WO2021200526A1 - Polymer-dispersed liquid crystal panel, polymer-dispersed liquid crystal device, and method for manufacturing polymer-dispersed liquid crystal panel - Google Patents

Abstract

The present invention provides a polymer-dispersed liquid crystal device that can be driven with low power consumption. This polymer-dispersed liquid crystal panel is provided with: a pair of transparent substrates; a pair of transparent electrode layers provided between the pair of transparent substrates; and a polymer-dispersed liquid crystal layer provided between the pair of transparent electrode layers, wherein the moisture content of the polymer-dispersed liquid crystal layer is 0.3 wt% or less.

Description

Method for manufacturing polymer-dispersed liquid crystal panel, polymer-dispersed liquid crystal device, and polymer-dispersed liquid crystal panel

The present invention relates to a polymer-dispersed liquid crystal panel, a polymer-dispersed liquid crystal display, and a method for manufacturing a polymer-dispersed liquid crystal panel.

Conventionally, a polymer-dispersed liquid crystal panel having a polymer-dispersed liquid crystal layer between a pair of transparent electrode layers is known (see, for example, Patent Document 1).

The polymer-dispersed liquid crystal panel can change the degree of scattering of transmitted light in the polymer-dispersed liquid crystal layer according to the amount of voltage applied to the pair of transparent electrode layers. By switching between and, it is possible to switch between a state in which light is scattered (scattered state) and a state in which light is transmitted (non-scattered state or transparent state).

One of the uses of such a polymer-dispersed liquid crystal panel is its use as a light control film. For example, by attaching a polymer-dispersed liquid crystal device including a polymer-dispersed liquid crystal panel and a drive circuit for driving the polymer-dispersed liquid crystal panel to an existing window glass, it can function as a blind shutter. ..

JP-A-2018-116273

The conventional polymer-dispersed liquid crystal display can be driven by a commercial AC power supply that can be easily used in homes and offices. However, driving by a commercial AC power supply has a problem that the frequency is short, so that the power consumption is large and the environmental load is large.

An object of the present invention is to provide a polymer-dispersed liquid crystal display capable of driving with low power consumption.

According to one aspect of the present invention, a pair of transparent substrates, a pair of transparent electrode layers provided between the pair of transparent substrates, and a polymer provided between the pair of transparent electrode layers. Provided is a polymer-dispersed liquid crystal panel comprising a polymer-dispersed liquid crystal film having a dispersed liquid crystal layer and having a water content of the polymer-dispersed liquid crystal layer of 0.3 wt% or less.
In one embodiment, 0.01 g / g / humidity of the polymer-dispersed liquid crystal film in an environment of 40 ° C. and 90% RH on the side opposite to the side where the transparent electrode layer of the pair of transparent substrates is provided. A pair of low moisture permeable substrates having m ^{2 / 24h or less are arranged.}
In one embodiment, the low moisture permeable substrate is a glass substrate.
In one embodiment, the thickness of the glass substrate is 10 μm or more.
In one embodiment, the low moisture permeable base material is a resin base material with a moisture barrier membrane.
In one embodiment, the polymer-dispersed liquid crystal panel further includes a sealing portion arranged so as to cover an end portion of the polymer-dispersed liquid crystal film, and the moisture permeability of the sealing portion is 40 ° C. and 90 ° C. It is 0.1 g / m ² / 24h or less under the% RH environment.
Via In one embodiment, the above transparent substrate, and the low moisture permeability substrate, a low moisture permeability adhesive layer is less than 0.1g ^/ m 2 ^/ 24h at the under 40 ° C. 90% RH environment moisture permeability It is pasted together.
In one embodiment, the moisture absorption of the transparent substrate is 0.1 wt% 24 h or more in a 40 ° C. 90% RH environment.
In one embodiment, the transparent substrate comprises a polyethylene terephthalate resin.
In one embodiment, the transparent substrate comprises a cycloolefin resin.
According to another aspect of the present invention, the polymer-dispersed liquid crystal layer is formed by applying a voltage between the polymer-dispersed liquid crystal panel and the pair of transparent electrode layers constituting the polymer-dispersed liquid crystal panel. Provided is a polymer-dispersed liquid crystal display including a drive circuit that puts the surface into a non-scattered state or a scattered state, and a power source that supplies a DC voltage to the drive circuit.
According to another aspect of the present invention, on the transparent electrode layer side surface of the first transparent electrode layered base material having the transparent base material and the transparent electrode layer provided on one side of the transparent base material. Applying an emulsion in which polymer particles and liquid crystal particles are dispersed in an aqueous solvent to form a coating layer, drying the coating layer to form a polymer-dispersed liquid crystal layer, and forming the polymer dispersion. A base material with a second transparent electrode layer having a transparent base material and a transparent electrode layer provided on one side of the transparent base material is placed on a mold liquid crystal layer, and the surface on the transparent electrode layer side is polymer-dispersed. The laminate is laminated so as to face the type liquid crystal layer to obtain a laminate, and the laminate is subjected to heat treatment to reduce the water content in the polymer-dispersed liquid crystal layer to 0.3 wt% or less. , A method for manufacturing a polymer-dispersed liquid crystal panel including.
In one embodiment, the moisture permeability of the laminated body after the heat treatment is 40 ° C. and 90% on the surface of the first transparent electrode layered base material and the second transparent electrode layered base material on the transparent base material side. Further including laminating a low moisture permeable base material of 0.01 g / m ² / 24h or less in an RH environment, the laminating of the low moisture permeable base material is performed within 60 minutes after the completion of the heat treatment. It is said.

According to the present invention, by controlling the water content in the polymer-dispersed liquid crystal layer, it is possible to obtain a polymer-dispersed liquid crystal apparatus capable of driving with low power consumption.

FIG. 3 is a schematic cross-sectional view of a PDLC panel according to one embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a PDLC panel according to another embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a PDLC panel according to still another embodiment of the present invention. It is a schematic front view of the PDLC panel by one Embodiment of this invention. It is a schematic front view of the PDLC apparatus according to one Embodiment of this invention. FIG. 5 is a schematic cross-sectional view taken along the line AA of the PDLC apparatus shown in FIG. It is a graph which shows the initial current value when the PDLC apparatus is continuously driven, and the current value after 120 hours drive. It is a graph which shows the change of the weight and the current value when the PDLC film is heated. It is a graph which shows the relationship between the type of a transparent base material, and the current value at the time of driving a PDLC panel.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments. In addition, each embodiment can be combined appropriately. Further, in the present specification, the transparent base material and the transparent electrode layer provided on one side thereof may be collectively referred to as a base material with a transparent electrode layer.

A. Overall Configuration of Polymer Dispersion Liquid Crystal Panel The Polymer Dispersed Liquid Crystal (Polymer Dispersed Liquid Crystal, hereinafter referred to as “PDLC”) panel according to the embodiment of the present invention comprises a pair of transparent base materials and the pair of transparent base materials. A PDLC film having a pair of transparent electrode layers provided between the two transparent electrode layers and a PDLC layer provided between the pair of transparent electrode layers, and the water content of the PDLC layer is 0.3 wt% or less. Is. Since the power consumption when a constant drive voltage is supplied is inversely proportional to the resistance, the PDLC device can be driven with low power consumption by reducing the water content in the PDLC layer and increasing the resistance. Can be obtained.

FIG. 1 is a schematic cross-sectional view of a PDLC panel according to one embodiment of the present invention. The PDLC panel 110a is formed between the pair of transparent base materials 10a and 10b, the pair of transparent electrode layers 20a and 20b provided between the pair of transparent base materials 10a and 10b, and the pair of transparent electrode layers 20a and 20b. The PDLC film 100 having the provided PDLC layer 30 is included.

FIG. 2 is a schematic cross-sectional view of a PDLC panel according to another embodiment of the present invention. The PDLC panel 110b has a pair of low moisture permeability base materials 102a on both sides of the PDLC film 100 (specifically, the side opposite to the side where the transparent electrode layers 20a and 20b of the pair of transparent base materials 10a and 10b are provided). , 102b are arranged, which is different from the PDLC panel 110a.

The transparent base materials 10a and 10b and the low moisture permeable base materials 102a and 102b are typically bonded via any suitable adhesive layer (for example, an adhesive layer or an adhesive layer). In one embodiment, the transparent substrate 10a and the low moisture permeable substrate 102a and / or the transparent substrate 10b and the low moisture permeable substrate 102b are bonded together via a low moisture permeable adhesive layer (not shown). There is.

FIG. 3 is a schematic cross-sectional view of a PDLC panel according to still another embodiment of the present invention. The PDLC panel 110c differs from the PDLC panel 100b in that it includes a sealing portion 104 that covers the end of the PDLC film 100. In the illustrated example, the low moisture permeable base materials 102a and 102b have a shape corresponding to the PDLC film 100 and have a slightly larger dimension, and the sealing portion is PDLC so that the ends of the PDLC panel 110c are flush with each other. It is provided on the peripheral edge of the edge of the film 100.

A-1. PDLC film A PDLC film has a pair of transparent substrates, a pair of transparent electrode layers provided between the pair of transparent substrates, and a PDLC layer provided between the pair of transparent electrode layers. .. The PDLC panel may further have other layers, depending on the purpose. Examples of other layers include a refractive index adjusting layer, a hard coat layer, a protective layer, an adhesive layer and the like.

As described above, the PDLC film can change the degree of scattering of transmitted light (resulting in haze) in the PDLC layer according to the amount of voltage applied to the pair of transparent electrode layers. By switching between the added state and the non-scattered state (transparent state), it is possible to switch between the scattered state and the non-scattered state (transparent state).

In one embodiment, the PDLC film may have, for example, 70% to 92%, more preferably 75% to 90% haze in the scattered state. Further, the PDLC film may have a haze of, for example, less than 30%, preferably 15% or less, more preferably 0.1% to 12% in a transparent state.

A-1-1. Transparent base material The transparent base material constitutes a base material with a transparent electrode layer by providing a transparent electrode layer on one side thereof. The base material with a transparent electrode layer may have a hard coat layer on one side or both sides of the transparent base material, if necessary, and a refractive index adjusting layer may be provided between the transparent base material and the transparent electrode layer. You may have.

The surface resistance value of the base material with the transparent electrode layer is preferably 1Ω / □ to 1000Ω / □, more preferably 5Ω / □ to 300Ω / □, and further preferably 10Ω / □ to 200Ω / □.

The haze value of the base material with the transparent electrode layer is preferably 20% or less, more preferably 10% or less, and further preferably 0.1% to 10%.

The total light transmittance of the base material with the transparent electrode layer is preferably 30% or more, more preferably 60% or more, and further preferably 80% or more.

The transparent substrate can be formed using any suitable material. Preferably, a polymer film containing a thermoplastic resin as a main component can be used as the transparent base material. Examples of the thermoplastic resin include cycloolefin resins such as polynorbornene; acrylic resins; polyester resins such as polyethylene terephthalate; polycarbonate resins; cellulose resins and the like. Of these, cycloolefin-based resins, polyethylene terephthalate-based resins, and polycarbonate-based resins can be preferably used. The above-mentioned thermoplastic resin may be used alone or in combination of two or more.

The humidity absorption of the transparent substrate is, for example, 0.1 wt% / 24 h or more, preferably 0.2 wt% / 24 h or more, and more preferably 0.5 wt% / 24 h to 5 wt% / in an environment of 40 ° C. and 90% RH. It can be 24 hours. When the moisture absorption of the transparent substrate is within the above range, the water content of the PDLC layer can be preferably controlled by heat treatment. The hygroscopicity is a value indicating how much water is absorbed under high temperature and high humidity, and is obtained based on the change in weight before and after placing in high temperature and high humidity. The moisture absorption can change depending on the surface area, but since the transparent substrate has a sufficiently large length and width with respect to the thickness, the amount of moisture absorption changes substantially in proportion to the thickness. In the present specification, the moisture absorption of the transparent base material is the moisture absorption when the thickness of the transparent base material is 50 μm.

The thickness of the transparent base material is preferably 20 μm to 200 μm, more preferably 30 μm to 100 μm.

A-1-2. Transparent electrode layer The transparent electrode layer can be formed by using, for example, a metal oxide such as indium tin oxide (ITO), zinc oxide (ZnO), and tin oxide (SnO _2). In this case, the metal oxide may be an amorphous metal oxide or a crystallized metal oxide.

The transparent electrode layer can also be formed of metal nanowires such as silver nanowires (AgNW), carbon nanotubes (CNTs), organic conductive films, metal layers or laminates thereof.

The transparent electrode layer may be patterned in a desired shape according to the purpose.

The thickness of the transparent electrode layer is preferably 0.01 μm to 0.10 μm, and more preferably 0.01 μm to 0.045 μm.

A-1-3. PDLC layer The PDLC layer typically has a structure in which droplets of a liquid crystal compound are dispersed in a resin matrix. In the PDLC layer, the orientation state of the liquid crystal compound changes according to the voltage applied between the transparent electrode layers, and this changes the scattering degree of the transmitted light to change the scattered state and the transparent state. You can switch.

In one embodiment, the PDLC layer becomes transparent when a voltage is applied, and becomes a scattered state when no voltage is applied (normal mode). In this embodiment, when no voltage is applied, the liquid crystal compound is not oriented, so that it is in a light scattering state. When the voltage is applied, the liquid crystal compound is oriented and the refractive index of the liquid crystal compound and the refractive index of the resin matrix are aligned. As a result, it becomes transparent.

In another embodiment, the PDLC layer becomes a scattered state when a voltage is applied, and becomes a transparent state when a voltage is not applied (reverse mode). In this embodiment, the alignment film provided on the surface of the transparent electrode layer causes the liquid crystal compound to be oriented and becomes transparent when no voltage is applied, and the orientation of the liquid crystal compound is disturbed by the application of voltage to cause a scattered state.

The water content of the PDLC layer is typically 0.3 wt% or less, preferably 0.25 wt% or less, more preferably 0.2 wt% or less, still more preferably 0.15 wt% or less. If the water content in the PDLC layer exceeds 0.3 wt%, the current value when a voltage is applied may increase and the power consumption may increase, so that the effect of the present invention may not be obtained. The water content of the PDLC layer may also be 0.0 wt% or higher, for example 0.01 wt% or higher or 0.05 wt% or higher.

As the liquid crystal compound, any suitable non-polymerized liquid crystal compound is used. For example, nematic type, smectic type and cholesteric type liquid crystal compounds can be mentioned. From the viewpoint of achieving excellent transparency in the transmission mode, it is preferable to use a nematic liquid crystal compound. Examples of the nematic liquid crystal compound include biphenyl compounds, phenylbenzoate compounds, cyclohexylbenzene compounds, azoxybenzene compounds, azobenzene compounds, azomethine compounds, terphenyl compounds, biphenylbenzoate compounds, and cyclohexylbiphenyl compounds. , Phenylpyridine compounds, cyclohexylpyrimidine compounds, cholesterol compounds and the like.

The average particle size of the liquid crystal compound droplets when viewed from the direction perpendicular to the main surface of the PDLC layer is, for example, 2 μm to 10 μm, preferably 3 μm to 9 μm. The average particle size of the droplets of the liquid crystal compound is the volume average particle size.

The content ratio of the liquid crystal compound in the PDLC layer is, for example, 10% by weight or more, preferably 30% by weight or more, more preferably 35% by weight or more, still more preferably 40% by weight or more. The content ratio is, for example, 90% by weight or less, preferably 70% by weight or less.

The resin forming the resin matrix can be appropriately selected according to the light transmittance, the refractive index of the liquid crystal compound, and the like. Examples thereof include water-soluble resins such as urethane-based resins, polyvinyl alcohol-based resins, polyethylene-based resins, polypropylene-based resins, and acrylic-based resins, or water-dispersible resins.

The content ratio of the matrix resin in the PDLC layer is, for example, 90% by weight or less, preferably 70% by weight or less, more preferably 65% by weight or less, still more preferably 60% by weight or less. The content ratio is, for example, 10% by weight or more, preferably 30% by weight or more.

The thickness of the PDLC layer is preferably 2 μm to 30 μm, more preferably 3 μm to 20 μm, and even more preferably 5 μm to 15 μm.

A-2. Low Moisture Permeability Base Material The low moisture permeability base material prevents moisture from penetrating the base material with the transparent electrode layer and invading the PDLC layer, and as a result, keeps the water content of the PDLC layer within a predetermined range. Can contribute to doing so.

Moisture permeability of low moisture permeability substrate, for example, 40 ° C. or less 0.01g ^/ m 2 ^/ 24h under 90% RH environment, preferably not more than 0.005g ^/ m 2 ^/ 24h, more preferably 0.001 g / It can be m ² / 24h or less. When the moisture permeability of the low moisture permeability base material is within the above range, the effect of the present invention can be more preferably obtained.

The low moisture permeability base material may have any suitable composition as long as it has a desired moisture permeability. The low moisture permeability base material may be, for example, a single-layer base material or a laminated body having two or more layers.

As the single-layer low moisture-permeable base material, a glass base material can be preferably exemplified. Examples of the glass constituting the glass base material include soda-lime glass, borosilicate glass, aluminosilicate glass, quartz glass and the like according to the classification according to the composition. Further, according to the classification according to the alkaline component, non-alkali glass and low-alkali glass can be mentioned.

The thickness of the glass substrate is, for example, 10 μm or more, preferably 50 μm to 3000 μm, and more preferably 50 μm to 2000 μm. When the thickness of the glass base material is within the above range, it is possible to more preferably prevent the PDLC layer from absorbing moisture, and it is possible to prevent the workability when being attached to the window frame or the like from being lowered due to the increase in weight. obtain.

Examples of the low-moisture-permeable base material which is a laminated body include a resin base material having a water barrier membrane having a resin base material and a water barrier membrane provided on one side or both sides thereof.

Examples of the thermoplastic resin forming the resin base material include cycloolefin resins such as polynorbornene; acrylic resins; polyester resins such as polyethylene terephthalate; polycarbonate resins; cellulose resins and the like.

The thickness of the resin base material is, for example, 20 μm to 200 μm, preferably 30 μm to 100 μm.

Moisture barrier film, for example, silicon oxide _(SiO X), silicon nitride _(SiN X), silicon oxynitride (SiON) and aluminum oxide (AlO) the inorganic material chemical vapor deposition such as chemical vapor deposition (CVD) or atomic layer deposition It can be formed by forming a film on a resin substrate using the (ALD) method or the like.

The thickness of the moisture barrier membrane is, for example, 0.05 μm to 5 μm, preferably 0.1 μm to 2 μm.

A-3. Encapsulation The encapsulation can prevent moisture from entering from the edges of the PDLC film and, as a result, can contribute to keeping the moisture content of the PDLC layer within a predetermined range.

Moisture permeability of the sealing portion is not more than 0.1g ^/ m 2 ^/ 24h under example 40 ° C. 90% RH environment, preferably 0.05g ^/ m 2 ^/ 24h or less, more preferably 0.01 g / ^{m 2} It can be less than / 24h. When the moisture permeability of the sealing portion is within the above range, the effect of the present invention can be more preferably obtained.

The thickness of the sealing portion is, for example, 1 μm to 1000 μm, preferably 10 μm to 100 μm.

As the material for forming the sealing portion, any suitable material can be used as long as the desired moisture permeability can be obtained. For example, a curable resin composition such as an epoxy resin, a polyester resin, an acrylic resin, an amide resin, a silicone resin, or a urethane resin is applied to the sealing portion so as to cover the peripheral edge of the PDLC film. And can be formed by curing.

A-4. Low Moisture Permeable Adhesive Layer The low moisture permeable adhesive layer prevents moisture from penetrating the substrate with the transparent electrode layer and invading the PDLC layer, and as a result, keeps the moisture content of the PDLC layer within a predetermined range. Can contribute to doing so.

Moisture permeability of low moisture permeability adhesive layer is, for example 40 ° C. or less 0.1g ^/ m 2 ^/ 24h under 90% RH environment, preferably not more than 0.05g ^/ m 2 ^/ 24h, more preferably 0.01 g / It can be m ² / 24h or less. When the moisture permeability of the low moisture permeability adhesive layer is within the above range, the effect of the present invention can be more preferably obtained.

The thickness of the low moisture-permeable adhesive layer is, for example, 1 μm to 1000 μm, preferably 10 μm to 100 μm.

As the material for forming the low moisture permeability adhesive layer, any adhesive composition and pressure-sensitive adhesive composition can be used as long as the desired moisture permeability can be obtained.

In one embodiment, the low moisture permeable adhesive layer can be formed by a hot melt adhesive. Examples of the hot melt adhesive include ethylene vinyl acetate (EVA) type hot melt adhesives, olefin type hot melt adhesives, acrylic type hot melt adhesives and the like. Of these, EVA-based hot melt adhesives can be preferably used because good adhesion can be obtained.

B. PDLC Panel Manufacturing Method The PDLC panel manufacturing method according to the embodiment of the present invention is as follows.
On the surface of the first transparent electrode layer-attached base material having the transparent base material and the transparent electrode layer provided on one side of the transparent base material, polymer particles and liquid crystal particles are contained in an aqueous solvent. To form a coating layer by applying an emulsion in which the particles are dispersed (step I),
The coating layer is dried to form a PDLC layer (step II).
On the PDLC layer, a base material with a second transparent electrode layer having a transparent base material and a transparent electrode layer provided on one side of the transparent base material is provided, and the surface on the transparent electrode layer side is the PDLC layer. Laminating them so as to face each other to obtain a laminated body (step III), and subjecting the laminated body to heat treatment to reduce the water content in the PDLC layer to 0.3 wt% or less (step IV). Including, preferably
^{0.01 g / m 2} on the transparent substrate side surface of the first transparent electrode layered substrate and the second transparent electrode layered substrate of the laminated body after the heat treatment in an environment where the moisture permeability is 40 ° C. and 90% RH. Further comprising laminating a low moisture permeable substrate of 24 hours or less (step V). According to the above manufacturing method, the PDLC panel according to Item A can be preferably obtained.

Conventionally, the PDLC layer obtained by applying and drying an emulsion in which polymer particles and liquid crystal particles are dispersed in an aqueous solvent is from the viewpoint of ensuring adhesion to a substrate with a transparent electrode layer laminated on the emulsion layer. , Made by drying to a relatively high water content. On the other hand, in the above-mentioned production method, the water content is controlled within a predetermined range by further subjecting the PDLC layer, which has been dried once and sandwiched between the base materials with the transparent electrode layer, to heat treatment. As a result, the PDLC panel according to item A can be preferably obtained, and as a result, a PDLC device capable of driving with low power consumption can be preferably obtained. Hereinafter, each step will be specifically described.

B-1. Process I
In step I, a polymer in an aqueous solvent is placed on the surface of the first transparent electrode layer-attached base material having the transparent base material and the transparent electrode layer provided on one side of the transparent base material on the transparent electrode layer side surface. An emulsion in which particles and liquid crystal particles are dispersed (hereinafter, may be referred to as an emulsion coating liquid) is applied to form a coating layer.

The first base material with a transparent electrode layer is obtained by forming a transparent electrode layer on one side of the transparent base material by, for example, sputtering. After forming a metal oxide layer by sputtering, it can be crystallized by annealing. Annealing is performed, for example, by heat treatment at 120 ° C. to 300 ° C. for 10 minutes to 120 minutes. The transparent base material and the transparent electrode layer are as described in Section A.

The polymer particles and liquid crystal particles contained in the emulsion coating liquid may be water-dispersible resin or water-soluble resin and liquid crystal compound particles (droplets) exemplified as the matrix-forming resin according to Item A, respectively.

The emulsion coating liquid can be obtained by mixing a resin emulsion in which polymer particles are dispersed in an aqueous solvent and a liquid crystal emulsion in which liquid crystal particles are dispersed in an aqueous solvent. If necessary, any suitable aqueous solvent or additive (for example, dispersant, surface conditioner) may be further added at the time of mixing. Alternatively, the emulsion coating liquid can also be prepared by adding a liquid crystal compound and a water-dispersible resin to an aqueous solvent and mechanically dispersing them. As the aqueous solvent, water or a mixed solvent of water and a water-miscible organic solvent can be typically used.

The solid content concentration of the emulsion coating liquid can be, for example, 50% by weight to 90% by weight, preferably 60% by weight to 80% by weight.

Any appropriate method can be adopted as the coating method of the emulsion coating liquid. For example, a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, a die coating method, a curtain coating method, a spray coating method, a knife coating method (comma coating method, etc.) and the like can be mentioned. Further, the coating thickness can be appropriately set according to the thickness desired for the PDLC layer.

B-2. Process II
In step II, the coating layer is dried to form a PDLC layer. Specifically, by drying the coating layer to remove the aqueous solvent, the polymer particles are fused to each other to form a resin matrix, and as a result, the liquid crystal particles are dispersed in the resin matrix PDLC. Layers are formed.

In one embodiment, the water content of the PDLC layer formed in step II exceeds 0.5 wt%, preferably 0.6 wt% or more, more preferably 0.8 wt% to 2 wt%, still more preferably 0. It can be between 8 wt% and 1 wt%. If the water content is low, the adhesion to the second transparent electrode layered base material laminated in step III may be insufficient.

The drying temperature and drying time can be appropriately set according to the thickness of the coating layer, the concentration of the emulsion coating liquid, and the like. The drying temperature can be, for example, 20 ° C to 80 ° C, preferably 25 ° C to 50 ° C. The drying time can be, for example, 1 minute to 120 minutes, preferably 5 minutes to 30 minutes.

B-3. Step III
In step III, a base material with a second transparent electrode layer having a transparent base material and a transparent electrode layer provided on one side of the transparent base material is placed on the PDLC layer on the surface on the transparent electrode layer side. Is laminated so as to face the PDLC layer to obtain a laminated body. The obtained laminate has a structure of [transparent base material / transparent electrode layer / PDLC layer / transparent electrode layer / transparent base material]. The lamination can be performed while applying a laminating pressure using a laminator from the viewpoint of obtaining sufficient adhesion.

The same description as for the first transparent electrode layered base material can be applied to the second transparent electrode layered base material. The first transparent electrode layered base material and the second transparent electrode layered base material may have the same configuration or different configurations.

B-4. Process IV
In step IV, the laminate is subjected to heat treatment to reduce the water content in the PDLC layer to 0.3 wt% or less. The heat treatment is preferably performed so that the water content in the PDLC layer is 0.25 wt% or less, more preferably 0.2 wt% or less.

The heat treatment can be performed, for example, by placing the laminate in a heating environment. The heating temperature and heating time can be appropriately set according to the desired water content. The heating temperature can be, for example, 40 ° C. to 90 ° C., preferably 50 ° C. to 80 ° C., and more preferably 50 ° C. to 70 ° C. The heating time is, for example, 1 hour or more, preferably 3 hours or more, more preferably 5 hours or more, still more preferably 10 hours or more, still more preferably 30 hours or more, still more preferably 50 hours or more, still more preferably 70. It can be more than an hour. The upper limit of the heating time can be, for example, 150 hours or less, preferably 100 hours or less, from the viewpoint of production efficiency.

B-5. Process V
In step V, the moisture permeability of the laminated body (PDLC film) after the heat treatment is 40 ° C. and 90% on the surface of the base material with the first transparent electrode layer and the base material with the second transparent electrode layer on the transparent base material side. A low moisture permeable base material having a pressure of 0.01 g / m ^{2 / 24h or less is bonded under an RH environment.}

The bonding between the first transparent electrode layered base material or the second transparent electrode layered base material and the low moisture permeability base material can be performed via any suitable adhesive layer. The adhesive layer is preferably a low moisture permeability adhesive layer. The low moisture permeable base material and the low moisture permeable adhesive layer are as described in Section A.

When the adhesive layer is formed by a hot melt adhesive, the bonding is performed on a PDLC film having the composition of [base material with first transparent electrode layer / PDLC layer / base material with second transparent electrode layer]. A hot melt adhesive and a low moisture permeability base material (preferably a glass base material) are laminated in this order on both sides, and [low moisture permeability base material / hot melt adhesive / PDLC film / hot melt adhesive / low moisture permeability This can be done by producing a laminate having the composition of [base material] and hot-pressing the laminate.

The bonding between the first transparent electrode layered base material or the second transparent electrode layered base material and the low moisture permeability base material is preferably carried out within 120 minutes, more preferably within 60 minutes after the heat treatment in step IV. It is said. When left at room temperature for a long time after the heat treatment, the PDLC layer can absorb moisture through the base material with the transparent electrode layer.

B-6. Other Steps The above manufacturing method may further include additional steps other than steps I to V, if necessary. Examples of the additional step include a step of forming a sealing portion, a step of manufacturing an electrode, and the like. The formation of the sealing portion is preferably performed after step V. The production of the electrode may be performed before or after the step V, but is preferably performed after the step V.

The electrode can be formed on a transparent electrode layer exposed at the extending portion by extending a part of the PDLC film outward from the low moisture permeable base material. For example, as shown in FIG. 4, a part of the PDLC film 100 is extended outward from the low moisture permeability base material 102a (102b), and in the extending portion, one base material with a transparent electrode layer and PDLC Remove the layer. As a result, the transparent electrode layer 20b (20a) of the other base material with the transparent electrode layer is exposed, and an electrode is formed on the exposed transparent electrode layer.

C. PDLC device FIG. 5 is a schematic front view of the PDLC device 200 according to one embodiment of the present invention, and FIG. 6 is a schematic cross-sectional view taken along the line AA of the PDLC device shown in FIG. The PDLC device 200 is a flat and rectangular device. The PDLC device 200 has a rectangular PDLC panel 110, and by driving the PDLC panel 110, it is possible to switch between a transparent state in which light is transmitted and a scattering state in which light is scattered.

The PDLC device 200 can function as a blind shutter for the window 300 by being attached to the window 300. For example, the PDLC panel 110 in the normal mode is in a scattered state when no drive voltage is applied, and is completely whitened. Therefore, one side in the depth direction (Y-axis direction in the figure). Although the other side cannot be visually recognized from the above, it becomes transparent by applying a driving voltage, and the depth direction can be visually recognized.

As shown in FIG. 5, the PDLC device 200 includes a PDLC panel 110, a frame 120, a battery 130, and a drive circuit 140.

The PDLC panel 110 is the PDLC panel according to item A, and is a flat plate-shaped and rectangular member in the present embodiment. As shown in FIGS. 5 and 6, the PDLC panel 110 has an outer peripheral edge sandwiched by a frame 120.

The frame 120 is a frame-shaped member provided with a constant width and a constant thickness along the outer peripheral edge of the PDLC panel 110 (that is, the four sides of the PDLC panel 110). The external dimensions of the frame 120 are substantially the same as the internal dimensions of the sash 310 as the window frame included in the window 300. As a result, the PDLC device 200 can be easily attached to the window 300 in a state of being overlapped with the window glass 320 included in the window 300 by being fitted inside the sash 310.

The battery 130 supplies a DC voltage to the drive circuit 140. The battery 130 may be a primary battery or a secondary battery. As the secondary battery, various secondary batteries such as a lithium ion battery and a lithium polymer battery can be used.

As described in item A, the PDLC panel 110 is driven by applying a DC voltage because the water content in the PDLC layer is adjusted to a predetermined range and the resistance at the time of applying a voltage can be increased. Power consumption can be reduced.

The drive circuit 140 generates a drive voltage for the PDLC panel 110. Specifically, the drive circuit 140 generates a DC drive voltage higher than the voltage generated by the battery 130. The drive circuit 140 drives the PDLC panel 110 by applying the generated drive voltage between the pair of transparent electrode layers 20a and 20b.

The drive circuit 140 is electrically connected to the transparent electrode layers 20a and 20b of the PDLC panel 110 by wiring (not shown). Specifically, a part of the transparent electrode layers 20a and 20b is exposed to form an exposed portion, an electrode is formed in the exposed portion, and the electrode and the drive circuit are connected via wiring. As a result, a drive voltage can be applied from the drive circuit 140 to the transparent electrode layers 20a and 20b.

The drive circuit 140 may be configured to generate a DC drive voltage whose polarity changes periodically. By applying a DC voltage whose polarity is periodically reversed, low power consumption and stable driving become possible. The polarity reversal period can be, for example, 1 second or more and 2 hours or less, preferably 1 second or more and 1 hour or less, and more preferably 1 second or more and 30 minutes or less.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. Unless otherwise specified, "parts" and "%" in the examples are based on weight.

≪Measurement of water content≫
The water content was measured using a Karl Fischer titer. Specifically, the sample ^{was cut into 5 cm 2} (1 cm × 5 cm) and stored under each condition. Then, the sample is separated into a laminate of [PET / ITO] and [PDLC / ITO / PET], each is weighed, put into a heated vaporization section, and the gas generated at 150 ° C. is introduced into the titration cell to introduce the water content. Was measured. The water content of the PDLC layer was determined by subtracting the water content of the [PET / ITO] laminate from the water content of the [PDLC / ITO / PET] laminate.
Coulometric titration type moisture measuring device: Mitsubishi Chemical Analytech, CA-200 type Heat vaporizer: Mitsubishi Chemical Analytech, VA-200 type Method: Heat vaporization method / 150 ° C
≪Measurement of thickness≫
The spectroscopic interference method was used for the film thickness measurement. The film thickness was obtained by analyzing a peculiar spectrum depending on the film thickness by injecting white light into the sample.
≪Measurement of moisture permeability≫
The moisture permeability was measured in accordance with JIS standard K7129.

[Example 1]
(Preparation of base material with transparent electrode layer)
By forming an ITO film on one side of a PET film having a thickness of 188 μm by sputtering, a first transparent electrode layered base material and a second transparent electrode-based base material were obtained.

(Preparation of emulsion coating liquid)
50 parts by weight of an aqueous aliphatic polyurethane latex (manufactured by Geneca, trade name "Neorez R-967", including 35% by weight of latex particles) is added to 50 parts by weight of a liquid crystal compound (manufactured by Chisso, trade name "JM1000XX"). After that, the mixture was stirred with an Excel autohomogenizer (manufactured by Nippon Seiki Co., Ltd.) while maintaining the stirring portion at 40 ° C. to obtain an emulsion coating liquid. The viscosity of the emulsion coating liquid was 65 mPas.

(Preparation of PDLC film)
An emulsion coating solution was applied to the surface of the ITO film of the base material with the first transparent electrode layer and dried at 25 ° C. for 10 minutes to form a PDLC layer having a thickness of 24 μm. On the obtained PDLC layer, a base material with a second transparent electrode layer was laminated so that the ITO film side faced the PDLC layer, so that they were brought into close contact with each other. As a result, a PDLC film was obtained. In the obtained PDLC film, the water content of the PDLC layer was 1.0 wt%.

(Heat treatment)
The obtained PDLC film was subjected to heat treatment at 70 ° C. for 3 days. In the PDLC film after the heat treatment, the water content of the PDLC layer was 0.24 wt%.

(Lumber with low moisture permeability)
Immediately after the heat treatment, the EVA hot melt resin and the glass base material (thickness 1000 μm) were placed on both sides of the PDLC film in this order, and heat pressing was performed to obtain [glass base material / adhesive layer / PDLC film / adhesive layer]. A PDLC panel having the composition of [/ glass substrate] was obtained. The thickness of the adhesive layer formed from the EVA hot melt resin was 40 μm, and the moisture permeability was 0.01 g / m ² / 24h under a 90 ° C. 90% RH environment.

(Formation of sealing part)
A curable epoxy resin composition (manufactured by ThreeBond Co., Ltd., product name "TB2022") is applied to the peripheral edge of the PDLC film of the PDLC panel so that the ends are flush with each other, and the sealing portion is cured. Was formed. The thickness of the formed sealing portion was 100 μm, and the moisture permeability was 0.01 g / m ² / 24h under a 90% RH environment at 40 ° C.

(Manufacturing of PDLC device)
An electrode was prepared on the PDLC panel according to a conventional method, and a drive circuit and a battery were connected to obtain a PDLC device 1. The drive circuit is configured to boost the DC voltage of 1.5 V supplied from the battery and apply a DC voltage of 70 V between the transparent electrodes while reversing the polarity at a 1-minute cycle.

[Example 2]
PDLC apparatus 2 was obtained in the same manner as in Example 1 except that the sealing portion was not formed.

[Example 3]
PDLC devices 3A and 3B were obtained in the same manner as in Example 1 except that the glass substrates were not bonded to both sides of the PDLC film.

[Example 4]
PDLC devices 4A and 4B were obtained in the same manner as in Example 1 except that the glass substrates were not bonded to both sides of the PDLC film and the sealing portion was not provided.

[Example 5]
PDLC devices 5A and 5B were used in the same manner as in Example 1 except that a PET film having a thickness of 50 μm was used instead of the PET film having a thickness of 188 μm and glass substrates were not bonded to both sides of the PDLC film. Obtained.

[Example 6]
Example 1 and Example 1 except that a PET film having a thickness of 50 μm was used instead of the PET film having a thickness of 188 μm, glass substrates were not attached to both sides of the PDLC film, and a sealing portion was not formed. Similarly, PDLC devices 6A and 6B were obtained.

[Example 7]
By subjecting a commercially available PDLC device (manufactured by Becat Co., Ltd., “Kasmy”) to heat treatment at 70 ° C. for 3 days, and then providing a sealing portion for sealing the end portion of the PDLC film in the same manner as in Example 1. , PDLC devices 7A and 7B were obtained. The water content of the PDLC layer after the heat treatment was 0.26 wt%.

[Example 8]
PDLC devices 8A and 8B were obtained by subjecting a commercially available PDLC device (manufactured by Becat Co., Ltd., "Kasmy") to heat treatment at 70 ° C. for 3 days.

≪Drive reliability test≫
The PDLC apparatus was continuously driven by applying a DC voltage of 70 V while reversing the polarity at a cycle of 1 minute in an environment of 40 ° C. and 90% RH. The initial current value and the current value after driving for 120 hours were measured with a multimeter. The results are shown in FIG.

As shown in FIG. 7, the initial current values of all the PDLC devices of Examples 1 to 8 in which the water content of the PDLC layer was reduced by heat treatment were extremely low, and low power consumption was realized. In particular, the PDLC devices of Examples 1 and 2 in which the water content of the PDLC layer is reduced by heat treatment and glass substrates are provided on both sides of the PDLC film are extremely low, which is equal to or less than the initial level even after 120 hours of continuous driving. It shows the current value, and from this, it can be seen that it can be driven with low power consumption for a long time. On the other hand, in the PDLC devices of Examples 3 to 8 in which the PDLC film is not sandwiched between glass substrates, the initial current value is low and low power consumption is realized, but the PDLC device is passed through the base material with a transparent electrode layer over time. As a result of the PDLC layer absorbing moisture, it is considered that the current value after 120 hours has increased.

[Test Example 1]
The PDLC film before heat treatment produced in Example 1 was cut into a size of 100 m × 100 m and used as a measurement sample (N = 3). The measurement sample was placed in an oven at 70 ° C., heated for 190 hours, and then the weight when left at room temperature and the current value when DC70V was applied were measured over time. The initial weight of the measurement sample was 5.8 g. The current value was measured on a sample that had returned to room temperature by being taken out of the oven and left for 5 minutes. The results are shown in FIG.

As shown in FIG. 8, the sample weight decreased sharply from the time the oven was put into the oven to about 10 hours. The decrease in sample weight continued slowly thereafter, and tended to saturate after about 60 hours. The same tendency is seen for the current value, and the current value decreases sharply within about 10 hours after being put in the oven, and the decrease in the current value tends to saturate after about 60 hours have passed. rice field. In addition, after taking it out of the oven and returning it to room temperature, the weight gradually increased, and the current value tended to recover accordingly. From this, the current value decreases (as a result, the resistance value increases) due to the decrease in the water content in the PDLC layer due to the heat treatment, and the current value due to the PDLC layer absorbing moisture after the heat treatment. Can be recovered (as a result, the resistance value decreases).

[Test Example 2]
(Sample 1)
PDLC film in the same manner as in Example 1 except that a PET film having a thickness of 50 μm (humidity absorption under a 90 ° C. and 90% RH environment: 0.2 wt% / 24 h) was used instead of the PET film having a thickness of 188 μm. Was produced. The obtained PDLC film was heat-treated at 70 ° C. for 120 hours. Next, an electrode was produced by cutting out into a size of 50 m × 50 m.

(Sample 2)
Same as Example 1 except that a cycloolefin (COP) film having a thickness of 50 μm (humidity absorption at 40 ° C. and 90% RH environment: 0.2 wt% / 24 h) was used instead of the PET film having a thickness of 188 μm. To prepare a PDLC film with electrodes.

(Sample 3)
A PDLC film with electrodes was produced in the same manner as in Example 1 except that a glass film having a thickness of 50 μm was used instead of the PET film having a thickness of 188 μm.

(Sample 4)
The same as in Example 1 except that a PET film with a moisture barrier film (moisture permeability under a 40 ° C. 90% RH environment: 0.0001 g / m ^{2 / 24h) was used instead of the PET film having a thickness of 188 μm.} , A PDLC film with electrodes was prepared. A silicon nitride film was used as the moisture barrier film.

The PDLC films with electrodes of the above samples 1 to 4 were placed in an oven at 70 ° C. and further subjected to heat treatment. When the heat treatment time was 0 hour, 24 hours, and 48 hours, the PDLC film with electrodes was connected to the drive circuit and the battery to drive, and the current value at that time was measured with a multimeter. The current value was measured on the PDLC film that had returned to room temperature by being taken out of the oven and left for 5 minutes. The results are shown in FIG.

As shown in FIG. 9, the current value of the PDLC film (Samples 1 and 2) using the transparent substrate having high moisture absorption is as low as about 25 μA immediately after the start of the heat treatment, and is 10 μA or less after 24 hours. rice field. On the other hand, the current value of the PDLC film (Samples 3 and 4) using the transparent substrate having low moisture permeability was a value exceeding 200 μA immediately after the start of the heat treatment, and was a high value exceeding 100 μA even after 48 hours. From this, it can be seen that the effect of removing water from the PDLC layer by heat treatment can be preferably obtained by using a transparent base material having high moisture absorption (moisture permeability). Further, considering the results of Examples 1 to 8 together, a PDLC film is prepared using a transparent substrate having high moisture absorption (moisture permeability), and the PDLC film is heat-treated to remove water from the PDLC layer. Therefore, it can be seen that the PDLC layer can be maintained in a state of low water content for a long time by providing low moisture permeability substrates on both sides thereof.

The present invention can be suitably used for a light control film or the like.

10 Transparent base material 20 Transparent electrode layer 30 PDLC layer 100 PDLC film 102 Low moisture permeability base material 104 Sealing part 110 PDLC panel 120 Frame 130 Battery 140 Drive circuit 200 PDLC device

Claims (13)

1. A polymer having a pair of transparent substrates, a pair of transparent electrode layers provided between the pair of transparent substrates, and a polymer-dispersed liquid crystal layer provided between the pair of transparent electrode layers. Including distributed LCD film,
   A polymer-dispersed liquid crystal panel in which the water content of the polymer-dispersed liquid crystal layer is 0.3 wt% or less.
2. On the side of the polymer-dispersed liquid crystal film opposite to the side where the transparent electrode layer of the pair of transparent substrates is provided, the moisture permeability is 0.01 g / m ² / 24h or less in a 90% RH environment at 40 ° C. The polymer-dispersed liquid crystal panel according to claim 1, wherein a pair of low-moisture-permeable substrates are arranged.
3. The polymer-dispersed liquid crystal panel according to claim 2, wherein the low-moisture-permeable base material is a glass base material.
4. The polymer-dispersed liquid crystal panel according to claim 3, wherein the thickness of the glass substrate is 10 μm or more.
5. The polymer-dispersed liquid crystal panel according to claim 2, wherein the low-moisture-permeable base material is a resin base material with a moisture barrier film.
6. Further including a sealing portion arranged so as to cover the end portion of the polymer-dispersed liquid crystal film,
   The polymer-dispersed liquid crystal panel according to any one of claims 2 to 5, wherein the sealing portion has a moisture permeability of 0.1 g / m ^{2 / 24h or less under a 90% RH environment at 40 ° C.}
7. Said transparent substrate, wherein the a low moisture permeability substrate, and the moisture permeability is bonded via a low moisture permeability adhesive layer is not more than 0.1gg / m 2 / ^24h under 40 ° C. 90% RH environment , The polymer-dispersed liquid crystal panel according to any one of claims 2 to 6.
8. The polymer-dispersed liquid crystal panel according to any one of claims 1 to 7, wherein the transparent substrate has a humidity absorption of 0.1 wt% / 24 hours or more in a 90 ° C. 90% RH environment.
9. The polymer-dispersed liquid crystal panel according to any one of claims 1 to 8, wherein the transparent base material contains a polyethylene terephthalate resin.
10. The polymer-dispersed liquid crystal panel according to any one of claims 1 to 8, wherein the transparent substrate contains a cycloolefin-based resin.
11. The polymer-dispersed liquid crystal panel according to any one of claims 1 to 10 and
    A drive circuit that puts the polymer-dispersed liquid crystal layer into a non-scattering state or a scattered state by applying a voltage between the pair of transparent electrode layers constituting the polymer-dispersed liquid crystal panel.
    A polymer-dispersed liquid crystal display including a power supply that supplies a DC voltage to the drive circuit.
12. On the surface of the first transparent electrode layer-attached base material having the transparent base material and the transparent electrode layer provided on one side of the transparent base material, polymer particles and liquid crystal particles are contained in an aqueous solvent. To form a coating layer by applying an emulsion in which the particles are dispersed,
    The coating layer is dried to form a polymer-dispersed liquid crystal layer.
    On the polymer-dispersed liquid crystal layer, a base material with a second transparent electrode layer having a transparent base material and a transparent electrode layer provided on one side of the transparent base material is provided on the surface of the transparent electrode layer side. The laminate is laminated so as to face the polymer-dispersed liquid crystal layer to obtain a laminate, and the laminate is subjected to heat treatment to reduce the water content in the polymer-dispersed liquid crystal layer to 0.3 wt% or less. To
    A method for manufacturing a polymer-dispersed liquid crystal panel, including the above.
13. 0.01 g of the first transparent electrode layered base material and the second transparent electrode layered base material of the heat-treated laminate on the transparent base material side surface at a moisture permeability of 40 ° C. and 90 RH environment%. Further including laminating a low moisture permeable substrate of / m ^{2 / 24h or less,}
    The method for manufacturing a polymer-dispersed liquid crystal panel according to claim 12, wherein the low-moisture-permeable base material is bonded within 60 minutes after the completion of the heat treatment.
    

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