, or a monofunctional alkoxyalkyl methacrylate containing a saturated alkoxyalkyl group having from 2 to 12 carbon atoms;
the content of the second acrylic compound constituting the ionizing radiation cured resin layer is 35% by mass or more and 85% by mass or less of the ionizing radiation cured resin layer,
the third acrylic compound is an acrylic compound having one or more and three or less of the functional groups and a polyethylene oxide chain, and having a double bond equivalent of 300 g/eq or more and 700 g/eq or less;
A light control device, characterized in that a content ratio of the third acrylic compound constituting the ionizing radiation curable resin layer relative to a content ratio of the first acrylic compound constituting the ionizing radiation curable resin layer is 0.25 or more. forming a coating layer containing an ionizing radiation curable composition and a liquid crystal composition between a first transparent electrode layer and a second transparent electrode layer;
and forming a light control layer between the first transparent electrode layer and the second transparent electrode layer, the light control layer including an ionizing radiation cured resin layer that defines a gap and the liquid crystal composition that fills the gap, by irradiating the coating layer with ionizing radiation;
A method for manufacturing a light-controlling sheet for changing the haze of the light-controlling layer by changing a voltage applied between the first transparent electrode layer and the second transparent electrode layer, comprising:
The acryloyl group and the methacryloyl group are functional groups,
the first acrylic compound is an acrylic compound having three or more of the functional groups and a double bond equivalent of 150 g/eq or less;
the content of the first acrylic compound constituting the ionizing radiation curable composition is 2% by mass or more and 50% by mass or less of the ionizing radiation curable composition,
the second acrylic compound is a monofunctional alkyl acrylate containing a saturated alkyl group having from 2 to 12 carbon atoms, a monofunctional alkoxyalkyl acrylate containing a saturated alkoxyalkyl group having from 2 to 12 carbon atoms, a monofunctional alkyl methacrylate containing a saturated alkyl group having from 2 to 12 carbon atoms, or a monofunctional alkoxyalkyl methacrylate containing a saturated alkoxyalkyl group having from 2 to 12 carbon atoms;
the content of the second acrylic compound constituting the ionizing radiation cured resin layer is 35% by mass or more and 85% by mass or less of the ionizing radiation cured resin layer,
the third acrylic compound is an acrylic compound having one or more and three or less of the functional groups and a polyethylene oxide chain, and having a double bond equivalent of 300 g/eq or more and 700 g/eq or less;
The method for producing a light-controlling sheet, wherein the content of the third acrylic compound constituting the ionizing radiation cured resin layer is 5% by mass or more and 20% by mass or less of the ionizing radiation cured resin layer. forming a coating layer containing an ionizing radiation curable composition and a liquid crystal composition between a first transparent electrode layer and a second transparent electrode layer;
and forming a light control layer between the first transparent electrode layer and the second transparent electrode layer, the light control layer including an ionizing radiation cured resin layer that defines a gap and the liquid crystal composition that fills the gap, by irradiating the coating layer with ionizing radiation;
A method for manufacturing a light-controlling sheet for changing the haze of the light-controlling layer by changing a voltage applied between the first transparent electrode layer and the second transparent electrode layer, comprising:
The acryloyl group and the methacryloyl group are functional groups,
the first acrylic compound is an acrylic compound having three or more of the functional groups and a double bond equivalent of 150 g/eq or less;
the content of the first acrylic compound constituting the ionizing radiation curable composition is 2% by mass or more and 50% by mass or less of the ionizing radiation curable composition,
the second acrylic compound is a monofunctional alkyl acrylate containing a saturated alkyl group having from 2 to 12 carbon atoms, a monofunctional alkoxyalkyl acrylate containing a saturated alkoxyalkyl group having from 2 to 12 carbon atoms, a monofunctional alkyl methacrylate containing a saturated alkyl group having from 2 to 12 carbon atoms, or a monofunctional alkoxyalkyl methacrylate containing a saturated alkoxyalkyl group having from 2 to 12 carbon atoms;
the content of the second acrylic compound constituting the ionizing radiation cured resin layer is 35% by mass or more and 85% by mass or less of the ionizing radiation cured resin layer,
the third acrylic compound is an acrylic compound having one or more and three or less of the functional groups and a polyethylene oxide chain, and having a double bond equivalent of 300 g/eq or more and 700 g/eq or less;
A method for producing a light-controlling sheet, wherein a content ratio of the third acrylic compound constituting the ionizing radiation cured resin layer relative to a content ratio of the first acrylic compound constituting the ionizing radiation cured resin layer is 0.25 or more.

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