Polymer-dispersed liquid crystal film and method for manufacturing polymer-dispersed liquid crystal film

Abstract

This invention provides a polymer-dispersed liquid crystal film capable of switching between a transparent state and a scattering state only in specific regions. The polymer-dispersed liquid crystal film of this invention sequentially comprises: a first transparent conductive film, a polymer-dispersed liquid crystal layer comprising a polymer matrix and liquid crystal droplets dispersed in the polymer matrix, and a second transparent conductive film. The polymer-dispersed liquid crystal layer, when viewed from above, has a first region and a second region with different haze changes due to applied voltage. The haze change in the first region due to applied voltage is less than that in the second region. The liquid crystal droplets in the first region comprise non-polymerizable liquid crystal compounds and liquid crystal polymers.

Description

Technical Field

[0001] This invention relates to a polymer-dispersed liquid crystal film and a method for manufacturing the polymer-dispersed liquid crystal film. Prior Technology

[0002] In recent years, dimming films that exhibit different appearances depending on the applied voltage have been applied to various applications such as advertising, signage boards, and smart windows.

[0003] A PDLC film, which has a polymer-dispersed liquid crystal (PDLC) layer between a pair of transparent electrode layers, is a type of dimming film. By switching between a voltage-applied state and a voltage-free state, it can switch between a light-scattering state (scattering state) and a light-transmitting state (non-scattering state or transparent state). Specifically, the PDLC layer includes a polymer matrix and droplets of liquid crystal compounds dispersed in the polymer matrix (liquid crystal droplets). The liquid crystal droplets can become scattering particles due to the refractive index difference between the liquid crystal compounds in the liquid crystal droplets and the polymer matrix, thus causing light scattering.

[0004] The aforementioned PDLC film typically presents a cloudy appearance under scattering conditions, thus it can exhibit two appearances: cloudy (scattering state) and transparent (non-scattering state). However, considering design considerations, there is a demand for dimming films that can present other appearances.

[0005] Regarding the above-mentioned requirements, Patent Document 1 proposes a dimming film that can adjust the overall incident light amount by using a dichroic material instead of a liquid crystal compound, thereby presenting a transparent appearance in a non-scattering state and a colored appearance in a scattering state. [Previous Technical Documents] [Patent Literature]

[0006] Patent Document 1: Japanese Patent Application Publication No. 2002-189123 Summary of the Invention

[0007] [The problem the invention aims to solve]

[0008] In the previous dimming film, the switching between transparent and scattering states was performed on the entire surface of the film, and it was not possible to switch only in a specific area.

[0009] The present invention was made to solve the aforementioned problems, and its main objective is to provide a polymer-dispersed liquid crystal film that can switch between a transparent state and a scattering state only in a specific region. [Technical means to solve the problem]

[0010] According to one aspect of the present invention, a polymer-dispersed liquid crystal film is provided, which sequentially comprises: a first transparent conductive film, a polymer-dispersed liquid crystal layer comprising a polymer matrix and liquid crystal droplets dispersed in the polymer matrix, and a second transparent conductive film. The polymer-dispersed liquid crystal layer has, in a top view, a first region and a second region with different haze changes due to applied voltage. The haze change in the first region due to applied voltage is less than the change in the second region. The liquid crystal droplets in the first region comprise non-polymerizable liquid crystal compounds and liquid crystal polymers. In one embodiment, the liquid crystal droplets in the second region comprise both non-polymerizable liquid crystal compounds and polymerizable liquid crystal compounds. In one embodiment, 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. [] In one embodiment, the liquid crystal polymer contained in the liquid crystal droplets in the first region is a polymerized product of the polymeric liquid crystal compound contained in the liquid crystal droplets in the second region. In one embodiment, the difference between the haze in the first region and the haze in the second region increases as voltage is applied. In one embodiment, the liquid crystal polymer contained in the liquid crystal droplet in the first region is in an unaligned state. In one embodiment, the difference between the haze in the first region and the haze in the second region decreases as voltage is applied. In one embodiment, the liquid crystal polymer contained in the liquid crystal droplet in the first region is oriented in a specific direction. According to another aspect of the present invention, a method for manufacturing a polymer-dispersed liquid crystal film is provided, comprising: coating a coating liquid comprising a polymer matrix forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, and a solvent onto a first transparent conductive film to obtain a coating layer; drying the coating layer to obtain a polymer-dispersed liquid crystal layer comprising a polymer matrix and liquid crystal droplets comprising the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound dispersed in the polymer matrix; depositing a second transparent conductive film onto the polymer-dispersed liquid crystal layer; and irradiating the polymer-dispersed liquid crystal layer with active energy lines in a specific pattern under a voltage applied between the first transparent conductive film and the second transparent conductive film to form a first region comprising liquid crystal droplets, wherein the liquid crystal droplets comprise a liquid crystal polymer as a polymerization product of the polymerizable liquid crystal compound and the non-polymerizable liquid crystal compound. According to another aspect of the present invention, a method for manufacturing a polymer-dispersed liquid crystal film is provided, comprising: coating a coating liquid comprising a polymer matrix forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, and a solvent onto a first transparent conductive film to obtain a coating layer; drying the coating layer to obtain a polymer-dispersed liquid crystal layer comprising a polymer matrix and liquid crystal droplets comprising the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound dispersed in the polymer matrix; depositing a second transparent conductive film onto the polymer-dispersed liquid crystal layer; and irradiating the polymer-dispersed liquid crystal layer with active energy lines in a specific pattern in a state where no voltage is applied between the first transparent conductive film and the second transparent conductive film to form a first region comprising liquid crystal droplets, wherein the liquid crystal droplets comprise a liquid crystal polymer as a polymerization product of the polymerizable liquid crystal compound and the non-polymerizable liquid crystal compound. In one embodiment, the coating liquid is an emulsion coating liquid comprising the above-mentioned non-polymerizable liquid crystal compound and liquid crystal particles of the above-mentioned polymerizable liquid crystal compound dispersed in the above-mentioned solvent. In one embodiment, the weight ratio (liquid crystal compound: polymer matrix forming resin) of the total content of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound in the coating liquid to the content of the polymer matrix forming resin is 30:70 to 70:30. In one embodiment, the weight ratio of the non-polymerizable liquid crystal compound to the polymerizable liquid crystal compound in the coating liquid (non-polymerizable liquid crystal compound: polymerizable liquid crystal compound) is 99:1 to 70:30. [Effects of the Invention]

[0011] According to an embodiment of the present invention, within a liquid crystal droplet containing a liquid crystal polymer, the alignment of the liquid crystal compound is restricted, thus suppressing haze changes caused by variations in the applied voltage state. Therefore, by changing the applied voltage state while maintaining a liquid crystal polymer within the liquid crystal droplet in the desired region, haze changes in that region can be suppressed, while haze changes in other regions can be prevented. As a result, a dimming film that exhibits a specific patterned appearance in either the case of applied voltage or no voltage applied, and a highly uniform appearance in another case, can be provided. Simple Explanation of the Diagram

[0012] Figure 1(a) is a schematic top view of an example of a PDLC membrane according to the first embodiment of the present invention, (b) is a schematic cross-sectional view illustrating the state of the PDLC membrane shown in (a) when no voltage is applied, and (c) is a schematic cross-sectional view illustrating the state of the PDLC membrane shown in (a) when a voltage is applied. Figure 2(a) is a schematic top view of an example of a PDLC membrane according to the second embodiment of the present invention, (b) is a schematic cross-sectional view illustrating the state of the PDLC membrane shown in (a) when no voltage is applied, and (c) is a schematic cross-sectional view illustrating the state of the PDLC membrane shown in (a) when a voltage is applied. Figure 3 is a schematic diagram illustrating one example of a method for manufacturing the PDLC film of the present invention. Figure 4 is a schematic diagram illustrating one example of a method for manufacturing the PDLC film of the present invention. Implementation

[0013] The preferred embodiments of the present invention will be described below, but the present invention is not limited to these embodiments. Furthermore, in this specification, the "~" indicating a numerical range includes both the upper and lower limits of the value.

[0014] A. Polymer-dispersed liquid crystal film The polymer-dispersed liquid crystal (PDLC) film of the present invention sequentially comprises: a first transparent conductive film, a PDLC layer comprising a polymer matrix and liquid crystal droplets dispersed in the polymer matrix, and a second transparent conductive film. The PDLC layer has a first region and a second region with different haze changes due to the applied voltage when viewed from above. The haze change in the first region due to the applied voltage is smaller than the change in the second region. The liquid crystal droplets in the first region comprise non-polymerizable liquid crystal compounds and liquid crystal polymers.

[0015] A-1. PDLC film of the first embodiment Figure 1(a) is a schematic top 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 sequentially comprises: a first transparent conductive film 10, a PDLC layer 20 comprising a polymer matrix 22 and liquid crystal droplets 24 dispersed in the polymer matrix 22, and a second transparent conductive film 30. The PDLC layer 20, in top view, has a first region A and a second region B with different haze changes due to the applied voltage. The liquid crystal droplets 24 in the first region A comprise a non-polymerizable liquid crystal compound 24a and a liquid crystal polymer 24c, typically with the liquid crystal polymer 24c existing in a non-aligned state. The liquid crystal droplets 24 in the second region B comprise a non-polymerizable liquid crystal compound 24a and a polymerizable liquid crystal compound 24b. Furthermore, in this specification, the phrase "in a non-oriented state" means that the compound is not arranged in a certain regularity.

[0016] As shown in Figure 1(b), in the PDLC film 100a without applied voltage, the non-polymerizable liquid crystal compound 24a and liquid crystal polymer 24c in the liquid crystal droplets 24 of region A are both in an unaligned state, and the non-polymerizable liquid crystal compound 24a and polymerizable liquid crystal compound 24b in the liquid crystal droplets 24 of region B are also in an unaligned state. Therefore, scattering of transmitted light occurs in both regions. Thus, both region A and region B can be in a scattering state, resulting in the PDLC film 100a being in a scattering state across its entire main surface.

[0017] On the other hand, as shown in Figure 1(c), in the PDLC film 100a under applied voltage, the non-polymerizable liquid crystal compound 24a and polymerizable liquid crystal compound 24b in the liquid crystal droplets 24 in region B are aligned in a direction perpendicular to the main surface of the transparent conductive films 10 and 30, suppressing the scattering of transmitted light, thus reducing the haze in this region. On the other hand, in region A, the presence of the non-aligned liquid crystal polymer 24c hinders the alignment of the non-polymerizable liquid crystal compound 24a, thereby maintaining the non-aligned state, and thus the scattering of transmitted light still occurs. Therefore, the amount of haze change in region A due to applied voltage is less than that in region B, and the difference between the haze in region A and region B increases with the application of voltage.

[0018] As described above, when no voltage is applied, the main surface of the PDLC film 100a is in a scattering state, presenting a cloudy appearance. On the other hand, by applying voltage, the haze of only the second region decreases significantly, resulting in a cloudy appearance in the first region and a transparent appearance in the second region. Therefore, the PDLC film 100a can present different appearances by switching between applying and not applying voltage.

[0019] The voltage applied to the PDLC film when voltage is applied is the voltage that causes the PDLC film to operate (operation voltage), for example, it can be 5 V to 200 V, preferably 10 V to 100 V. In this specification, "haze when voltage is applied" means the haze when the PDLC film is subjected to the operation voltage, for example, the haze when a voltage of 5 V or more, 10 V or more, or 20 V or more is applied.

[0020] The haze of the PDLC film in the region corresponding to the first region (hereinafter, sometimes simply referred to as "haze of the first region") when no voltage is applied is, for example, 50% to 100%, preferably 70% to 100%. The haze of the first region when voltage is applied is, for example, 40% to 100%, preferably 60% to 100%. The change in haze of the first region caused by the applied voltage (|haze when no voltage is applied - haze when voltage is applied|) is, for example, 0% to 40%, preferably 0% to 30%.

[0021] The haze of the PDLC film in the region corresponding to the second region (hereinafter, sometimes simply referred to as "haze of the second region") when no voltage is applied is, for example, 50% to 100%, preferably 70% to 100%. The haze of the second region when voltage is applied is, for example, 1% to 20%, preferably 1% to 10%. The change in haze of the second region caused by the applied voltage (|haze when no voltage is applied - haze when voltage is applied|) is, for example, 30% to 99%, preferably 60% to 99%.

[0022] The change in haze in the first region caused by the applied voltage is less than the change in haze in the second region caused by the applied voltage, with the difference being, for example, 10% to 99%, preferably 30% to 99%.

[0023] The total light transmittance of the PDLC film in the region corresponding to the first region (hereinafter, sometimes simply referred to as "the total light transmittance of the first region") when no voltage is applied 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 according to JIS K 7361.

[0024] The total light transmittance of the PDLC film in the region corresponding to the second region (hereinafter, sometimes simply referred to as "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%.

[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 transparent conductive film The first transparent conductive film 10 is typically characterized by having a first transparent substrate 12 and a first transparent electrode layer 14 disposed on one side thereof. The first transparent conductive film 10 may have a hard coating on one or both sides of the first transparent substrate 12 as needed, and may also have a refractive index adjustment layer between the first transparent substrate 12 and the first transparent electrode layer 14.

[0027] The surface resistivity of the first transparent conductive film is preferably 1 Ω / □ to 1000 Ω / □, more preferably 5 Ω / □ to 300 Ω / □, and even more preferably 10 Ω / □ to 200 Ω / □.

[0028] The haze value of the first transparent conductive film is preferably below 20%, more preferably below 10%, and even more preferably 0.1% to 10%.

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

[0030] The first transparent substrate can be formed from any suitable material. Specifically, polymeric substrates such as films or plastic substrates are preferred. This is because they offer excellent smoothness and wettability to the composition used to form the transparent electrode layer, and also allow for significant improvements in productivity through continuous production using rollers.

[0031] The material constituting the first transparent substrate is typically a polymer film with thermoplastic resin as the main component. Examples of thermoplastic resins include: polyester resins; cyclic olefin resins such as polyvinyl chloride; acrylic resins; polycarbonate resins; and cellulose resins. Polyester resins, cyclic olefin resins, or acrylic resins are preferred. These resins exhibit excellent transparency, mechanical strength, thermal stability, and water resistance. The aforementioned thermoplastic resins can be used alone or in combination of two or more. Furthermore, optical films used in polarizing plates (e.g., low-phase-difference substrates, high-phase-difference substrates, phase-difference plates, absorptive polarizing films, selective polarizing reflective films, etc.) can also be used as the first transparent substrate.

[0032] The thickness of the first transparent substrate is preferably less than 200 μm, 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 less than 200 μm, the function of the PDLC layer can be fully realized.

[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 can be formed, for example, using metal oxides such as indium tin oxide (ITO), zinc oxide (ZnO), or tin oxide (SnO2). Preferably, a transparent electrode layer containing ITO is formed. Transparent electrode layers containing ITO exhibit excellent transparency. The first transparent electrode layer can be patterned into a desired shape according to the purpose.

[0035] The 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 with transmittance within this range, a high transmittance is achieved in the transparent state. The higher the transmittance, the better, but its upper limit is, for example, 99%.

[0036] Preferably, the first transparent electrode layer contains grains. The presence of grains improves light transmittance. The method of grain formation is not limited; for example, grains can be formed appropriately by heating under atmospheric conditions. The area occupancy of the 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 is, for example, 100%. If the area occupancy of the grains is within the above range, light transmittance can be improved. Furthermore, the area occupancy of the grains can be calculated by observing the surface of the transparent electrode layer using a transmission electron microscope (TEM) and based on the area ratio of the crystalline 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, there is a risk of deterioration in adhesion to the substrate. The upper limit of the surface roughness Ra of the first transparent electrode layer is preferably less than 1.2 nm, more preferably less than 1.0 nm, and even more preferably less than 1.0 nm, and particularly preferably less than 0.8 nm. If the surface roughness Ra of the first transparent electrode layer is too large, it may become difficult to form grains appropriately. Furthermore, the surface roughness Ra in this specification 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. When the thickness of the transparent electrode layer is less than 10 nm, there is a risk of a decrease in the area occupancy of the grains. 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. When the thickness of the transparent electrode layer exceeds 50 nm, there is a risk of deterioration in transmittance, and also a risk of increased surface roughness of the transparent electrode layer.

[0039] The first transparent electrode layer is formed on one side of the first transparent substrate, for example, by sputtering. After the metal oxide layer is formed 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 refractive index adjustment layer can control the hue and / or transmittance of the PDLC film. The refractive index adjustment layer can be a single layer or a laminate of two or more layers.

[0041] The refractive index of the refractive index adjustment layer is preferably 1.3~1.8, more preferably 1.35~1.7, and even more preferably 1.38~1.68. In the case of a single layer, such as when the transparent electrode layer is ITO, a lower refractive index is desired to optically mitigate the refractive index of ITO, for example, preferably 1.38~1.46. This can appropriately reduce interfacial reflection between the transparent substrate and the transparent electrode layer.

[0042] The refractive index adjusting layer is formed by inorganic materials, organic materials, or mixtures of inorganic and organic materials. Examples of materials that can form the refractive index adjusting layer include: inorganic materials such as NaF, Na₃AlF₆, LiF, MgF₂, CaF₂, SiO₂, LaF₃, CeF₃, Al₂O₃, TiO₂, Ta₂O₅, ZrO₂, ZnO, ZnS, and SiO₂x (x is 1.5 or more but less than 2); and organic materials such as acrylic resin, epoxy resin, urethane resin, melamine resin, alkyd resin, and siloxane polymers. Especially preferred organic materials are thermosetting resins containing a mixture of melamine resin, alkyd resin, and organosilicon condensates.

[0043] The refractive index adjustment layer can contain nanoparticles with an average particle size 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.

[0044] The content of nanoparticles in the refractive index adjustment layer is preferably 0.1 wt% to 90 wt%. More preferably, the content of nanoparticles in the refractive index adjustment layer is 10 wt% to 80 wt%, and even more preferably 20 wt% to 70 wt%.

[0045] Examples of inorganic oxides that form nanoparticles include: silicon oxide, hollow nano-silica, titanium dioxide, aluminum oxide, zinc oxide, tin oxide, zirconium oxide, and niobium oxide. Among these, silicon oxide, titanium oxide, aluminum oxide, zinc oxide, tin oxide, zirconium oxide, and niobium oxide are preferred. One of these oxides may be used alone, or two or more may be used in combination.

[0046] 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 too small, continuous coating is difficult. Furthermore, if the thickness of the refractive index adjustment layer is too large, there is a tendency for the transparency to decrease in the transparent state or for cracks to easily form.

[0047] The refractive index adjustment layer can be made of the above-mentioned materials and formed by coating methods such as wet coating, gravure coating or bar coating, vacuum evaporation, sputtering, ion plating, etc.

[0048] A-1-2. PDLC layer The PDLC layer 20 comprises a polymer matrix 22 and droplets (liquid crystal droplets) 24 of liquid crystal compounds dispersed in the polymer matrix 22. As shown in FIG1, 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 non-polymerizable liquid crystal compounds 24a and non-aligned liquid crystal polymers 24c. The liquid crystal droplets 24 in the second region B comprise non-polymerizable liquid crystal compounds 24a and polymerizable liquid crystal compounds 24b. The first region A and the second region B can be formed in any suitable pattern according to the design required for the PDLC film.

[0049] The polymer matrix can contain any suitable resin. The resin for forming the polymer matrix can be appropriately selected based on factors such as light transmittance, the refractive index of the liquid crystal compound, and the adhesion to the transparent conductive film. For example, water-soluble or water-dispersible resins such as urethane resins, polyvinyl alcohol resins, polyethylene resins, polypropylene resins, and acrylic resins are preferred. The resin for forming the polymer matrix can be used alone or in combination.

[0050] The content ratio of the polymer matrix in the PDLC layer is between the first and second regions, for example, 30% to 70% by weight, preferably 35% to 65% by weight, and more preferably 40% to 60% by weight. If the content ratio of the polymer matrix is ​​within this range, the following effects can be obtained: good dimming function with appropriate operating voltage, good mechanical strength, and prevention of liquid crystal leakage from the ends.

[0051] As a non-polymerizable liquid crystal compound, any suitable liquid crystal compound can be used. Preferably, a liquid crystal compound having a birefringence Δn of 0.05 to 0.50 (=ne-no; ne is the refractive index along the long axis of the liquid crystal compound molecule, and no is the refractive index along the short axis of the liquid crystal compound molecule) at a wavelength of 589 nm is used, and more preferably, a birefringence Δn of 0.10 to 0.45 is used.

[0052] The dielectric anisotropy of nonpolymerizable liquid crystal compounds can be positive or negative. Examples of nonpolymerizable liquid crystal compounds include nematic, smectic, and cholesteric liquid crystal compounds. Nematic liquid crystal compounds are preferred for achieving excellent transparency in the transparent state.

[0053] Examples of nematic liquid crystal compounds include: biphenyl compounds, phenyl benzoate compounds, cyclohexylbenzene compounds, oxazobenzene compounds, azobenzene compounds, methyleneazo compounds, terphenyl compounds, biphenyl benzoate compounds, cyclohexylbiphenyl compounds, phenylpyridine compounds, cyclohexylpyrimidine compounds, cholesterol compounds, and fluorine compounds. These low-molecular-weight liquid crystal compounds can be used alone or in combination.

[0054] The polymerizable liquid crystal compound can be appropriately selected based on factors such as light transmittance and compatibility with non-polymerizable liquid crystal compounds. The polymerizable liquid crystal compound can be a cross-linked type with two or more functions. Examples of polymerizable liquid crystal compounds include those described in Japanese Patent Publication No. 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US4388453), WO93 / 22397, EP0261712, DE19504224, DE4408171, and GB2280445. A specific example of such a polymerizable liquid crystal compound is BASF's trade name LC242. A nematic liquid crystal monomer is preferred as the polymerizable liquid crystal compound.

[0055] Liquid crystal polymers are representative of the polymerized products of the aforementioned polymeric liquid crystal compounds. Polymers can be formed by the polymerization of polymeric liquid crystal compounds, and network structures can be formed by cross-linking, but these are non-liquid crystals. Therefore, the transformation to liquid crystal phase, glassy phase, or crystalline phase caused by temperature changes, which is characteristic of liquid crystal compounds, does not occur in liquid crystal polymers.

[0056] The liquid crystal polymer in liquid crystal droplets is typically present in an unaligned state. By making the liquid crystal polymer in the liquid crystal droplet unaligned, even when a voltage is applied, the first region can maintain a high haze (e.g., 40% to 100%, preferably 60% to 100%).

[0057] 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 70% by weight, preferably 35% to 65% by weight, and even more preferably 40% to 60% by weight. Furthermore, the weight ratio of the non-polymerizable liquid crystal compound to the liquid crystal polymer in the first region (non-polymerizable liquid crystal compound: liquid crystal polymer) is, for example, 99:1 to 70:30, preferably 95:5 to 80:20. Also, the total content ratio of the polymer matrix, the non-polymerizable liquid crystal compound, and the liquid crystal polymer in the first region can be, for example, 90% to 99.9% by weight, preferably 95% to 99.9% by weight.

[0058] The total content ratio of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound in the second region is, for example, 30% to 70% by weight, preferably 35% to 65% by weight, and even more preferably 40% to 60% by weight. Furthermore, 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, for example, 99:1 to 70:30, preferably 95:5 to 80:20. Also, the total content ratio of the polymer matrix, the non-polymerizable liquid crystal compound, and the polymerizable liquid crystal compound in the second region can be, for example, 90% to 99.9% by weight, preferably 95% to 99.9% by weight.

[0059] As detailed in section B, the PDLC layer having regions 1 and 2 can be formed by polymerizing the liquid crystal compound in a specific region of the PDLC layer containing liquid crystal droplets containing both non-polymerizable liquid crystal compounds and polymerizable liquid crystal compounds to form a liquid crystal polymer; in this case, the specific region becomes region 1, and the other regions become region 2. Therefore, in regions 1 and 2, the liquid crystal droplets can further contain a polymerization initiator. The content ratio of the polymerization initiator is as described in section B. Furthermore, unreacted polymerizable liquid crystal compounds may remain in the liquid crystal droplets in region 1. The content ratio of unreacted polymerizable liquid crystal compounds in region 1 is, for example, 3% by weight or less, preferably 1% by weight or less. Furthermore, in the liquid crystal droplets in region 2, it is preferable that liquid crystal polymers are substantially absent. The content ratio of liquid crystal polymers in region 2 is, for example, 3% by weight or less, preferably 1% by weight or less.

[0060] The average particle size of the liquid crystal droplets can 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, so the light passes through the droplets without being scattered, which may result in insufficient haze. Conversely, if the average particle size is too large, the droplet size is much larger than the wavelength of light, which may also result in insufficient haze. Furthermore, the average particle size of the liquid crystal droplets in the PDLC layer mentioned above refers to the volume average particle size of the liquid crystal droplets when viewed from a direction perpendicular to the main surface of the PDLC film.

[0061] The thickness of the PDLC layer is typically 2 μm to 40 μm, preferably 3 μm to 35 μm, and even more preferably 4 μm to 30 μm.

[0062] A-1-3. Second transparent conductive film The second transparent conductive film 30 is typically characterized by having a second transparent substrate 32 and a second transparent electrode layer 34 disposed on one side thereof. The second transparent conductive film 30 may have a hard coating on one or both sides of the second transparent substrate 32 as needed, and may also have a refractive index adjustment layer between the second transparent substrate 32 and the second transparent electrode layer 34.

[0063] The surface resistivity of the second transparent conductive film is preferably 1 Ω / □ to 1000 Ω / □, more preferably 5 Ω / □ to 300 Ω / □, and even more preferably 10 Ω / □ to 200 Ω / □.

[0064] The haze value of the second transparent conductive film is preferably below 20%, more preferably below 10%, and even more preferably 0.1% to 10%.

[0065] The total light transmittance of the second transparent conductive film is preferably 30% or more, more preferably 60% or more, and even more preferably 80% or more.

[0066] The same descriptions as those for the first transparent substrate and the first transparent electrode layer can be applied to the second transparent substrate and the first transparent electrode layer. The second transparent conductive film may have the same structure as the first transparent conductive film, or it may have a different structure from the first transparent conductive film.

[0067] A-2. PDLC film of embodiment 2 Figure 2(a) is a schematic top view of an example of a PDLC film according to the 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 a voltage is applied. The PDLC film 100b sequentially includes: a first transparent conductive film 10, a PDLC layer 20 comprising a polymer matrix 22 and liquid crystal droplets 24 dispersed in the polymer matrix 22, and a second transparent conductive film 30. The PDLC layer 20 has a first region A and a second region B with different haze changes due to the applied voltage when viewed from top. The liquid crystal droplets 24 in the first region A comprise a non-polymerizable liquid crystal compound 24a and a liquid crystal polymer 24c, and representatively, the liquid crystal polymer 24c is oriented in a specific direction (in the example shown, the direction perpendicular to the main surface of the transparent conductive films 10 and 30). The liquid crystal droplets 24 in region B contain non-polymerizable liquid crystal compound 24a and polymerizable liquid crystal compound 24b. []

[0068] As shown in Figure 2(b), in the PDLC film 100b without applied voltage, the non-polymerizable liquid crystal compound 24a and polymerizable liquid crystal compound 24b in the liquid crystal droplets 24 in region B are both in an unaligned state, thus causing scattering of transmitted light. On the other hand, in region A, the non-polymerizable liquid crystal compound 24a is aligned along the alignment direction of the liquid crystal polymer 24c, thereby suppressing the scattering of transmitted light. Therefore, in the PDLC film 100b, region A can be transparent, and region B can be scattering.

[0069] On the other hand, as shown in Figure 2(c), in the PDLC film 100b under applied voltage, the non-polymerizable liquid crystal compound 24a and polymerizable liquid crystal compound 24b in the liquid crystal droplets 24 in region B are aligned in a direction perpendicular to the main surface of the transparent conductive films 10 and 30, suppressing the scattering of transmitted light, resulting in a decrease in haze. On the other hand, in region A, the alignment of the non-polymerizable liquid crystal compound 24a does not change significantly, thus still suppressing the scattering of transmitted light. Therefore, the amount of haze change in region A due to applied voltage is less than that in region B, and the difference in haze between region A and region B decreases with the application of voltage.

[0070] As described above, the PDLC film 100b exhibits a transparent first region and a cloudy second region when no voltage is applied. By applying voltage, the haze in the second region is significantly reduced, and both regions become transparent, resulting in an overall transparent appearance on the main surface. Therefore, the PDLC film 100b can exhibit different appearances by switching between applying and not applying voltage.

[0071] The voltage applied to the PDLC film when the voltage is applied is the voltage that can make the PDLC film operate (operation voltage), for example, it can be 5 V to 200 V, preferably 10 V to 100 V.

[0072] 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 haze in the first region caused by the applied voltage (|haze when no voltage is applied - haze when voltage is applied|) is, for example, 0% to 20%, preferably 0% to 10%.

[0073] 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 haze in the second region caused by the applied voltage (|haze when no voltage is applied - haze when voltage is applied|) is, for example, 30% to 99%, preferably 60% to 99%.

[0074] The change in haze in the first region caused by the applied voltage is less than the change in haze in the second region caused by the applied voltage, with the difference being, for example, 10% to 99%, preferably 30% to 99%.

[0075] 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%.

[0076] 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%.

[0077] The thickness of the PDLC film is, for example, 30 μm to 250 μm, preferably 50 μm to 150 μm.

[0078] Regarding the PDLC film of the second embodiment, the first transparent conductive film and the second transparent conductive film can be described in the same way as the first transparent conductive film and the second transparent conductive film in the PDLC film of the first embodiment. Furthermore, regarding the PDLC layer, except that the liquid crystal polymer contained in the liquid crystal droplets in the first region is aligned in a specific direction, the same way as the PDLC layer in the PDLC film of the first embodiment can be described.

[0079] In the first region of the PDLC layer, the liquid crystal polymer contained in the liquid crystal droplet is aligned in a specific direction. Preferably, the liquid crystal polymer is aligned in a direction substantially perpendicular to the main surfaces of the first and second transparent conductive films, for example, at an angle of 90°±5°, more preferably 90°±3°. By aligning the liquid crystal polymer in the liquid crystal droplet in a specific direction, even without applied voltage, the first region can maintain a low haze (e.g., 1%~20%, more preferably 1%~10%).

[0080] B. Manufacturing method of polymer-dispersed liquid crystal film According to one embodiment of the present invention, a method for manufacturing a polymer-dispersed liquid crystal (PDLC) film is provided. The method for manufacturing a PDLC film according to an embodiment of the present invention includes: (Step A) A coating liquid comprising a polymer matrix forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, and a solvent is coated onto the first transparent conductive film to obtain a coating layer; (Step B) The coating layer is dried to obtain a PDLC layer comprising a polymer matrix and liquid crystal droplets containing the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound dispersed in the polymer matrix; (Step C) Deposit a second transparent conductive film onto the PDLC layer; and (Step D) The PDLC layer is irradiated with active energy lines in a specific pattern to form a first region containing liquid crystal droplets, wherein the liquid crystal droplets contain a liquid crystal polymer, which is a polymerization product of the polymerizable liquid crystal compound, and the non-polymerizable liquid crystal compound. According to the method for manufacturing a PDLC film according to an embodiment of the present invention, a PDLC layer having a first region in which the liquid crystal droplets contain both a non-polymerizable liquid crystal compound and a liquid crystal polymer, and a second region in which the liquid crystal droplets contain both a non-polymerizable liquid crystal compound and a polymerizable liquid crystal compound, can be formed, resulting in a suitable PDLC film as described in item A.

[0081] In one embodiment, the active energy line irradiation in step D is performed without voltage applied between the first transparent conductive film and the second transparent conductive film. In another embodiment, the active energy line irradiation in step D is performed with voltage applied between the first transparent conductive film and the second transparent conductive film.

[0082] B-1. Step A In step A, a coating liquid comprising a polymer matrix forming resin, a non-polymeric liquid crystal compound, a polymeric liquid crystal compound, and a solvent is coated onto the first transparent conductive film to obtain a coating layer.

[0083] The coating liquid described above is preferably an emulsion (hereinafter sometimes referred to as "emulsion coating liquid") consisting of liquid crystal particles containing non-polymerizable liquid crystal compounds and polymerizable liquid crystal compounds dispersed in a solvent. In one embodiment, the coating liquid is an emulsion coating liquid consisting of polymer matrix forming resin particles and liquid crystal particles containing non-polymerizable liquid crystal compounds and polymerizable liquid crystal compounds dispersed in a solvent. The emulsion coating liquid preferably further contains a polymerization initiator in the liquid crystal particles, and may further contain any suitable additives depending on the purpose.

[0084] As a solvent, water or a mixture of water-miscible organic solvents is preferred. Examples of water-miscible organic solvents include: C1-3 alcohols, acetone, and DMSO (dimethyl sulfoxide). For non-polymerizable liquid crystal compounds, polymerizable liquid crystal compounds, and resins for forming polymer matrices, see section A-1-2. Examples of optional additives include: dispersants, leveling agents, and crosslinking agents.

[0085] The content ratio of liquid crystal compounds in the solid components of the coating liquid (the total content ratio of non-polymeric liquid crystal compounds and polymeric liquid crystal compounds) can be, for example, 30% to 70% by weight, more preferably 35% to 65% by weight, and even more preferably 40% to 60% by weight.

[0086] The weight ratio of non-polymerizable liquid crystal compound to polymerizable liquid crystal compound 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.

[0087] The content of the polymer matrix forming resin in the solid component of the coating liquid can be, for example, 30% to 70% by weight, more preferably 35% to 65% by weight, and even more preferably 40% to 60% by weight.

[0088] The weight ratio of the liquid crystal compound content (total content of non-polymerizable liquid crystal compound and polymerizable liquid crystal compound) to the polymer matrix forming resin content in the coating liquid (liquid crystal compound: polymer matrix forming resin) can be, for example, 30:70~70:30, more preferably 35:65~65:35, and even more preferably 40:60~60:40. Furthermore, the total content ratio of polymer matrix forming resin, non-polymerizable liquid crystal compound, and polymerizable liquid crystal compound in the solid components of the coating liquid can be, for example, 90%~99.9% by weight, more preferably 95%~99.9% by weight.

[0089] The average particle size of the liquid crystal particles is preferably 0.3 μm or more, and more preferably 0.4 μm or more. Furthermore, the average particle size of the liquid crystal particles is preferably 9 μm or less, and more preferably 8 μm or less. If the average particle size of the liquid crystal particles is within this range, the average particle size of the liquid crystal droplets in the PDLC layer can be within the desired range. Moreover, the above-mentioned average particle size of the liquid crystal particles is the volume average particle size.

[0090] The average particle size of the liquid crystal particles preferably has a relatively narrow particle size distribution. The coefficient of variation (CV) of the average particle size of the liquid crystal particles may be less than 0.40, preferably less than 0.35, and more preferably less than 0.30. In one embodiment, an emulsion coating liquid that substantially does not contain liquid crystal particles with a particle size less than 0.3 μm or greater than 9 μm can be used (e.g., an emulsion coating liquid in which the volume of liquid crystal particles with a particle size less than 0.3 μm or greater than 9 μm is 10% or less relative to the total volume of liquid crystal particles).

[0091] The average particle size of the resin particles used 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. Different types of resin and / or two or more types of resin particles with different average particle sizes can be used. The average particle size of the resin particles used for forming the polymer matrix refers to the volume average median particle size, which can be measured using a dynamic light scattering particle size distribution measuring device.

[0092] As polymerization initiators, any suitable photopolymerization initiator can be used depending on the purpose and desired properties. Specific examples of photopolymerization initiators include: 2,2-dimethoxy-2-phenylacetophenone, acetophenone, benzophenone, benzoyl peroxide, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, benzoyl ether, benzoin dimethyl ketal, N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone, 1-(4-isopropylphenyl)-2 -Hydroxy-2-methylpropane-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-dipentoxyphenylphosphine oxide, bis(2,6-dimethoxy-benzoyl)-(2,4,4-trimethyl-pentyl)-phosphine oxide, 9-oxosulfuron It is a compound. The photopolymerization initiator can be used alone or in combination with two or more. The content ratio of the photopolymerization initiator relative to 100 parts by weight of the polymerizable liquid crystal compound is preferably 0.1 parts by weight to 10 parts by weight, and more preferably 0.5 parts by weight to 5 parts by weight.

[0093] Examples of dispersants include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. The content ratio of the dispersant relative to 100 parts by weight of the emulsion coating liquid is preferably 0.05 parts by weight to 10 parts by weight, and more preferably 0.1 parts by weight to 1 part by weight.

[0094] Examples of leveling agents include acrylic leveling agents, fluorinated leveling agents, and silicone leveling agents. The content ratio of the leveling agent relative to 100 parts by weight of the emulsion coating liquid is preferably 0.05 parts by weight to 10 parts by weight, and more preferably 0.1 parts by weight to 1 part by weight.

[0095] Examples of crosslinking agents include aziridine-based crosslinking agents and isocyanate-based crosslinking agents. The crosslinking agent content ratio is preferably 0.5 to 10 parts by weight, and more preferably 0.8 to 5 parts by weight, relative to 100 parts by weight of the emulsion coating liquid.

[0096] Emulsion coating solutions can be prepared, for example, by mixing a resin emulsion or resin particle dispersion containing resin particles for forming a polymer matrix, a liquid crystal emulsion containing liquid crystal particles containing a liquid crystal compound and a polymerization initiator, and any additives (e.g., dispersants, leveling agents, crosslinking agents). A solvent may also be added during mixing as needed. Alternatively, emulsion coating solutions can be prepared by adding a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, a water-dispersible resin, a polymerization initiator, and any additives to a solvent and then mechanically dispersing it.

[0097] The aforementioned resin emulsions and liquid crystal emulsions can be prepared, for example, by mechanical emulsification, microchannel method, or membrane emulsification. Liquid crystal emulsions are preferably prepared by membrane emulsification. Membrane emulsification allows for the suitable acquisition of emulsions with uniform particle size distribution. For details regarding membrane emulsification, please refer to Japanese Patent Application Publication No. 4-355719 and Japanese Patent Application Publication No. 2015-40994 (which are incorporated herein by reference).

[0098] The concentration of solids in the emulsion coating solution can be, for example, 20% to 60% by weight, preferably 30% to 50% by weight.

[0099] The viscosity of the emulsion coating solution can be adjusted appropriately to ensure suitable coating of the first transparent conductive film. The viscosity of the emulsion coating solution during coating is preferably 20 mPas to 400 mPas, more preferably 30 mPas to 300 mPas, and even more preferably 40 mPas to 200 mPas. When the viscosity is below 20 mPas, there is a risk that the solvent's convective rheology will be significant during drying, leading to instability in the thickness of the PDLC layer. Furthermore, when the viscosity exceeds 400 mPas, there is a risk that the beads of the emulsion coating solution will be unstable. The viscosity of the emulsion coating solution can be measured, for example, using a rheometer MCR302 manufactured by Anton Paar. The viscosity value here is the shear viscosity value under conditions of 20°C and a shear rate of 1000 (1 / s).

[0100] The emulsion coating solution is typically coated on the transparent electrode layer side surface of the first transparent conductive film. The first transparent conductive film is described in section A-1-1.

[0101] As a coating method, any suitable method can be used. Examples include: roller coating, spin coating, wire rod coating, dip coating, die coating, curtain coating, spray coating, and blade coating (such as corner wheel coating). Among these, roller coating is preferred. For example, regarding coating performed by roller coating using a slit die, please refer to the description in Japanese Patent Application Publication No. 2019-5698.

[0102] 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.

[0103] B-2. Step B In step B, the coating layer is dried to obtain a PDLC layer comprising a polymer matrix and liquid crystal droplets containing non-polymerizable liquid crystal compounds and polymerizable liquid crystal compounds dispersed in the polymer matrix. By drying the coating layer to remove the solvent, the polymer matrix is ​​formed by the fusion of resin particles, thereby forming a PDLC layer with a structure in which liquid crystal droplets are dispersed in the polymer matrix.

[0104] The coating layer can be dried by any suitable method. Specific examples of drying methods include: heat drying, hot air drying, etc. When the emulsion coating liquid contains a crosslinking agent, a crosslinked structure of the polymer matrix can be formed during drying.

[0105] The optimal drying temperature is 20℃~150℃, more preferably 25℃~80℃. The optimal drying time is 1 minute~100 minutes, more preferably 2 minutes~10 minutes.

[0106] B-3. ​​Step C In step C, a second transparent conductive film is deposited on the PDLC layer. This yields a PDLC film having a first transparent conductive film, a PDLC layer, and a second transparent conductive film in sequence.

[0107] Regarding the second conductive film, as described in section A-1-3, the deposition of the second transparent conductive film on the PDLC layer is performed with the second transparent electrode layer side facing the PDLC layer. From the viewpoint of obtaining sufficient adhesion, this deposition can preferably be performed using a laminating machine, applying a lamination pressure of 0.006 MPa / m to 7 MPa / m, more preferably 0.06 MPa / m to 0.7 MPa / m.

[0108] B-4. Step D In step D, the PDLC layer is irradiated with active energy lines in a specific pattern to form a first region containing liquid crystal droplets. These liquid crystal droplets contain a liquid crystal polymer, a polymerization product of a polymerizable liquid crystal compound, and a non-polymerizable liquid crystal compound. Specifically, in the irradiated region (irradiated area), the polymerizable liquid crystal compound in the liquid crystal droplets polymerizes to form a liquid crystal polymer, resulting in liquid crystal droplets containing both a non-polymerizable liquid crystal compound and a liquid crystal polymer. Conversely, in the unirradiated region (unirradiated area), the polymerizable liquid crystal compound exists in an unreacted state, resulting in liquid crystal droplets containing both a non-polymerizable liquid crystal compound and a polymerizable liquid crystal compound. Therefore, the irradiated region of the PDLC layer becomes the first region A containing liquid crystal droplets containing both a non-polymerizable liquid crystal compound and a liquid crystal polymer, and the unirradiated region becomes the second region B containing liquid crystal droplets containing both a non-polymerizable liquid crystal compound and a polymerizable liquid crystal compound. The liquid crystal polymer contained in the liquid crystal droplets in the first region A is a polymerization product of the polymerizable liquid crystal compound contained in the liquid crystal droplets in the second region B. Furthermore, the ratio of non-polymerizable liquid crystal compounds to polymerizable liquid crystal compounds in the droplets in the unirradiated area can roughly correspond to the ratio of non-polymerizable liquid crystal compounds to polymerizable liquid crystal compounds in the coating liquid when the liquid crystal droplets are initially formed. []

[0109] Irradiation with active energy rays is achieved through a photomask with a specific pattern. Active energy rays can be ultraviolet light, infrared light, X-rays, alpha rays, beta rays, gamma rays, and electron beams. Ultraviolet light is preferred. Furthermore, the active energy rays are preferably collimated light with high directivity from the irradiation source.

[0110] The ultraviolet irradiation conditions can be appropriately set according to the type of polymerizable liquid crystal compound, the transmittance of the transparent conductive film, and the absorption wavelength of the photopolymerization initiator. The irradiation intensity can be, for example, 0.1 mW / cm² to 1000 mW / cm², preferably 1 mW / cm² to 100 mW / cm². The irradiation dose can be, for example, 10 mJ / cm² to 10000 mJ / cm², preferably 100 mJ / cm² to 5000 mJ / cm². The irradiation temperature can be, for example, -20℃ to 80℃, preferably -20℃ to 60℃.

[0111] Figures 3 and 4 are schematic diagrams illustrating an example of active energy line irradiation in the manufacturing method of the PDLC film according to an embodiment of the present invention. In the embodiment shown in Figure 3, the active energy line irradiation is performed with a dielectric photomask 40, without voltage applied between the first transparent conductive film 10 and the second transparent conductive film 30. According to this embodiment, in the liquid crystal droplets 24 of the irradiation region of the PDLC layer 20, the polymerizable liquid crystal compound 24b polymerizes in a non-aligned state, and therefore the formed liquid crystal polymer 24c is also in 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.

[0112] In the embodiment shown in Figure 4, the active energy line irradiation system is a dielectric photomask 40, performed with a voltage applied between the first transparent conductive film 10 and the second transparent conductive film 30. According to this embodiment, in the liquid crystal droplets 24 of the irradiation region of the PDLC layer 20, the polymerizable liquid crystal compound 24b polymerizes in a state where it is aligned along the electric field in a specific direction (in the example shown, a direction perpendicular to the main surfaces of the transparent conductive films 10 and 30), thus forming an aligned liquid crystal polymer 24c. Therefore, according to this embodiment, the PDLC film of the second embodiment described in item A-2 can be suitably obtained. Furthermore, the voltage applied during active energy line irradiation is not limited as long as the desired alignment (in other words, the desired haze in the first region) can be achieved; for example, it can be 10 V to 200 V, preferably 20 V to 100 V.

[0113] In one embodiment, by irradiating the PDLC film with active energy lines using a photomask having multiple light-transmitting portions with different aperture ratios, a first region can be formed in the region corresponding to each light-transmitting portion at a ratio corresponding to its aperture ratio. Therefore, in the obtained PDLC film, the region corresponding to each light-transmitting portion can display a haze corresponding to its aperture ratio when viewed as a whole.

[0114] For example, by using a photomask with an aperture ratio that continuously increases from the right end to the left end, and irradiating active energy lines without applying voltage, a PDLC film can be obtained in which the entire surface is in a scattering state when no voltage is applied, and exhibits an appearance where the haze continuously increases from the right end to the left end when voltage is applied. As another example, by using a photomask with an aperture ratio that continuously increases from the right end to the left end, and irradiating active energy lines with voltage applied, a PDLC film can be obtained in which the entire surface is in a transparent state when voltage is applied, and exhibits an appearance where the haze continuously decreases from the right end to the left end when no voltage is applied. [Example]

[0115] The present invention will now be specifically described by way of examples, but the present invention is not limited to these examples in any way. The methods for measuring each characteristic are described below. Also, unless otherwise specified, "parts" and "%" in the examples and comparative examples are based on weight.

[0116] (1) Thickness The measurements were performed using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C"). (2) Volume average particle size of liquid crystal particles in liquid crystal emulsion 0.1% by weight of liquid crystal emulsion was added to 200 ml of an electrolyte aqueous solution (manufactured by Coulter, "ISOTON II"). The resulting mixture was used as the test sample. Using a Multisizer 3 (manufactured by Coulter, pore size = 20 μm), the volume of each particle size from 0.4 μm to 12 μm was statistically analyzed by dividing it into 256 discrete particles at logarithmic intervals, and the volume average particle size was calculated. Furthermore, when particles larger than 12 μm were present, the pore size was set to 30 μm, and the volume of each particle size from 0.6 μm to 18 μm was statistically analyzed by dividing it into 256 discrete particles at logarithmic intervals, and the volume average particle size was calculated. (3) Average particle size of resin particles A few drops of resin dispersion were added to 100 mL of water to prepare the test sample. Using a dynamic light scattering particle size distribution analyzer (manufactured by Microtrac, device name "Nanotrac150"), the test sample was placed in the measurement holder of the device, and the concentration that could be measured was confirmed by the monitor of the device before the measurement was performed. (4) Haze The product name "NDH4000" manufactured by Nippon Denshoku Co., Ltd. was used, and the test was conducted based on JIS K 7136.

[0117] [Example 1] (First and second transparent conductive films) An ITO layer is formed on one side of a PET substrate (thickness: 50 μm) by sputtering, thereby obtaining a transparent conductive film with a structure of [transparent substrate / transparent electrode layer].

[0118] (Preparation of emulsion coating solution) A liquid crystal emulsion was prepared by mixing 53.7 parts of a nonpolymerizable liquid crystal compound (manufactured by JNC Corporation, 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 BASF Corporation, product name "PALIOCOLOR LC-242"), 0.1 parts of a photopolymerization initiator (manufactured by IGM Corporation, product name "OMNIRAD651"), 39.8 parts of pure water, and 0.5 parts of a dispersant (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd., "Noigen ET159"). The mixture was stirred at 100 rpm for 10 minutes using a homogenizer. The average particle size of the liquid crystal particles in the obtained liquid crystal emulsion was 3.4 μm. The above liquid crystal emulsion (38.4 parts), polyether-based polyurethane resin aqueous dispersion (manufactured by DSM Corporation, trade name "NeoRez R967", average polymer particle size: 80 nm, CV value = 0.27, solid content: 40 wt%) (19.1 parts), polyester-based polyurethane resin aqueous dispersion (manufactured by Sanyo Chemical Co., Ltd., trade name "UCOAT C-102", average polymer particle size: 168 nm, CV value = 0.23, solid content: 45 wt%) (17.0 parts), leveling agent (manufactured by DIC Corporation, product name "F-444"), crosslinking agent (tris[3-(2-methylaziridin-1-yl)propionic acid] = trimethyl propyltrimethyl ester), and pure water (24.3 parts) were mixed to obtain an emulsion coating solution (solid content concentration: 40 wt%).

[0119] (Emulsion coating solution application and drying) The above-mentioned emulsion coating solution was applied to the ITO layer of the first transparent conductive film to form a coating layer with a thickness of 20 μm. The coating was performed using a slit nozzle at a linear speed of 6 m / min. Subsequently, the coating layer was dried at 25°C for 8 minutes to form a PDLC layer with a thickness of 8 μm.

[0120] (Layering of the second transparent conductive film) A second transparent conductive film is deposited on the PDLC layer using a laminating machine with a lamination pressure of 0.4 MPa / m, with an ITO layer facing the PDLC layer. This yields the PDLC film.

[0121] (Irradiation with active energy lines) On both sides of the PDLC film, a portion of the transparent conductive film is half-cut to the transparent substrate, exposing the transparent electrode layer. This exposed portion is then removed and used as an electrode. A photomask with a specific pattern is placed on the PDLC film with the electrode treatment applied. A voltage of 50 V is applied to one side, and the film is exposed to UV-LED (Ultraviolet-Light Emitting Diode) lamp (manufactured by Hamamatsu Photonics, product name "C11924-101", peak wavelength 365 nm) at 10 mW / cm² for 10 minutes.

[0122] [Example 2] The PDLC film was obtained by irradiating it with ultraviolet light without applying voltage (applied voltage: 0 V), otherwise in the same manner as in Example 1.

[0123] The optical properties of the PDLC films obtained in the examples were evaluated using the following methods. The results are shown in Table 1. Optical properties The haze of the PDLC film was measured using an AC power supply "EC750SA" manufactured by NF Circuit Design Company when an AC voltage of 0 V to 50 V was applied.

[0124] [Table 1] Apply voltage (V) Example 1 Example 2 Area 1 (Irradiated area) Area 2 (Unirradiated area) Area 1 (Irradiated area) Area 2 (Unirradiated area) Haze (%) 0 6.8 94.2 94.2 94.2 2 6.8 94.2 94.2 94.2 4 6.8 94.1 94.2 94.1 6 6.8 93.2 94.1 93.2 8 6.7 87.5 94.1 87.5 10 6.6 70.0 94.1 70.0 12 6.5 49.4 94.0 49.4 14 6.4 35.3 93.9 35.3 16 6.3 26.9 93.7 26.9 18 6.2 21.9 93.5 21.9 20 6.1 18.3 93.2 18.3 22 6.0 15.9 92.8 15.9 24 5.9 14.1 92.3 14.1 26 5.8 12.5 91.5 12.5 28 5.7 11.4 90.7 11.4 30 5.6 10.4 89.7 10.4 35 5.3 8.6 87.2 8.6 40 5.1 7.3 84.2 7.3 45 4.9 6.4 81.1 6.4 50 4.7 5.7 77.9 5.7

[0125] As shown in Table 1, in all the PDLC films obtained in the embodiments, the change in fog intensity caused by the applied voltage in the first region (irradiated region) was less than the change in fog intensity in the second region (unirradiated region). Furthermore, the PDLC film of Embodiment 1, in the absence of applied voltage, exhibits a specific pattern composed of a transparent first region and a cloudy second region, and when a voltage of 50 V is applied, it exhibits a highly uniform appearance with the entire main surface being transparent. On the other hand, the PDLC film of Embodiment 2, in the absence of applied voltage, exhibits a highly uniform appearance with the entire main surface being cloudy, and when a voltage of 50 V is applied, it exhibits a specific pattern composed of a cloudy first region and a transparent second region. [Industrial Applicability]

[0126] The PDLC film of this invention can be suitable for various applications such as advertising, guide boards and displays, and smart windows.

[0127] 10: First transparent conductive film 12: First transparent substrate 14: First transparent electrode layer 20: PDLC layer 22: Polymer matrix 24:LCD droplets 24a: Non-polymerizable liquid crystal compound 24b: Polymerizable liquid crystal compound 24c: Liquid Crystal Polymer 30: Second transparent conductive film 32: Second transparent substrate 34: Second transparent electrode layer 100: PDLC membrane 100a: PDLC membrane 100b: PDLC membrane A: Area 1 B: Area 2

Claims

1. A polymer-dispersed liquid crystal film, comprising, in sequence: a first transparent conductive film, a polymer-dispersed liquid crystal layer comprising a polymer matrix and liquid crystal droplets dispersed in the polymer matrix, and a second transparent conductive film, wherein the polymer-dispersed liquid crystal layer has, in a top view, a first region and a second region with different haze changes due to an applied voltage, wherein the haze change in the first region due to the applied voltage is less than the change in the second region, wherein the liquid crystal droplets in the first region comprise a non-polymerizable liquid crystal compound and a liquid crystal polymer, and wherein the liquid crystal droplets in the second region comprise a non-polymerizable liquid crystal compound and a polymerizable liquid crystal compound.

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

30.

3. The polymer-dispersed liquid crystal film of claim 1 or 2, wherein the liquid crystal polymer contained in the liquid crystal droplets in the first region is a polymerized product of the polymeric liquid crystal compound contained in the liquid crystal droplets in the second region.

4. The polymer-dispersed liquid crystal film of claim 1 or 2, wherein the difference between the haze of the first region and the haze of the second region increases with the application of voltage.

5. The polymer-dispersed liquid crystal film of claim 4, wherein the liquid crystal polymer contained in the liquid crystal droplets in the first region is in an unaligned state.

6. The polymer-dispersed liquid crystal film of claim 1 or 2, wherein the difference between the haze of the first region and the haze of the second region decreases with the application of voltage.

7. The polymer-dispersed liquid crystal film of claim 6, wherein the liquid crystal polymer contained in the liquid crystal droplets in the first region is oriented in a specific direction.

8. A method for manufacturing a polymer-dispersed liquid crystal film, comprising: A coating layer is obtained by coating a first transparent conductive film with a coating liquid comprising a polymer matrix forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, and a solvent; the coating layer is dried to obtain a polymer-dispersed liquid crystal layer comprising a polymer matrix and liquid crystal droplets containing the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound dispersed in the polymer matrix; a second transparent conductive film is deposited on the polymer-dispersed liquid crystal layer; and while a voltage is applied between the first and second transparent conductive films, the polymer-dispersed liquid crystal layer is irradiated with active energy lines in a specific pattern; the irradiated area becomes a first region containing liquid crystal droplets, wherein the liquid crystal droplets contain liquid crystal polymers and the non-polymerizable liquid crystal compound, and the liquid crystal polymer is a polymerization product of the polymerizable liquid crystal compound; the non-irradiated area becomes a second region, and the amount of haze change in the second region due to the applied voltage is greater than that in the first region.

9. A method for manufacturing a polymer-dispersed liquid crystal film, comprising: A coating layer is obtained by coating a first transparent conductive film with a coating liquid comprising a polymer matrix forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, and a solvent; the coating layer is dried to obtain a polymer-dispersed liquid crystal layer comprising a polymer matrix and liquid crystal droplets containing the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound dispersed in the polymer matrix; a second transparent conductive film is deposited on the polymer-dispersed liquid crystal layer; and, without applying a voltage between the first and second transparent conductive films, the polymer-dispersed liquid crystal layer is irradiated with active energy lines in a specific pattern; the irradiated area becomes a first region containing liquid crystal droplets, wherein the liquid crystal droplets contain a liquid crystal polymer and the non-polymerizable liquid crystal compound, and the liquid crystal polymer is a polymerization product of the polymerizable liquid crystal compound; the unirradiated area becomes a second region, and the amount of haze change in the second region due to the applied voltage is greater than that in the first region.

10. A method for manufacturing a polymer-dispersed liquid crystal film as claimed in claim 8 or 9, wherein the coating liquid is an emulsion coating liquid comprising the non-polymerizable liquid crystal compound and liquid crystal particles of the polymerizable liquid crystal compound dispersed in the solvent.

11. The method for manufacturing a polymer-dispersed liquid crystal film as claimed in claim 8 or 9, wherein the weight ratio (liquid crystal compound: polymer matrix forming resin) of the total content of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound in the coating liquid to the content of the polymer matrix forming resin is 30:70 to 70:

30.

12. The method for manufacturing a polymer-dispersed liquid crystal film as claimed in claim 8 or 9, wherein the weight ratio (non-polymerized liquid crystal compound: polymerized liquid crystal compound) of the coating liquid to the non-polymerized liquid crystal compound is 99:1 to 70:30.

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