Polymer-dispersed liquid crystal film

Abstract

To provide a polymer-dispersed liquid crystal film with which it is possible to switch between a transparent state and a scattering state in only a prescribed region, and a polymer-dispersed liquid crystal film whose light fastness is improved.SOLUTION: Provided is a polymer-dispersed liquid crystal film that includes, in the order stated, a first conductive substrate, a polymer-dispersed liquid crystal layer that includes a polymer matrix and liquid crystal liquid drops and photoinitiator that are dispersed in the polymer matrix, and a second conductive substrate. The polymer-dispersed liquid crystal layer has, in a plan view, a first and a second region whose haze change amounts due to voltage application are different, the haze change amount in the first region due to voltage application being smaller than the haze change amount in the second region due to voltage application, the liquid crystal liquid drops in the second region including a polymerizable liquid crystal compound and a non-polymerizable liquid crystal compound, the liquid crystal liquid drops in the first region including a liquid crystal polymer, which is a polymer of the polymerizable liquid crystal compound, and a non-polymerizable liquid crystal compound, the first conductive substrate including an ultraviolet ray cut layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a polymer-dispersed liquid crystal film. [Background technology]

[0002] In recent years, dimmable films that exhibit different appearances depending on the applied voltage have been applied to various uses such as advertisements, signboards, smart windows, and other displays.

[0003] A PDLC film having a polymer dispersed liquid crystal (PDLC) layer between a pair of transparent electrode layers is a type of dimmable film that can switch between a state in which light is scattered (scattering state) and a state in which light is transmitted (non-scattering state or transparent state) by switching between a voltage applied state and a state in which no voltage is applied. Specifically, the PDLC layer contains a polymer matrix and droplets of liquid crystal compound dispersed in the polymer matrix (liquid crystal droplets), and due to the difference in refractive index between the liquid crystal compound in the liquid crystal droplets and the polymer matrix, the liquid crystal droplets can become scattering particles and cause light scattering.

[0004] The PDLC film described above generally exhibits a cloudy appearance in the scattering state, and can therefore exhibit two appearances: cloudy (scattered state) and transparent (non-scattered state). However, considering design aesthetics, there is a demand for dimmable films that can exhibit other appearances.

[0005] In relation to the above requirements, Patent Document 1 proposes a dichroic film that allows adjustment of the total amount of incident light. This dichroic film uses a dichroic substance instead of a liquid crystal compound, resulting in a film that appears transparent in a non-scattering state and colored in a scattering state. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2002-189123 [Overview of the project] [Problems that the invention aims to solve]

[0007] In conventional dimmable films, the switching between transparent and scattering states is performed across the entire film surface, and it was not possible to perform this switching only in a predetermined area.

[0008] The present invention was made to solve the above-mentioned conventional problems, and its primary objective is to provide a polymer-dispersed liquid crystal film that can switch between a transparent state and a scattering state only in a predetermined region, and a further objective is to improve the light resistance of such a polymer-dispersed liquid crystal film. [Means for solving the problem]

[0009] [1] A polymer-dispersed liquid crystal film according to an embodiment of the present invention comprises, in this order, a first conductive substrate, a polymer-dispersed liquid crystal layer comprising a polymer matrix, liquid crystal droplets dispersed in the polymer matrix and a photopolymerization initiator, and a second conductive substrate, wherein the polymer-dispersed liquid crystal layer has, in a plan view, a first region and a second region in which the amount of change in haze due to the application of a voltage is different, the amount of change in haze due to the application of a voltage in the first region is smaller than the amount of change in haze due to the application of a voltage in the second region, the liquid crystal droplets in the second region comprise a polymerizable liquid crystal compound and a nonpolymerizable liquid crystal compound, the liquid crystal droplets in the first region comprise a liquid crystal polymer which is a polymer of the polymerizable liquid crystal compound and the nonpolymerizable liquid crystal compound, and the first conductive substrate comprises an ultraviolet cut layer. [2] In the polymer-dispersed liquid crystal film described in [1] above, the absorbance of the ultraviolet-cutting layer at a wavelength of 350 nm may be 2 or more. [3] In the polymer-dispersed liquid crystal film described in [1] or [2] above, when the maximum absorption wavelength on the longest wavelength side of the photopolymerization initiator is Anm, the absorbance of the ultraviolet-cutting layer in the wavelength range of A-30nm to A+50nm may be 5 or more. [4] In the polymer-dispersed liquid crystal film described in any of [1] to [3] above, when the maximum absorption wavelength on the longest wavelength side of the photopolymerization initiator is Anm, the absorbance of the ultraviolet-cutting layer at a wavelength of A+70nm may be 1.8 or higher. [5] In the polymer-dispersed liquid crystal film described in any of [1] to [4] above, the photopolymerization initiator may have a maximum absorption wavelength in the range of 300 nm to 340 nm. [6] In the polymer-dispersed liquid crystal film described in any of [1] to [5] above, the second conductive substrate may include an ultraviolet-cutting layer or a reflective layer. [7] In the polymer-dispersed liquid crystal film described in any of [1] to [6] above, the weight ratio of the non-polymerizable liquid crystal compound to the polymerizable liquid crystal compound in the second region (non-polymerizable liquid crystal compound: polymerizable liquid crystal compound) may be 99:1 to 70:30. [8] In the polymer-dispersed liquid crystal film described in any of [1] to [7] above, the difference between the haze of the first region and the haze of the second region may increase by the application of voltage. [9] In the polymer-dispersed liquid crystal film described in any of [1] to [7] above, the difference between the haze of the first region and the haze of the second region may be reduced by the application of voltage. [Effects of the Invention]

[0010] According to embodiments of the present invention, within the liquid crystal droplets of the first region, the orientation of the liquid crystal compound is restricted by the liquid crystal polymer, resulting in suppression of haze changes caused by changes in the applied voltage. On the other hand, within the liquid crystal droplets of the second region, the orientation state of the liquid crystal compound changes according to the applied voltage, allowing for a significant change in haze. Therefore, by forming the first and second regions in a desired pattern, a light-adjustable film can be provided that exhibits an appearance with a predetermined pattern in either the case of applied voltage or no voltage, and an appearance with high uniformity in the other case. Furthermore, by including an ultraviolet-cutting layer in at least one of the pair of conductive substrates sandwiching the PDLC layer, the problem of liquid crystal polymer being generated within the liquid crystal droplets of the second region due to exposure to sunlight, etc., which reduces the amount of haze change in the second region, can be prevented, thereby improving light resistance. [Brief explanation of the drawing]

[0011] [Figure 1] (a) is a schematic plan view of an example of a PDLC film according to the first embodiment of the present invention, (b) is a schematic cross-sectional view illustrating the state of the PDLC film shown in (a) when no voltage is applied, and (c) is a schematic cross-sectional view illustrating the state of the PDLC film shown in (a) when voltage is applied. [Figure 2] This is a schematic cross-sectional view of an example of a first conductive substrate that can be used in a PDLC film according to an embodiment of the present invention. [Figure 3] (a) is a schematic plan view of an example of a PDLC film according to a second embodiment of the present invention, (b) is a schematic cross-sectional view illustrating the state of the PDLC film shown in (a) when no voltage is applied, and (c) is a schematic cross-sectional view illustrating the state of the PDLC film shown in (a) when voltage is applied. [Figure 4] This is a schematic diagram illustrating an example of a method for producing the PDLC film of the present invention. [Figure 5] This is a schematic diagram illustrating an example of a method for producing the PDLC film of the present invention. [Figure 6] This is a schematic cross-sectional view of a modified example of a PDLC film according to an embodiment of the present invention. [Figure 7] Schematic cross-sectional view of a modified example of a PDLC film according to an embodiment of the present invention. [Figure 8] Schematic cross-sectional view of an example of a reflective layer that can be used in a PDLC film according to an embodiment of the present invention. [Figure 9] Graph showing the light resistance evaluation results of the PDLC film of Comparative Example 1. [Figure 10] Graph showing the light resistance evaluation results of the PDLC films of Examples 1 to 3 and the absorption spectra of the ultraviolet cut layers used in the PDLC films. **Embodiments for Carrying Out the Invention**

[0012] Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to these embodiments. For the sake of clearer explanation, the drawings may schematically represent the width, thickness, shape, etc. of each part as compared with the embodiments, but this is merely an example and does not limit the interpretation of the present invention. Each embodiment can be appropriately combined unless such an understanding is clearly inappropriate from the context. Also, in this specification, "~" representing a numerical range includes the numerical values of its upper and lower limits.

[0013] A. Polymer Dispersed Liquid Crystal Film A polymer dispersed liquid crystal (PDLC) film according to an embodiment of the present invention includes a first conductive substrate, a polymer dispersed liquid crystal layer including a polymer matrix, liquid crystal droplets dispersed in the polymer matrix, and a photopolymerization initiator, and a second conductive substrate in this order. The first conductive substrate includes an ultraviolet cut layer. The polymer dispersed liquid crystal layer has a first region and a second region in which the amount of change in haze due to the application of voltage is different in a plan view, and the amount of change in haze due to the application of voltage in the first region is smaller than the amount of change in haze due to the application of voltage in the second region. The liquid crystal droplets in the second region include a polymerizable liquid crystal compound and a non-polymerizable liquid crystal compound. The liquid crystal droplets in the first region include a liquid crystal polymer that is a polymer of the polymerizable liquid crystal compound and the non-polymerizable liquid crystal compound.

[0014] A-1. PDLC film of the first embodiment Figure 1(a) is a schematic plan view of an example of a PDLC film according to the first embodiment of the present invention, (b) is a schematic cross-sectional view illustrating the state of the PDLC film shown in (a) when no voltage is applied, and (c) is a schematic cross-sectional view illustrating the state of the PDLC film shown in (a) when a voltage is applied. The PDLC film 100a includes, in this order, a first conductive substrate 10 including an ultraviolet cut layer 16, a PDLC layer 20 including a polymer matrix 22, liquid crystal droplets 24 dispersed in the polymer matrix 22 and a photopolymerization initiator 26, and a second conductive substrate 30. In a plan view, the PDLC layer 20 has a first region A and a second region B, where the amount of change in haze due to the application of voltage is different. The liquid crystal droplets 24 in the second region B include a polymerizable liquid crystal compound 24a and a non-polymerizable liquid crystal compound 24b. The liquid crystal droplets 24 in the first region A include a liquid crystal polymer 24c and a non-polymerizable liquid crystal compound 24b. Typically, the liquid crystal polymer 24c exists in an unoriented state. The photopolymerization initiator 26 is dispersed in the polymer matrix 22, and at least a portion of it is also contained in the liquid crystal droplets 24. In this specification, when a compound is said to be in a "non-oriented state," it means that the compound is not arranged in a certain regularity.

[0015] As shown in Figure 1(b), in the PDLC film 100a when no voltage is applied, both the non-polymerizable liquid crystal compound 24b and the liquid crystal polymer 24c in the liquid crystal droplets 24 in the first region A are in an unoriented state, and both the polymerizable liquid crystal compound 24a and the non-polymerizable liquid crystal compound 24b in the liquid crystal droplets 24 in the second region B are in an unoriented state. Therefore, scattering of transmitted light occurs in both regions. Thus, both the first region A and the second region B can be in a scattering state, and as a result, the entire main surface of the PDLC film 100a can be in a scattering state.

[0016] On the other hand, as shown in Figure 1(c), in the PDLC film 100a when voltage is applied, both the polymerizable liquid crystal compound 24a and the non-polymerizable liquid crystal compound 24b in the liquid crystal droplets 24 in the second region B are oriented perpendicular to the main surfaces of the first conductive substrate 10 and the second conductive substrate 30, and the scattering of transmitted light is suppressed, so the haze in that region decreases. On the other hand, in the first region A, the orientation of the non-polymerizable liquid crystal compound 24b is hindered by the presence of the non-oriented liquid crystal polymer 24c, and the non-oriented state is maintained, so scattering of transmitted light still occurs. Therefore, the amount of change in haze due to the application of voltage in the first region is smaller than the amount of change in the second region, and the difference between the haze in the first region and the haze in the second region increases with the application of voltage.

[0017] As described above, when no voltage is applied, the entire main surface of the PDLC film 100a is in a scattered state and exhibits a cloudy appearance. However, when a voltage is applied, only the haze in the second region decreases significantly, and the first region may become cloudy while the second region becomes transparent. Therefore, the PDLC film 100a can exhibit different appearances by switching between the application and absence of voltage.

[0018] The voltage applied to the PDLC film when voltage is applied is a voltage capable of operating the PDLC film (operating voltage), and may be, for example, 5V to 200V, preferably 10V to 100V. In this specification, "haze when voltage is applied" means the haze when the operating voltage is applied to the PDLC film, and may be, for example, the haze when a voltage of 5V or more, 10V or more, or 20V or more is applied.

[0019] The haze in the region of the PDLC film corresponding to the first region described above when no voltage is applied (hereinafter sometimes simply referred to as "haze of the first region") is, for example, 50% to 100%, preferably 70% to 100%. The haze in the first region when voltage is applied is, for example, 40% to 100%, preferably 60% to 100%. The amount of change in the haze of the first region due to the application of voltage (|haze when no voltage is applied - haze when voltage is applied|) is, for example, 0% to 40%, preferably 0% to 30%.

[0020] The haze in the region of the PDLC film corresponding to the second region described above when no voltage is applied (hereinafter sometimes simply referred to as "haze in the second region") is, for example, 50% to 100%, preferably 70% to 100%. The haze in the second region when voltage is applied is, for example, 1% to 20%, preferably 1% to 10%. The amount of change in the haze in the second region due to the application of voltage (|haze when no voltage is applied - haze when voltage is applied|) is, for example, 30% to 99%, preferably 60% to 99%.

[0021] The change in haze in the first region due to the application of voltage is smaller than the change in haze in the second region due to the application of voltage, and the difference is, for example, 10% to 99%, preferably 30% to 99%.

[0022] The total light transmittance of the region of the PDLC film corresponding to the first region when no voltage is applied (hereinafter sometimes simply referred to as "total light transmittance of the first region") is, for example, 50% to 95%, preferably 60% to 90%. The total light transmittance of the first region when voltage is applied is, for example, 50% to 95%, preferably 60% to 90%. The total light transmittance can be measured in accordance with JIS K 7361.

[0023] The total light transmittance of the region of the PDLC film corresponding to the second region described above when no voltage is applied (hereinafter sometimes simply referred to as "total light transmittance of the second region") is, for example, 50% to 95%, preferably 60% to 90%. The total light transmittance of the second region when voltage is applied is, for example, 70% to 95%, preferably 80% to 90%.

[0024] Under conditions of 30℃ and 55%RH, xenon light was applied at 120W / m². 2The change in haze Va (|haze with voltage applied - haze without voltage applied|) due to voltage application (e.g., 50V) in the second region after 125 hours of irradiation at (300nm-400nm) and the change in haze Vb due to voltage application (e.g., 50V) in the second region before irradiation satisfy, for example, the relationship (Vb-Va) / Vb×100≦5, and preferably the relationship (Vb-Va) / Vb×100≦3.

[0025] The thickness of the PDLC film is, for example, 30 μm to 250 μm, preferably 50 μm to 150 μm.

[0026] A-1-1. First conductive base material The first conductive substrate 10 includes a first transparent substrate 12, a first transparent electrode layer 14 provided on one side of the substrate, and an ultraviolet cut layer 16 provided on the other side. The first conductive substrate 10 may further have any suitable functional layers as needed. For example, the first conductive substrate 10 may have hard coat layers on one or both sides of the ultraviolet cut layer 16, or it may have a refractive index adjustment layer between the first transparent substrate 12 and the first transparent electrode layer 14. The first conductive substrate is positioned on the side of the PDLC film that is exposed to light including ultraviolet light (e.g., sunlight, light emitted from various light sources).

[0027] The surface resistance of the first conductive substrate on the first transparent electrode layer side is preferably 1Ω / □ to 1000Ω / □, more preferably 5Ω / □ to 300Ω / □, and even more preferably 10Ω / □ to 200Ω / □.

[0028] The haze value of the first conductive substrate is preferably 20% or less, more preferably 10% or less, and even more preferably 0.1% to 10%.

[0029] The total light transmittance of the first conductive substrate is preferably 30% or more, more preferably 60% or more, and even more preferably 80% or more.

[0030] The first transparent substrate 12 can be formed using any suitable material. Specifically, polymer substrates such as films and plastic substrates are preferably used. This is because they have excellent smoothness and wettability for the transparent electrode layer forming composition, and productivity can be greatly improved by continuous production using rolls.

[0031] The material constituting the first transparent substrate is typically a polymer film mainly composed of a thermoplastic resin. Examples of thermoplastic resins include polyester resins, cycloolefin resins such as polynorbornene, acrylic resins, polycarbonate resins, and cellulose resins. Among these, polyester resins, cycloolefin resins, or acrylic resins are preferred. These resins are excellent in terms of transparency, mechanical strength, thermal stability, and moisture shielding properties. The above thermoplastic resins may be used alone or in combination of two or more types. It is also possible to use optical films used in polarizing plates, such as low phase difference substrates, high phase difference substrates, phase difference plates, absorption polarizing films, and polarization selective reflection films, as the first transparent substrate.

[0032] The thickness of the first transparent substrate is preferably 200 μm or less, more preferably 3 μm to 100 μm, and even more preferably 5 μm to 70 μm. By setting the thickness of the first transparent substrate to 200 μm or less, the functionality of the PDLC layer can be fully exhibited.

[0033] The total light transmittance of the first transparent substrate is preferably 30% or more, more preferably 60% or more, and even more preferably 80% or more.

[0034] The first transparent electrode layer 14 can be formed using a metal oxide such as indium tin oxide (ITO), zinc oxide (ZnO), or tin oxide (SnO2). Preferably, a transparent electrode layer containing ITO is formed. A transparent electrode layer containing ITO has excellent transparency. The first transparent electrode layer can be patterned into a desired shape depending on the purpose.

[0035] The light transmittance of the first transparent electrode layer is preferably 85% or higher, more preferably 87% or higher, and even more preferably 90% or higher. By using a transparent electrode layer having a light transmittance within this range, high light transmittance is obtained in the transparent state. A higher light transmittance is preferable, but its upper limit is, for example, 99%.

[0036] Preferably, the first transparent electrode layer contains crystal grains. Including crystal grains can improve light transmittance. There are no limitations on the method of forming the crystal grains, but for example, crystal grains can be suitably formed by heating in air. The area occupancy rate of crystal grains in the transparent electrode layer is, for example, 30% or more, preferably 50% or more, and more preferably 80% or more. The upper limit of this area occupancy rate is, for example, 100%. If the area occupancy rate of crystal grains is within the above range, light transmittance can be improved. The area occupancy rate of crystal grains can be calculated by observing the surface of the transparent electrode layer with a transmission electron microscope (TEM) and taking the area ratio of the crystal grain region to the amorphous region.

[0037] The surface roughness Ra of the first transparent electrode layer is, for example, 0.1 nm or more. If the surface roughness Ra of the first transparent electrode layer is less than 0.1 nm, adhesion to the substrate may deteriorate. The upper limit of the surface roughness Ra of the first transparent electrode layer is preferably less than 1.2 nm, more preferably 1.0 nm or less, even more preferably less than 1.0 nm, and particularly preferably 0.8 nm or less. If the surface roughness Ra of the first transparent electrode layer is too large, it may become difficult to form suitable crystal grains. In this specification, surface roughness Ra refers to the arithmetic mean roughness Ra measured by AFM (Atomic Force Microscope).

[0038] The thickness of the first transparent electrode layer is, for example, 10 nm or more, preferably 15 nm or more. If the thickness of the first transparent electrode layer is less than 10 nm, the area occupancy rate of the crystal grains may decrease. The upper limit of the thickness of the first transparent electrode layer is, for example, 50 nm or less, preferably 35 nm or less, more preferably less than 30 nm, and even more preferably 27 nm or less. If the thickness of the first transparent electrode layer exceeds 50 nm, the transmittance may deteriorate, and the surface roughness of the first transparent electrode layer may increase.

[0039] The first transparent electrode layer is formed on one side of the first transparent substrate, for example, by sputtering. After forming the 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 to 120 minutes.

[0040] The UV-blocking layer 16 blocks at least a portion of ultraviolet light, for example, at least a portion of light with wavelengths of 300 nm to 380 nm. The absorbance of the UV-blocking layer at a wavelength of 350 nm is, for example, 2 or more, preferably 3 or more, more preferably 4 or more, even more preferably 5 or more, and for example, 8 or less.

[0041] In one embodiment, when the maximum absorption wavelength on the longest wavelength side of the photopolymerization initiator contained in the PDLC layer is Anm, the absorbance of the UV-cut layer over the entire wavelength range from A-30nm to A+50nm is, for example, 4.5 or higher, preferably 5 or higher, more preferably 5.5 or higher, even more preferably 6 or higher, and for example, 8 or lower. By having a high absorbance over a predetermined range including the maximum absorption wavelength on the longest wavelength side of the photopolymerization initiator in the UV-cut layer, the light resistance of the PDLC film can be suitably improved.

[0042] In one embodiment, when the maximum absorption wavelength on the longest wavelength side of the photopolymerization initiator contained in the PDLC layer is Anm, the absorbance of the UV-cut layer at a wavelength A+70nm is, for example, 1.8 or higher, preferably 2 or higher, and for example, 5 or lower. By having the UV-cut layer have an absorbance of a predetermined level or higher at a wavelength 70nm greater than the maximum absorption wavelength on the longest wavelength side of the photopolymerization initiator, the light resistance of the PDLC film can be suitably improved.

[0043] The UV-blocking layer transmits visible light. The minimum transmittance of the UV-blocking layer in the wavelength range of 450 nm to 600 nm is preferably 80% or higher, more preferably 85% or higher, and even more preferably 90% or higher.

[0044] The UV-blocking layer has any suitable configuration. For example, the UV-blocking layer may include a coating layer having UV-blocking properties, a resin film having UV-blocking properties, an adhesive layer having UV-blocking properties, etc., and may include one selected from these alone, or may include two or more selected from these so as a whole have the desired optical properties.

[0045] A coating layer having ultraviolet (UV) blocking ability (UV-blocking coating layer) can be formed directly on the surface of a first transparent substrate by, for example, applying a UV-blocking coating liquid containing an ultraviolet absorber and / or an ultraviolet reflector to the first transparent substrate. Alternatively, for example, the UV-blocking coating layer may be formed by applying a UV-blocking coating liquid to the surface of another substrate and then laminated to the first transparent substrate as a substrate with a UV-blocking coating layer.

[0046] Examples of resin films with UV-blocking capabilities (UV-blocking resin films) include resin films containing UV absorbers and / or UV reflectors, and resin films utilizing nano-lamination technology.

[0047] An adhesive layer with UV-blocking capabilities (UV-blocking adhesive layer) is typically an adhesive layer containing a UV absorber and / or UV reflector.

[0048] Any suitable UV absorber and UV reflector can be used. Examples of UV absorbers include benzophenone-based UV absorbers such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, and 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, as well as 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-dicumylphenyl)phenylbenzotriazole, 2-(2'-hydroxy-3'-dodecyl-5'-methylphenyl)benzotriazole, and 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazole- Benzotriazole-based UV absorbers such as 2-yl(phenol), acrylate-based UV absorbers such as ethyl-2-cyano-3,3'-diphenyl acrylate and 2-ethylhexyl-2-cyano-3,3'-diphenyl acrylate, salicylate-based UV absorbers such as phenyl salicylate and 4-t-butylphenyl salicylate, 2-ethoxy-2'-ethyloxalic acid bisanilide, 2-ethoxy-5-t- Examples of UV absorbers include oxanilide-based UV absorbers such as tyl-2'-ethyloxalic acidobisanilide, and triazine-based UV absorbers such as 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]phenol, 1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and 1,3,5-tri[[3,5-bis-(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]. Examples of UV reflectors include aluminum, zinc, copper, brass, stainless steel, zinc oxide, and titanium dioxide. UV absorbers and UV reflectors may be used individually or in combination of two or more.

[0049] Commercially available products can be used as the UV-blocking layer. Examples of commercially available film products that can be used as the UV-blocking layer include Fujifilm's "TJ25UL," Konica Minolta's "KC8UA," and Nexfil's "U4-400CL."

[0050] The refractive index adjustment layer can control the hue and / or transmittance of the PDLC film. The refractive index adjustment layer may consist of a single layer or a laminate of two or more layers.

[0051] The refractive index of the refractive index adjustment layer is preferably 1.3 to 1.8, more preferably 1.35 to 1.7, and even more preferably 1.38 to 1.68. In the case of a single layer, for example, if the transparent electrode layer is ITO, a rather low refractive index is desirable so that the refractive index of ITO can be optically relaxed, for example, preferably 1.38 to 1.46. This allows for a suitable reduction of interfacial reflection between the transparent substrate and the transparent electrode layer.

[0052] The refractive index adjustment layer is formed from inorganic materials, organic materials, or mixtures of inorganic and organic materials. Materials used to form the refractive index adjustment layer include NaF, Na3AlF6, LiF, MgF2, and CaF. 2、 SiO2, LaF3, CeF3, Al2O3, TiO2, Ta2O5, ZrO2, ZnO, ZnS, SiO x Examples include inorganic materials (where x is 1.5 or more and less than 2), and organic materials such as acrylic resins, epoxy resins, urethane resins, melamine resins, alkyd resins, and siloxane polymers. In particular, it is preferable to use a thermosetting resin consisting of a mixture of melamine resin, alkyd resin, and an organic silane condensate as the organic material.

[0053] The refractive index adjustment layer may contain nanoparticles with an average particle diameter of 1 nm to 100 nm. By including nanoparticles in the refractive index adjustment layer, the refractive index of the refractive index adjustment layer itself can be easily adjusted.

[0054] The content of nanoparticles in the refractive index adjustment layer is preferably 0.1% to 90% by weight. More preferably, the content of nanoparticles in the refractive index adjustment layer is 10% to 80% by weight, and even more preferably 20% to 70% by weight.

[0055] Examples of inorganic oxides that form nanoparticles include silicon dioxide (silica), hollow nanosilica, titanium dioxide, aluminum oxide, zinc oxide, tin oxide, zirconium oxide, and niobium oxide. Among these, silicon dioxide (silica), titanium dioxide, aluminum oxide, zinc oxide, tin oxide, zirconium oxide, and niobium oxide are preferred. These may be used individually or in combination of two or more.

[0056] The thickness of the refractive index adjustment layer is preferably 10 nm to 200 nm, more preferably 20 nm to 150 nm, and even more preferably 30 nm to 130 nm. If the thickness of the refractive index adjustment layer is excessively small, it is difficult to form a continuous film. Conversely, if the thickness of the refractive index adjustment layer is excessively large, the transparency in the transparent state tends to decrease, and cracks tend to occur more easily.

[0057] The refractive index adjustment layer can be formed using the above-mentioned materials by coating methods such as wet coating, gravure coating, or bar coating, as well as by vacuum deposition, sputtering, ion plating, etc.

[0058] The first conductive substrate is not limited to the configuration shown in the illustration. For example, as shown in Figure 2, a first conductive substrate 10a can be used which includes a first transparent substrate 12 that also serves as an ultraviolet-cutting layer 16 and a first transparent electrode layer 14 disposed on one side of it. The first transparent substrate 12a is, for example, a polymer film containing an ultraviolet absorber, and the ultraviolet absorber and polymer film are as described above.

[0059] A-1-2.PDLC layer The PDLC layer 20 comprises a polymer matrix 22, droplets of liquid crystal compounds (liquid crystal droplets) 24 dispersed in the polymer matrix 22, and a photopolymerization initiator 26. As shown in Figure 1, the PDLC layer 20 has a first region A and a second region B. The liquid crystal droplets 24 in the first region A comprise an unoriented liquid crystal polymer 24c and a non-polymerizable liquid crystal compound 24b, while the liquid crystal droplets 24 in the second region B comprise a polymerizable liquid crystal compound 24a and a non-polymerizable liquid crystal compound 24b. The first region A and the second region B can be formed in any suitable pattern depending on the desired design of the PDLC film.

[0060] The polymer matrix can be composed of any suitable resin. The resin for forming the polymer matrix can be appropriately selected according to factors such as light transmittance, refractive index of the liquid crystal compound, and adhesion to the conductive substrate. For example, water-soluble or water-dispersible resins such as urethane resins, polyvinyl alcohol resins, polyethylene resins, polypropylene resins, and acrylic resins can be preferably used. The resins for forming the polymer matrix may be used individually or in combination.

[0061] The polymer matrix content in the PDLC layer is, for example, 30% to 69.9% by weight, preferably 35% to 65% by weight, and more preferably 40% to 60% by weight, in both the first and second regions. When the polymer matrix content is within this range, effects such as good dimming function at an appropriate operating voltage, good mechanical strength, and prevention of liquid crystal leakage from the edges can be obtained.

[0062] Any suitable liquid crystal compound can be used as the non-polymerizable liquid crystal compound. Preferably, a liquid crystal compound having a birefringence Δn of 0.05 to 0.50 at a wavelength of 589 nm (=ne-no; ne is the refractive index in the long axis direction of the liquid crystal compound molecule, and no is the refractive index in the short axis direction of the liquid crystal compound molecule) is used, more preferably a birefringence Δn of 0.10 to 0.45.

[0063] The dielectric anisotropy of the non-polymerizable liquid crystal compound may be positive or negative. The non-polymerizable liquid crystal compound may be, for example, a nematic, smectic, or cholesteric liquid crystal compound. It is preferable to use a nematic liquid crystal compound because it can achieve excellent transparency in the transparent state.

[0064] Examples of nematic liquid crystal compounds include biphenyl compounds, phenylbenzoate compounds, cyclohexylbenzene compounds, azoxybenzene compounds, azobenzene compounds, azomethine compounds, terphenyl compounds, biphenylbenzoate compounds, cyclohexylbiphenyl compounds, phenylpyridine compounds, cyclohexylpyrimidine compounds, cholesterol compounds, and fluorine compounds. These low-molecular-weight liquid crystal compounds may be used individually or in combination.

[0065] Polymerizable liquid crystal compounds can be appropriately selected according to factors such as light transmittance and compatibility with non-polymerizable liquid crystal compounds. Polymerizable liquid crystal compounds may also be of a bifunctional or crosslinked type. Examples of polymerizable liquid crystal compounds include polymerizable mesogenic compounds described in JP 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US4388453), WO93 / 22397, EP0261712, DE19504224, DE4408171, and GB2280445. A specific example of such a polymerizable mesogenic compound is BASF's trade name LC242. As the polymerizable liquid crystal compound, nematic liquid crystal monomers are preferred.

[0066] Liquid crystal polymers are typically polymers of the polymerizable liquid crystal compounds mentioned above. Polymers are formed by the polymerization of polymerizable liquid crystal compounds, and network structures can be formed by crosslinking, but these are non-liquid crystal. Therefore, in liquid crystal polymers, for example, the transitions to liquid crystal phase, glass phase, and crystalline phase due to temperature changes, which are characteristic of liquid crystal compounds, do not occur.

[0067] The liquid crystal polymer typically exists in a non-oriented state within the liquid crystal droplet. Because the liquid crystal polymer in the liquid crystal droplet is in a non-oriented state, the first region can maintain a high haze (e.g., 40% to 100%, preferably 60% to 100%) even when a voltage is applied.

[0068] The total content ratio of the non-polymerizable liquid crystal compound and the liquid crystal polymer in the first region is, for example, 30% to 69.9% by weight, preferably 35% to 65% by weight, and more preferably 40% to 60% by weight. The weight content ratio (non-polymerizable liquid crystal compound: liquid crystal polymer) of the non-polymerizable liquid crystal compound and the liquid crystal polymer in the first region is, for example, 99:1 to 70:30, preferably 95:5 to 80:20. The total content ratio of the polymer matrix, the non-polymerizable liquid crystal compound, and the liquid crystal polymer in the first region may be, for example, 90% to 99.9% by weight, preferably 95% to 99.9% by weight.

[0069] The total content ratio of non-polymerizable liquid crystal compounds and polymerizable liquid crystal compounds in the second region is, for example, 30% to 69.9% by weight, preferably 35% to 65% by weight, and more preferably 40% to 60% by weight. The weight content ratio (non-polymerizable liquid crystal compound: polymerizable liquid crystal compound) of non-polymerizable liquid crystal compounds to polymerizable liquid crystal compounds in the second region is, for example, 99:1 to 70:30, preferably 95:5 to 80:20. The total content ratio of polymer matrix, non-polymerizable liquid crystal compounds, and polymerizable liquid crystal compounds in the second region may be, for example, 90% to 99.9% by weight, preferably 95% to 99.9% by weight.

[0070] As photopolymerization initiators, for example, those that can initiate polymerization of the polymerizable liquid crystal compound by ultraviolet irradiation are used. Specifically, examples include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and the like.

[0071] Examples of benzoin ether-based photopolymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, and anisole methyl ether. Examples of acetophenone-based photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, and 4-(t-butyl)dichloroacetophenone. Examples of α-ketol-based photopolymerization initiators include 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. Examples of aromatic sulfonyl chloride-based photopolymerization initiators include 2-naphthalenesulfonyl chloride. Examples of photoactive oxime-based photopolymerization initiators include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime. Examples of benzoin-based photopolymerization initiators include benzoin. Examples of benzyl-based photopolymerization initiators include benzyl. Examples of benzophenone-based photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone. Examples of ketal-based photopolymerization initiators include benzyldimethylketal. Examples of thioxanthone-based photopolymerization initiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0072] The photopolymerization initiator has a maximum absorption wavelength in the range of 300 nm to 340 nm, preferably 320 nm to 340 nm. By using such a photopolymerization initiator, the PDLC film according to the embodiment of the present invention can be easily produced, and the effect of preventing the unintended formation of liquid crystal polymer due to the UV-cutting layer can be suitably obtained.

[0073] The content ratio of the photopolymerization initiator in the PDLC layer is preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the total of the polymerizable liquid crystal compound and liquid crystal polymer.

[0074] As detailed in Section B, a PDLC layer having a first region and a second region can be formed by polymerizing a polymerizable liquid crystal compound in a predetermined region of a PDLC layer containing liquid crystal droplets containing a polymerizable liquid crystal compound and a non-polymerizable liquid crystal compound to form a liquid crystal polymer. In this case, the predetermined region becomes the first region, and the other region becomes the second region. At this time, unreacted polymerizable liquid crystal compounds may remain in the liquid crystal droplets in the first region. The content of unreacted polymerizable liquid crystal compounds in the first region is, for example, 3% by weight or less, preferably 1% by weight or less. Furthermore, it is preferable that the liquid crystal polymer is substantially absent in the liquid crystal droplets in the second region. The content of liquid crystal polymer in the second region is, for example, 3% by weight or less, preferably 1% by weight or less.

[0075] The average particle size of the liquid crystal droplets may be, for example, 0.3 μm to 9 μm, preferably 0.4 μm to 8 μm. If the average particle size of the liquid crystal droplets is too small, the droplet size is smaller than the wavelength of light, causing the light to pass through the droplets without scattering, which can result in insufficient haze. Conversely, if the average particle size is too large, the droplet size is larger than the wavelength of light, which can also result in insufficient haze. The average particle size of the liquid crystal droplets in the PDLC layer is the volume-average particle size of the liquid crystal droplets when viewed from a direction perpendicular to the main surface of the PDLC film.

[0076] The thickness of the PDLC layer is typically 2 μm to 40 μm, preferably 3 μm to 35 μm, and more preferably 4 μm to 30 μm.

[0077] A-1-3.Second conductive base material The second conductive substrate 30 typically comprises a second transparent substrate 32 and a second transparent electrode layer 34 provided on one side thereof. The second conductive substrate 30 may optionally have a hard coat layer on one or both sides of the second transparent substrate 32, and may also have a refractive index adjustment layer between the second transparent substrate 32 and the second transparent electrode layer 34.

[0078] The surface resistance of the second conductive substrate on the second transparent electrode layer side is preferably 1Ω / □ to 1000Ω / □, more preferably 5Ω / □ to 300Ω / □, and even more preferably 10Ω / □ to 200Ω / □.

[0079] The haze value of the second conductive substrate is preferably 20% or less, more preferably 10% or less, and even more preferably 0.1% to 10%.

[0080] The total light transmittance of the second conductive substrate is preferably 30% or more, more preferably 60% or more, and even more preferably 80% or more.

[0081] The same explanation as for the first transparent substrate and the first transparent electrode layer can be applied to the second transparent substrate and the second transparent electrode layer, respectively.

[0082] A-2. PDLC film of the second embodiment Figure 3(a) is a schematic plan view of an example of a PDLC film according to a second embodiment of the present invention, (b) is a schematic cross-sectional view illustrating the state of the PDLC film shown in (a) when no voltage is applied, and (c) is a schematic cross-sectional view illustrating the state of the PDLC film shown in (a) when voltage is applied. The PDLC film 100b includes, in this order, a first conductive substrate 10 including an ultraviolet cut layer 16, a PDLC layer 20 including a polymer matrix 22, liquid crystal droplets 24 dispersed in the polymer matrix 22 and a photopolymerization initiator 26, and a second conductive substrate 30. In a plan view, the PDLC layer 20 has a first region A and a second region B, the amount of change in haze due to the application of voltage is different. The liquid crystal droplets 24 in the second region B include a polymerizable liquid crystal compound 24a and a non-polymerizable liquid crystal compound 24b. The liquid crystal droplets 24 in the first region A include a liquid crystal polymer 24c and a non-polymerizable liquid crystal compound 24b. Typically, the liquid crystal polymer 24c is oriented in a predetermined direction (in the illustrated example, perpendicular to the main surfaces of the first conductive substrate 10 and the second conductive substrate 30). The photopolymerization initiator 26 is dispersed in the PDLC layer 20, and at least a portion of it is also contained in the liquid crystal droplets 24.

[0083] As shown in Figure 3(b), in the PDLC film 100b when no voltage is applied, both the polymerizable liquid crystal compound 24a and the non-polymerizable liquid crystal compound 24b in the liquid crystal droplet 24 in the second region B are in an unoriented state, resulting in scattering of transmitted light. On the other hand, in the first region A, the non-polymerizable liquid crystal compound 24b is oriented along the orientation direction of the liquid crystal polymer 24c, resulting in suppression of scattering of transmitted light. Therefore, in the PDLC film 100b, the first region A can be transparent, and the second region B can be in a scattering state.

[0084] On the other hand, as shown in Figure 3(c), in the PDLC film 100b when voltage is applied, both the polymerizable liquid crystal compound 24a and the non-polymerizable liquid crystal compound 24b in the liquid crystal droplets 24 in the second region B are oriented perpendicular to the main surfaces of the first conductive substrate 10 and the second conductive substrate 30, suppressing the scattering of transmitted light and resulting in a decrease in haze. On the other hand, in the first region A, the orientation of the polymerizable liquid crystal compound 24b does not change significantly due to orientation restriction by the liquid crystal polymer 24c, and therefore the scattering of transmitted light is still suppressed. Thus, the amount of change in haze due to the application of voltage in the first region is smaller than the amount of change in the second region, and the difference between the haze in the first region and the haze in the second region decreases with the application of voltage.

[0085] As described above, when no voltage is applied, the PDLC film 100b exhibits an appearance in which the first region is transparent and the second region is cloudy. When voltage is applied, the haze in the second region decreases significantly, both regions become transparent, and as a result, the entire main surface can exhibit a transparent appearance. Therefore, the PDLC film 100b can exhibit different appearances by switching between the application and absence of voltage.

[0086] The voltage applied to the PDLC film when voltage is applied is a voltage capable of operating the PDLC film (operating voltage), and can be, for example, 5V to 200V, preferably 10V to 100V.

[0087] The haze in the first region when no voltage is applied is, for example, 1% to 20%, preferably 1% to 10%. The haze in the first region when voltage is applied is, for example, 1% to 20%, preferably 1% to 10%. The change in the haze in the first region due to the application of voltage (|haze when no voltage is applied - haze when voltage is applied|) is, for example, 0% to 20%, preferably 0% to 10%.

[0088] The haze in the second region when no voltage is applied is, for example, 50% to 100%, preferably 70% to 100%. The haze in the second region when voltage is applied is, for example, 1% to 20%, preferably 1% to 10%. The change in the haze in the second region due to voltage application (|haze when no voltage is applied - haze when voltage is applied|) is, for example, 30% to 99%, preferably 60% to 99%.

[0089] The change in haze in the first region due to the application of voltage is smaller than the change in haze in the second region due to the application of voltage, and the difference is, for example, 10% to 99%, preferably 30% to 99%.

[0090] The total light transmittance of the first region when no voltage is applied is, for example, 70% to 95%, preferably 80% to 90%. The total light transmittance of the first region when voltage is applied is, for example, 70% to 95%, preferably 80% to 90%.

[0091] The total light transmittance of the second region when no voltage is applied is, for example, 50% to 95%, preferably 60% to 90%. The total light transmittance of the second region when voltage is applied is, for example, 70% to 95%, preferably 80% to 90%.

[0092] Under conditions of 30℃ and 55%RH, xenon light was applied at 120W / m². 2 The change in haze Va (|haze with voltage applied - haze without voltage applied|) due to voltage application (e.g., 50V) in the second region after 125 hours of irradiation at (300nm-400nm) and the change in haze Vb due to voltage application (e.g., 50V) in the second region before irradiation satisfy, for example, the relationship (Vb-Va) / Vb×100≦5, and preferably the relationship (Vb-Va) / Vb×100≦3.

[0093] The thickness of the PDLC film is, for example, 30 μm to 250 μm, preferably 50 μm to 150 μm.

[0094] With respect to the PDLC film of the second embodiment, the same descriptions as those for the first conductive substrate and the second conductive substrate in the PDLC film of the first embodiment can be applied to the first conductive substrate and the second conductive substrate, respectively. Furthermore, with respect to the PDLC layer, the same descriptions as those for the PDLC layer in the PDLC film of the first embodiment can be applied, except that the liquid crystal polymer contained in the liquid crystal droplets in the first region is oriented in a predetermined direction.

[0095] In the first region of the PDLC layer, the liquid crystal polymer contained in the liquid crystal droplets is oriented in a predetermined direction. Preferably, the liquid crystal polymer is oriented at an angle of approximately 90°±5°, preferably 90°±3°, with respect to the main surfaces of the first and second conductive substrates. Because the liquid crystal polymer in the liquid crystal droplets is oriented in a predetermined direction, the first region can maintain low haze (e.g., 1% to 20%, preferably 1% to 10%) even when no voltage is applied.

[0096] B. Method for manufacturing polymer-dispersed liquid crystal film The PDLC film described in Section A can be manufactured by any suitable manufacturing method. For example, the above PDLC film is (Step A1) To create an unpatterned PDLC film comprising, in this order: a first conductive substrate; a polymer matrix; a PDLC layer comprising liquid crystal droplets containing a non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound dispersed in the polymer matrix, and a photopolymerization initiator; and a second conductive substrate, and (Step A2) An active energy ray is irradiated from the second conductive substrate side of the unpatterned PDLC film in a predetermined pattern to polymerize the polymerizable liquid crystal compound, thereby forming a first region containing liquid crystal droplets that include the liquid crystal polymer and the non-polymerizable liquid crystal compound. It can be manufactured by a manufacturing method (manufacturing method A) that includes [the specified component]. According to the above-described method for manufacturing a PDLC film, a PDLC layer can be formed having a first region in which liquid crystal droplets contain a liquid crystal polymer and a non-polymerizable liquid crystal compound, and a second region in which liquid crystal droplets contain a polymerizable liquid crystal compound and a non-polymerizable liquid crystal compound. As a result, the PDLC film described in Section A can be suitably obtained. In the description of the method for manufacturing a PDLC film, a PDLC layer or PDLC film in which the first region and the second region are formed may be referred to as a patterned PDLC layer or patterned PDLC film, and a PDLC layer or PDLC film in which the first region and the second region are not formed may be referred to as an unpatterned PDLC layer or unpatterned PDLC film.

[0097] In one embodiment, the active energy ray irradiation in step A2 is performed without applying a voltage between the first conductive substrate and the second conductive substrate. In another embodiment, the active energy ray irradiation in step A2 is performed with a voltage applied between the first conductive substrate and the second conductive substrate.

[0098] B-1. Process A1 In step A1, an unpatterned PDLC film is prepared, comprising, in this order: a first conductive substrate; a polymer matrix; a PDLC layer containing liquid crystal droplets dispersed in the polymer matrix and the polymerizable liquid crystal compound, and a photopolymerization initiator; and a second conductive substrate.

[0099] Process A1 is, for example, (Step A1-1) A coating solution containing a polymer matrix forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, a photopolymerization initiator, and a solvent is applied to either the first conductive substrate or the second conductive substrate to obtain a coated layer. (Step A1-2) Dry the coated layer to obtain an unpatterned PDLC layer comprising a polymer matrix, liquid crystal droplets containing the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound dispersed in the polymer matrix, and a photopolymerization initiator, and (Step A1-3) Laminating the other substrate onto the above unpatterned PDLC layer. Includes.

[0100] In step A1-1, a coating solution containing a polymer matrix forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, a photopolymerization initiator, and a solvent is applied to either the first conductive substrate or the second conductive substrate to obtain a coated layer.

[0101] The above coating solution is preferably an emulsion (hereinafter sometimes referred to as "emulsion coating solution") in which liquid crystal particles containing a non-polymerizable liquid crystal compound and a polymerizable liquid crystal compound are dispersed in a solvent. In one embodiment, the coating solution is an emulsion coating solution in which resin particles for forming a polymer matrix and liquid crystal particles containing a non-polymerizable liquid crystal compound and a polymerizable liquid crystal compound are dispersed in a solvent. The emulsion coating solution further contains a photopolymerization initiator and may further contain any suitable additives depending on the purpose.

[0102] As the solvent, water or a mixed solvent of water and a water-miscible organic solvent can be preferably used. Examples of water-miscible organic solvents include C1-3 alcohols, acetone, and DMSO. Non-polymerizable liquid crystal compounds, polymerizable liquid crystal compounds, and resins for forming polymer matrices are as described in Section A. Optional additives include dispersants, leveling agents, and crosslinking agents.

[0103] The content ratio of liquid crystal compounds in the solid content of the coating solution (total content ratio of non-polymerizable liquid crystal compounds and polymerizable liquid crystal compounds) can be, for example, 30% to 69.9% by weight, preferably 35% to 65% by weight, and more preferably 40% to 60% by weight.

[0104] The weight ratio of non-polymerizable liquid crystal compounds to polymerizable liquid crystal compounds in the coating solution (non-polymerizable liquid crystal compound: polymerizable liquid crystal compound) is preferably 99:1 to 70:30, and more preferably 95:5 to 80:20.

[0105] The content of the polymer matrix-forming resin in the solid content of the coating liquid may be, for example, 30% to 69.9% by weight, preferably 35% to 65% by weight, and more preferably 40% to 60% by weight.

[0106] The weight ratio of the liquid crystal compound content (total content of non-polymerizable liquid crystal compounds and polymerizable liquid crystal compounds) to the polymer matrix-forming resin content (liquid crystal compound: polymer matrix-forming resin) in the coating solution may be, for example, 30:70 to 70:30, preferably 35:65 to 65:35, and more preferably 40:60 to 60:40. Furthermore, the total content ratio of the polymer matrix-forming resin, non-polymerizable liquid crystal compounds, and polymerizable liquid crystal compounds in the solid content of the coating solution may be, for example, 90% to 99.9% by weight, preferably 95% to 99.9% by weight.

[0107] The average particle diameter of the liquid crystal particles is preferably 0.3 μm or more, and more preferably 0.4 μm or more. Furthermore, the average particle diameter of the liquid crystal particles is preferably 9 μm or less, and more preferably 8 μm or less. If the average particle diameter of the liquid crystal particles is within this range, the average particle diameter of the liquid crystal droplets in the PDLC layer can be set to a desired range. Note that the above average particle diameter of the liquid crystal particles is the volume-average particle diameter.

[0108] The average particle size of the liquid crystal particles preferably has a relatively narrow particle size distribution. The coefficient of variation (CV value) of the average particle size of the liquid crystal particles may be, for example, less than 0.40, preferably 0.35 or less, and more preferably 0.30 or less. In one embodiment, an emulsion coating solution that substantially does not contain liquid crystal particles with a particle size of less than 0.3 μm or greater than 9 μm (for example, an emulsion coating solution in which the ratio of the volume of liquid crystal particles with a particle size of less than 0.3 μm or greater than 9 μm to the total volume of liquid crystal particles is 10% or less) may be used.

[0109] The average particle size of the resin particles for forming the polymer matrix is ​​preferably 10 nm to 500 nm, more preferably 30 nm to 300 nm, and even more preferably 50 nm to 200 nm. Two or more types of resin particles with different resin types and / or average particle sizes may be used. The average particle size of the resin particles for forming the polymer matrix refers to the volume-average median diameter and can be measured using a dynamic light scattering particle size distribution analyzer.

[0110] The photopolymerization initiator and its content are as described in Section A.

[0111] Examples of dispersants include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. The content of the dispersant is preferably 0.05 to 10 parts by weight, and more preferably 0.1 to 1 part by weight, per 100 parts by weight of the emulsion coating solution.

[0112] Examples of leveling agents include acrylic leveling agents, fluorine leveling agents, and silicone leveling agents. The content ratio of the leveling agent is preferably 0.05 to 10 parts by weight, and more preferably 0.1 to 1 part by weight, per 100 parts by weight of the emulsion coating liquid.

[0113] Examples of crosslinking agents include aziridine-based crosslinking agents and isocyanate-based crosslinking agents. The content ratio of the crosslinking agent is preferably 0.5 to 10 parts by weight, and more preferably 0.8 to 5 parts by weight, per 100 parts by weight of the emulsion coating liquid.

[0114] Emulsion coating solutions can be prepared, for example, by mixing a resin emulsion or resin particle dispersion containing polymer matrix-forming resin particles, a liquid crystal emulsion containing liquid crystal particles, a photopolymerization initiator, and optional additives (e.g., dispersants, leveling agents, crosslinking agents). If necessary, a solvent may be added during mixing. Alternatively, emulsion coating solutions can also be prepared by adding a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, a water-dispersible resin, a photopolymerization initiator, and optional additives to a solvent and mechanically dispersing them.

[0115] The above-mentioned resin emulsions and liquid crystal emulsions can be prepared, for example, by mechanical emulsification, microchannel methods, membrane emulsification, etc. Among these, liquid crystal emulsions are preferably prepared by membrane emulsification. By membrane emulsification, emulsions with a uniform particle size distribution can be suitably obtained. For details of membrane emulsification, refer to the disclosures in Japanese Patent Publication No. 4-355719 and Japanese Patent Publication No. 2015-40994 (these are incorporated herein by reference).

[0116] The solid content concentration of the emulsion coating solution may be, for example, 20% to 60% by weight, preferably 30% to 50% by weight.

[0117] The viscosity of the emulsion coating solution can be appropriately adjusted to ensure suitable application to the substrate. The viscosity of the emulsion coating solution during application is preferably 20 mPas to 400 mPas, more preferably 30 mPas to 300 mPas, and even more preferably 40 mPas to 200 mPas. If the viscosity is less than 20 mPas, significant convection of the solvent may occur during drying, potentially leading to an unstable PDLC layer thickness. Furthermore, if the viscosity exceeds 400 mPas, the emulsion coating solution bead may be unstable. The viscosity of the emulsion coating solution can be measured, for example, using an Anton Paar rheometer MCR302. Here, the shear viscosity value is used under conditions of 20°C and a shear rate of 1000 (1 / s).

[0118] The emulsion coating solution is typically applied to the transparent electrode layer side surface of either the first or second conductive substrate. These substrates are as described in Section A.

[0119] Any suitable coating method can be used. Examples include roll coating, spin coating, wire bar coating, dip coating, die coating, curtain coating, spray coating, and knife coating (comma coating, etc.). Among these, roll coating is preferred. For example, regarding coating by roll coating using a slot die, refer to the description in Japanese Patent Application Publication No. 2019-5698.

[0120] The thickness of the coating layer is preferably 3 μm to 40 μm, more preferably 4 μm to 30 μm, and even more preferably 5 μm to 20 μm. Within this range, a PDLC layer with excellent thickness uniformity can be obtained.

[0121] In step A1-2, the coated layer is dried to obtain an unpatterned PDLC layer containing a polymer matrix, liquid crystal droplets dispersed in the polymer matrix, and a photopolymerization initiator. Drying removes the solvent from the coated layer, and the resin particles for forming the polymer matrix fuse together, thereby forming a PDLC layer having a structure in which liquid crystal droplets containing polymerizable liquid crystal compounds and non-polymerizable liquid crystal compounds, and a photopolymerization initiator are dispersed in the polymer matrix.

[0122] The coating layer can be dried by any suitable method. Specific examples of drying methods include heat drying and hot air drying. If the emulsion coating solution contains a crosslinking agent, a crosslinked structure of the polymer matrix may be formed during drying.

[0123] The drying temperature is preferably 20°C to 150°C, and more preferably 25°C to 80°C. The drying time is preferably 1 minute to 100 minutes, and more preferably 2 minutes to 10 minutes.

[0124] In step A1-3, the other substrate is laminated on top of the unpatterned PDLC layer. This results in an unpatterned PDLC film having a first conductive substrate, an unpatterned PDLC layer, and a second conductive substrate in that order.

[0125] The lamination of the first conductive substrate or the second conductive substrate onto the PDLC layer is carried out so that the transparent electrode layer side faces the PDLC layer. From the viewpoint of obtaining sufficient adhesion, this lamination can preferably be carried out using a laminator, applying a lamination pressure of 0.006 MPa / m to 7 MPa / m, more preferably 0.06 MPa / m to 0.7 MPa / m.

[0126] B-2. Process A2 In step A2, an active energy ray is irradiated from the second conductive substrate side of the unpatterned PDLC film in a predetermined pattern to polymerize the polymerizable liquid crystal compound, forming a first region containing liquid crystal droplets that include the liquid crystal polymer and the non-polymerizable liquid crystal compound. Specifically, in the region irradiated with the active energy ray (irradiated region), the polymerizable liquid crystal compound in the liquid crystal droplet polymerizes to produce a liquid crystal polymer, resulting in the formation of liquid crystal droplets containing the liquid crystal polymer and the non-polymerizable liquid crystal compound. On the other hand, in the region not irradiated with the active energy ray (non-irradiated region), the polymerizable liquid crystal compound remains unreacted, resulting in liquid crystal droplets containing both the polymerizable and non-polymerizable liquid crystal compounds. Therefore, the irradiated region of the PDLC layer becomes the first region A containing liquid crystal droplets that include the liquid crystal polymer and the non-polymerizable liquid crystal compound, and the non-irradiated region becomes the second region B containing liquid crystal droplets that include the polymerizable and non-polymerizable liquid crystal compound. Furthermore, the content ratio of polymerizable liquid crystal compounds to non-polymerizable liquid crystal compounds in the droplets in the non-irradiated area can generally correspond to the content ratio at the beginning of liquid crystal droplet formation, i.e., the content ratio of polymerizable liquid crystal compounds to non-polymerizable liquid crystal compounds in the coating solution.

[0127] Irradiation of the active energy ray is performed through a photomask having a predetermined pattern. As the active energy ray, ultraviolet rays, infrared rays, X-rays, α-rays, β-rays, γ-rays, electron beams, etc. are used. Among them, ultraviolet rays are preferred. Further, it is preferable that the active energy ray is collimated light having high straightness from the irradiation source.

[0128] The irradiation conditions of the ultraviolet rays can be appropriately set according to the type of the polymerizable liquid crystal compound, the transmittance of the second conductive substrate, the absorption wavelength of the photoinitiator, etc. The irradiation intensity is, for example, 0.1 mW / cm 2 ~1000 mW / cm 2 , preferably 1 mW / cm 2 ~100 mW / cm 2 and can be. The irradiation dose is, for example, 10 mJ / cm 2 ~10000 mJ / cm 2 , preferably 100 mJ / cm 2 ~5000 mJ / cm 2 and can be. The irradiation temperature can be, for example, -20°C to 80°C, preferably -20°C to 60°C.

[0129] FIG. 4 and FIG. 5 are schematic views each explaining an example of active energy ray irradiation in the method for manufacturing a PDLC film according to an embodiment of the present invention. In the embodiment shown in FIG. Example 4, the active energy ray irradiation is performed through the photomask 40 without applying a voltage between the first conductive substrate 10 and the second conductive substrate 30. According to this embodiment, in the liquid crystal droplets 24 in the irradiation region of the PDLC layer 20, since the polymerizable liquid crystal compound 24a polymerizes in a non-aligned state, the formed liquid crystal polymer 24c also becomes a non-aligned state. Therefore, according to this embodiment, the PDLC film of the first embodiment described in item A-1 can be suitably obtained.

[0130] In the embodiment shown in Figure 5, the active energy ray irradiation is performed by applying a voltage between the first conductive substrate 10 and the second conductive substrate 30 via a photomask 40. According to this embodiment, in the liquid crystal droplets 24 of the irradiated area of ​​the PDLC layer 20, the polymerizable liquid crystal compound 24a polymerizes while oriented in a predetermined direction along the electric field (in the illustrated example, perpendicular to the main surfaces of the first conductive substrate 10 and the second conductive substrate 30), thereby forming a liquid crystal polymer 24c with this orientation fixed. Therefore, according to this embodiment, the PDLC film of the second embodiment described in Section A-2 can be suitably obtained. The voltage applied during active energy ray irradiation is not limited as long as the desired orientation (in other words, the desired haze in the first region) is achieved, and can be, for example, 10V to 200V, preferably 20V to 100V.

[0131] In one embodiment, by irradiating with active energy rays using a photomask having multiple light-transmitting areas with different aperture ratios, a first region can be formed in the region corresponding to each light-transmitting area at a ratio corresponding to its aperture ratio. Therefore, in the resulting PDLC film, the regions corresponding to each light-transmitting area may exhibit haze corresponding to their aperture ratio in the overall view.

[0132] For example, by using a photomask in which the aperture ratio continuously increases from the right end to the left end, and irradiating it with active energy rays without applying a voltage, a PDLC film can be obtained that exhibits an appearance in which the entire surface is in a scattering state when no voltage is applied, and haze continuously increases from the right end to the left end when a voltage is applied. Alternatively, for example, by using a photomask in which the aperture ratio continuously increases from the right end to the left end, and irradiating it with active energy rays while applying a voltage, a PDLC film can be obtained that exhibits an appearance in which the entire surface is transparent when a voltage is applied, and haze continuously decreases from the right end to the left end when no voltage is applied.

[0133] In the above-described method A for manufacturing the PDLC film, an unpatterned PDLC film is prepared by including a first conductive substrate, an unpatterned PDLC layer, and a second conductive substrate in that order, and the unpatterned PDLC film is irradiated with active energy rays from the second conductive substrate side. However, the method for manufacturing the PDLC film is not limited to this embodiment.

[0134] For example, the PDLC film described above can be manufactured by a manufacturing method (manufacturing method B) which includes, in this order, creating an unpatterned PDLC film comprising a second conductive substrate, an unpatterned PDLC layer, and a second conductive substrate; irradiating the unpatterned PDLC film with active energy rays in a predetermined pattern from either side of the unpatterned PDLC film; and providing an ultraviolet-cutting layer on the outside of either of the second conductive substrates. The active energy ray irradiation is performed with or without voltage applied between the two substrates.

[0135] For example, the PDLC film described above can be manufactured by a manufacturing method (manufacturing method C) that includes, in this order, creating an unpatterned PDLC film comprising a second conductive substrate, an unpatterned PDLC layer, and a second conductive substrate; providing an ultraviolet-cutting layer on the outside of either of the second conductive substrates; and irradiating the second conductive substrate without the ultraviolet-cutting layer with active energy rays in a predetermined pattern. The active energy ray irradiation is performed with or without voltage applied between the two substrates.

[0136] Since the second conductive substrate provided with the UV-cutting layer can correspond to the first conductive substrate, a patterned PDLC film containing a first conductive substrate with a UV-cutting layer, a patterned PDLC layer, and a second conductive substrate can also be obtained by manufacturing methods B and C.

[0137] C. Variations C-1. Variation 1 Figure 6 is a schematic cross-sectional view illustrating the configuration of a modified example of a PDLC film according to an embodiment of the present invention. The PDLC film 100c comprises, in this order, a first conductive substrate 10 including a first ultraviolet cut layer 16, a PDLC layer 20 including a polymer matrix (not shown), liquid crystal droplets (not shown) dispersed in the polymer matrix, and a photopolymerization initiator (not shown), and a second conductive substrate 30 including a second ultraviolet cut layer 36. The PDLC layer 20 is a patterned PDLC layer having a first region and a second region as shown in Figure 1 or Figure 3. That is, the PDLC film 100c differs from the PDLC film 100a or 100b in that the second conductive substrate 30 includes a second ultraviolet cut layer 36. Since the PDLC film 100c has ultraviolet cut layers on both sides of the patterned PDLC layer, its light resistance can be more favorably improved.

[0138] C-2. Variation 2 Figure 7 is a schematic cross-sectional view illustrating the configuration of another modified example of a PDLC film according to an embodiment of the present invention. The PDLC film 100d comprises, in this order, a first conductive substrate 10 including a first ultraviolet-cutting layer 16, a PDLC layer 20 including a polymer matrix (not shown), liquid crystal droplets (not shown) dispersed in the polymer matrix, and a photopolymerization initiator (not shown), and a second conductive substrate 30 including a reflective layer 38. The PDLC layer 20 is a patterned PDLC layer having a first region and a second region as shown in Figure 1 or Figure 3. That is, the PDLC film 100d differs from the PDLC film 100a or 100b in that the second conductive substrate 30 includes a reflective layer 38.

[0139] According to the PDLC film 100d, light incident on the scattered PDLC layer 20 from the first conductive substrate 10 is reflected by the reflective layer 38 and scattered by the PDLC layer 20, resulting in light containing a large scattered reflection component being emitted from the first conductive substrate 10. On the other hand, light incident on the transparent (non-scattering) PDLC layer 20 from the first conductive substrate 10 is reflected by the reflective layer 38 while scattering in the PDLC layer 20 is suppressed, resulting in light containing a large specular reflection component being emitted from the conductive transparent substrate 10. As a result, the scattered region exhibits a less glossy appearance (matte appearance), while the transparent region exhibits a glossy appearance (metallic appearance). Therefore, by forming the first and second regions in a desired pattern and switching the voltage application state, it is possible to switch between a state where the entire main surface has a glossy or less glossy appearance, and a state where only a part of the surface has a glossy or less glossy appearance.

[0140] In the illustrated example, the second conductive substrate 30 has a second transparent electrode layer 34, a second transparent substrate 32, and a reflective layer 38 in that order. The configuration of the second conductive substrate 30 including the reflective layer 38 is not limited to the illustrated example. For example, as illustrated in Figure 8(a), the second conductive substrate 30a may have a reflective layer 38, a second transparent electrode layer 34, and a second transparent substrate 32 in that order. Alternatively, as illustrated in Figure 8(b), the second conductive substrate 30b may have a second transparent substrate 32 and a conductive reflective layer 35 provided on one side (the PDLC layer side). Here, the conductive reflective layer means a layer that can perform both the function of a reflective layer and the function of an electrode layer. The reflective layer may be used in the form of a reflective film with a protective layer provided on one or both of its surfaces.

[0141] The reflective layer 38 preferably has specular reflectivity. Examples of specular reflectivity reflective layers include, for example, a metallic reflective layer composed of aluminum, tin, gold, silver, iron, chromium, cobalt, nickel, or alloys thereof, and a metallic-looking nano-laminated film (for example, "Picasus" manufactured by Toray Industries) made by laminating hundreds to thousands of different polymers to a thickness of several nanometers. The metallic reflective layer can serve as a conductive reflective layer, combining the functions of both a reflective layer and an electrode layer.

[0142] The thickness of the reflective layer may be, for example, 0.01 μm to 0.10 μm, preferably 0.01 μm to 0.45 μm, in the case of a metal reflective layer, and for example, 20 μm to 300 μm, preferably 30 μm to 250 μm, in the case of a nano-laminated film.

[0143] The reflective layer can be formed by vacuum deposition methods such as vacuum evaporation, sputtering, or ion plating.

[0144] The PDLC film 100d can be obtained, for example, by a manufacturing method that includes: creating an unpatterned PDLC film comprising, in this order, a second conductive substrate without a reflective layer, an unpatterned PDLC layer, and a second conductive substrate with a reflective layer; irradiating the unpatterned PDLC film with active energy rays from the side of the second conductive substrate without a reflective layer; and providing an ultraviolet cut layer on the outside of the second conductive substrate without a reflective layer. The active energy ray irradiation is performed with or without voltage applied between the two substrates. [Examples]

[0145] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way to these examples. The measurement methods for each characteristic are as follows. Unless otherwise specified, "parts" and "%" in the examples and comparative examples are based on weight.

[0146] (1) Thickness The measurement was performed using a digital micrometer (manufactured by Anritsu, product name "KC-351C"). (2) Volume-average particle diameter of liquid crystal particles in liquid crystal emulsion 0.1% by weight of a liquid crystal emulsion was added to 200 ml of an electrolyte aqueous solution (Isoton II, Coulter). The resulting mixture was used as a measurement sample and divided into 256 equal intervals from 0.4 μm to 12 μm using a Multisizer 3 (Coulter, aperture size = 20 μm). The volume of each discretized particle size was statistically analyzed to calculate the volume-average particle size. If particles larger than 12 μm were present, the aperture size was set to 30 μm, and the mixture was divided into 256 equal intervals from 0.6 μm to 18 μm using a logarithmic basis. The volume of each discretized particle size was statistically analyzed to calculate the volume-average particle size. (3) Average particle size of resin particles A sample was prepared by adding a few drops of resin dispersion to 100 mL of water. Using a dynamic light scattering particle size distribution analyzer (Microtrac, name "Nanotrac150"), the sample was placed in the instrument's measurement holder, and after confirming that the concentration was measurable on the instrument's monitor, measurement was performed. (4) Hayes Measurements were taken using product name "NDH4000" manufactured by Nippon Denshoku Co., Ltd., in accordance with JIS K 7136. For PDLC films containing an ultraviolet-cutting layer, the ultraviolet-cutting layer was removed before measurement. (5) Absorbance The film to be measured was measured using the Hitachi High-Tech Science "UH-4150AD+" with an attached direct incidence detector.

[0147] [Example 1] (Fabrication of conductive substrates) An ITO layer was formed on one side of a PET substrate (manufactured by Toyobo Co., Ltd., product name "Cosmoshine", thickness: 50 μm) by sputtering to obtain a conductive substrate having a [transparent substrate / transparent electrode layer] configuration. The absorbance of the PET substrate at a wavelength of 350 nm was 0.15.

[0148] (Preparation of emulsion coating solution) A liquid crystal emulsion was prepared by mixing 53.7 parts of a non-polymerizable liquid crystal compound (manufactured by JNC, product name "LX-153XX", birefringence Δn=0.149 (ne=1.651, no=1.502), viscosity=48.5 mPa·s), 5.9 parts of a polymerizable liquid crystal compound (manufactured by Merck, product name "RM257"), 0.1 part of a photopolymerization initiator (manufactured by IGM, product name "OMNIRAD184", maximum absorption wavelengths 243 nm, 331 nm), 39.8 parts of pure water, and 0.5 parts of a dispersant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., "Neugen ET159") and stirring the mixture in a homogenizer at 100 rpm for 10 minutes. The average particle size of the liquid crystal particles in the obtained liquid crystal emulsion was 3.4 μm. An emulsion coating solution (solid content concentration: 40 wt%) was obtained by mixing 38.4 parts of the above liquid crystal emulsion, 19.1 parts of a polyether-based polyurethane resin aqueous dispersion (manufactured by DSM, trade name "NeoRez R967", average polymer particle size: 80 nm, CV value = 0.27, solid content: 40 wt%), 17.0 parts of a polyester-based polyurethane resin aqueous dispersion (manufactured by Sanyo Chemical Industries, trade name "U-Coat C-102", average polymer particle size: 168 nm, CV value = 0.23, solid content: 45 wt%), 0.1 parts of a leveling agent (manufactured by DIC, product name "F-444"), 1.1 parts of a crosslinking agent (tris[3-(2-methylaziridin-1-yl)propionic acid]=propyridinetrimethyl) and 24.3 parts of pure water.

[0149] (Application and drying of emulsion coating solution) The above emulsion coating solution was applied to the ITO layer surface of the conductive substrate to form a coating layer with a thickness of 20 μm. The coating was performed using a slot die at a line speed of 6 m / min. Next, the coating layer was dried at 25°C for 8 minutes to form an unpatterned PDLC layer with a thickness of 8 μm.

[0150] (Preparation of unpatterned PDLC film) Using a laminator, another conductive substrate was laminated on top of the unpatterned PDLC layer with a lamination pressure of 0.4 MPa / m, so that the ITO layer faced the unpatterned PDLC layer. This resulted in an unpatterned PDLC film.

[0151] (Irradiation with activated energy rays) On both sides of an unpatterned PDLC film, a portion of the conductive substrate was half-cut down to the transparent substrate to expose the transparent electrode layer, and this exposed portion was removed and used as an electrode. A photomask having a predetermined pattern was placed on the electrode-treated unpatterned PDLC film, and a voltage of 50V was applied while using a UV-LED lamp (Hamamatsu Photonics, product name "C11924-101", peak wavelength 365nm) at a rate of 10mW / cm². 2 The film was exposed to light for 10 minutes. This formed a first region in the PDLC layer containing an oriented liquid crystal polymer and a non-polymerizable liquid crystal compound, and a second region containing a polymerizable liquid crystal compound and a non-polymerizable liquid crystal compound, thereby obtaining a patterned PDLC film having the configuration of [conductive substrate / patterned PDLC layer / conductive substrate]. The obtained patterned PDLC film showed a haze of 7.8% in the irradiated area and 88.0% in the non-irradiated area when no voltage was applied. When a 50V AC voltage was applied, the haze in the irradiated area was 3.7% and the haze in the non-irradiated area was 3.6%.

[0152] (Lamination of UV-blocking layers) A UV-absorbing triacetylcellulose (TAC) film (Konica Minolta, "KC8UA", 80 μm thick) was laminated to one conductive substrate surface of the above-mentioned patterned PDLC via an acrylic adhesive layer to act as an ultraviolet-cutting layer. This resulted in a patterned PDLC film having the following structure: [First conductive substrate (KC8UA / PET substrate / ITO layer) / Patterned PDLC layer / Second conductive substrate (ITO layer / PET substrate)].

[0153] [Example 2] A patterned PDLC film having the configuration of [first conductive substrate (U4-400CL / PET substrate / ITO layer) / patterned PDLC layer / second conductive substrate (ITO layer / PET substrate)] was obtained in the same manner as in Example 1, except that a UV-absorbing film "U4-400CL" (60 μm thick) manufactured by Nexfil was laminated as an ultraviolet-cutting layer.

[0154] [Example 3] A patterned PDLC film having the configuration of [first conductive substrate (TJ25UL / U4-400CL / PET substrate / ITO layer) / patterned PDLC layer / second conductive substrate (ITO layer / PET substrate)] was obtained in the same manner as in Example 1, except that a UV-absorbing film "U4-400CL" and a UV-absorbing TAC film (manufactured by Fujifilm Corporation, "TJ25UL", thickness 25 μm) were laminated in this order from the PDLC layer side as the UV-cutting layer.

[0155] [Comparative Example 1] The patterned PDLC film before the UV-cutting layer was laminated was used as the patterned PDLC film for Comparative Example 1.

[0156] <Lightfastness Evaluation 1> From one side of the patterned PDLC film of Comparative Example 1, xenon light was shone at 120 W / m² using a Super Xenon Weather Meter SX-75 (manufactured by Suga Test Instruments Co., Ltd., under conditions of 30°C and 55% RH). 2 The PDLC film was irradiated at (300nm-400nm) for 125 hours, and a voltage was applied to the PDLC film after the predetermined irradiation time. The haze in the non-irradiated area was then measured. The measurement results are shown in Figure 9.

[0157] <Lightfastness Evaluation 2> The patterned PDLC films of Examples 1-3 were exposed to xenon light at 120 W / m² from the first conductive substrate side using a Super Xenon Weather Meter SX-75 (manufactured by Suga Test Instruments Co., Ltd., 30°C, 55% RH conditions). 2The PDLC film was irradiated at (300nm-400nm) for 125 hours. The haze in the non-irradiated region was measured for the PDLC film before and after irradiation when a voltage of 0V to 50V was applied. The measurement results, along with the absorption spectrum of the UV-cut layer, are shown in Figure 10.

[0158] Figures 9 and 10 show that by providing an ultraviolet-cutting layer on the side of the patterned PDLC film exposed to ultraviolet light, the reduction in the amount of haze change in the non-irradiated area is suppressed. Specifically, in Example 1, the haze in the non-irradiated area of ​​the patterned PDLC film was 3.6% and 86.5% when a 50V voltage was applied and when no voltage was applied, respectively, before xenon light irradiation. After 125 hours of irradiation, the haze was 15.0% and 82.0%, respectively, when a 50V voltage was applied and when no voltage was applied. In addition, in the light resistance evaluation of the patterned PDLC film of Comparative Example 1, the haze in the non-irradiated area was 3.6% and 88.0% when a 50V voltage was applied and when no voltage was applied, respectively, before xenon light irradiation. After 125 hours of irradiation, the haze was 52.7% and 85.3%, respectively. Furthermore, in Example 3, which is provided with an ultraviolet-cutting layer having high absorbance across the entire wavelength range of 300 nm to 380 nm and at a wavelength of 400 nm, the rate of change in the amount of haze before and after xenon light irradiation was 0.3% or less, indicating extremely excellent light resistance. [Industrial applicability]

[0159] The PDLC film of the present invention is suitably used in various applications such as advertisements, signboards, smart windows, and other displays. [Explanation of Symbols]

[0160] 100 PDLC film 10 First conductive base material 20 PDLC layers 22 Polymer Matrix 24 liquid crystal droplets 24a Polymerizable liquid crystal compound 24b Non-polymerizable liquid crystal compound 24c liquid crystal polymer 30 Second conductive base material

Claims

1. The material comprises, in this order, a first conductive substrate, a polymer-dispersed liquid crystal layer containing a polymer matrix, liquid crystal droplets dispersed in the polymer matrix, and a photopolymerization initiator, and a second conductive substrate. The polymer-dispersed liquid crystal layer has, in a plan view, a first region and a second region in which the amount of change in haze due to the application of voltage is different. The amount of change in haze due to the application of voltage in the first region is smaller than the amount of change in haze due to the application of voltage in the second region. The liquid crystal droplet in the second region comprises a polymerizable liquid crystal compound and a non-polymerizable liquid crystal compound. The liquid crystal droplet in the first region comprises a liquid crystal polymer which is a polymer of the polymerizable liquid crystal compound and the non-polymerizable liquid crystal compound, The first conductive substrate includes an ultraviolet-cutting layer, Polymer-dispersed liquid crystal film.

2. The polymer-dispersed liquid crystal film according to claim 1, wherein the absorbance of the ultraviolet-cutting layer at a wavelength of 350 nm is 2 or more.

3. The polymer-dispersed liquid crystal film according to claim 1, wherein, when the maximum absorption wavelength on the longest wavelength side of the photopolymerization initiator is A nm, the absorbance of the ultraviolet-cutting layer in the wavelength range of A-30 nm to A+50 nm is 5 or more.

4. The polymer-dispersed liquid crystal film according to claim 1, wherein, when the maximum absorption wavelength on the longest wavelength side of the photopolymerization initiator is A nm, the absorbance of the ultraviolet-cutting layer at a wavelength of A + 70 nm is 1.8 or more.

5. The polymer-dispersed liquid crystal film according to claim 1, wherein the photopolymerization initiator has a maximum absorption wavelength in the range of 300 nm to 340 nm.

6. The polymer-dispersed liquid crystal film according to claim 1, wherein the second conductive substrate includes an ultraviolet-cutting layer or a reflective layer.

7. The polymer-dispersed liquid crystal film according to claim 1, wherein the weight ratio of the non-polymerizable liquid crystal compound to the polymerizable liquid crystal compound in the second region (non-polymerizable liquid crystal compound: polymerizable liquid crystal compound) is 99:1 to 70:

30.

8. The polymer-dispersed liquid crystal film according to claim 1, wherein the difference between the haze of the first region and the haze of the second region increases when a voltage is applied.

9. The polymer-dispersed liquid crystal film according to claim 1, wherein the difference between the haze of the first region and the haze of the second region is reduced by the application of voltage.

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