Liquid crystal element and emulsion composition

Abstract

A liquid crystal element includes two substrates with transparent conductive films configured in opposition, a liquid crystal-polymer composite film interposed between the two substrates with transparent conductive films, wherein the liquid crystal-polymer composite film has a polymer matrix and a liquid crystal composition surrounded by the polymer matrix, the liquid crystal composition contains a liquid crystal component and a dichroic dye, the liquid crystal component has a positive dielectric anisotropy, a NI point of 110°C or higher and 150°C or lower, a refractive index anisotropy of 0.01 or higher and 0.1 or lower, and the liquid crystal-polymer composite film is switchable between a transparent state and a colored state by applying a voltage.

Description

Technical Field

[0001] This invention relates to a liquid crystal element and an emulsion composition. More specifically, it relates to a liquid crystal element capable of switching between a transparent state and a colored state, and an emulsion composition usable in the liquid crystal element. Background Technology

[0002] In recent years, the demand for smart glass capable of electrically switching transparency has been increasing. As dimming materials for smart glass, liquid crystal methods, electrochromic methods, and SPD (Suspend Particle Device) methods have been proposed. Among these, the liquid crystal method has attracted much attention due to its extremely short response time and lack of stress on the user.

[0003] In liquid crystal technology, PDLC (Polymer Dispersed Liquid Crystals) is well known (Non-Patent Document 1). PDLC has the following structure: a liquid crystal-polymer composite film formed by dispersing particulate liquid crystal in a polymer matrix, sandwiched between two transparent conductive substrates.

[0004] In PDLCs, normal mode driving is the most common. In normal mode, without applied voltage, the liquid crystal molecules align along the walls of the polymer matrix, creating a refractive index mismatch between the liquid crystal region and the polymer matrix. This mismatch causes light scattering, resulting in cloudiness and thus acting as a masking effect. Conversely, when a voltage is applied to the PDLC, the liquid crystal molecules align along the electric field direction, achieving a refractive index match between the liquid crystal region and the polymer matrix, allowing light to pass through and making the PDLC transparent.

[0005] PDLCs are already in practical use as dimming blinds in windows, doors, and partitions of trains, automobiles, commercial buildings, hospitals, and other buildings for aesthetic and privacy purposes. They are also used as display devices for text and graphics.

[0006] PDLCs possess flexibility due to the aforementioned liquid crystal-polymer composite film structure, enabling the fabrication of film elements. Furthermore, these film elements can be cut and shaped. Utilizing these characteristics, users can easily attach them to glass for installation.

[0007] In recent years, due to increased awareness of energy conservation, attempts have been made to reduce air conditioning load by using smart glass on windows and controlling the amount of solar radiation entering the room. However, in the case of PDLC (Power Filter Glass), although it is possible to switch between light scattering and non-scattering, the scattering is essentially forward scattering, resulting in light transmission through the elements. Therefore, it is almost impossible to control the amount of transmitted light, and thus does not contribute to energy conservation.

[0008] Patent documents 1-3 disclose smart glass using a guest-host type liquid crystal (GH liquid crystal) method, which involves adding dichroic pigments to a liquid crystal. Because the guest-host type liquid crystal method switches between a transparent and colored state by electrically switching the light absorption of the liquid crystal element, it is possible to control the amount of light transmitted. However, in order to make guest-host type liquid crystals into film elements that can be cut and shaped, a matrix that surrounds the liquid crystal and supports the film structure, like PDLC, is required.

[0009] Patent documents 4-6 disclose a guest-host type PDLC composed of a combination of PDLC and guest-host type liquid crystal, which is expected to be a film element that can control the amount of light transmitted.

[0010] In Patent Document 4, the liquid crystal-polymer composite film is manufactured by using polymerization-induced phase separation via photopolymerization. In the method of Patent Document 4, the dichroic pigment in the liquid crystal hinders photopolymerization by absorbing light, resulting in poor curing of the polymer matrix and thus causing reliability issues with the liquid crystal element. This problem becomes particularly significant when improving the light-shielding properties of the liquid crystal element.

[0011] In Patent Document 5, the liquid crystal-polymer composite film is manufactured using an aqueous emulsion composition. Compared to the manufacturing method in Patent Document 4 that utilizes polymerization-induced phase separation, this method of using an emulsion composition has the advantages of easily obtaining the desired film structure and avoiding reliability degradation due to poor curing of the polymer matrix. Therefore, liquid crystal elements with further improved light-shielding properties can be obtained. According to Patent Document 5, if the birefringence (Δn) of the liquid crystal is 0.15 or less and the order parameter S of the dichroic pigment is 0.75 or more, then the visible light transmittance of the PDLC varies by 30% or more and the haze in the transparent state is 10% or less. However, the visible light transmittance here refers to the linear transmittance of straight light without including scattered light. When forward-scattered light is included, the variation in the amount of transmitted light is still very small, so there is a problem that the amount of solar radiation is almost impossible to control.

[0012] In Patent Document 6, by controlling the anisotropy of the refractive index and the ordering parameters of the host-guest type liquid crystal, a liquid crystal element with a wide range of visible light transmittance (dynamic range) and low haze was obtained. However, the liquid crystal element in Patent Document 6 exhibits a dynamic range variation in visible light transmittance when driven at high temperatures for extended periods, potentially compromising its reliability. In automotive applications, the interior temperature can sometimes be extremely high, thus this dynamic range variation hinders the expansion of liquid crystal elements into automotive applications.

[0013] Patent Document 1: Japanese Patent Publication No. 2016-510907 Patent Document 2: Japanese Patent Publication No. 2016-536634 Patent Document 3: Japanese Patent Publication No. 2017-511895 Patent Document 4: Japanese Patent Application Publication No. 2011-190314 Patent Document 5: Japanese Patent Application Publication No. 60-252687 Patent Document 6: Japanese Patent Application Publication No. 2000-347223

[0014] Non-patent literature 1: D.A. Higgins, Advanced Materials 2000, 12, No. 4 Summary of the Invention

[0015] The objective of this invention is to provide a liquid crystal element that, in a liquid crystal element that can electrically control the amount of light transmitted and can be cut into shape, has a high dynamic range of visible light transmittance and exhibits minimal decrease in dynamic range even after being driven at high temperatures.

[0016] The inventors discovered that by using a liquid crystal component with specified dielectric constant anisotropy and refractive index anisotropy as the liquid crystal component in a liquid crystal composition containing a liquid crystal component and a dichroic pigment, and by increasing the Ni point (nematic-isotropic phase transition temperature), the liquid crystal element exhibits a high dynamic range of visible light transmittance variation, maintaining this dynamic range even after driving at high temperatures. Thus, the present invention is complete. In other words, the essence of the present invention is as follows.

[0017] [1] A liquid crystal element, comprising: two substrates with transparent conductive films arranged opposite to each other, and a liquid crystal-polymer composite film sandwiched between the two substrates with transparent conductive films, wherein, The liquid crystal-polymer composite film has a polymer matrix and a liquid crystal composition surrounded by the polymer matrix. The liquid crystal composition contains liquid crystal components and dichroic pigments. The dielectric constant of the liquid crystal component is positively anisotropic, and the Ni point is above 110°C and below 150°C. The refractive index anisotropy of the liquid crystal component is greater than 0.01 and less than 0.1. The liquid crystal-polymer composite film can be switched between a transparent state and a colored state by applying voltage.

[0018] [2] According to the liquid crystal element of [1], wherein the average particle size of the liquid crystal composition is 2 μm or more and 50 μm or less.

[0019] [3] According to the liquid crystal element of [1], wherein the average particle size of the liquid crystal composition is 0.01 μm or more and less than 2 μm.

[0020] [4] The liquid crystal element according to any one of [1] to [3], wherein the dichroic pigment contains anthraquinone pigment and / or azo pigment.

[0021] [5] The liquid crystal element according to any one of [1] to [4], wherein the content of the dichroic pigment is 0.1% by mass or more and 20% by mass or less relative to 100% by mass of the liquid crystal composition.

[0022] [6] The liquid crystal element according to any one of [1] to [5], wherein the liquid crystal component is a nematic liquid crystal or a chiral nematic liquid crystal.

[0023] [7] The liquid crystal element according to any one of [1] to [6], wherein the polymer constituting the polymer matrix contains at least one selected from polyurethane, polyacrylic, polyvinyl alcohol and their modifiers.

[0024] [8] The liquid crystal element according to any one of [1] to [7], wherein the total light transmittance of the colored state is 0.1% or more and 30% or less.

[0025] [9] The liquid crystal element according to any one of [1] to [8], wherein the total light transmittance of the transparent state is greater than 30% and less than 80%.

[0026]

[10] An emulsion composition comprising an emulsion composition wherein a liquid crystal composition is dispersed in an aqueous medium, wherein, The medium contains dispersed or dissolved polymers. The liquid crystal composition contains liquid crystal components and dichroic pigments. The dielectric constant of the liquid crystal component is positively anisotropic, and the Ni point is above 110°C and below 150°C. The refractive index anisotropy of the liquid crystal component is greater than 0.01 and less than 0.1.

[0027]

[11] According to the emulsion composition of

[10] , wherein the average particle size of the liquid crystal composition in the emulsion composition is 2 μm or more and 50 μm or less.

[0028]

[12] According to the emulsion composition of

[10] , wherein the average particle size of the liquid crystal composition in the emulsion composition is 0.01 μm or more and less than 2 μm.

[0029]

[13] The emulsion composition according to any one of

[10] to

[12] , wherein the dichroic pigment contains anthraquinone pigment and / or azo pigment.

[0030]

[14] The emulsion composition according to any one of

[10] to

[13] , wherein the content of the dichroic pigment is 0.1% by mass or more and 20% by mass or less relative to 100% by mass of the liquid crystal composition.

[0031]

[15] The emulsion composition according to any one of

[10] to

[14] , wherein the liquid crystal component is a nematic liquid crystal or a chiral nematic liquid crystal.

[0032]

[16] The emulsion composition according to any one of

[10] to

[15] , wherein the polymer contains at least one selected from polyurethane, polyacrylic acid, polyvinyl alcohol and its modifiers. Invention Effects

[0033] According to the present invention, a liquid crystal element is provided that can improve the electrically controllable amount of light transmitted and can be cut and shaped. Furthermore, this element combines high light-shielding capacity and a wide dynamic range, and the decrease in dynamic range can be suppressed even when driven at high temperatures.

[0034] Based on the above characteristics, the liquid crystal element of the present invention is very useful in windows, screens, displays, etc. For example, it can be used as a viewing element in windows and partitions of buildings and vehicles. In addition, it can be used as a display for billboards, shop windows, computer terminals, projections, etc. Because the liquid crystal element of the present invention has high driving reliability, especially at high temperatures, it is particularly useful in environments where temperatures rise under direct sunlight, such as in automotive applications. Attached Figure Description

[0035] Figure 1 The graph shows the haze (dynamic range ΔHaze) after 65 hours, 133 hours, and 228 hours from the start of continuous driving in Examples 3, 4, and Comparative Example 2. Figure 2 This is a graph showing the total light transmittance (dynamic range ΔTT) after 65 hours, 133 hours, and 228 hours from the start of continuous driving in Examples 3, 4, and Comparative Example 2. Figure 3 The graphs represent the haze (dynamic range ΔHaze) after 65 hours, 133 hours, and 228 hours from the start of continuous driving in Examples 7, 8, and Comparative Example 4. Figure 4This is a graph showing the total light transmittance (dynamic range ΔTT) after 65 hours, 133 hours, and 228 hours from the start of continuous driving in Examples 7, 8, and Comparative Example 4. Detailed Implementation

[0036] The present invention will now be described in detail. The following description is merely one example of an embodiment of the present invention. The present invention is not limited to the following description as long as it does not depart from its spirit. It can be arbitrarily modified and implemented without departing from the spirit of the present invention.

[0037] (Liquid Crystal Components) The liquid crystal element of the present invention comprises two substrates with transparent conductive films arranged opposite each other, and a liquid crystal-polymer composite film sandwiched between the two substrates with transparent conductive films. The liquid crystal-polymer composite film has a polymer matrix and a liquid crystal composition surrounded by the polymer matrix. The liquid crystal composition contains a liquid crystal component and a dichroic pigment. The dielectric constant of the liquid crystal component is positive, its Ni point is 110°C or higher and 150°C or lower, and its refractive index is 0.01 or higher and 0.1 or lower. The liquid crystal-polymer composite film can switch between a transparent state and a colored state by applying a voltage.

[0038] [mechanism] In the liquid crystal element of the present invention, the aforementioned liquid crystal-polymer composite film is formed by having a polymer matrix and a liquid crystal composition surrounded by the aforementioned polymer matrix, thus creating a flexible and scalable liquid crystal element. The liquid crystal composition contains liquid crystal components and dichroic pigments, thereby exhibiting sufficient light absorption capacity in the colored state. Furthermore, by setting the Ni point of the liquid crystal component to 110°C or higher and 150°C or lower, a wide dynamic range is achieved, maintaining its dynamic range for a longer period even under high-temperature driving. Increasing the orderliness (order parameter) of the liquid crystal is one method to expand the dynamic range, and the orderliness tends to increase with a higher Ni point. However, when the Ni point is too high, the lower limit temperature for operation as a nematic phase increases, causing a deviation from the practical temperature range. Specifically, when the Ni point is greater than 150°C, the lower limit for operation as a nematic phase often exceeds 0°C. Therefore, the Ni point of the liquid crystal component used in the present invention is set to 150°C or lower.

[0039] The dielectric constant anisotropy (Δε) of the liquid crystal component used in this invention is positive. Therefore, the resulting liquid crystal-polymer composite film is transparent when a voltage is applied and colored when no voltage is applied. However, it can also have the memory property that a voltage needs to be applied only when switching between the transparent state and the colored state.

[0040] In this invention, voltage refers to DC voltage, AC voltage, pulse voltage, or a combination thereof that represents an effective value above a threshold. In this invention, the transparent state refers to the state of the liquid crystal-polymer composite film when a voltage is applied or when no voltage is applied. Among the states when a voltage is applied and when no voltage is applied, the state with the higher total light transmittance of the liquid crystal-polymer composite film is considered transparent. In addition, in this invention, the coloring state refers to the state of the liquid crystal-polymer composite film when the voltage is applied or when no voltage is applied. Among the states when the voltage is applied and when no voltage is applied, the state with the lower total light transmittance of the liquid crystal-polymer composite film is the coloring state.

[0041] [Liquid Crystal-Polymer Composite Film] The liquid crystal-polymer composite film (hereinafter, sometimes referred to as "the liquid crystal-polymer composite film of the present invention") contained in the liquid crystal element of the present invention has a polymer matrix (hereinafter, sometimes referred to as "the polymer matrix of the present invention") and a liquid crystal composition (hereinafter, sometimes referred to as "the liquid crystal composition of the present invention") surrounded by the polymer matrix. Such liquid crystal-polymer composite films are generally known as PDLCs.

[0042] The liquid crystal-polymer composite film, comprising a polymer matrix and a liquid crystal composition surrounded by the polymer matrix, enables the liquid crystal element to be flexible. Furthermore, by having such a structure, leakage of the liquid crystal composition is minimized even when the liquid crystal element is cut, and the polymer matrix protects the liquid crystal composition from deteriorating factors such as oxygen or moisture, thus enabling cutting and shaping.

[0043] <Liquid Crystal Composition> The liquid crystal composition of the present invention can be dispersed in a polymer matrix or arranged regularly. The shape of the liquid crystal composition of the present invention can be any of a sphere, an ellipsoid of revolution, a cylinder, a triangular prism, a square prism, a hexagonal prism, or a variation thereof. Among these, regular polygonal prisms such as spheres, ellipsoids of revolution, cylinders, regular triangular prisms, regular square prisms, and regular hexagonal prisms tend to weaken the light scattering of the liquid crystal-polymer composite film, increase the light absorption of the dichroic pigment during coloring, and reduce the haze in the transparent state, and are therefore preferred.

[0044] From the perspective of the transparency of the obtained element, the average particle size of the liquid crystal composition, when viewed from the surface of the liquid crystal-polymer composite film, is preferably 2 μm or more, more preferably 5 μm or more. Furthermore, it is preferably 50 μm or less, more preferably 30 μm or less. By setting the average particle size to the lower limit or above, the light scattering of the liquid crystal-polymer composite film tends to be weaker, and the haze in the transparent state is reduced. Simultaneously, by weakening the light scattering of the colored liquid crystal-polymer composite film, it is relatively helpful to improve the light absorption of the dichroic pigment, enabling more transparent control of the total light transmittance. By setting the average particle size to the upper limit or below, the graininess of the liquid crystal composition tends to disappear, and the uniformity of the appearance of the liquid crystal element becomes better.

[0045] From the perspective of the light-shielding properties of the obtained element, the average particle size of the liquid crystal composition, when viewed from the surface of the liquid crystal-polymer composite film, is preferably 0.01 μm or more, more preferably 0.1 μm or more. Furthermore, it is preferably less than 2 μm, more preferably 1 μm or less. By making the average particle size less than the above-mentioned upper limit, the light scattering of the liquid crystal-polymer composite film tends to be stronger, the haze in the light-shielding state increases, and the dynamic range (the difference in haze between the colored state and the transparent state) increases. Simultaneously, the light absorption opportunity of the dichroic pigments tends to increase due to multiple scattering, the total light transmittance becomes lower, and the dynamic range (the difference in total light transmittance between the colored state and the transparent state) increases. However, when the average particle size is less than the above-mentioned lower limit (which is quite small compared to the wavelength of visible light), its effect weakens; therefore, the average particle size of the liquid crystal composition is preferably greater than or equal to the above-mentioned lower limit.

[0046] The average particle size of the above-mentioned liquid crystal composition is the median particle size based on the number of particles. When observing the surface of the liquid crystal-polymer composite film, if the shape of the liquid crystal composition is not a circle, but a polygon such as an ellipse, triangle, quadrilateral, or hexagon, or a deformation of these shapes, the particle size can be referenced to the diameter of the smallest circumscribed circle.

[0047] The liquid crystal composition of the present invention contains a liquid crystal component (hereinafter, sometimes referred to as "the liquid crystal component of the present invention") and a dichroic pigment (hereinafter, sometimes referred to as "the dichroic pigment of the present invention"). Such liquid crystal compositions are generally known as guest-host type liquid crystals.

[0048] While not particularly limited, the content of the dichroic pigment is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, relative to 100% by mass of the liquid crystal composition. Furthermore, the content of the dichroic pigment is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, relative to 100% by mass of the liquid crystal composition. By setting the content of the dichroic pigment to the lower limit or above, the liquid crystal element tends to exhibit greater light absorption due to its colored state, while the amount of light transmitted decreases. By setting the content of the dichroic pigment to the upper limit or below, the separation and precipitation of the dichroic pigment tends to become less likely, thereby improving the reliability of the liquid crystal element.

[0049] The liquid crystal composition may also contain additives, to a extent that it does not impair the performance of the liquid crystal element of the present invention. Specifically, it may contain polymer precursors, polymerization initiators, light stabilizers, antioxidants, thickeners, polymerization inhibitors, photosensitizers, binders, defoamers, surfactants, chiral reagents, etc.

[0050] The chiral reagent can be any chiral compound compatible with the liquid crystal component, and can be synthetic or commercially available. Furthermore, it can exhibit both liquid crystal properties and polymerizable functional groups. Moreover, it can be dextrorotatory or levorotatory, or a combination of dextrorotatory and levorotatory chiral reagents can be used. Furthermore, from the perspective of reducing the driving voltage and response speed of the liquid crystal element, chiral reagents with a large positive value of dielectric anisotropy and low viscosity are preferred as chiral reagents, and chiral reagents with a large helical twisting power, which is an indicator of the force by which the chiral reagent twists the liquid crystal, are even more preferred.

[0051] Commercially available chiral reagents include, for example: CB15 (trade name, manufactured by Merck), C15 (trade name, manufactured by Merck), S-811 (trade name, manufactured by Merck), R-811 (trade name, manufactured by Merck), S-1011 (trade name, manufactured by Merck), R-1011 (trade name, manufactured by Merck), etc.

[0052] When the liquid crystal composition of the present invention contains a chiral reagent, there is no particular limitation on its content, but the reciprocal (1 / p) of the chiral pitch p [μm] determined by the ratio of the amount of liquid crystal component to the amount of chiral reagent is preferably 0.01 to 0.5 [ / μm], and particularly preferably 0.01 to 0.3 [ / μm]. If the reciprocal (1 / p) of the chiral pitch is above the lower limit value mentioned above, the light absorption efficiency of the dichroic pigment becomes higher, and the light-blocking property of the colored state can be improved; if it is below the upper limit value mentioned above, voltage rise can be suppressed.

[0053] <Liquid crystal composition> The dielectric anisotropy (Δε) of the liquid crystal component in this invention is positive. In this case, a normal mode is formed that is colored when no voltage is applied and transparent when a voltage is applied.

[0054] The Ni point (nematic-isotropic phase transition temperature) of the liquid crystal component of the present invention is 110°C or higher and 150°C or lower, preferably 120°C or higher and 140°C or lower. When the Ni point is above the lower limit mentioned above, the dynamic range of transmittance variation tends to be maintained even under continuous driving at high temperatures of around 90°C. Furthermore, the higher the Ni point, the wider the dynamic range of transmittance variation. On the other hand, as the Ni point increases, the lower limit of the nematic phase tends to increase as well; therefore, from the perspective of operating at low temperatures, it is preferable that the Ni point is below the upper limit mentioned above.

[0055] There is no particular limitation on the method for determining the Ni point of liquid crystal components, but it can be obtained by temporarily making the liquid crystal composition compatible and observing the phase transition or phase separation caused by temperature rise using a polarizing microscope.

[0056] The refractive index anisotropy (Δn) of the liquid crystal component of the present invention is 0.01 or more, preferably 0.02 or more, and more preferably 0.03 or more. Furthermore, it is 0.1 or less, preferably 0.10 or less. By setting Δn to the upper limit or below, light scattering at the interface between the polymer matrix and the liquid crystal composition tends to decrease, thereby reducing the haze in the transparent state. On the other hand, by setting Δn to the lower limit or above, the order parameter of the liquid crystal composition tends to increase.

[0057] The refractive index anisotropy of the liquid crystal component is obtained by directly calculating the normal optical refractive index (no) and the extraordinary optical refractive index (ne) of the liquid crystal component, and taking the difference between the two (Δn = ne - no). If it is difficult to calculate directly, the phase difference (retardation: R) when passing through a sample of thickness d can also be calculated and divided by the thickness d to obtain the anisotropy (R = Δnd).

[0058] Nematic liquid crystals, cholesteric liquid crystals, and smectic liquid crystals can be used as the liquid crystal component. Nematic liquid crystals or cholesteric liquid crystals are preferred due to their low cost. Furthermore, cholesteric liquid crystals (chiral nematic liquid crystals) can be prepared by adding a chiral reagent to a nematic liquid crystal.

[0059] When using known liquid crystal materials as liquid crystal components, specific examples include low-molecular-weight compounds or mixtures such as biphenyl, phenylcyclohexane, and cyclohexylcyclohexane compounds described in the *Handbook of Liquid Crystal Devices* (JKS 142, ed.), Japan Industrial News (1989), pp. 152-192, and the *Liquid Crystal Handbook* (JL) edited by the Liquid Crystal Handbook Editorial Committee (Maruzen Co., Ltd., 2000), pp. 260-330. Alternatively, high-molecular-weight compounds or mixtures described in the *Liquid Crystal Handbook* (Maruzen Co., Ltd., 2000), can also be used. Examples of compounds constituting nematic liquid crystals include the following.

[0060] [Chemistry 1]

[0061] From the perspective of the high-speed responsiveness of liquid crystal elements and the manufacturability of emulsions, liquid crystals with low viscosity and high dielectric anisotropy are preferred as nematic liquid crystals and cholesteric liquid crystals (chiral nematic liquid crystals).

[0062] <Dichroic Pigments> The dichroic pigment contained in the liquid crystal composition of the present invention can be any dichroic pigment compound compatible with the liquid crystal component, and can be a dichroic pigment with positive or negative Δε. Furthermore, it may itself exhibit liquid crystal properties.

[0063] Specifically, examples of dichroic dyes used in this invention include azo dyes, anthraquinone dyes, naphthoquinone dyes, perylene dyes, quinoline ketone dyes, tetraazine dyes, and benzothiadiazole dyes. When using known dichroic dyes, azo dyes, anthraquinone dyes, or mixtures thereof described in the *Handbook of Liquid Crystal Devices*, edited by the 142nd Committee of the Japanese Society for the Promotion of Science (JSP), published by the Japan Industrial News Agency (1989), pp. 192-196 and 724-730, can be used. Among these, dyes containing anthraquinone or azo dyes are preferred because they have high light absorption coefficients, tend to have higher solubility and better lightfastness in liquid crystal components. Dichroic pigments can be used alone or in mixtures. There are no particular limitations, but it is preferred that anthraquinone and / or azo pigments contain at least 20% by mass, and more preferably at least 50% by mass.

[0064] Specific examples of the dichroic pigments of the present invention include compounds represented by the following formula.

[0065] [Chemistry 2]

[0066] In the above formula, X independently represents -NH- or -S-, n represents 0 or 1, and Ar represents phenylene or naphthylene. R represents a hydrogen atom, alkyl, alkoxy, cyclohexyl, phenyl, phenylcyclohexyl, or cyclohexylcyclohexyl, optionally having these substituents.

[0067] <Polymer matrix> As the polymer matrix of the present invention, a hydrophilic polymer is preferably used. In this case, there is no particular limitation as long as it is hydrophilic, but it is preferable to select one whose refractive index is consistent with the normal optical refractive index (no) of the liquid crystal component. Typically, the no of the liquid crystal component is about 1.5, so the refractive index of the polymer matrix is ​​preferably 1.45 or higher and 1.55 or lower.

[0068] As the polymer matrix, natural polymers such as gelatin and gum arabic can be used; synthetic polymers such as polyvinyl alcohol, polyurethane, polyurea, polyacrylic acid, polyamine, polyamide, polyethylene, polypropylene, polystyrene, and polyacrylonitrile, as well as their modified forms; and copolymers such as methacrylate / acrylonitrile, urethane / acrylate, and acrylate / acrylonitrile. In addition, crosslinking agents can be used to introduce crosslinked structures into the polymer.

[0069] The polymer preferably has high dispersibility or solubility in water, and is preferably gelatin, polyvinyl alcohol, polyurethane, polyurea, polyacrylic acid, polyamine, and their modified forms. More preferably, it is selected from at least one of polyurethane, polyacrylic acid, polyvinyl alcohol, and their modified forms; even more preferably, it is selected from at least one of polyurethane, polyacrylic acid, and their modified forms; and particularly preferably, it is polyacrylic acid. These polymers can be used in single-component or in combination of two or more.

[0070] Polyurethanes are classified according to the skeletons of their respective polyisocyanates and polyols. Examples of polyisocyanate skeletons include aliphatic polyurethanes composed of aliphatic carbon skeletons and aromatic polyurethanes containing aromatic rings in the polyisocyanate. Aliphatic polyurethanes are preferred due to their high lightfastness. Examples of polyol skeletons include polyether-based, polyester-based, and polycarbonate-based, with polyether-based systems preferred for their good film adhesion.

[0071] Polyacrylic acids are polymers composed of various acrylate monomers. Examples of acrylic monomers include compounds represented by the following formula.

[0072] [Chemistry 3]

[0073] In the above formula, X 1 R represents a hydrogen atom or a methyl group.1 The term refers to a hydrogen atom, a halogen atom, a hydroxyl group, a straight-chain or branched alkyl group optionally having a substituent having 1 or more and 20 or fewer carbon atoms, a straight-chain or branched alkoxy group optionally having a substituent having 1 or more and 20 or fewer carbon atoms, or a cyclic hydrocarbon group optionally having a substituent having 1 or more and 10 or fewer carbon atoms.

[0074] Polyacrylic acids can also be copolymerized with monomers other than acrylates to form copolymers, such as acrylate-styrene, acrylate-vinyl acetate, acrylate-acrylonitrile, acrylate-urethane, acrylate-ester, and acrylate-silicone. The main chain can be formed using copolymers of acrylates and other monomers, or other polymers can be grafted onto the polyacrylic acid main chain.

[0075] The polymer matrix may also contain low molecular weight molecules, without impairing the performance of the liquid crystal element of the present invention. Examples of such low molecular weight molecules include: light stabilizers, antioxidants, thickeners, polymerization inhibitors, photosensitizers, adhesives, defoamers, surfactants, and water-soluble pigments.

[0076] <Ratio of liquid crystal composition to polymer matrix> In the liquid crystal-polymer composite film of the present invention, the ratio of the total mass of the liquid crystal composition to the total mass of the polymer matrix is ​​preferably 0.5 or more, more preferably 1 or more, when the total mass of the polymer matrix is ​​set to 1. Furthermore, it is preferably 4 or less, more preferably 3 or less. By making the ratio of the total mass of the liquid crystal composition to the total mass of the polymer matrix at or above the aforementioned lower limit, the haze in the transparent state tends to be low, and the driving voltage tends to be low. By making the ratio of the total mass of the liquid crystal composition to the total mass of the polymer matrix at or below the aforementioned upper limit, the impact resistance and adhesion of the liquid crystal-polymer composite film tend to be improved.

[0077] [Substrate with transparent conductive film] The following describes a representative configuration of the transparent conductive film substrate of the present invention, but it is not limited thereto.

[0078] Examples of substrate materials include: inorganic transparent materials such as glass and quartz, metals, metal oxides, semiconductors, ceramics, plastic sheets, and plastic films—all colorless and transparent materials. These substrates can be used as single boards or in multiple layers. To protect the substrate from scratches and stains, a hard coating and a sharp cut-off layer and a bandpass layer that block light in specific wavelength ranges can also be applied to the substrate.

[0079] The transparent conductive film constituting the electrode is formed on the aforementioned substrate, for example, by forming a thin film of metal oxide, metal, semiconductor, organic conductive material, etc., on the entire surface or a portion of the substrate using known coating, printing, or sputtering vapor deposition methods. Alternatively, it can be formed by partial etching after the conductive thin film is formed. In particular, for obtaining large-area liquid crystal elements, from the perspective of productivity and processability, it is desirable to use electrode substrates formed by sputtering or printing vapor deposition methods to form ITO (indium tin oxide and tin oxide mixture) electrodes on transparent polymer films such as PET.

[0080] Wiring for connecting electrodes to each other or to the outside can also be provided on the substrate. For example, it can be an electrode substrate for segment driving, an electrode substrate for matrix driving, an electrode substrate for active matrix driving, etc.

[0081] Furthermore, the entire surface or a portion of the electrode surface disposed on the substrate may also be covered by a protective film or alignment film formed of organic compounds such as polyimide, polyamide, organosilicon, and cyanide, or inorganic compounds such as SiO2, TiO2, and ZrO2, or mixtures thereof.

[0082] The substrate can be oriented in a way that aligns the liquid crystal with respect to the substrate surface. In the case of orientation, for example, both substrates can be parallel or perpendicularly oriented, or one substrate can be parallel and the other perpendicularly oriented, i.e., a mixture. In these orientation processes, the electrode surface can be directly rubbed, or conventional alignment films such as polyimide used in TN liquid crystals and STN liquid crystals can be used, or photo-alignment can be performed.

[0083] The opposing substrate may suitably have an adhesive layer comprising a resin body in its peripheral portion, the resin body being used to bond and support the substrate.

[0084] In this invention, the ends or cut surfaces of the liquid crystal element can be sealed with adhesive tapes, thermosetting tapes, thermosetting resins, photocurable resins, moisture-curing resins, room-temperature curing adhesives, anaerobic adhesives, epoxy adhesives, silicone adhesives, fluoropolymer adhesives, polyester adhesives, vinyl chloride adhesives, and other curable resins and thermoplastic resins, thereby preventing the leakage of the internal liquid crystal composition. Furthermore, this sealing also helps prevent the liquid crystal element from deteriorating. As a method of protecting the end face, the entire end face can be covered, or a curable resin or thermoplastic resin can flow into the liquid crystal element from the end and cure thereafter, or an adhesive tape can be used to cover it.

[0085] Between the relatively arranged substrates with transparent conductive films, spacers such as spherical or cylindrical glass, plastic, ceramic, or plastic films may be present. The spacers may be liquid crystal-polymer composite films containing components of the emulsion composition of the present invention, existing between the substrates, or they may be dispersed on the substrates during the assembly of liquid crystal elements, or they may be mixed with adhesives and exist in the adhesive layer.

[0086] [Manufacturing method of liquid crystal-polymer composite film] The liquid crystal-polymer composite film of the present invention can be manufactured by coating the emulsion composition of the present invention (described later) onto a substrate with a transparent conductive film and then drying it. As the coating method, known coating methods such as rod coating, doctor blade coating, air knife coating, die coating, screen coating, microgravure roller coating, reverse roller coating, kiss roller coating, dip roller coating, spin coating, and spray coating can be used. The substrate can be cleaned appropriately according to its properties.

[0087] The wet film thickness during coating is preferably 10 μm or more, more preferably 20 μm or more. Furthermore, it is preferably 120 μm or less, more preferably 100 μm or less. By keeping the wet film thickness at or above the aforementioned lower limit, the liquid crystal composition can be uniformly coated without uneven density. By keeping the wet film thickness at or below the aforementioned upper limit, the driving voltage tends to decrease to a practical value, and the haze in the transparent state becomes lower.

[0088] The drying temperature for drying the coating emulsion composition is preferably 40°C or higher, more preferably 50°C or higher. Furthermore, it is preferably 100°C or lower, more preferably 80°C or lower. By setting the drying temperature above the aforementioned lower limit, the drying time tends to be shortened to a practical time, and the amount of residual moisture in the film is reduced, thereby improving the reliability of the liquid crystal element. By setting the drying temperature below the aforementioned upper limit, the emulsion composition tending to dry is less prone to structural damage such as coalescence and phase inversion.

[0089] [Total light transmittance] The total light transmittance in this specification was measured using the method specified in JIS K7136. In addition, in this specification, light refers to visible light (wavelength 380nm~780nm), and the total light transmittance is measured in the visible light region.

[0090] The total light transmittance of the colored state of the liquid crystal element of the present invention is preferably 30% or less, more preferably 25% or less, and even more preferably 20% or less. By setting the total light transmittance of the colored state below the above-mentioned upper limit value, it is easier to reduce the amount of light transmitted in the colored state, thereby improving the light-shielding performance. On the other hand, the total light transmittance of the colored state is preferably 0.1% or more, more preferably 0.3% or more, and even more preferably 0.5% or more. By setting the total light transmittance of the colored state above the above-mentioned lower limit value, it is easier to maintain a wide dynamic range.

[0091] The total light transmittance of the liquid crystal element in its transparent state according to the present invention is preferably greater than 30%, more preferably 50% or more, and even more preferably 55% or more. Furthermore, the total light transmittance in the transparent state is preferably 80% or less, more preferably 70% or less. By ensuring the total light transmittance in the transparent state is within these ranges, the transparency of the element can be guaranteed.

[0092] The dynamic range of the total light transmittance (the difference between the total light transmittance in the colored state and the transparent state, ΔTT) of the liquid crystal element of the present invention is preferably 30 or more, and more preferably 35 or more. Within this range, the resulting element is easily identifiable.

[0093] [Haze] The haze in this manual is measured using the method described in JIS K7136.

[0094] From the perspective of transparency, the haze of the colored state of the liquid crystal element of the present invention is preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less. By setting the haze of the colored state to the upper limit value or below, the light absorption of the dichroic pigment in the colored state can be relatively increased, resulting in a more transparent colored state. On the other hand, the haze of the colored state is preferably 10% or more, more preferably 20% or more, and even more preferably 30% or more. By setting the haze of the colored state to the lower limit value or above, it is easier to further reduce glare from external light. Furthermore, from the perspective of light-shielding properties, the haze of the colored state of the liquid crystal element of the present invention is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. By setting the haze of the colored state to the lower limit value or above, the chance of light absorption by dichroic pigments due to multiple scattering tends to increase, and the total light transmittance further decreases. On the other hand, the haze of the colored state is preferably 99% or less. By setting the haze of the colored state to the upper limit value or below, it is possible to reduce the haze when transparent.

[0095] The haze of the transparent state of the liquid crystal element of the present invention is preferably 16% or less, more preferably 10% or less, and even more preferably 6% or less. Furthermore, the haze in the transparent state is preferably 0% or more, more preferably 1% or more. By achieving haze in these ranges in the transparent state, a film with good transparency and visibility is tended to be obtained.

[0096] The dynamic range of haze (the difference in haze between the colored state and the transparent state, ΔHaze) of the liquid crystal element of the present invention is preferably 45 or more, and more preferably 50 or more. Within this range, the contrast between light-blocking and transparency becomes clear, and the difference between seeing and not seeing the scene through the film becomes distinct.

[0097] [Emulsion Composition] The emulsion composition of the present invention is an emulsion composition formed by dispersing a liquid crystal composition in an aqueous medium, wherein the medium disperses or dissolves a polymer, the liquid crystal composition contains a liquid crystal component and a dichroic pigment, the liquid crystal component has a positive dielectric constant anisotropy, a Ni point of 110°C or higher and 150°C or lower, and a refractive index anisotropy of 0.01 or higher and 0.1 or lower.

[0098] The liquid crystal composition contained in the emulsion composition of the present invention is not particularly limited, and examples include the liquid crystal composition used in the liquid crystal element of the present invention described above. Furthermore, the water-containing medium contained in the emulsion composition is not particularly limited, and examples include pure water or a mixture of water and an organic solvent.

[0099] Examples of organic solvents include alcohols, ketones, ethers, esters, carboxylic acids, and amines. Organic solvents can be water-soluble or oil-soluble to the extent that they are only slightly soluble in water, but it is preferable to use an amount that is uniformly dissolved in water.

[0100] Examples of polymers dispersed or dissolved in a medium include: natural polymers such as gelatin and gum arabic; synthetic polymers such as polyvinyl alcohol, polyurethane, polyurea, polyacrylic acid, polyamine, polyamide, polyethylene, polypropylene, polystyrene, and polyacrylonitrile, as well as their modified forms; and copolymers such as methacrylate / acrylonitrile, urethane / acrylate, and acrylate / acrylonitrile.

[0101] The polymer preferably has high dispersibility or solubility in water, and is preferably gelatin, polyvinyl alcohol, polyurethane, polyurea, polyacrylic acid, polyamine, and their modified forms. More preferably, it is selected from at least one of polyurethane, polyacrylic acid, polyvinyl alcohol, and their modified forms; even more preferably, it is selected from at least one of polyurethane, polyacrylic acid, and their modified forms; and particularly preferably, it is polyacrylic acid. It should be noted that a single polymer can be used, or two or more polymers can be used in combination.

[0102] In this invention, polymer dispersion refers to the state in which polymer particles are suspended in a medium, and polymer dissolution refers to the state in which polymers are sufficiently dissociated into a homogeneous system through solvation. For details on polymer dispersion and dissolution, please refer to "Color Materials" (2004), Vol. 77, No. 4, pp. 169-176.

[0103] In the emulsion composition of the present invention, the liquid crystal composition is dispersed in a medium containing water, but it can be dispersed directly in liquid form or in the form of microcapsule liquid crystals formed by encapsulating the peripheral portion of the liquid crystal composition with polymers, silicon oxide compounds, inorganic nanoparticles, etc. Examples of polymers that can be used as capsules for microcapsule liquid crystals include: natural polymers such as gelatin and gum arabic; synthetic polymers such as polyvinyl alcohol, polyurethane, polyurea, polyacrylic acid, polyamine, polyamide, polyethylene, polypropylene, polystyrene, and polyacrylonitrile, and their modified forms; and copolymers such as methacrylate / acrylonitrile, urethane / acrylate, and acrylate / acrylonitrile.

[0104] The emulsion composition of the present invention may also contain additives, to a extent that it does not impair the performance of the liquid crystal element manufactured using the emulsion composition. Specific examples of additives include: surfactants, emulsifiers, dispersants, anti-settling agents, film-forming aids, leveling agents, light stabilizers, antioxidants, thickeners, polymerization inhibitors, photosensitizers, binders, defoamers, water-soluble dyes, chiral reagents, etc.

[0105] Regarding the size of the liquid crystal composition, from the perspective of the transparency of the obtained liquid crystal element, the average particle size is preferably 2 μm or more, more preferably 5 μm or more. Furthermore, it is preferably 50 μm or less, more preferably 30 μm or less. By setting the average particle size to the aforementioned lower limit or above, the light scattering of the obtained liquid crystal-polymer composite film tends to be weaker, and the haze in the transparent state is reduced. Simultaneously, by weakening the light scattering of the colored liquid crystal-polymer composite film, it is relatively helpful to improve the light absorption of the dichroic pigment, enabling more transparent control of the total light transmittance. By setting the average particle size to the aforementioned upper limit or below, the graininess of the liquid crystal composition tends to disappear, and the uniformity of the appearance of the obtained liquid crystal element becomes better.

[0106] On the other hand, from the perspective of the light-shielding properties of the obtained liquid crystal element, the average particle size of the liquid crystal composition is preferably 0.01 μm or more, more preferably 0.1 μm or more. Furthermore, it is preferably less than 2 μm, more preferably 1 μm or less. By making the average particle size less than the above-mentioned upper limit, the light scattering of the obtained liquid crystal-polymer composite film tends to be stronger, the haze in the light-shielding state increases, and the dynamic range (the difference in haze between the colored state and the transparent state) increases. Simultaneously, the light absorption opportunity of the dichroic pigment due to multiple scattering increases, tending to result in a lower total light transmittance, and the dynamic range (the difference in total light transmittance between the colored state and the transparent state) increases. However, when the average particle size is less than the above-mentioned lower limit (which is quite small compared to the wavelength of visible light), its effect weakens; therefore, the average particle size of the liquid crystal composition is preferably more than the above-mentioned lower limit.

[0107] The average particle size mentioned above is the median particle size based on the number of particles. Regarding the shape and average particle size of the liquid crystal composition, as previously described for the liquid crystal composition of the present invention.

[0108] In the emulsion composition of the present invention, when the total mass of the polymer dispersed or dissolved in the medium is set to 1, the total mass of the liquid crystal composition is preferably 0.5 or more, more preferably 1 or more. Furthermore, it is preferably 4 or less, more preferably 3 or less. By making the total mass of the liquid crystal composition relative to the total mass of the polymer at or above the aforementioned lower limit, the haze of the transparent state of the liquid crystal element obtained using the emulsion composition of the present invention tends to decrease, and the driving voltage tends to decrease. By making the total mass of the liquid crystal composition relative to the total mass of the polymer at or below the aforementioned upper limit, the impact resistance and adhesion of the liquid crystal element obtained using the emulsion composition of the present invention tend to improve.

[0109] [Liquid crystal composition] The liquid crystal components contained in the liquid crystal composition are not particularly limited, but examples include the liquid crystal components used in the liquid crystal element of the present invention described above. The dielectric constant anisotropy (Δε) of the liquid crystal component is positive. In this case, a normal mode is formed that is colored when no voltage is applied and transparent when a voltage is applied.

[0110] Furthermore, the Ni point (nematic-isotropic phase transition temperature) of the liquid crystal component is 110°C or higher and 150°C or lower, preferably 120°C or higher and 140°C or lower. When the Ni point is above the lower limit mentioned above, it tends to maintain a dynamic range of transmittance variation even under continuous driving at high temperatures of around 90°C. In addition, the higher the Ni point, the wider the dynamic range of transmittance variation. On the other hand, as the Ni point increases, the lower limit of the nematic phase tends to increase as well. Therefore, from the perspective of operating at low temperatures, it is preferable that the Ni point is below the upper limit mentioned above. The method for determining the Ni point of the liquid crystal composition is as described above.

[0111] The refractive index anisotropy (Δn) of the liquid crystal component is 0.01 or more, preferably 0.02 or more, and more preferably 0.03 or more. Furthermore, it is 0.1 or less, preferably 0.10 or less. By setting Δn to the upper limit or below, light scattering at the interface between the polymer matrix and the liquid crystal composition tends to decrease, thereby reducing the haze in the transparent state. On the other hand, by setting Δn to the lower limit or above, the order parameter of the liquid crystal composition tends to increase. The method for determining the refractive index anisotropy of liquid crystal components is as described above.

[0112] Nematic liquid crystals, cholesteric liquid crystals, and smectic liquid crystals can be used as the liquid crystal component. Nematic liquid crystals or cholesteric liquid crystals are preferred due to their low cost. Furthermore, cholesteric liquid crystals (chiral nematic liquid crystals) can be prepared by adding a chiral reagent to a nematic liquid crystal. When using cholesteric liquid crystals (chiral nematic liquid crystals), the reciprocal of the chiral spacing p [μm] (1 / p) is preferably 0.01 to 0.5 [ / μm], particularly preferably 0.01 to 0.3 [ / μm]. If the reciprocal of the chiral spacing is above or below the aforementioned lower limit, the light absorption efficiency of the dichroic pigment increases, improving the light-blocking properties of the colored state; if it is below or below the aforementioned upper limit, voltage rise can be suppressed.

[0113] Specific examples of using known liquid crystal materials as liquid crystal components are described in the description of the liquid crystal components of the present invention above, and specific example compounds are also described above.

[0114] [Dichroic pigment] The dichroic pigments contained in the liquid crystal composition are not particularly limited, but examples include the dichroic pigments used in the liquid crystal elements of the present invention described above. Anthraquinone dyes and / or azo dyes are preferred because they tend to have high light absorption coefficients, resulting in higher solubility and better lightfastness in the liquid crystal. Dichroic pigments can be used alone or in mixtures. There are no particular limitations, but it is preferred that anthraquinone and / or azo pigments contain at least 20% by mass, and more preferably at least 50% by mass.

[0115] While not particularly limited, the content of the dichroic pigment is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, relative to 100% by mass of the liquid crystal composition. Furthermore, the content of the dichroic pigment is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, relative to 100% by mass of the liquid crystal composition. By setting the content of the dichroic pigment to the lower limit or above, the liquid crystal element obtained using the emulsion composition of the present invention tends to exhibit greater light absorption due to its colored state, while the amount of transmitted light decreases. By setting the content of the dichroic pigment to the upper limit or below, the separation and precipitation of the dichroic pigment tends to become less likely, thereby improving the reliability of the liquid crystal element.

[0116] [Method for manufacturing emulsion composition] The method for manufacturing the emulsion composition of the present invention is not particularly limited, but it can be manufactured, for example, by the following methods. Manufacturing method (1) Mixing a liquid crystal composition as an oil phase with an aqueous medium as an aqueous phase, and after an emulsification process, adding a liquid containing dispersed or dissolved polymers to the aqueous medium. Manufacturing method (2) involves mixing a liquid crystal composition as an oil phase with a liquid in which a polymer is dispersed or dissolved in an aqueous medium as an aqueous phase, and performing an emulsification process. Manufacturing method (3) The powder or slurry of microcapsule liquid crystal, which is formed by encapsulating the peripheral part of the liquid crystal composition with polymer, silicon oxide compound, inorganic nanoparticle, etc., is mixed with a medium containing water. After a dispersion process, a liquid containing polymer is added to the medium containing water. Manufacturing method (4) The powder or slurry of the above-mentioned microcapsule liquid crystal is mixed with a liquid containing polymer dispersed or dissolved in a water-containing medium, and a dispersion process is carried out.

[0117] Manufacturing methods (1) and (3) are preferred because the mixture can be emulsified or dispersed in a low viscosity state, thus enabling low-energy manufacturing and easy control of the particle size of the liquid crystal composition.

[0118] Commercially available aqueous resin emulsions can be used as liquids in which polymers are dispersed or dissolved in an aqueous medium. Specific examples are shown below. Aqueous carbamate emulsions: NeoRez R-9660, NeoRez R-972, NeoRez R-9637, NeoRez R-9679, NeoRez R-960, NeoRez R-2170, NeoRez R-966, NeoRez R-967, NeoRez R-986, NeoRez R-9603, NeoRez R-4000, NeoRez R-9404, NeoRez R-600, NeoRez R-650, NeoRez R-1010 manufactured by DSM; SuperFlex 126, SuperFlex 130, SuperFlex 150, SuperFlex 150HS, SuperFlex 170, SuperFlex 210, SuperFlex 300, SuperFlex 420, SuperFlex 420NS, SuperFlex... 460, SuperFlex 460S, SuperFlex 470, SuperFlex 500M, SuperFlex620, SuperFlex 650, SuperFlex 740, SuperFlex 820, SuperFlex 830HS, SuperFlex 860, SuperFlex 870, SuperFlex E-2000, SuperFlex E-4800; NEOSTECKER 200, NEOSTECKER 400, NEOSTECKER 700, NEOSTECKER 1200, NEOSTECKER X-7096, EVAFANOL HA-107C, EVAFANOL HA-50C, EVAFANOLHA-170, EVAFANOL HA-560, EVAFANOL manufactured by Nikka Chemical Company HA-15, EVAFANOL AP-12, EVAFANOL APC-55. Aqueous acrylic emulsions: NeoCryl A-633, NeoCryl A-639, NeoCryl A-655, NeoCryl A-662, NeoCryl A-1091, NeoCryl A-1092, NeoCryl A-1093, NeoCryl A-1094, NeoCryl A-2091, NeoCryl A-2092, NeoCryl A-6016, NeoCryl A-6057, NeoCryl A-6069, NeoCryl A-6092, NeoCryl A-614, NeoCryl A-550, NeoCryl A-1105, NeoCryl A-1125, NeoCryl A-1127, NeoCryl XK-12, NeoCryl XK-16, NeoCryl XK-30, NeoCryl XK-36, NeoCryl XK-52, NeoCryl XK-190, NeoCryl XK-188, NeoCryl XK-240, manufactured by DSM;RIKABOND 702, RIKABOND 727, RIKABOND 743N, RIKABOND 745, RIKABOND 752, RIKABOND 801, RIKABOND 940, RIKABOND 972, RIKABOND 1711, RIKABOND 1752, RIKABOND6520, RIKABOND 6720, RIKABOND 7110, RIKABOND 7180, RIKABOND 7525, RIKABOND 7820, RIKABOND 8020, RIKABOND 8030, RIKABOND DM60, RIKABOND DM772, RIKABOND DM774, RIKABOND LDM6740, RIKABOND LDM7522, RIKABOND LDM7523, RIKABOND ES-65, RIKABONDES-90, RIKABOND ES-620, RIKABOND ET-700, RIKABOND ET-831, RIKABOND HS-5, RIKABONDHS-531, RIKABOND AP-601, RIKABOND AP-96, RIKABOND AP-620, RIKABOND AP-700, RIKABOND AP-80, RIKABOND 710A, RIKABOND 730L, RIKABOND 731L, RIKABOND 952B, RIKABOND 966A, RIKABOND 7320, RIKABOND 7400, RIKABOND FK-420, RIKABOND FK-64S, RIKABOND FK-66IS, FK-66N, FK-68H, RIKABOND FK-471, RIKABOND FK-475, RIKABOND FK-489, RIKABOND FK-284, RIKABOND FK-600S, RIKABOND FK-3830, RIKABOND FK-3840, RIKABOND FK-6100, Mowinyl VDM7410, Mowinyl 4061, Mowinyl4080, Mowinyl 4090, Mowinyl 4050, Mowinyl S-71, Mowinyl 461, Mowinyl 650, Mowinyl AP-60L, Mowinyl 490;ThreeBond manufactures the ThreeBond 1549, ThreeBond 1549B, ThreeBond 1555C, and ThreeBond 1555D.

[0119] NeoRez R-966, NeoRez R-967, NeoCryl A-1125, NeoCryl A-1127, RIKABONDFK-471, RIKABOND ES-620, RIKABOND LDM7522, Mowinyl 4061, Mowinyl 4080, Mowinyl 4090, and ThreeBond 1549 are preferred due to their excellent dispersion stability in the oil phase.

[0120] To obtain a stable emulsion, it is preferable to add a surfactant or dispersion stabilizer before the emulsification or dispersion process. The surfactant is not particularly limited; it can be ionic or nonionic, low molecular weight or high molecular weight, non-reactive or reactive.

[0121] The amount of surfactant added is not particularly limited, but it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, relative to the liquid crystal composition. Furthermore, it is preferably 20% by mass or less, more preferably 10% by mass or less. By keeping the amount of surfactant added within the above range, the dispersion of the emulsion tends to be stabilized, while the particle size of the liquid crystal composition can be controlled within a desired range.

[0122] The surfactants described above can be added to the liquid crystal composition or to a water-containing medium, depending on their solubility.

[0123] Examples of surfactants include the following surfactants. Anionic surfactants such as carboxylates, sulfonates, sulfates, and phosphates; Cationic surfactants such as amine salts and quaternary ammonium salts; Amphoteric surfactants such as alkylamino fatty acid salts, alkylamine oxides, betaine, sulfobetaine, amide sulfobetaine, carboxybetaine, and imidazoline; Ether-type surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene aryl alkyl ethers, polyoxyethylene aryl alkyl aryl ethers, polyoxyethylene polyoxypropylene block adducts, alkyl glucosides, and polyether-modified organosilicon; ester-type surfactants include glycerol fatty acid esters, dehydrated sorbitan fatty acid esters, and sucrose fatty acid esters; ester-ether-type surfactants include polyoxyethylene fatty acid esters, polyoxyethylene dehydrated sorbitan fatty acid esters, and polyoxyethylene sucrose fatty acid esters; acetyl-type surfactants include acetyl-modified polyvinyl alcohol; and nonionic surfactants include fatty acid alkanolamides.

[0124] Anionic surfactants are preferred due to their high water solubility and dispersion stability, with sulfonates being particularly preferred. Furthermore, nonionic surfactants are preferred because they can improve the electrical reliability of the liquid crystal element. Ether-type or ester-type surfactants are preferred, with polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene aryl ethers, polyoxyethylene arylalkyl ethers, and polyoxyethylene polyoxypropylene block adducts being particularly preferred.

[0125] There are no particular limitations on what constitutes a dispersion stabilizer; examples include the following dispersion stabilizers. Polyvinyl alcohol, polyvinylpyrrolidone, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, polyethylene glycol, polyacrylic acid, polymethacrylic acid, polyurethane, polyamine, polyamide, polyether, maleic acid copolymer, gelatin, starch, chitosan, corn starch and other polymers and their modified products; Copolymers of methacrylate / acrylonitrile, urethane / acrylate, acrylate / acrylonitrile, etc. Microparticles of inorganic oxides such as silica microparticles, titanium dioxide microparticles, and aluminum oxide microparticles: Polyvinyl alcohol and its modified forms, polyurethane, and polyamide are preferred due to their high dispersion stability. Examples of dispersing stabilizers include substances that are examples of polymers constituting a polymer matrix, which are included as polymers constituting a polymer matrix when contained in emulsion compositions and liquid crystal-polymer composite films.

[0126] The degree of saponification of polyvinyl alcohol is preferably 80 mol% or more, more preferably 85 mol% or more. Furthermore, it is preferably 95 mol% or less, more preferably 91 mol% or less. Within these ranges of saponification degree, the solubility in water-containing media tends to be high. The degree of polymerization of polyvinyl alcohol is preferably 100 or more, more preferably 300 or more. Furthermore, it is preferably 2500 or less, more preferably 1000 or less. Within these ranges, the degree of polymerization tends to result in excellent film flexibility.

[0127] Specific examples of polyvinyl alcohol include: GOHSENOL GL-03, GOHSENOL GL-05, GOHSENOL GM-14L, GOHSENOL GM14, GOHSENOL GH-17, GOHSENOL GH-17R, GOHSENOL GH-20, GOHSENOL GH-23, GOHSENOL AL-06, GOHSENOL P-610, and GOHSENOL C-500 manufactured by Nippon Synthetic Chemicals Co., Ltd.; Kuraray Poval 25-88KL, Kuraray Poval 32-97KL, Kuraray Poval 3-86SD, Kuraray Poval 105-88KX, and Kuraray Poval 200-88KX manufactured by Kuraray Co., Ltd.; and Denka Poval H-12, Denka Poval H-17, Denka Poval H-24, and Denka Poval manufactured by Denka Co., Ltd. B-05, Denka Poval B-17, Denka Poval B-20, Denka Poval B-24, Denka Poval B-33, etc.

[0128] In the manufacture of emulsion compositions, there are no particular limitations on the emulsification and dispersion methods. Examples include: mechanically pulverizing particles using mixers, homogenizers, homogenizing blenders, dispersers, high-pressure emulsifiers, co-mixers, colloid mills, ultrasonic dispersers, etc.; and extruding liquid from pores using porous membranes, microchannels, inkjet printers, etc.

[0129] Of the above, when manufacturing an emulsion composition with an average particle size of 2 μm or more and 50 μm or less, the method of extruding liquid from the pores of a porous membrane (membrane emulsification) allows for precise control of the particle size distribution and is easy to manufacture, therefore it is preferred. There are no particular limitations on the porous membrane, but Shirasu porous glass or the like can be used.

[0130] When manufacturing an emulsion composition with an average particle size of 0.01 μm or more and less than 2 μm, an emulsion composition with an average particle size of 2 μm or more and less than 50 μm can be manufactured by temporarily using a film emulsification method or the like. By further mechanically crushing the particles using a high-pressure emulsifier or an ultrasonic disperser, a uniform emulsion composition can be easily manufactured.

[0131] Crosslinking agents can be appropriately used in emulsion compositions. The use of crosslinking agents tends to improve the water resistance and impact resistance of liquid crystal-polymer composite films.

[0132] There are no particular limitations on the crosslinking agent, but the following crosslinking agents can be cited as examples. Epoxy compounds such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerol diglycidyl ether, polyglycerol polyglycidyl ether, and diglycidyl aniline; γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyldimethoxymethylsilane, γ-glycidoxypropyldiethoxymethylsilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriethoxysilane and other epoxysilane compounds; 3-Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane and other aminosilane compounds; Mercaptosilane compounds such as γ-mercaptopropyltrimethoxysilane; Hydrazide compounds such as carbohydrazide, oxalic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide; Aminourea resin; Polycarbodiimide resins; Tetramethylolmethane-tris(β-aziridinylpropionate), trimethylolpropane-tris(β-aziridinylpropionate), methylenebis[N-(1-aziridinylcarbonyl)-4-aniline], N,N'-hexamethylenebis(1-aziridinylcarboxamide), N,N'-hexamethyleneethylene-1,6-bis(1-aziridinylcarboxamide), and other aziridinium compounds (containing ethylimino groups); Compounds containing acetylacetoxy groups; compounds containing oxazoline groups; Polyethylene polyamine; Polyethyleneimine; Polyamide polyamine; Polyamide polyurea; Alkylated polyhydroxymethyl melamine; Glyoxal; Water-dispersible isocyanates; capped isocyanates; compounds containing carbodiimide groups; divinyl sulfone; lactate titanate.

[0133] When using epoxy compounds and epoxysilane compounds, catalysts such as imidazole compounds, amine compounds, and phosphorus compounds can also be added.

[0134] Among the above, acylhydrazine compounds, compounds containing oxazoline groups, compounds containing carbodiimide groups, and terminal isocyanates are preferred because they have fast crosslinking speed and low toxicity.

[0135] Polymers and crosslinking agents can be used in any combination, but combinations of polyurethane with oxazoline-containing compounds, polyurethane with carbodiimide-containing compounds, polyurethane with capped isocyanates, and polyacrylic acids with hydrazide compounds are preferred due to their high crosslinking reactivity. Furthermore, from the perspective of the stability of the resulting emulsion composition, combinations of polyacrylic acids and carbodiimide-containing compounds are preferred.

[0136] The amount of crosslinking agent added is not particularly limited, but it is preferably 0.1% by mass or more, more preferably 1% by mass or more, relative to the crosslinked polymer. Furthermore, it is preferably 20% by mass or less, more preferably 10% by mass or less. With the amount of crosslinking agent added within the above range, the water resistance and impact resistance of the liquid crystal-polymer composite film tend to improve while maintaining its flexibility. The crosslinking agent can be added either as a one-component agent initially added to the emulsion composition or as a two-component agent added just before coating onto the substrate.

[0137] The viscosity of the emulsion composition of the present invention is preferably 10 mPa·s or more, more preferably 100 mPa·s or more. Furthermore, it is preferably 10000 mPa·s or less, more preferably 2000 mPa·s or less. With the viscosity within the above range, it is easier to coat the liquid crystal-polymer composite film with uniform thickness and to increase the coating speed, thereby increasing productivity.

[0138] In order to control the viscosity of the emulsion composition of the present invention within the above-mentioned range, viscosity modifiers such as thickeners, thixotropic agents, and viscosity reducers can be used.

[0139] As a viscosity modifier, there are no particular limitations; examples of substances that can be cited as dispersion stabilizers can be found.

[0140] The content of the liquid crystal composition in the emulsion composition is preferably 20% by mass or more, more preferably 30% by mass or more. Furthermore, it is preferably 70% by mass or less, more preferably 65% ​​by mass or less. By keeping the content of the liquid crystal composition within the above range, cissing that occurs when coating the emulsion composition onto the substrate tends to be suppressed, and the particle size of the liquid crystal composition and the viscosity of the emulsion composition can be easily controlled within the above ranges.

[0141] The particle size of the polymer used in the emulsion composition is preferably 1 nm or more, more preferably 10 nm or more. Furthermore, it is preferably 1000 nm or less, more preferably 200 nm or less. Within these ranges, it is easier to control the viscosity of the emulsion composition within these ranges.

[0142] Furthermore, the preferred molecular weight of the polymer is 1.0 × 10⁻⁶. 3 The above, more preferably 1.0×10 4That's all. Furthermore, 1.0 × 10⁻⁶ is preferred. 6 Hereinafter, 1.0 × 10 is preferred. 5 The following applies. By ensuring that the molecular weight of the polymer is within the aforementioned range, it becomes easier to control the viscosity of the emulsion composition within the aforementioned range. Example

[0143] The present invention will now be described in more detail through embodiments, but the present invention is not limited to the following embodiments as long as it does not depart from its spirit.

[0144] [Example 1] A nematic liquid crystal with Δn = 0.09 and NI point = 125°C is used as the liquid crystal component. The anthraquinone-based blue dichroic pigment (D-1) and the azo-based yellow dichroic pigment (D-2) are mixed in the following proportions to obtain a black liquid crystal composition (L-1).

[0145] [Chemistry 4]

[0146] <Liquid Crystal Composition Ratio> Nematic liquid crystal: 92.0% by mass D-1: 3.4% by mass D-2: 0.6% by mass NKX-3739: 1.0% by mass CB-15: 3.0% by mass Content of dichroic pigment relative to 100% by mass of the liquid crystal composition: 5% by mass

[0147] 50% by mass of a 1.5% by mass aqueous solution of sodium dodecylbenzenesulfonate was added relative to 50% by mass of the liquid crystal composition (L-1), and emulsified through Shirasu porous glass to obtain an o / w emulsion (E-1). Adding 7% by weight of polyvinyl alcohol GOHSENOL GH-17R (manufactured by Mitsubishi Chemical Co., Ltd.) to 93% by weight of waterborne acrylic emulsion RIKABOND ES-620 (manufactured by Nippon Paint Resin Co., Ltd.) and stirring yields a white latex (W-1). Add 45 parts by weight of white latex (W-1) to 55 parts by weight of o / w emulsion (E-1) and stir until homogeneous to obtain emulsion composition (I-1).

[0148] The average particle size of the liquid crystal composition in the emulsion composition (I-1) is 10 μm. If the mass of the polymer (P-1) dispersed or dissolved in the aqueous phase of the emulsion composition (I-1) is set to 1, then the mass of the liquid crystal composition (L-1) is 1.14.

[0149] As a substrate, a film with a transparent ITO electrode deposited on a 125 μm thick PET film substrate was used. An emulsion composition (I-1) was applied to the ITO film on this substrate by rod coating, and dried at 50°C to obtain a liquid crystal-polymer composite film with a thickness of 30 μm. Microscopic observation of the liquid crystal-polymer composite film on the film surface revealed that liquid crystal composition with an average particle size of 10 μm was dispersed in the polymer matrix. A liquid crystal-polymer composite film substrate is bonded to another substrate at 80°C in a relative manner to obtain a liquid crystal element (F-1). The liquid crystal element (F-1) is flexible and can be cut into shape using scissors. That is, the liquid crystal element (F-1) can be cut into shape.

[0150] The liquid crystal element (F-1) displays black when the voltage is OFF and becomes transparent in normal mode when the voltage is ON (a rectangular wave with a frequency of 100Hz and a frequency of 50Vrms). When the voltage is OFF, the haze is 70.3% and the total light transmittance is 23.9%. If a voltage of 100Vrms is applied, the haze becomes 9.6% and the total light transmittance becomes 54.5%.

[0151] [Example 2] Except for using a nematic liquid crystal with Δn = 0.08 and NI point = 140°C as a liquid crystal component, a black liquid crystal composition (L-2) was obtained by mixing in the same manner as in Example 1. 50% by mass of a 1.5% by mass sodium dodecylbenzenesulfonate aqueous solution was added relative to 50% by mass of the liquid crystal composition (L-2), and emulsified through Shirasu porous glass to obtain an o / w emulsion (E-2). Add 45 parts by weight of white latex (W-1) to 55 parts by weight of o / w emulsion (E-2) and stir until homogeneous to obtain emulsion composition (I-2). The average particle size of the liquid crystal composition in the emulsion composition (I-2) is 10 μm. If the mass of the polymer (P-1) dispersed or dissolved in the aqueous phase of the emulsion composition (I-2) is set to 1, then the mass of the liquid crystal composition (L-2) is 1.15.

[0152] Using the emulsion composition (I-2), a liquid crystal element (F-2) was obtained in the same manner as in Example 1. Microscopic observation of the liquid crystal-polymer composite film of the liquid crystal element (F-2) revealed that liquid crystal components with an average particle size of 10 μm were dispersed within the polymer matrix. The liquid crystal element (F-2) is flexible and can be cut into shape using scissors. That is, the liquid crystal element (F-2) can be cut into shape. The liquid crystal element (F-2) displays black when the voltage is OFF and becomes transparent in normal mode when the voltage is ON (a rectangular wave with a frequency of 100Hz and a frequency of 50Vrms). When the voltage is OFF, the haze is 72.8% and the total light transmittance is 25.2%. If a voltage of 100Vrms is applied, the haze becomes 15.8% and the total light transmittance becomes 55.2%.

[0153] [Comparative Example 1] Except for using a nematic liquid crystal with Δn = 0.08 and NI point = 96°C as the liquid crystal component, a black liquid crystal composition (L-3) was obtained in the same manner as in Example 1. 50% by mass of a 1.5% by mass sodium dodecylbenzenesulfonate aqueous solution was added relative to 50% by mass of the liquid crystal composition (L-3), and emulsified through Shirasu porous glass to obtain an o / w emulsion (E-3). Add 45 parts by weight of white latex (W-1) to 55 parts by weight of o / w emulsion (E-3) and stir until homogeneous to obtain emulsion composition (I-3). The average particle size of the liquid crystal composition in the emulsion composition (I-3) is 10 μm. If the mass of the polymer (P-1) dispersed or dissolved in the aqueous phase of the emulsion composition (I-3) is set to 1, then the mass of the liquid crystal composition (L-3) is 1.14.

[0154] Using the emulsion composition (I-3), a black liquid crystal element (F-3) was obtained in the same manner as in Example 1. Microscopic observation of the liquid crystal-polymer composite film of the liquid crystal element (F-3) revealed that liquid crystal components with an average particle size of 10 μm were dispersed within the polymer matrix. The liquid crystal element (F-3) is flexible and can be cut into shape using scissors. That is, the liquid crystal element (F-3) can be cut into shape. The liquid crystal element (F-3) displays black when the voltage is OFF and becomes transparent in normal mode when the voltage is ON (a rectangular wave with a frequency of 100Hz and a frequency of 50Vrms). When the voltage is OFF, the haze is 72.0% and the total light transmittance is 19.1%. If a voltage of 100Vrms is applied, the haze becomes 9.5% and the total light transmittance becomes 46.7%.

[0155] [Example 3] The liquid crystal element (F-1) obtained in Example 1 was placed in a thermostatic bath at 90°C and continuously driven by a rectangular wave with a frequency of 100Hz and a frequency of 50Vrms. After continuous driving for 65 hours, 133 hours, and 228 hours, the element was removed, allowed to return to room temperature, and the haze and total light transmittance were measured in the same manner as in Example 1. The difference (dynamic range) between ON and OFF states was set as ΔHaze and ΔTT, respectively, and no significant changes from the initial values ​​were observed. The results are shown in Table 1 below.

[0156] [Table 1] Table 1

[0157] [Example 4] The liquid crystal element (F-2) obtained in Example 2 was placed in a constant temperature bath at 90°C, and a rectangular wave with a frequency of 100Hz and 50Vrms was applied to continuously drive it in the same way as in Example 3. Continuous operation was initiated, and the device was removed after 65 hours, 133 hours, and 228 hours to allow it to return to room temperature. Haze and total light transmittance were then measured. The difference between ON and OFF was set as ΔHaze and ΔTT, and no significant changes from the initial values ​​were observed. The results are shown in Table 2 below.

[0158] [Table 2] Table 2

[0159] [Comparative Example 2] The liquid crystal element (F-3) obtained in Comparative Example 1 was placed in a constant temperature bath at 90°C, and a rectangular wave with a frequency of 100Hz and 50Vrms was applied to continuously drive it in the same manner as in Example 3. Continuous operation was initiated, and the device was removed after 65 hours, 133 hours, and 228 hours to allow it to return to room temperature. Haze and total light transmittance were then measured. The difference between ON and OFF was set as ΔHaze and ΔTT, and a significant decrease was observed after 65 hours. The results are shown in Table 3 below.

[0160] [Table 3] Table 3

[0161] The haze (dynamic range ΔHaze) and total light transmittance (dynamic range ΔTT) of Examples 3, 4, and Comparative Example 2 after 65 hours, 133 hours, and 228 hours from the start of continuous drive are as follows: Figure 1 and 2 As shown. As can be seen from the above embodiments and comparative examples, by using the NI point of the liquid crystal component within a specific range, the visible light transmittance of the liquid crystal element has a high range of variation (dynamic range), and the dynamic range can be maintained even after driving at high temperature.

[0162] [Example 5] The o / w emulsion (E-1) prepared in Example 1 was ultrasonically dispersed for 10 minutes using an ultrasonic disperser (UH-600) manufactured by SMT Corporation to obtain o / w emulsion (E-5). Add 45 parts by weight of white latex (W-1) to 55 parts by weight of o / w emulsion (E-5) and stir until homogeneous to obtain emulsion composition (I-5). The average particle size of the liquid crystal composition in the emulsion composition (I-5) is 0.2 μm. If the mass of the polymer (P-1) dispersed or dissolved in the aqueous phase of the emulsion composition (I-5) is set to 1, then the mass of the liquid crystal composition (L-1) is 1.14.

[0163] Using the emulsion composition (I-5), a liquid crystal element (F-5) was obtained in the same manner as in Example 1. Microscopic observation of the liquid crystal-polymer composite film of the liquid crystal element (F-5) revealed that liquid crystal components with an average particle size of 0.2 μm were dispersed within the polymer matrix. The liquid crystal element (F-5) is flexible and can be cut into shape using scissors. That is, the liquid crystal element (F-5) can be cut into shape. The liquid crystal element (F-5) displays black when the voltage is OFF and becomes transparent in normal mode when the voltage is ON (a rectangular wave with a frequency of 100Hz and a frequency of 50Vrms). When the voltage is OFF, the haze is 74.0% and the total light transmittance is 22.7%. If a voltage of 100Vrms is applied, the haze becomes 5.7% and the total light transmittance becomes 66.3%.

[0164] [Example 6] The o / w emulsion (E-2) prepared in Example 2 was ultrasonically dispersed for 10 minutes using an ultrasonic disperser (UH-600) manufactured by SMT Corporation to obtain o / w emulsion (E-6). Add 45 parts by weight of white latex (W-1) to 55 parts by weight of o / w emulsion (E-6) and stir until homogeneous to obtain emulsion composition (I-6). The average particle size of the liquid crystal composition in the emulsion composition (I-6) is 0.2 μm. If the mass of the polymer (P-1) dispersed or dissolved in the aqueous phase of the emulsion composition (I-6) is set to 1, then the mass of the liquid crystal composition (L-2) is 1.16.

[0165] Using the emulsion composition (I-6), a liquid crystal element (F-6) was obtained in the same manner as in Example 1. Microscopic observation of the liquid crystal-polymer composite film of the liquid crystal element (F-6) revealed that liquid crystal components with an average particle size of 0.2 μm were dispersed within the polymer matrix. The liquid crystal element (F-6) is flexible and can be cut into shape using scissors. That is, the liquid crystal element (F-6) can be cut into shape. The liquid crystal element (F-6) displays black when the voltage is OFF and becomes transparent in normal mode when the voltage is ON (a rectangular wave with a frequency of 100Hz and a frequency of 50Vrms). When the voltage is OFF, the haze is 67.7% and the total light transmittance is 25.8%. If a voltage of 100Vrms is applied, the haze becomes 8.8% and the total light transmittance becomes 59.8%.

[0166] [Comparative Example 3] The o / w emulsion (E-3) prepared in Comparative Example 1 was ultrasonically dispersed for 10 minutes using an ultrasonic disperser (UH-600) manufactured by SMT Corporation to obtain o / w emulsion (E-7). Add 45 parts by weight of white latex (W-1) to 55 parts by weight of o / w emulsion (E-7) and stir until homogeneous to obtain emulsion composition (I-7). The average particle size of the liquid crystal composition in the emulsion composition (I-7) is 0.2 μm. If the mass of the polymer (P-1) dispersed or dissolved in the aqueous phase of the emulsion composition (I-7) is set to 1, then the mass of the liquid crystal composition (L-3) is 1.14.

[0167] Using the emulsion composition (I-7), a black liquid crystal element (F-7) was obtained in the same manner as in Example 1. Microscopic observation of the liquid crystal-polymer composite film of the liquid crystal element (F-7) revealed that liquid crystal components with an average particle size of 0.2 μm were dispersed within the polymer matrix. The liquid crystal element (F-7) is flexible and can be cut into shape using scissors. That is, the liquid crystal element (F-7) can be cut into shape. The liquid crystal element (F-7) represents the normal mode drive, which colors black when the voltage is OFF and becomes transparent when the voltage is ON (a rectangular wave with a frequency of 100Hz and a frequency of 50Vrms). When the voltage is OFF, the haze is 59.6% and the total light transmittance is 27.1%. If a voltage of 100Vrms is applied, the haze becomes 8.4% and the total light transmittance becomes 54.4%.

[0168] [Example 7] The liquid crystal element (F-5) obtained in Example 5 was placed in a thermostatic bath at 90°C and continuously driven by a rectangular wave with a frequency of 100Hz and a frequency of 50Vrms. After continuous driving for 65 hours, 133 hours, and 228 hours, the element was removed and allowed to return to room temperature. Haze and total light transmittance were measured in the same manner as in Example 1. The difference between ON and OFF states (dynamic range) was set as ΔHaze and ΔTT, respectively. No significant changes from the initial values ​​were observed. The results are shown in Table 4 below.

[0169] [Table 4] Table 4

[0170] [Example 8] The liquid crystal element (F-6) obtained in Example 6 was placed in a constant temperature bath at 90°C, and a rectangular wave with a frequency of 100Hz and 50Vrms was applied to continuously drive it in the same way as in Example 7. Continuous operation was initiated, and the device was removed after 65 hours, 133 hours, and 228 hours to allow it to return to room temperature. Haze and total light transmittance were then measured. The difference between ON and OFF was set as ΔHaze and ΔTT, and no significant changes from the initial values ​​were observed. The results are shown in Table 5 below.

[0171] [Table 5] Table 5

[0172] [Comparative Example 4] The liquid crystal element (F-7) obtained in Comparative Example 3 was placed in a constant temperature bath at 90°C, and a rectangular wave with a frequency of 100Hz and 50Vrms was applied to continuously drive it in the same manner as in Example 7. Continuous operation was initiated, and the device was removed after 65 hours, 133 hours, and 228 hours to allow it to return to room temperature. Haze and total light transmittance were then measured. The difference between ON and OFF was set as ΔHaze and ΔTT, and a significant decrease was observed after 65 hours. The results are shown in Table 6 below.

[0173] [Table 6] Table 6

[0174] The haze (dynamic range ΔHaze) and total light transmittance (dynamic range ΔTT) of Examples 7, 8, and Comparative Example 4 after 65 hours, 133 hours, and 228 hours from the start of continuous drive are as follows: Figure 3 and 4 As shown. As can be seen from the above embodiments and comparative examples, by using the NI point of the liquid crystal component within a specific range, the visible light transmittance of the liquid crystal element has a high range of variation (dynamic range), and the dynamic range can be maintained even after driving at high temperature.

[0175] [Example 9] Except for using a nematic liquid crystal with Δn = 0.096 and NI point = 130.6°C as a liquid crystal component, a black liquid crystal composition (L-8) was obtained by mixing in the same manner as in Example 1. A 50% by mass aqueous solution of 1.5% by mass sodium dodecylbenzenesulfonate was added relative to a 50% by mass liquid crystal composition (L-8), and emulsified through Shirasu porous glass to obtain an o / w emulsion (E-8). Add 45 parts by weight of white latex (W-1) to 55 parts by weight of o / w emulsion (E-8) and stir until homogeneous to obtain emulsion composition (I-8). The average particle size of the liquid crystal composition in the emulsion composition (I-8) is 10 μm. If the mass of the polymer (P-1) dispersed or dissolved in the aqueous phase of the emulsion composition (I-8) is set to 1, then the mass of the liquid crystal composition (L-8) is 1.17.

[0176] Using the emulsion composition (I-8), a liquid crystal element (F-8) was obtained in the same manner as in Example 1. Microscopic observation of the liquid crystal-polymer composite film of the liquid crystal element (F-8) revealed that liquid crystal components with an average particle size of 10 μm were dispersed within the polymer matrix. The liquid crystal element (F-8) is flexible and can be cut into shape using scissors. That is, the liquid crystal element (F-8) can be cut into shape. The liquid crystal element (F-8) displays black when the voltage is OFF and becomes transparent in normal mode when the voltage is ON (a rectangular wave with a frequency of 100Hz and a frequency of 50Vrms). When the voltage is OFF, the haze is 73.1% and the total light transmittance is 23.7%. If a voltage of 100Vrms is applied, the haze becomes 7.2% and the total light transmittance becomes 56.3%.

[0177] [Example 10] Except for using a nematic liquid crystal with Δn = 0.095 and NI point = 129.5°C as a liquid crystal component, a black liquid crystal composition (L-9) was obtained by mixing in the same manner as in Example 1. 50% by mass of a 1.5% by mass sodium dodecylbenzenesulfonate aqueous solution was added relative to 50% by mass of the liquid crystal composition (L-9), and emulsified through Shirasu porous glass to obtain an o / w emulsion (E-9). Add 45 parts by weight of white latex (W-1) to 55 parts by weight of o / w emulsion (E-9) and stir until homogeneous to obtain emulsion composition (I-9). The average particle size of the liquid crystal composition in the emulsion composition (I-9) is 10 μm. If the mass of the polymer (P-1) dispersed or dissolved in the aqueous phase of the emulsion composition (I-9) is set to 1, then the mass of the liquid crystal composition (L-9) is 1.25.

[0178] Using the emulsion composition (I-9), a liquid crystal element (F-9) was obtained in the same manner as in Example 1. Microscopic observation of the liquid crystal-polymer composite film of the liquid crystal element (F-9) revealed that liquid crystal components with an average particle size of 10 μm were dispersed within the polymer matrix. The liquid crystal element (F-9) is flexible and can be cut into shape using scissors. That is, the liquid crystal element (F-9) can be cut into shape. The liquid crystal element (F-9) displays black when the voltage is OFF and becomes transparent in normal mode when the voltage is ON (a rectangular wave with a frequency of 100Hz and a frequency of 50Vrms). When the voltage is OFF, the haze is 72.5% and the total light transmittance is 24.4%. If a voltage of 100Vrms is applied, the haze becomes 7.6% and the total light transmittance becomes 57.3%.

[0179] [Comparative Example 5] Except for using a nematic liquid crystal with Δn = 0.164 and NI point = 120.7°C as a liquid crystal component, a black liquid crystal composition (L-10) was obtained by mixing in the same manner as in Example 1. 50% by mass of a 1.5% by mass sodium dodecylbenzenesulfonate aqueous solution was added relative to 50% by mass of the liquid crystal composition (L-10), and emulsified through Shirasu porous glass to obtain an o / w emulsion (E-10). Add 45 parts by weight of white latex (W-1) to 55 parts by weight of o / w emulsion (E-10) and stir until homogeneous to obtain emulsion composition (I-10). The average particle size of the liquid crystal composition in the emulsion composition (I-10) is 10 μm. If the mass of the polymer (P-1) dispersed or dissolved in the aqueous phase of the emulsion composition (I-10) is set to 1, then the mass of the liquid crystal composition (L-10) is 1.17.

[0180] Using the emulsion composition (I-10), a liquid crystal element (F-10) was obtained in the same manner as in Example 1. Microscopic observation of the liquid crystal-polymer composite film of the liquid crystal element (F-10) revealed that liquid crystal components with an average particle size of 10 μm were dispersed within the polymer matrix. The liquid crystal element (F-10) is flexible and can be cut into shape using scissors. That is, the liquid crystal element (F-10) can be cut into shape. The liquid crystal element (F-10) displays black when the voltage is OFF and becomes transparent in normal mode when the voltage is ON (a rectangular wave with a frequency of 100Hz and a frequency of 50Vrms). When the voltage is OFF, the haze is 83.3% and the total light transmittance is 24.7%. If a voltage of 100Vrms is applied, the haze becomes 18.2% and the total light transmittance becomes 58.0%.

[0181] [Comparative Example 6] Except for using a nematic liquid crystal with Δn = 0.195 and NI point = 129.9°C as a liquid crystal component, a black liquid crystal composition (L-11) was obtained by mixing in the same manner as in Example 1. 50% by mass of a 1.5% by mass aqueous solution of sodium dodecylbenzenesulfonate was added relative to 50% by mass of the liquid crystal composition (L-11), and emulsified through Shirasu porous glass to obtain an o / w emulsion (E-11). Add 45 parts by weight of white latex (W-1) to 55 parts by weight of o / w emulsion (E-11) and stir until homogeneous to obtain emulsion composition (I-11). The average particle size of the liquid crystal composition in the emulsion composition (I-11) is 10 μm. If the mass of the polymer (P-1) dispersed or dissolved in the aqueous phase of the emulsion composition (I-11) is set to 1, then the mass of the liquid crystal composition (L-11) is 1.17.

[0182] Using the emulsion composition (I-11), a liquid crystal element (F-11) was obtained in the same manner as in Example 1. Microscopic observation of the liquid crystal-polymer composite film of the liquid crystal element (F-11) revealed that liquid crystal components with an average particle size of 10 μm were dispersed within the polymer matrix. The liquid crystal element (F-11) is flexible and can be cut into shape using scissors. That is, the liquid crystal element (F-11) can be cut into shape. The liquid crystal element (F-11) displays black when the voltage is OFF and becomes transparent in normal mode when the voltage is ON (a rectangular wave with a frequency of 100Hz and a frequency of 50Vrms). When the voltage is OFF, the haze is 84.3% and the total light transmittance is 26.6%. If a voltage of 100Vrms is applied, the haze becomes 22.2% and the total light transmittance becomes 60.1%.

[0183] Although the dynamic range of haze and total light transmittance of the liquid crystal elements (F-10) and (F-11) fabricated in Comparative Examples 5 and 6 is the same as that in Examples 9 and 10, the haze is high when voltage is applied and the transparency is lacking.

[0184] Although the invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various changes can be made without departing from the intent and scope of the invention. This application is based on Japanese Patent Application 2021-31559, filed on March 1, 2021, the entire contents of which are incorporated herein by reference.

Claims

1. A liquid crystal element, comprising: Two substrates with transparent conductive films arranged opposite each other, and a liquid crystal-polymer composite film sandwiched between the two substrates with transparent conductive films, wherein... The liquid crystal-polymer composite film has a polymer matrix and a liquid crystal composition surrounded by the polymer matrix. The liquid crystal composition contains liquid crystal components and dichroic pigments. The dielectric constant of the liquid crystal component is positively anisotropic, and the Ni point is above 110°C and below 150°C. The refractive index anisotropy of the liquid crystal component is greater than 0.01 and less than 0.

1. The liquid crystal-polymer composite film can switch between a transparent state and a colored state by applying voltage.

2. The liquid crystal element according to claim 1, wherein, The average particle size of the liquid crystal composition is 2 μm or more and 50 μm or less.

3. The liquid crystal element according to claim 1, wherein, The average particle size of the liquid crystal composition is greater than or equal to 0.01 μm and less than 2 μm.

4. The liquid crystal element according to any one of claims 1 to 3, wherein, The dichroic pigments contain anthraquinone pigments and / or azo pigments.

5. The liquid crystal element according to any one of claims 1 to 3, wherein, The content of the dichroic pigment is 0.1% by mass or more and 20% by mass or less relative to 100% by mass of the liquid crystal composition.

6. The liquid crystal element according to any one of claims 1 to 3, wherein, The liquid crystal component is a nematic liquid crystal or a chiral nematic liquid crystal.

7. The liquid crystal element according to any one of claims 1 to 3, wherein, The polymer constituting the polymer matrix contains at least one selected from polyurethane, polyacrylic acid, polyvinyl alcohol, and their modifiers.

8. The liquid crystal element according to any one of claims 1 to 3, wherein, The total light transmittance of the tinted state is 0.1% or more and 30% or less.

9. The liquid crystal element according to any one of claims 1 to 3, wherein, The total light transmittance of the transparent state is greater than 30% and less than 80%.

10. An emulsion composition, which is an emulsion composition formed by dispersing a liquid crystal composition in an aqueous medium, wherein, The medium contains dispersed or dissolved polymers. The liquid crystal composition contains liquid crystal components and dichroic pigments. The dielectric constant of the liquid crystal component is positively anisotropic, and the Ni point is above 110°C and below 150°C. The refractive index anisotropy of the liquid crystal component is greater than 0.01 and less than 0.

1.

11. The emulsion composition according to claim 10, wherein, The average particle size of the liquid crystal composition in the emulsion composition is 2 μm or more and 50 μm or less.

12. The emulsion composition according to claim 10, wherein, The average particle size of the liquid crystal composition in the emulsion composition is greater than or equal to 0.01 μm and less than 2 μm.

13. The emulsion composition according to any one of claims 10 to 12, wherein, The dichroic pigments contain anthraquinone pigments and / or azo pigments.

14. The emulsion composition according to any one of claims 10 to 12, wherein, The content of the dichroic pigment is 0.1% by mass or more and 20% by mass or less relative to 100% by mass of the liquid crystal composition.

15. The emulsion composition according to any one of claims 10 to 12, wherein, The liquid crystal component is a nematic liquid crystal or a chiral nematic liquid crystal.

16. The emulsion composition according to any one of claims 10 to 12, wherein, The polymer contains at least one selected from polyurethane, polyacrylic acid, polyvinyl alcohol, and their modifiers.

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