Liquid crystal capsules and capsule solutions, optical films, optical devices, transmittance variable devices using the same

Abstract

This invention relates to a liquid crystal capsule comprising: a core containing liquid crystal and an emulsifier; and a polymer shell formed on the surface of the core; wherein the emulsifier comprises a sorbitan ester-based compound having a molar mass of 1220 g / mol or less, and the sorbitan ester-based compound containing an intramolecular carbon-carbon double bond. Furthermore, this invention relates to a liquid crystal capsule comprising: a core containing liquid crystal and an emulsifier; and a polymer shell formed on the surface of the core; wherein the emulsifier comprises a sorbitan ester-based compound, and the emulsifier further comprises at least one second emulsifier selected from compounds based on acetylenic diols and compounds based on polysorbate esters.

Description

Technical Field

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2025-0016668, filed on February 10, 2025, and Korean Patent Application No. 10-2025-0186071, filed on November 28, 2025, the entire contents of which are incorporated herein by reference.

[0003] This invention relates to liquid crystal capsules that can produce a high rate of change in transmittance even at low voltages, as well as capsule solutions, optical films, optical devices, and transmittance variable devices using the same. Background Technology

[0004] Polymer-dispersed liquid crystals (PDLC) films are composite materials in which liquid crystal molecules of several micrometers are dispersed in a polymer and disposed between conductive films. These films can be applied to high-brightness projection displays or high-contrast reflective display devices. The driving principle of PDLCs is that light incident on the polymer layer in which liquid crystals are dispersed is scattered and remains opaque due to the refractive index difference between the liquid crystals and the polymer. However, by applying an electric field, the orientation of the liquid crystals is changed, thereby altering the refractive index and controlling light scattering and transmission to achieve a transparent state.

[0005] Therefore, PDLC devices do not require a separate polarizer and thus do not structurally require a polarizing plate. Furthermore, they do not require an alignment process in processing, allowing for simple fabrication. They can be applied to smart glass for buildings and automobiles, corresponding to switchable windows and smart screens, and also as black PDLC films for transparent OLEDs. Moreover, depending on the material used as the substrate, they can be manufactured in a flexible form.

[0006] Specifically, liquid crystal-based smart windows refer to active windows that can control transmittance using glass comprising individual liquid crystal layers, and are a technology applicable not only to buildings but also to the mobile sector. Using existing polymer-dispersed liquid crystal (PDLC) technology, liquid crystal domains with dimensions of several micrometers can be prepared by mixing liquid crystals with monomers capable of photopolymerization or thermal polymerization and by phase separation between the polymer and liquid crystals occurring during polymerization. In PDLC films, the liquid crystals within these micrometer-sized domains possess refractive indices that match or mismatch with the polymer matrix depending on the application of a voltage switch, thus enabling PDLC films to achieve light-blocking / light-transmitting modes.

[0007] In particular, in the manufacture of color PDLCs containing dyes, there are problems such as anisotropic dyes not being uniformly oriented in the polymer according to an electric field, and especially, the polymer matrix being contaminated by the dye. Therefore, various studies are being conducted on liquid crystal composites with capsule structures in which liquid crystals and anisotropic dyes are encapsulated in a polymer shell. These composites exhibit excellent mechanical and physical properties, high uniformity, and are able to prevent the polymer matrix from being contaminated by the dye.

[0008] However, since the liquid crystal and anisotropic dye are encapsulated in a polymer shell, there is a limitation: due to the high interaction caused by the increased contact area between the liquid crystal enclosed in the capsule and the material contained in the capsule shell, the alignment of the liquid crystal only changes when a higher voltage is applied. Summary of the Invention

[0009] Technical issues

[0010] The present invention aims to provide a liquid crystal capsule that can induce a high rate of change in transmittance even at low voltages.

[0011] Furthermore, the present invention aims to provide capsule solutions, optical films, optical devices, and variable transmittance devices manufactured using liquid crystal capsules.

[0012] Technical solution

[0013] To address the above issues, this specification provides a liquid crystal capsule comprising: a core containing liquid crystal and an emulsifier; and a polymer shell formed on the surface of the core; wherein the emulsifier comprises a sorbitol ester-based compound having a molar mass of 1220 g / mol or less, and the sorbitol ester-based compound contains an intramolecular carbon-carbon double bond.

[0014] This specification also provides a liquid crystal capsule comprising: a core containing liquid crystal and an emulsifier; and a polymer shell formed on the surface of the core; wherein the emulsifier comprises a sorbitan ester-based compound, and the emulsifier further comprises at least one second emulsifier selected from compounds based on alkynyl glycol and compounds based on polysorbate.

[0015] This instruction manual also provides a capsule solution, which contains liquid crystal capsules and a solvent.

[0016] This specification also provides an optical film comprising an adhesive resin and a liquid crystal domain dispersed in the adhesive resin, wherein the haze is 10% or less when a voltage is applied, and the threshold voltage is 60 V or less, said threshold voltage being the voltage at which the transmittance reaches 10% of the maximum transmittance measured when the voltage is applied.

[0017] This specification also provides optical devices, including optical films.

[0018] This specification also provides a variable transmittance device, which includes an optical film.

[0019] The following describes in more detail a liquid crystal capsule according to a specific embodiment of the present invention, as well as the capsule solution, optical film, optical device and variable transmittance device using the same.

[0020] Unless otherwise expressly stated in this specification, the terminology is intended to refer to particular embodiments only and is not intended to limit the invention.

[0021] Unless the phrase explicitly indicates the opposite, the singular form used in this specification also includes the plural form.

[0022] As used in this specification, "comprising / including" means a specific feature, region, integer, step, operation, element, and / or component, and does not exclude the presence or addition of additional specific features, regions, integers, steps, operations, elements, components, and / or groups.

[0023] Furthermore, in this specification, terms including ordinal numbers such as "first" and "second" are used for the purpose of distinguishing one component from another, and are not limited by ordinal numbers. For example, within the scope of this invention, the first component may also be referred to as the second component, and similarly, the second component may be referred to as the first component.

[0024] In this specification, a derivative compound is a compound that, when an organic compound is considered as a parent compound, has been modified (e.g., by introducing functional groups, oxidation, reduction, and substitution of atoms) to the extent that the structure and properties of the parent compound are not significantly altered.

[0025] The invention will be described in more detail below.

[0026] 1. Liquid crystal capsule

[0027] According to one embodiment of the present invention, a liquid crystal capsule may be provided, comprising: a core containing liquid crystal and an emulsifier; and a polymer shell formed on the surface of the core; wherein the emulsifier comprises a sorbitol ester-based compound having a molar mass of 1220 g / mol or less, and the sorbitol ester-based compound comprising an intramolecular carbon-carbon double bond.

[0028] The inventors determined and completed the present invention through experiments: a liquid crystal capsule, as in one embodiment, uses a compound based on dehydrated sorbitan ester with a molar mass of 1220 g / mol or less and containing intramolecular carbon-carbon double bonds as an emulsifier contained in the core inside the capsule along with the liquid crystal, thereby reducing the anchoring energy with the surface in contact with the liquid crystal, and causing the vertical alignment of the liquid crystal due to the radial alignment of the liquid crystal, resulting in a high rate of change of transmittance even at lower voltages.

[0029] Specifically, one embodiment of the liquid crystal capsule may include a core containing liquid crystal. The liquid crystal capsule structure according to the invention is characterized by containing liquid crystal within an interior encapsulated by a polymer shell. This improves the uniformity of the liquid crystal particles.

[0030] Liquid crystals are not particularly limited, and examples include nematic liquid crystals, smectic liquid crystals, cholesteric liquid crystals, and chiral nematic liquid crystals. The specific type of liquid crystal compound is not limited, and various conventionally known liquid crystals can be used without restriction. Liquid crystal compounds are not particularly limited, but can be composed of fluorine-based or cyano-based compounds, or mixtures thereof.

[0031] Additionally, the core may contain an emulsifier. The emulsifier is a surfactant used to form liquid crystal droplets, and by increasing the surface energy in contact with the liquid crystal, it causes the liquid crystal to align radially, thereby inducing vertical alignment of the liquid crystal and resulting in a high rate of change of transmittance even at lower voltages.

[0032] Emulsifiers may contain compounds based on sorbitan esters. Sorbitan ester-based compounds may include one or more of the following: sorbitan esters, their derivatives, or mixtures of two or more types thereof.

[0033] Compounds based on sorbitol esters can contain intramolecular carbon-carbon double bonds. When a compound containing intramolecular carbon-carbon double bonds (C=C) of sorbitol ester-based compounds exhibits enhanced interaction between the double bonds in the emulsifier molecules aligned towards the central axis of the liquid crystal and the liquid crystal molecules, the liquid crystal can exhibit radial alignment. Therefore, high transmittance variations can be achieved even at lower voltages.

[0034] Compounds based on sorbitol esters are reaction products of sorbitol and carboxylic acids containing intramolecular carbon-carbon double bonds. The carboxylic acid containing the intramolecular carbon-carbon double bond can have 10 to 30 carbon atoms, or 15 to 30 carbon atoms, or 16 to 30 carbon atoms, or 17 to 30 carbon atoms, or 15 to 20 carbon atoms, or 16 to 20 carbon atoms, or 17 to 20 carbon atoms, or 17 to 19 carbon atoms. A specific example of a carboxylic acid containing an intramolecular carbon-carbon double bond is oleic acid.

[0035] The molar mass of compounds based on sorbitol esters can be 1220 g / mol or less, or 800 g / mol or less, or 100 g / mol or more, or 100 g / mol to 1220 g / mol, or 100 g / mol to 800 g / mol, or 400 g / mol to 700 g / mol, or 400 g / mol to 500 g / mol, or 600 g / mol to 700 g / mol.

[0036] On the other hand, if the molar mass of the compound based on sorbitol esters is excessively increased to more than 1220 g / mol, problems such as reduced stability of oil-in-water emulsions and increased haze of optical films may occur when using liquid crystals to prepare capsules.

[0037] More specifically, the molar mass of compounds based on sorbitan esters can be 800 g / mol or less, or 100 g / mol to 800 g / mol, or 400 g / mol to 700 g / mol, or 400 g / mol to 500 g / mol. Specific examples of compounds based on sorbitan esters having the above molar masses are sorbitan monooleate.

[0038] The HLB (Hydrophile Lipophile Balance) value of compounds based on sorbitan esters having a molar mass of 800 g / mol or less, or 100 g / mol to 800 g / mol, or 400 g / mol to 700 g / mol, or 400 g / mol to 500 g / mol is 4 to 4.5. HLB can be calculated using the following mathematical formula 1.

[0039] [Mathematical Expression 1]

[0040] HLB = 20 × (MH / M)

[0041] In mathematical formula 1, MH is the molecular weight (or molar mass) of the hydrophilic group, and M is the molecular weight (or molar mass) of the emulsifier.

[0042] Furthermore, the molar mass of compounds based on sorbitan esters can be 800 g / mol or less, or 100 g / mol to 800 g / mol, or 400 g / mol to 700 g / mol, or 600 g / mol to 700 g / mol. Specific examples of compounds based on sorbitan esters having the above molar masses are sorbitan dioleate.

[0043] Furthermore, the sorbitol-based compounds can be mixtures of two or more types of sorbitol-based compounds with different molar masses. More specifically, the sorbitol-based compounds can be mixtures of sorbitol-based compounds with a molar mass of 400 g / mol to 500 g / mol and sorbitol-based compounds with a molar mass of 600 g / mol to 700 g / mol.

[0044] There is no particular limitation on the molar ratio of the compound based on sorbitol ester with a molar mass of 400 g / mol to 500 g / mol to the compound based on sorbitol ester with a molar mass of 600 g / mol to 700 g / mol, and the molar ratio of the compound based on sorbitol ester with a molar mass of 400 g / mol to 500 g / mol to the compound based on sorbitol ester with a molar mass of 600 g / mol to 700 g / mol can be 10:1 to 1:10, or 5:1 to 1:5, or 3:1 to 1:3.

[0045] To illustrate with a more specific example, a mixture of two or more types of sorbitan ester-based compounds with different molar masses can be a mixture of sorbitan sesquioleate (a 1:1 molar ratio of sorbitan monooleate (molar mass: 428.61 g / mol) and sorbitan dioleate (molar mass: 693 g / mol)).

[0046] The aforementioned sorbitan ester-based compounds are mixtures of sorbitan ester-based compounds with a molar mass of 400 g / mol to 500 g / mol and sorbitan ester-based compounds with a molar mass of 600 g / mol to 700 g / mol, wherein the HLB (Hydrophile Lipophile Balance) value of the mixture is 3.5 to 3.9.

[0047] Meanwhile, based on 100 parts by weight of liquid crystal, the emulsifier content can be from 0.1 parts by weight to 50 parts by weight, or 0.1 parts by weight to 20 parts by weight, or 0.5 parts by weight to 20 parts by weight, or 1 part by weight to 20 parts by weight, or 5 parts by weight to 11 parts by weight. When the emulsifier content is excessively reduced based on 100 parts by weight of liquid crystal, there is a limitation that it is difficult to sufficiently induce a high rate of change in transmittance even at lower voltages due to the vertical alignment of the liquid crystal caused by the emulsifier. Furthermore, when the emulsifier content is excessively increased based on 100 parts by weight of liquid crystal, the problem may arise that excessive emulsifier forms micelles, causing a sharp decrease in the surface tension of the solution.

[0048] Additionally, the core may contain anisotropic dyes. There are no particular restrictions on the anisotropic dyes, as long as they are dopable anisotropic dyes. Specifically, they can be S-428, M-483, M412 (Mitsui Fine Chemicals), etc.

[0049] Simultaneously, the core may also contain siloxane-based additives. Siloxane-based additives are additives capable of reducing the interfacial tension of liquid crystals. Therefore, the liquid crystal capsule in which siloxane-based additives and liquid crystal are simultaneously contained within the core can sufficiently reduce the surface anchoring energy of the liquid crystal within the capsule.

[0050] The molar mass of siloxane-based additives can be 500 g / mol or less, or 100 g / mol to 500 g / mol. Siloxane-based additives may include trisiloxane-based compounds. Trisiloxane-based compounds may include trisiloxane compounds or their derivatives. As specific examples, siloxane-based additives may be octamethyltrisiloxane or hexamethylcyclotrisiloxane.

[0051] Specifically, based on 100 parts by weight of liquid crystal, the content of the siloxane-based additive can be from 0.1 parts by weight to 50 parts by weight, or from 0.1 parts by weight to 20 parts by weight, or from 0.5 parts by weight to 20 parts by weight, or from 0.5 parts by weight to 10 parts by weight, or from 0.9 parts by weight to 1 part by weight. When the content of the siloxane-based additive in 100 parts by weight of liquid crystal is excessively reduced, the surface tension reduction effect of the liquid crystal caused by the siloxane-based additive cannot be fully realized, thus limiting the insufficient reduction of the surface anchoring energy of the liquid crystal in the capsule. Furthermore, when the content of the siloxane-based additive in 100 parts by weight of liquid crystal is excessively increased, the liquid crystal state (intermediate phase state) may change into an isotropic liquid phase.

[0052] Furthermore, the liquid crystal capsule of the embodiment may include a polymer shell formed on the surface of the core. The shell may be a single-layer shell made of a single polymer material, or a double-layer shell made of different polymer materials, or a multi-layer shell with three or more layers to achieve further improved mechanical properties and particle uniformity. Therefore, the uniformity of the liquid crystal particles can be improved, and simultaneously, the problem of contamination caused by dyes can be mitigated.

[0053] The material forming the shell has the same refractive index as the matrix polymer in which the liquid crystal composite is dispersed. There are no particular limitations on specific examples, but it can be selected, for example, from polyvinyl alcohol, polyurea, polyacrylic acid, polyurethane, polyamide (including nylon), polyacetal and polyester.

[0054] However, to give a specific example, the polymer shell formed on the surface of the core can be made of glyoxal-crosslinked polyvinyl alcohol (PVA) resin. There are no particular restrictions on the type of PVA, and various PVAs with different molecular weights or degrees of saponification can be appropriately selected depending on the purpose. Glyoxal is used as the crosslinking agent for PVA.

[0055] Meanwhile, the average diameter of the liquid crystal capsule can range from 100 nm to 300 nm. When the average diameter of the liquid crystal capsule decreases excessively, there are problems with increased driving voltage and power consumption. In addition, when the average diameter of the liquid crystal capsule increases excessively, visible light is scattered, causing high haze.

[0056] Liquid crystal capsules can be groups of individual particles with an average diameter of 100 nm to 300 nm, wherein the individual fine particles contained in such a group can have an average diameter of 100 nm to 300 nm. More specifically, 60% or 80% of the individual fine particles contained in the group can have a diameter of 100 nm to 300 nm.

[0057] Meanwhile, according to another embodiment of the present invention, a liquid crystal capsule can be provided, comprising: a core containing liquid crystal and an emulsifier; and a polymer shell formed on the surface of the core; wherein the emulsifier comprises a sorbitan ester-based compound, and the emulsifier further comprises at least one second emulsifier selected from compounds based on alkynyl glycol and compounds based on polysorbitan ester.

[0058] The inventors have determined and completed the present invention through experiments: a liquid crystal capsule, as in one embodiment, contains at least one second emulsifier, selected from compounds based on alkynyl glycol and polysorbate, in addition to compounds based on sorbitol esters, as an emulsifier in a core contained within the capsule along with the liquid crystal. This reduces the anchoring energy to the surface in contact with the liquid crystal, and causes the liquid crystal to align vertically due to the change in liquid crystal alignment to radial alignment, thereby resulting in a high rate of change of transmittance even at lower voltages.

[0059] In particular, compared to cases where only sorbitan ester-based compounds are used as emulsifiers, by also including at least one second emulsifier selected from alkynyl glycol-based compounds and polysorbate-based compounds, the movement of liquid crystal molecules can be promoted or the emulsion stability of the liquid crystal can be increased. Therefore, during repeated driving of the liquid crystal cell, contrast is increased and stable electro-optical properties can be ensured.

[0060] Specifically, another embodiment of the liquid crystal capsule may include a core containing liquid crystal. The liquid crystal capsule structure according to the invention is characterized by containing liquid crystal within an interior encapsulated by a polymer shell. This improves the uniformity of the liquid crystal particles.

[0061] Liquid crystals are not particularly limited, and examples may include nematic liquid crystals, smectic liquid crystals, cholesteric liquid crystals, and chiral nematic liquid crystals. The specific type of liquid crystal compound is not limited, and various conventionally known liquid crystals can be used without restriction. Liquid crystal compounds are not particularly limited, but may consist of fluorine-based or cyano-based compounds, or mixtures thereof.

[0062] Simultaneously, the core may also contain an emulsifier. The emulsifier is a surfactant used to form liquid crystal droplets. By increasing the surface energy of the liquid crystal contact, and because the liquid crystal alignment becomes radial, it causes vertical alignment of the liquid crystal, thereby resulting in a high rate of change of transmittance even at lower voltages.

[0063] Emulsifiers may contain compounds based on sorbitan esters. Sorbitan ester-based compounds may include sorbitan esters, their derivatives, or mixtures of two or more of these types.

[0064] Compounds based on sorbitol esters can contain intramolecular carbon-carbon double bonds. When a compound containing intramolecular carbon-carbon double bonds (C=C) of sorbitol ester-based compounds exhibits enhanced interaction between the double bonds in the emulsifier molecules aligned towards the central axis of the liquid crystal and the liquid crystal molecules, the liquid crystal can exhibit radial alignment. Therefore, high transmittance variations can be achieved even at lower voltages.

[0065] Compounds based on sorbitol esters are reaction products of sorbitol and carboxylic acids containing intramolecular carbon-carbon double bonds. These carboxylic acids can have 10 to 30, 15 to 30, 16 to 30, 17 to 30, 15 to 20, 16 to 20, 17 to 20, or 17 to 19 carbon atoms. A specific example of a carboxylic acid containing an intramolecular carbon-carbon double bond is oleic acid.

[0066] The molar mass of compounds based on sorbitol esters can be 1220 g / mol or less, or 800 g / mol or less, or 100 g / mol or more, or 100 g / mol to 1220 g / mol, or 100 g / mol to 800 g / mol, or 400 g / mol to 700 g / mol, or 400 g / mol to 500 g / mol, or 600 g / mol to 700 g / mol.

[0067] On the other hand, if the molar mass of the compound based on sorbitol esters is excessively increased to more than 1220 g / mol, problems such as reduced stability of oil-in-water emulsions and increased haze of optical films may occur when using liquid crystals to prepare capsules.

[0068] More specifically, the molar mass of compounds based on sorbitan esters can be 800 g / mol or less, or 100 g / mol to 800 g / mol, or 400 g / mol to 700 g / mol, or 400 g / mol to 500 g / mol. Specific examples of compounds based on sorbitan esters having the above molar masses are sorbitan monooleate.

[0069] The HLB (Hydrophile Lipophile Balance) value of compounds based on sorbitan esters having a molar mass of 800 g / mol or less, or 100 g / mol to 800 g / mol, or 400 g / mol to 700 g / mol, or 400 g / mol to 500 g / mol is 4 to 4.5. HLB can be calculated using the following mathematical formula 1.

[0070] [Mathematical Expression 1]

[0071] HLB = 20 × (MH / M)

[0072] In mathematical formula 1, MH is the molecular weight (or molar mass) of the hydrophilic group, and M is the molecular weight (or molar mass) of the emulsifier.

[0073] Furthermore, the molar mass of compounds based on sorbitan esters can be 800 g / mol or less, or 100 g / mol to 800 g / mol, or 400 g / mol to 700 g / mol, or 600 g / mol to 700 g / mol. Specific examples of compounds based on sorbitan esters having the above molar masses are sorbitan dioleate.

[0074] Furthermore, the sorbitol-based compounds can be mixtures of two or more types of sorbitol-based compounds with different molar masses. More specifically, the sorbitol-based compounds can be mixtures of sorbitol-based compounds with a molar mass of 400 g / mol to 500 g / mol and sorbitol-based compounds with a molar mass of 600 g / mol to 700 g / mol.

[0075] There is no particular limitation on the molar ratio of a sorbitol-based compound with a molar mass of 400 g / mol to 500 g / mol to a sorbitol-based compound with a molar mass of 600 g / mol to 700 g / mol. The sorbitol-based compound with a molar mass of 400 g / mol to 500 g / mol to a sorbitol-based compound with a molar mass of 600 g / mol to 700 g / mol can be mixed in a molar ratio of 10:1 to 1:10, or 5:1 to 1:5, or 3:1 to 1:3.

[0076] To illustrate with a more specific example, a mixture of two or more types of sorbitan ester-based compounds with different molar masses can be a mixture of sorbitan sesquioleate (a 1:1 molar ratio mixture of sorbitan monooleate (molar mass: 428.61 g / mol): sorbitan dioleate (molar mass: 693 g / mol)).

[0077] The aforementioned sorbitol-based compounds (which are mixtures of sorbitol-based compounds with a molar mass of 400 g / mol to 500 g / mol and sorbitol-based compounds with a molar mass of 600 g / mol to 700 g / mol) have an HLB (Hydrophile Lipophile Balance) value of 3.5 to 3.9.

[0078] Simultaneously, the emulsifier may also contain at least one second emulsifier selected from compounds based on acetylenic diols and compounds based on polysorbate esters. That is, the emulsifier may also contain a second emulsifier comprising one type of acetylenic diol-based compound, one type of polysorbate-based compound, or a mixture thereof. In this case, the sorbate-based compound may be the first emulsifier. The second emulsifier can relatively reduce the van der Waals interaction with the liquid crystal and, by sufficiently reducing the surface anchoring energy of the liquid crystal in the capsule, can induce a high rate of change in transmittance even at lower voltages.

[0079] Specifically, based on 100 parts by weight of the sorbitan ester-based compound (first emulsifier), the weight ratio of the second emulsifier can be from 1 part by weight to 1000 parts by weight, or from 10 parts by weight to 500 parts by weight, or from 10 parts by weight to 100 parts by weight. Within the range of these values, a high rate of change in transmittance can be induced even at lower voltages by sufficiently reducing the surface anchoring energy of the liquid crystal in the capsule.

[0080] On the other hand, if the weight ratio of the second emulsifier is excessively reduced based on 100 parts by weight of the sorbitan ester-based compound (the first emulsifier), the movement of liquid crystal molecules becomes difficult. Therefore, during repeated driving of the liquid crystal cell, the contrast may decrease, or stable electro-optical properties may not be guaranteed. Furthermore, if the weight ratio of the second emulsifier is excessively increased based on 100 parts by weight of the sorbitan ester-based compound (the first emulsifier), the problem may arise that the surface anchoring energy of the liquid crystal in the capsule cannot be sufficiently reduced, thus increasing the driving voltage.

[0081] More specifically, the second emulsifier may include a compound based on alkynyldiol. The alkynyldiol-based compound may include alkynyldiol compounds or derivatives thereof. As a specific example, the alkynyldiol-based compound may be 2,4,7,9-tetramethyl-5-decyn-4,7-diol. Because the alkynyldiol-based compound does not have an ethylene oxide repeating unit in its emulsifier structure, it can relatively reduce van der Waals interactions with fluorine-based liquid crystals compared to emulsifiers having an ethylene oxide repeating unit.

[0082] The HLB (Hydrophile Lipophile Balance) value of compounds based on alkynyldiols can be 2 to 5, or 3 to 4. Typically, to produce stable oil-in-water emulsions using conventional emulsifiers, the emulsifier needs to be adsorbed onto the aqueous / oil interface to form a liquid crystal. For this purpose, the HLB value of the emulsifier to be used must be carefully adjusted according to the polarity of the oil phase.

[0083] Compounds based on polysorbate esters can include all polysorbate ester compounds or their derivatives. Polysorbate esters refer to dehydrated sorbate esters whose molecules contain repeating polyoxyethylene units. Compounds based on polysorbate esters can be at least one compound selected from polysorbate ester 20, polysorbate ester 40, polysorbate ester 60, and polysorbate ester 80. That is, compounds based on polysorbate esters can be a type of polysorbate ester 20, a type of polysorbate ester 40, a type of polysorbate ester 60, a type of polysorbate ester 80, or mixtures thereof.

[0084] The molar mass of the polysorbate-based compound can be at least 1225 g / mol, at least 1300 g / mol, at most 1500 g / mol, 1225 g / mol to 1500 g / mol, or 1300 g / mol to 1500 g / mol.

[0085] More specifically, the polysorbate-based compound can be polysorbate 20 with a molar mass of 1225 g / mol to 1300 g / mol or 1225 g / mol to 1250 g / mol.

[0086] Furthermore, the polysorbate-based compound can be polysorbate 80 with a molar mass of 1300 g / mol to 1500 g / mol, or 1305 g / mol to 1350 g / mol.

[0087] Meanwhile, based on 100 parts by weight of liquid crystal, the emulsifier content can be from 0.1 parts by weight to 50 parts by weight, or 0.1 parts by weight to 20 parts by weight, or 0.5 parts by weight to 20 parts by weight, or 1 part by weight to 20 parts by weight, or 5 parts by weight to 11 parts by weight. When the emulsifier content is excessively reduced based on 100 parts by weight of liquid crystal, there is a limitation that it is difficult to sufficiently induce a high rate of change in transmittance even at lower voltages by inducing vertical alignment of the liquid crystal by the emulsifier. Furthermore, when the emulsifier content is excessively increased based on 100 parts by weight of liquid crystal, the problem may arise that excessive emulsifier forms micelles, causing a sharp decrease in the surface tension of the solution.

[0088] Additionally, the core can also contain anisotropic dyes. There are no particular restrictions on the anisotropic dyes, as long as they are dopable anisotropic dyes. Specifically, they can be S-428, M-483, M412 (Mitsui Fine Chemical), etc.

[0089] Simultaneously, the core may also contain siloxane-based additives. Siloxane-based additives are additives capable of reducing the interfacial tension of liquid crystals. Therefore, the liquid crystal capsule in which siloxane-based additives and liquid crystal are simultaneously contained within the core can sufficiently reduce the surface anchoring energy of the liquid crystal within the capsule.

[0090] The molar mass of siloxane-based additives can be 500 g / mol or less, or 100 g / mol to 500 g / mol. Siloxane-based additives may include trisiloxane-based compounds. Trisiloxane-based compounds may include trisiloxane compounds or their derivatives. As specific examples, siloxane-based additives may be octamethyltrisiloxane or hexamethylcyclotrisiloxane.

[0091] Specifically, based on 100 parts by weight of liquid crystal, the content of siloxane-based additives can be 0.1 to 50 parts by weight, or 0.1 to 20 parts by weight, or 0.5 to 20 parts by weight, or 0.5 to 10 parts by weight, or 0.9 to 1 part by weight. When the content of siloxane-based additives is excessively reduced based on 100 parts by weight of liquid crystal, the surface tension reduction effect of the siloxane-based additives on the liquid crystal cannot be fully achieved, thus limiting the insufficient reduction of the surface anchoring energy of the liquid crystal in the capsule. Furthermore, when the content of siloxane-based additives is excessively increased based on 100 parts by weight of liquid crystal, the liquid crystal state (intermediate phase state) may change into an isotropic liquid phase.

[0092] Additionally, one embodiment of the liquid crystal capsule may include a polymer shell formed on the surface of the core. The shell may be a single-layer shell made of a single polymer material, or a double-layer shell made of different polymer materials, or a multi-layer shell with three or more layers to achieve improved mechanical properties and particle uniformity. Therefore, the uniformity of the liquid crystal particles can be improved, while simultaneously mitigating contamination problems caused by dyes.

[0093] The material forming the shell has the same refractive index as the matrix polymer in which the liquid crystal composite is dispersed. There are no particular limitations on specific examples, but for example, it can be selected from polyvinyl alcohol, polyurea, polyacrylic acid, polyurethane, polyamide (including nylon), polyacetal and polyester.

[0094] However, to give a specific example, the polymer shell formed on the surface of the core can be made of glyoxal-crosslinked polyvinyl alcohol (PVA) resin. There are no particular restrictions on the type of PVA, and various PVAs with different molecular weights or degrees of saponification can be appropriately selected depending on the purpose. Glyoxal is used as the crosslinking agent for crosslinking the PVA.

[0095] Meanwhile, the average diameter of the liquid crystal capsule can range from 100 nm to 300 nm. When the average diameter of the liquid crystal capsule decreases excessively, there are problems with increased driving voltage and power consumption. In addition, when the average diameter of the liquid crystal capsule increases excessively, visible light is scattered, causing high haze.

[0096] Liquid crystal capsules can be groups of individual particles with an average diameter of 100 nm to 300 nm, wherein the individual fine particles contained in such a group can have an average diameter of 100 nm to 300 nm. More specifically, 60% or 80% of the individual fine particles contained in the group can have a diameter of 100 nm to 300 nm.

[0097] This application also provides uses for the liquid crystal capsule. The liquid crystal capsule of this application can be used in various light modulation devices suitable for liquid crystals. Therefore, this application provides a light modulation device comprising a substrate; and a liquid crystal layer formed on a surface of the substrate and containing the liquid crystal capsule. Methods and types of manufacturing light modulation devices are well known in the art, and known manufacturing methods can be used without limitation. Light modulation devices include, but are not limited to, smart windows, isotropic films, polarization control films, or flexible LCDs.

[0098] There are no significant limitations on the manufacturing method of liquid crystal capsules, and various conventionally known manufacturing methods for liquid crystal capsules can be applied without limitation. However, for example, it includes the following steps: (1) preparing a mixed solution by mixing a mixture of liquid crystal, emulsifier and polyvinyl alcohol (PVA) in a solvent, (2) forming droplets from the mixed solution, (3) placing polyvinyl alcohol (PVA) around the droplets, and (4) crosslinking polyvinyl alcohol (PVA) with glyoxal to form a polymer shell surrounding the liquid crystal, thereby manufacturing a liquid crystal capsule that encloses the liquid crystal in the polymer shell.

[0099] In (1) the process of preparing a mixed solution by mixing a mixture of liquid crystal, emulsifier and polyvinyl alcohol (PVA) in a solvent, the solvent is not particularly limited and can be appropriately selected according to the purpose, examples of which include water, such as pure water (e.g., ion-exchanged water, ultrafiltered water, reverse osmosis water and distilled water) or ultrapure water. Additives may be added as needed.

[0100] In (1) the process of preparing a mixed solution by mixing a mixture of liquid crystal, emulsifier and polyvinyl alcohol (PVA) in a solvent, there are no significant limitations on the examples of methods for mixing liquid crystal, emulsifier, polyvinyl alcohol (PVA) and additives with solvent, and various methods commonly used in emulsification reactions can be applied without limitation.

[0101] In (2) the process of forming droplets from the mixed solution, the droplets are dispersed in the dispersion medium, more specifically, the droplets are dispersed in the dispersion medium in a state in which the emulsifier covers the surrounding liquid crystal.

[0102] As a method for preparing droplets, one method that uses dispersion emulsification equipment to produce droplets can be mentioned.

[0103] There are no particular limitations on the dispersion and emulsification equipment, as long as droplets of the desired particle size are obtained, and it can be appropriately selected according to the purpose. For example, a homogenizer (a device for mixing liquids) or a homogenizer (a device for finely dividing and homogenizing particles) can be used. Furthermore, there are no particular limitations on the dispersion method. For example, any dispersion method such as stirring, ultrasonication, or high pressure can be used.

[0104] In this invention, various types of dispersion and emulsification equipment can be used as dispersion and emulsification equipment, such as high-speed homogenizers, ultrasonic homogenizers, high-pressure homogenizers, and homogenizing mixers.

[0105] Furthermore, a more preferred embodiment of the process for preparing droplets is a droplet preparation process comprising: a first preparation process for preparing droplets using a first dispersion emulsification device; and a second preparation process for preparing droplets with a particle diameter smaller than that obtained in the first preparation process using a second dispersion emulsification device.

[0106] There are no particular limitations on the first and second dispersion emulsification devices, as long as droplets of the desired particle size are obtained. For example, various dispersion emulsification devices, such as the high-speed homogenizer, ultrasonic homogenizer, high-pressure homogenizer, and homogenizing mixer mentioned above, can be appropriately combined and used.

[0107] During (3) the process of setting polyvinyl alcohol (PVA) around the droplets, aggregation of PVA around the liquid crystal composition can occur in the droplet dispersion at a predetermined temperature. For example, it is preferable to set the solution temperature of the droplet dispersion during aggregation to be equal to or higher than room temperature.

[0108] In the process of manufacturing liquid crystal capsules, the liquid crystal capsules comprise liquid crystal contained within a polymer shell, wherein the polymer shell is formed by (4) crosslinking polyvinyl alcohol (PVA) with the aforementioned glyoxal to surround the liquid crystal, preferably, the crosslinking reaction is carried out under acidic conditions. For acidic conditions, preferably, the pH is in the range of 1 to 5, more preferably, the pH is about 3.

[0109] 2. Capsule solution

[0110] Furthermore, according to another embodiment of the present invention, a capsule solution can be provided, comprising a liquid crystal capsule of one embodiment or another and a solvent. The details regarding the liquid crystal capsule are as described above for one embodiment and another embodiment.

[0111] There are no particular restrictions on the solvent, and it can be selected appropriately depending on the purpose. For example, water can be mentioned, such as pure water (including ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water) or ultrapure water.

[0112] The capsule solution contains liquid crystal capsules dispersed in a solvent. That is, the capsule solution can be a liquid crystal capsule dispersion. The capsule solution can also be used as a coating liquid for forming a liquid crystal layer. For example, a liquid crystal layer is formed by coating the capsule solution onto a supporting substrate to form a film.

[0113] 3. Optical film

[0114] Meanwhile, according to another embodiment of the invention, an optical film can be provided, the optical film comprising an adhesive resin and a liquid crystal domain dispersed in the adhesive resin, wherein the haze is 10% or less when a voltage is applied, and the threshold voltage is 60 V or less, the threshold voltage being the voltage at which the transmittance reaches 10% of the maximum transmittance measured when the voltage is applied.

[0115] Specifically, the optical film may contain an adhesive resin. The adhesive resin can be used as a binder to fix the liquid crystal domains while dispersing them within the optical film.

[0116] There are no particular limitations on the type of adhesive resin used; for example, various transparent materials widely used in the field of optical films can be used as adhesive resins without restriction. Specific examples of adhesive resins are also not particularly limited; for example, adhesive resins can be selected from polyvinyl alcohol, polyurea, polyurethane, polyamide (including nylon), polyacetal, and polyester.

[0117] Simultaneously, the optical film may contain liquid crystal domains dispersed in the binder resin. A liquid crystal domain refers to a region within the optical film containing liquid crystals. Because the optical film is formed with domains containing liquid crystals within specific areas, the liquid crystal domains can be more stably dispersed in the binder resin and can exhibit durability during the film-forming process. This is because the liquid crystal domains originate from liquid crystal capsules, which include a core containing liquid crystals and a polymer shell formed on the surface of the core.

[0118] It may include two or more liquid crystal domains, and each of the two or more liquid crystal domains may have an independent region. The two or more liquid crystal domains may be dispersed within the optical film, and these two or more liquid crystal domains may each have an independent region without overlapping. Therefore, during the film formation process, the liquid crystal domains can be more stably dispersed in the binder resin and can possess durability.

[0119] The liquid crystal domain may contain liquid crystal and emulsifier. The contents concerning the liquid crystal and emulsifier may include all the contents described in detail in one of the foregoing embodiments.

[0120] Specifically, the liquid crystal domain comprises liquid crystal and an emulsifier, wherein the emulsifier comprises a sorbitan ester-based compound, wherein the molar mass of the sorbitan ester-based compound is 1220 g / mol or less, and wherein the sorbitan ester-based compound may contain intramolecular carbon-carbon double bonds. That is, in another embodiment, the optical film may be derived from a liquid crystal capsule comprising: a core comprising liquid crystal and an emulsifier; and a polymer shell formed on the surface of the core; wherein the emulsifier comprises a sorbitan ester-based compound, wherein the molar mass of the sorbitan ester-based compound is 1220 g / mol or less, and wherein the sorbitan ester-based compound contains intramolecular carbon-carbon double bonds.

[0121] Furthermore, the liquid crystal domain comprises liquid crystal and an emulsifier, wherein the emulsifier comprises a sorbitan ester-based compound, and the emulsifier may further comprise one or more second emulsifiers selected from alkynyl glycol-based compounds and polysorbate-based compounds. That is, the optical film of another embodiment comprises: a core comprising liquid crystal and an emulsifier; and a polymer shell formed on the surface of the core; and may be derived from a liquid crystal capsule, wherein the emulsifier comprises a sorbitan ester-based compound, and further comprises one or more second emulsifiers selected from alkynyl glycol-based compounds and polysorbate-based compounds.

[0122] Furthermore, the liquid crystal domain may also contain anisotropic dyes. Details regarding the anisotropic dyes may include all of the information described above in one embodiment.

[0123] Furthermore, the liquid crystal domain may also contain siloxane-based additives. Details regarding siloxane-based additives can include all of the information described in detail in one embodiment.

[0124] The average diameter of the liquid crystal domain can range from 100 nm to 300 nm. That is, the liquid crystal domain can be a liquid crystal nanodomain. If the average diameter of the liquid crystal domain decreases excessively, the driving voltage increases, leading to increased power consumption. Furthermore, if the average diameter of the liquid crystal domain increases excessively, visible light is scattered, causing increased haze.

[0125] A liquid crystal domain can be a group of individual particles with an average diameter of 100 nm to 300 nm, wherein the individual fine particles contained in such a group can have an average diameter of 100 nm to 300 nm. More specifically, 95% or 99% of the individual fine particles contained in the group can have a diameter of 100 nm to 300 nm.

[0126] The liquid crystal domain can be derived from a liquid crystal capsule in one embodiment or a liquid crystal capsule solution in another embodiment.

[0127] More specifically, for example, an optical film can be formed by coating a capsule solution of another embodiment onto a support substrate to form a film.

[0128] Furthermore, the haze of the optical film when voltage is applied can be 10% or less, or 9% or less, or 8% or less, or 7.5% or less, or 5% or less, or 2.5% or less, or 3% or less, or 2.6% or less, or 2% or less, or 1.5% or less, or 1.2% or less, or 1.0% or less, or 0.1% or more, or 2.1% or more, or 2.6% or more, or 7% or more, or 7.6% or more, or a combination of these ranges.

[0129] The haze of an optical film when a voltage is applied refers to the haze value measured when a voltage is applied to the optical film. More specifically, there are no great restrictions on the types of voltages that can be applied, and voltages can range from 1 V to 100 V.

[0130] For a more specific example, haze 开 (The haze at an applied voltage of 100 V) can be 10% or less, or 9% or less, or 8% or less, or 7.5% or less, or 5% or less, or 2.5% or less, or 3% or less, or 2.6% or less, or 2% or less, or 1.5% or less, or 1.2% or less, or 1.0% or less, or 0.1% or more, or 2.1% or more, or 2.6% or more, or 7% or more, or 7.6% or more, or a combination of these ranges.

[0131] In addition, the haze of the optical film 关 (The haze at an applied voltage of 0 V) ​​can be 35% or less, or 30% or less, or 26% or less, or 25% or less, or 20% or less, or 16% or less, or 11% or more, or 20% or more, or 25% or more, or a combination of these ranges.

[0132] By achieving a haze within the aforementioned range, the optical film can exhibit more transparent optical properties both when a voltage is applied and when no voltage is applied. There are no limitations on the method used to measure the haze, and various methods widely known in the field of conventional liquid crystal-containing optical devices can be applied without restriction. However, for example, it can be measured using a haze meter (Nippon Denshoku Co., NDH7000) while a voltage is applied via a function generator.

[0133] The threshold voltage of the optical film (which is the voltage at which the transmittance reaches 10% of the maximum transmittance measured when the voltage is applied) can be 60 V or less, or 55 V or less, or 45 V or less, or 40 V or less, or 35 V or less, or 25 V or less, or 20 V or less, or 1 V or more, or 1 V to 60 V, or 1 V to 55 V, or 1 V to 45 V, or 1 V to 40 V, or 1 V to 35 V, or 1 V to 25 V, or 1 V to 20 V. The threshold voltage refers to the voltage at 10% of the maximum transmittance, and because the optical film has a threshold voltage within the above range, it can operate even at lower voltages. There are no limitations on the method used to measure the threshold voltage, and various methods widely known in the field of conventional liquid crystal-containing optical devices can be applied without limitation. However, as an example, it can be measured using a haze meter (Nippon Denshoku, NDH7000) while the voltage is applied via a function generator.

[0134] Specific details regarding optical films can be applied without restriction, drawing upon various conventionally known optical films. For example, all details regarding the structure, composition, manufacturing methods, physical properties, and applications of optical films can be applied without restriction, drawing upon a wide range of information widely known in the field of conventional films.

[0135] However, for example, optical films can be used for films with variable transmittance.

[0136] 4. Optical devices

[0137] Furthermore, according to another embodiment of the present invention, an optical device may be provided, which includes the optical film of the aforementioned other embodiment. Details regarding the optical film include those described above for the aforementioned other embodiment.

[0138] Regarding the aforementioned optical devices, various conventionally known optical devices can be applied without limitation. For example, the specific structure, dimensions, manufacturing methods, physical properties, and applications of optical devices can all be applied without limitation to various contents widely known in the conventional display field.

[0139] However, for example, the optical device can be a light modulation device that includes an optical film in another embodiment. While there are no particular limitations on specific examples of light modulation devices, they can include, for example, smart windows, isotropic films, polarization control films, or liquid crystal display devices, organic electroluminescent display devices, etc.

[0140] More specifically, examples of optical devices may include liquid crystal display elements comprising: a set of substrates arranged facing each other; electrodes formed on one or both of the opposite surfaces of each of the set of substrates; a liquid crystal layer formed by applying the liquid crystal capsule solution of the present invention, the liquid crystal layer being disposed between the substrates; and an electric field applying device for applying an electric field to the liquid crystal capsules of the present invention in the liquid crystal layer via the electrodes.

[0141] Furthermore, the threshold voltage of the optical device can be 60 V or less, or 55 V or less, or 45 V or less, or 40 V or less, or 35 V or less, or 25 V or less, or 20 V or less, or 1 V or more, or 1 V to 60 V, or 1 V to 55 V, or 1 V to 45 V, or 1 V to 40 V, or 1 V to 35 V, or 1 V to 25 V, or 1 V to 20 V. The threshold voltage refers to the voltage at 10% of the maximum transmittance, and because the optical device has a threshold voltage within the aforementioned range, it can be driven even at lower voltages. There are no limitations on the method for measuring the threshold voltage, and various methods widely known in the field of conventional liquid crystal-containing optical devices can be applied without restriction. However, for example, it can be measured by a haze meter (NDH7000, Nippon Denshoku Co.) while a voltage is applied via a function generator.

[0142] Furthermore, the contrast ratio of the optical device can be 10 or greater, or 15 or greater, or 17 or greater, or 18 or greater, or 20 or greater, or 30 or greater, or 33 or greater, or 40 or less, or 10 to 40, or 15 to 40, or 17 to 40, or 18 to 40, or 20 to 40, or 30 to 40, or 33 to 40. Contrast ratio refers to the ratio of transmittance at 100 V to transmittance at 0 V. Therefore, since the optical device has a contrast ratio within the aforementioned range, it can achieve excellent transmittance variability even at lower voltages. There are no limitations on the method used to measure the contrast ratio, and various methods known in the conventional field of liquid crystal optical devices can be applied without limitation. However, for example, it can be measured using a haze meter (Nippon Denshoku, NDH7000) while a voltage is applied via a function generator.

[0143] In addition, the haze of the optical device 开(The haze at an applied voltage of 100 V) can be 10% or less, or 9% or less, or 8% or less, or 7.5% or less, or 5% or less, or 2.5% or less, or 3% or less, or 2.6% or less, or 2% or less, or 1.5% or less, or 1.2% or less, or 1.0% or less, or 0.1% or more, or 2.1% or more, or 2.6% or more, or 7% or more, or 7.6% or more, or combinations of these values. Furthermore, the haze of the optical device... 关 (The haze at an applied voltage of 0 V) ​​can be 35% or less, or 30% or less, or 26% or less, or 25% or less, or 20% or less, or 16% or less, or 11% or more, or 20% or more, or 25% or more, or a combination of these ranges.

[0144] Depending on the haze within the aforementioned range, the optical device can achieve more transparent optical properties whether a voltage is applied or not. There are no limitations on the method used to measure the haze, and various methods known in the field of conventional liquid crystal-containing optical devices can be applied without restriction. However, for example, it can be measured using a haze meter (Nippon Denshoku Co., Ltd., NDH7000) while a voltage is applied via a function generator.

[0145] 5. Variable transmittance device

[0146] Furthermore, according to another embodiment of the present invention, a variable transmittance device can be provided, which includes the optical film of the aforementioned other embodiment. Details regarding the optical film are as described above for the aforementioned other embodiment.

[0147] For variable transmittance devices, various conventionally known variable transmittance devices can be applied without limitation. For example, details regarding the specific structure, dimensions, manufacturing methods, physical properties, and applications of variable transmittance devices can be applied without limitation, utilizing a wide range of techniques widely known in the conventional liquid crystal capsule field. However, by way of example, a variable transmittance device may include a transparent electrode layer and a variable transmittance layer, the variable transmittance layer comprising an optical film of one embodiment. More specifically, the variable transmittance layer may be positioned between two transparent electrode layers, and a voltage may be applied to the variable transmittance layer using a voltage application device. There are no particular limitations on the details of the voltage application device, and any conventionally known techniques can be applied without limitation.

[0148] The variable transmittance device of this application can be applied to all devices where transmittance variation can be applied. For example, the variable transmittance device of this application can be applied to sunroofs, automotive glass, goggles, sunglasses, or helmets, and a variable transmittance device can be provided. As long as the variable transmittance device includes the variable transmittance device of this application, there are no particular limitations on other parts or structures, and all details known in the art can be appropriately applied.

[0149] Beneficial effects

[0150] According to the present invention, liquid crystal capsules that can induce a high rate of change of transmittance even at low voltages can be provided, as well as capsule solutions, optical films, optical devices and transmittance variable devices using the same. Detailed Implementation

[0151] The invention will be described in more detail in the following embodiments. However, the following embodiments are merely illustrative examples of the invention, and the scope of the invention is not limited to the following embodiments.

[0152] <Examples and Comparative Examples: Preparation of Liquid Crystal Capsules and Capsule Solutions>

[0153] According to the composition shown in Table 1 below, polyvinyl alcohol (PVA), water, emulsifier, liquid crystal containing anisotropic dye, and additives were mixed and stirred. Then, emulsification was performed using an IKA T25 homogenizer at 18,000 rpm. Subsequently, a second emulsification was performed using a microfluidizer at 10,000 psi to form droplets.

[0154] Subsequently, the solution was heated to 40°C with stirring, and PVA was allowed to adsorb onto the surface of the droplets for 18 hours.

[0155] Subsequently, a 40% glyoxal aqueous solution was used as a crosslinking agent to crosslink the adsorbed PVA at 40°C for 18 hours under pH 3 conditions.

[0156] The supernatant recovered by centrifugation at 5000 rpm for 30 minutes was concentrated using a rotary evaporator to obtain a capsule solution containing liquid crystal capsules.

[0157] [Table 1]

[0158] Composition of Examples and Comparative Examples

[0159]

[0160] E1: Sorbitol monooleate (molar mass: 428.61 g / mol, HLB: 4.3)

[0161] E2: Sorbitol sesquioleate (a 1:1 molar mixture of sorbitol monooleate (molar mass: 428.61 g / mol) and sorbitol dioleate (molar mass: 693 g / mol), HLB: 3.7)

[0162] E3: 2,4,7,9-tetramethyl-5-decyn-4,7-diol (HLB: 3)

[0163] E4: Polysorbate 20 (molar mass: 1226 g / mol)

[0164] E5: Sorbitol monostearate

[0165] E6: Sorbitol Tristearate

[0166] E7: Polysorbate 80 (molar mass: 1309.65 g / mol)

[0167] A1: Octamethyltrisiloxane

[0168] <Experimental Example>

[0169] The physical properties of the liquid crystal capsules or capsule solutions obtained in the examples and comparative examples were measured using the following methods, and the results are shown in Table 2.

[0170] 1. Physical properties of liquid crystal capsule membranes

[0171] (1) Thickness (μm)

[0172] Liquid crystal capsule films were prepared by coating the capsule solution onto the ITO layer of a PET-ITO film using a film coater, followed by drying at 70°C for 2 hours. The thickness of the liquid crystal capsule films was measured using an Alpha step (KLA TENCOR Co.).

[0173] (2) T 关 (%), Haze 关 (%), Haze 开 (%), threshold voltage (V), CR

[0174] After laminating the ITO side of the PET-ITO film onto the top of the liquid crystal capsule film using a laminator (EXCELAM-SMART 655, GMP Co.), the electrode strip is attached to the ITO side.

[0175] T was measured using a haze meter (Nippon Denshoku Co., NDH7000). 关(This refers to the transmittance of the liquid crystal capsule film when no voltage is applied (transmittance at an applied voltage of 0 V)) and haze. 关 (This refers to the haze of the liquid crystal capsule film when no voltage is applied (haze at an applied voltage of 0 V)).

[0176] Then, while applying voltage through the function generator, the threshold voltage (which is the voltage at 10% of maximum transmittance) and haze are measured using a haze meter (NDH7000, Nippon Denshoku Co.). 开 (It is the haze at an applied voltage of 100 V) and contrast ratio (CR) (which is the ratio of transmittance at 100 V to transmittance at 0 V).

[0177] [Table 2]

[0178] Measurement results of experimental examples in the embodiments and comparative examples.

[0179]

[0180] As shown in Table 1 above, the liquid crystal capsule of the embodiment simultaneously satisfies 1) a threshold voltage of 60 V or less, 2) a CR of 10 or greater, and 3) a haze of 10% or less. 开 Therefore, it was determined that excellent transmittance variation rate and optical properties can be achieved while being operable at a lower voltage.

[0181] On the other hand, the CR of the liquid crystal capsules obtained in Comparative Examples 1 and 2 was less than 10, indicating a poorer rate of change in transmittance compared to the embodiments. Furthermore, the haze of the liquid crystal capsule obtained in Comparative Example 3 was... 开 The percentage exceeded 10%, indicating that the optical properties were inferior to those of the examples. Furthermore, for the liquid crystal capsule obtained in Comparative Example 4, a film could not be prepared, making it impossible to measure its physical properties.

Claims

1. A liquid crystal capsule, comprising: A core containing liquid crystal and emulsifier; as well as A polymer shell is formed on the surface of the core; The emulsifier mentioned above comprises a compound based on sorbitol esters. The sorbitol-based compound has a molar mass of 1220 g / mol or less, and the sorbitol-based compound contains an intramolecular carbon-carbon double bond.

2. The liquid crystal capsule according to claim 1, The sorbitol-based compound is a reaction product of sorbitol and a carboxylic acid containing an intramolecular carbon-carbon double bond, and the carboxylic acid containing an intramolecular carbon-carbon double bond has 10 to 30 carbon atoms.

3. The liquid crystal capsule according to claim 1, The molar mass of the sorbitol-based compound is 800 g / mol or less.

4. The liquid crystal capsule according to claim 3, The compound based on sorbitol esters is sorbitol monooleate.

5. The liquid crystal capsule according to claim 1, The sorbitol-based compound is a mixture of two or more sorbitol-based compounds with different molar masses.

6. The liquid crystal capsule according to claim 5, The mixture of two or more sorbitan ester-based compounds with different molar masses is sorbitan sesquioleate.

7. A liquid crystal capsule, comprising: A core containing liquid crystal and emulsifier; as well as A polymer shell is formed on the surface of the core; The emulsifier comprises a sorbitan ester-based compound, and the emulsifier further comprises at least one second emulsifier selected from compounds based on alkynyl glycol and compounds based on polysorbate.

8. The liquid crystal capsule according to claim 7, The second emulsifier is present in a weight ratio of 1 to 1000 parts by weight of the sorbitol-based compound, which is based on 100 parts by weight of the compound.

9. The liquid crystal capsule according to claim 7, The HLB value of the alkynyldiol-based compounds is 2 to 5.

10. The liquid crystal capsule according to claim 7, The molar mass of the polysorbate-based compound is 1225 g / mol or greater.

11. The liquid crystal capsule according to claim 7, The sorbitol-based compound has a molar mass of 1220 g / mol or less, and the sorbitol-based compound contains an intramolecular carbon-carbon double bond.

12. The liquid crystal capsule according to any one of claims 1 or 7, The core also contains siloxane-based additives.

13. A capsule solution comprising a liquid crystal capsule and a solvent according to any one of claims 1 or 7.

14. An optical film comprising an adhesive resin and a liquid crystal domain dispersed in the adhesive resin, The haze is 10% or less when the voltage is applied, and the threshold voltage is 60 V or less, which is the voltage at which the transmittance reaches 10% of the maximum transmittance measured when the voltage is applied.

15. The optical film according to claim 14, The liquid crystal domain comprises liquid crystal and an emulsifier, the emulsifier comprising a sorbitol ester-based compound having a molar mass of 1220 g / mol or less, and the sorbitol ester-based compound comprising an intramolecular carbon-carbon double bond.

16. The optical film according to claim 14, The liquid crystal domain comprises liquid crystal and an emulsifier, the emulsifier comprising a sorbitan ester-based compound, and the emulsifier further comprising at least one second emulsifier selected from alkynyl glycol-based compounds and polysorbitan ester-based compounds.

17. An optical device comprising the optical film according to claim 14.

18. A variable transmittance device comprising the optical film according to claim 14.

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