Liquid crystal capsule, and capsule liquid, optical film, optical device, and variable transmittance device using same
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-12-02
- Publication Date
- 2026-08-13
Abstract
Description
Liquid crystal capsule, and capsule liquid using the same, optical film, optical device, transmittance variable device
[0001] Cross-citation with related application(s)
[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2025-0016668 filed February 10, 2025 and Korean Patent Application No. 10-2025-0186071 filed November 28, 2025, and all contents disclosed in the documents of said Korean patent applications are incorporated herein as part of this specification.
[0003] The present invention relates to a liquid crystal capsule capable of inducing a high transmittance variability even at lower voltages, and a capsule liquid, an optical film, an optical device, and a transmittance variability device using the same.
[0004] Polymer Dispersed Liquid Crystals (PDLC) films are composite materials that can be applied to high-brightness projection displays or high-contrast reflective display devices, in which liquid crystal molecules of several micrometers are dispersed within a polymer between conductive films. The operating principle of PDLC is that light incident on a polymer layer in which liquid crystals are dispersed is scattered due to the difference in refractive index between the liquid crystals and the polymer, resulting in an opaque state; however, by applying an electric field, the direction of the liquid crystals is aligned, and by changing the refractive index, the scattering and transmission of light are controlled, resulting in a transparent state.
[0005] As such, PDLC devices do not require a separate polarizer, so they do not require a polarizer structurally, and they do not require an alignment process, allowing them to be manufactured in a simple manner. This makes them applicable to smart glass and smart screens for buildings and automobiles that correspond to switchable windows, and they can also be applied as black PDLC films for transparent OLEDs. In addition, they can be manufactured in a flexible form depending on the material used as the substrate.
[0006] Specifically, liquid crystal-based smart windows refer to active windows that can control transmittance using glass containing a separate liquid crystal layer, and this technology is applicable not only to buildings but also to the mobility sector. Through existing polymer dispersed liquid crystal (PDLC) technology, liquid crystal domains of several micrometers in size could be manufactured by mixing liquid crystals with monomers capable of photo or thermal polymerization and utilizing the phase separation between the polymer and the liquid crystal that occurs during polymerization. PDLC films can implement light-blocking or transmission modes by causing the liquid crystals within the domains of several micrometers in size to match or mismatch the refractive index of the polymer matrix depending on the application of voltage on / off.
[0007] In particular, when manufacturing color-modifying PDLCs containing dyes, issues arise such as the anisotropic dyes within the polymer not aligning uniformly according to the electric field, and specifically, contamination of the polymer matrix by the dyes occur. Consequently, various studies are underway on encapsulated liquid crystal composites in which the liquid crystal and anisotropic dye are encapsulated within a polymer shell, resulting in excellent mechanical properties, high uniformity, and the prevention of dye-induced contamination of the polymer matrix.
[0008] However, as the liquid crystal and anisotropic dye are encapsulated in a polymer shell, there was a limitation in that the orientation of the liquid crystal was changed only when a higher voltage was applied due to the high interaction that occurs as the contact area between the liquid crystal enclosed in the capsule and the material contained in the capsule shell increases.
[0009] The present invention is intended to provide a liquid crystal capsule capable of inducing a high transmittance variability even at lower voltages.
[0010] In addition, the present invention is intended to provide a capsule liquid, an optical film, an optical device, and a transmittance variable device manufactured using the liquid crystal capsule.
[0011] To solve the above problem, the present specification provides a liquid crystal capsule comprising: a core containing a 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, the molar mass of the sorbitan ester-based compound is 1220 g / mol or less, and the sorbitan ester-based compound comprises intramolecular carbon-carbon double bonds.
[0012] The present specification also provides a liquid crystal capsule comprising: a core containing a 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 one or more second emulsifiers selected from the group consisting of acetylenic diol-based compounds and polysorbate-based compounds.
[0013] In addition to the above, a capsule solution comprising the liquid crystal capsule and the solvent is provided.
[0014] The present specification also provides an optical film comprising a binder resin and a liquid crystal domain dispersed in the binder resin, wherein the haze is 10% or less when voltage is applied, and the threshold voltage, which is the voltage at 10% transmittance of the maximum transmittance when voltage is applied, is 60 V or less.
[0015] The present specification also provides an optical device comprising the optical film.
[0016] The present specification also provides a transmittance variable device comprising the optical film.
[0017] A liquid crystal capsule according to a specific embodiment of the invention, and a capsule liquid, an optical film, an optical device, and a transmittance variable device using the same, will be described in more detail below.
[0018]
[0019] Unless explicitly stated otherwise in this specification, technical terms are used merely to refer to specific embodiments and are not intended to limit the invention.
[0020] The singular forms used in this specification include plural forms unless the phrases clearly indicate otherwise.
[0021] As used in this specification, the meaning of 'includes' specifies certain characteristics, regions, integers, steps, actions, elements, and / or components, and does not exclude the existence or addition of other specific characteristics, regions, integers, steps, actions, elements, components, and / or groups.
[0022] Also, 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 said ordinal numbers. For example, within the scope of the present invention, the first component may also be named the second component, and similarly, the second component may be named the first component.
[0023] In this specification, a derivative compound refers to a compound that has been modified from a parent organic compound to the extent that the structure and properties of the parent compound are not significantly altered, such as through the introduction of functional groups, oxidation, reduction, or substitution of atoms.
[0024] The present invention will be described in more detail below.
[0025]
[0026] 1. Liquid crystal capsule
[0027] According to one embodiment of the invention, a liquid crystal capsule may be provided comprising: a core containing a 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, the molar mass of the sorbitan ester-based compound is 1220 g / mol or less, and the sorbitan ester-based compound comprises intramolecular carbon-intracarbon double bonds.
[0028] The inventors confirmed through experiments that, as in the liquid crystal capsule of the above embodiment, by using a sorbitan ester-based compound containing a molar mass of 1220 g / mol or less and containing double bonds between carbon atoms within the molecule as an emulsifier contained together with the liquid crystal in the inner core of the capsule, the anchoring energy with the surface to which the liquid crystal contacts is reduced, thereby changing the liquid crystal alignment to a radial shape and inducing vertical orientation of the liquid crystal, which can induce a high transmittance variability even at a lower voltage, and thus completed the invention.
[0029] Specifically, the liquid crystal capsule of the above embodiment may include a core containing liquid crystal. The liquid crystal capsule structure according to the present invention is characterized by containing liquid crystal inside a shell made of a polymer. This can improve the uniformity of the liquid crystal particles.
[0030] The liquid crystal is not particularly limited, but examples include nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, chiral nematic liquid crystal, etc. The specific type of liquid crystal compound is not limited, and various liquid crystals known in the prior art can be used without limitation. The liquid crystal compound is not particularly limited, but may be composed of fluorine-based or cyanide-based compounds, or a mixture thereof.
[0031] Meanwhile, the above-mentioned core may further include an emulsifier. The emulsifier is a surfactant used in the formation of liquid crystal droplets, and by increasing the surface energy contacted by the liquid crystal, the liquid crystal alignment changes to a radial shape, thereby inducing vertical alignment of the liquid crystal, which can induce a high transmittance variability even at lower voltages.
[0032] The above emulsifier may include a sorbitan ester-based compound. The above sorbitan ester-based compound may include the sorbitan ester or a derivative compound thereof, or a mixture of two or more of these.
[0033] The above sorbitan ester-based compound may include intramolecular carbon-carbon double bonds. When the sorbitan ester-based compound contains intramolecular carbon-carbon double bonds (C=C), the interaction between the double bonds within the emulsifier molecules aligned along the central axis within the liquid crystal and the liquid crystal molecules is strengthened, thereby causing the liquid crystal to exhibit a radial arrangement. As a result, high transmittance variability can be achieved even at lower voltages.
[0034] The above sorbitan ester compound is a reaction product of sorbitan and a carboxylic acid containing intramolecular carbon double bonds, and the carboxylic acid containing intramolecular carbon double bonds may 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. Specific examples of the carboxylic acid containing intramolecular carbon double bonds include oleic acid.
[0035] The above sorbitan ester-based compound may have a molar mass of 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 above sorbitan ester compound increases excessively to more than 1220 g / mol, problems may arise such as reduced oil-in-water emulsion stability and increased haze in the optical film when manufacturing capsules using liquid crystals.
[0037] More specifically, the sorbitan ester-based compound may have 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. Specific examples of sorbitan ester-based compounds having the molar mass described above may be sorbitan monooleate.
[0038] Sorbitan ester compounds 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, have a Hydrophile Lipophile Balance (HLB) value of 4 to 4.5. The HLB can be calculated using the following Equation 1.
[0039] [Mathematical Formula 1]
[0040] HLB = 20*(MH / M)
[0041] In the above 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] In addition, the sorbitan ester-based compound may have 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 600 g / mol to 700 g / mol. Specific examples of sorbitan ester-based compounds having the molar mass described above may be sorbitan dioleate.
[0043] Meanwhile, the above sorbitan ester-based compound may be a mixture of two or more sorbitan ester-based compounds having different molar masses. More specifically, the above sorbitan ester-based compound may be a mixture of a sorbitan ester-based compound having a molar mass of 400 g / mol to 500 g / mol and a sorbitan ester-based compound having a molar mass of 600 g / mol to 700 g / mol.
[0044] The molar ratio for mixing the sorbitan ester compound having a molar mass of 400 g / mol to 500 g / mol and the sorbitan ester compound having a molar mass of 600 g / mol to 700 g / mol is not particularly limited, and the sorbitan ester compound having a molar mass of 400 g / mol to 500 g / mol and the sorbitan ester compound having 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.
[0045] To explain with a more specific example, the mixture of two or more sorbitan ester compounds with different molar masses may be sorbitan sesquioleate (a mixture with a molar ratio of sorbitan monooleate (molar mass: 428.61 g / mol) : sorbitan dioleate (molar mass: 693 g / mol) of 1:1).
[0046] The above sorbitan ester compound is a mixture of a sorbitan ester compound with a molar mass of 400 g / mol to 500 g / mol and a sorbitan ester compound with a molar mass of 600 g / mol to 700 g / mol, and has an HLB (Hydrophile Lipophile Balance) value of 3.5 to 3.9.
[0047] Meanwhile, with respect to 100 parts by weight of the liquid crystal, the emulsifier content may 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 1 to 20 parts by weight, or 5 to 11 parts by weight. If the emulsifier content is excessively reduced with respect to 100 parts by weight of the liquid crystal, the vertical alignment of the liquid crystal by the emulsifier is induced, which has a limitation in that it is difficult to sufficiently induce a high transmittance variability even at lower voltages. In addition, if the emulsifier content is excessively increased with respect to 100 parts by weight of the liquid crystal, an excess amount of emulsifier may form colloidal micelles, causing a problem in which the surface tension of the solution drops sharply.
[0048] Meanwhile, the core may further include an anisotropic dye. The anisotropic dye is not particularly limited as long as it is a dopable anisotropic dye, and specifically may be S-428, M-483, M412 (Mitsui FineChemical), etc.
[0049] Meanwhile, the core may further include a siloxane-based additive. The siloxane-based additive is an additive capable of lowering the interfacial tension of the liquid crystal. Accordingly, a liquid crystal capsule containing the siloxane-based additive and the liquid crystal together in the core can sufficiently lower the surface anchoring energy of the liquid crystal within the capsule.
[0050] The above siloxane-based additive may have a molar mass of 500 g / mol or less, or 100 g / mol to 500 g / mol. The above siloxane-based additive may include a trisiloxane-based compound. The above trisiloxane-based compound may include a trisiloxane compound or a derivative thereof. As a specific example, the above siloxane-based additive may be octamethyltrisiloxane or hexamethylcyclotrisiloxane.
[0051] In particular, with respect to 100 parts by weight of the liquid crystal, the content of the siloxane-based additive may 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. If the content of the siloxane-based additive is excessively reduced with respect to 100 parts by weight of the liquid crystal, the effect of lowering the surface tension of the liquid crystal by the siloxane-based additive is not sufficiently realized, and there is a limitation in that the surface anchoring energy of the liquid crystal within the capsule cannot be sufficiently lowered. In addition, if the content of the siloxane-based additive is excessively increased with respect to 100 parts by weight of the liquid crystal, a problem may occur in which the liquid crystal state (mesophase state) changes into an isotropic liquid phase.
[0052] Meanwhile, the liquid crystal capsule of the above 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 or a multi-layer shell made of different polymer materials to achieve improved mechanical properties and particle uniformity. Accordingly, the uniformity of the liquid crystal particles can be improved, and the problem of contamination by dye can be improved at the same time.
[0053] The material forming the shell has the same refractive index as the matrix polymer in which the liquid crystal composite is dispersed, and while specific examples are not particularly limited, it may be selected from polyvinyl alcohol, polyurea, polyacrylic, polyurethane, polyamide including nylon, polyacetal, and polyester.
[0054] However, to give a specific example, the polymer shell formed on the surface of the core may be made of polyvinyl alcohol (PVA) resin crosslinked with glyoxal. There are no particular restrictions on the type of PVA, and various types of PVA with different molecular weights or saponification rates may be appropriately selected depending on the purpose. Glyoxal is used as the crosslinking agent for crosslinking the PVA.
[0055] Meanwhile, the average diameter of the liquid crystal capsule may be 100 nm to 300 nm. If the average diameter of the liquid crystal capsule is reduced excessively, there is a problem that the driving voltage increases and power consumption increases. In addition, if the average diameter of the liquid crystal capsule is increased excessively, there is a problem that visible light is scattered and haze increases.
[0056] The liquid crystal capsule may be a group of individual particles having an average diameter of 100 nm to 300 nm, and the individual particles included in this group may have an average diameter of 100 nm to 300 nm. More specifically, 60% or 80% of the individual particles included in the group may have a diameter of 100 nm to 300 nm.
[0057]
[0058] Meanwhile, according to another embodiment of the invention, a liquid crystal capsule may be provided comprising: a core containing a 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 one or more second emulsifiers selected from the group consisting of acetylenic diol-based compounds and polysorbate-based compounds.
[0059] The inventors confirmed through experiments that, as in the liquid crystal capsule of the above embodiment, by further including one or more second emulsifiers selected from the group consisting of acetylenic diol compounds and polysorbate compounds together with a sorbitan ester compound as an emulsifier contained in the inner core of the capsule along with the liquid crystal, the anchoring energy with the surface to which the liquid crystal contacts is reduced, thereby inducing vertical orientation of the liquid crystal as the liquid crystal changes to a radial shape, and thus a high transmittance variability can be induced even at a lower voltage, and thus completed the invention.
[0060] In particular, compared to the case where only sorbitan ester-based compounds are used as emulsifiers, by further including one or more second emulsifiers selected from the group consisting of acetylenic diol-based compounds and polysorbate-based compounds, the movement of liquid crystal molecules can be facilitated or the emulsification stability of the liquid crystal can be increased. As a result, the contrast ratio is increased and stable electro-optical characteristics can be secured during repeated operation of the liquid crystal cell.
[0061] Specifically, the liquid crystal capsule of the other embodiment above may include a core containing liquid crystal. The liquid crystal capsule structure according to the present invention is characterized by containing liquid crystal inside a shell made of a polymer. This can improve the uniformity of the liquid crystal particles.
[0062] The liquid crystal is not particularly limited, but examples include nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, chiral nematic liquid crystal, etc. The specific type of liquid crystal compound is not limited, and various liquid crystals known in the prior art can be used without limitation. The liquid crystal compound is not particularly limited, but may be composed of fluorine-based or cyanide-based compounds, or a mixture thereof.
[0063] Meanwhile, the above-mentioned core may further include an emulsifier. The emulsifier is a surfactant used in the formation of liquid crystal droplets, and by increasing the surface energy contacted by the liquid crystal, the liquid crystal alignment changes to a radial shape, thereby inducing vertical alignment of the liquid crystal, which can induce a high transmittance variability even at lower voltages.
[0064] The above emulsifier may include a sorbitan ester-based compound. The above sorbitan ester-based compound may include the sorbitan ester or a derivative compound thereof, or a mixture of two or more of these.
[0065] The above sorbitan ester-based compound may include intramolecular carbon-carbon double bonds. When the sorbitan ester-based compound contains intramolecular carbon-carbon double bonds (C=C), the interaction between the double bonds within the emulsifier molecules aligned along the central axis within the liquid crystal and the liquid crystal molecules is strengthened, thereby causing the liquid crystal to exhibit a radial arrangement. As a result, high transmittance variability can be achieved even at lower voltages.
[0066] The above sorbitan ester compound is a reaction product of sorbitan and a carboxylic acid containing intramolecular carbon double bonds, and the carboxylic acid containing intramolecular carbon double bonds may 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. Specific examples of the carboxylic acid containing intramolecular carbon double bonds include oleic acid.
[0067] The above sorbitan ester-based compound may have a molar mass of 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.
[0068] On the other hand, if the molar mass of the above sorbitan ester compound increases excessively to more than 1220 g / mol, problems may arise such as reduced oil-in-water emulsion stability and increased haze in the optical film when manufacturing capsules using liquid crystals.
[0069] More specifically, the sorbitan ester-based compound may have 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. Specific examples of sorbitan ester-based compounds having the molar mass described above may be sorbitan monooleate.
[0070] Sorbitan ester compounds 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, have a Hydrophile Lipophile Balance (HLB) value of 4 to 4.5. The HLB can be calculated using the following Equation 1.
[0071] [Mathematical Formula 1]
[0072] HLB = 20*(MH / M)
[0073] In the above 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.
[0074] In addition, the sorbitan ester-based compound may have 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 600 g / mol to 700 g / mol. Specific examples of sorbitan ester-based compounds having the molar mass described above may be sorbitan dioleate.
[0075] Meanwhile, the above sorbitan ester-based compound may be a mixture of two or more sorbitan ester-based compounds having different molar masses. More specifically, the above sorbitan ester-based compound may be a mixture of a sorbitan ester-based compound having a molar mass of 400 g / mol to 500 g / mol and a sorbitan ester-based compound having a molar mass of 600 g / mol to 700 g / mol.
[0076] The molar ratio for mixing the sorbitan ester compound having a molar mass of 400 g / mol to 500 g / mol and the sorbitan ester compound having a molar mass of 600 g / mol to 700 g / mol is not particularly limited, and the sorbitan ester compound having a molar mass of 400 g / mol to 500 g / mol and the sorbitan ester compound having 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.
[0077] To explain with a more specific example, the mixture of two or more sorbitan ester compounds with different molar masses may be sorbitan sesquioleate (a mixture with a molar ratio of sorbitan monooleate (molar mass: 428.61 g / mol) : sorbitan dioleate (molar mass: 693 g / mol) of 1:1).
[0078] The above sorbitan ester compound is a mixture of a sorbitan ester compound with a molar mass of 400 g / mol to 500 g / mol and a sorbitan ester compound with a molar mass of 600 g / mol to 700 g / mol, and has an HLB (Hydrophile Lipophile Balance) value of 3.5 to 3.9.
[0079] Meanwhile, the above emulsifier may further include one or more second emulsifiers selected from the group consisting of acetylenic diol-based compounds and polysorbate-based compounds. That is, the above emulsifier may further include a second emulsifier containing one acetylenic diol-based compound, one polysorbate-based compound, or a mixture thereof. In this case, the sorbitan ester-based compound may serve as the first emulsifier. The above second emulsifier can relatively reduce van der Waals interaction with the liquid crystal and sufficiently lower the surface anchoring energy of the liquid crystal within the capsule, thereby inducing a high transmittance variability even at lower voltages.
[0080] Specifically, with respect to 100 parts by weight of the sorbitan ester-based compound (first emulsifier), the weight ratio of the second emulsifier may be 1 to 1000 parts by weight, or 10 to 500 parts by weight, or 10 to 100 parts by weight. Within the range satisfying the above numerical range, the surface anchoring energy of the liquid crystal inside the capsule can be sufficiently lowered to induce a high transmittance variability even at lower voltages.
[0081] On the other hand, if the weight ratio of the second emulsifier is excessively reduced relative to 100 parts by weight of the sorbitan ester-based compound (first emulsifier), the movement of liquid crystal molecules may not be easy, resulting in a decrease in the contrast ratio or failure to secure stable electro-optical characteristics during repeated operation of the liquid crystal cell. In addition, if the weight ratio of the second emulsifier is excessively increased relative to 100 parts by weight of the sorbitan ester-based compound (first emulsifier), the surface anchoring energy of the liquid crystal inside the capsule may not be sufficiently lowered, which may cause a problem where the driving voltage increases.
[0082] More specifically, the second emulsifier may include an acetylenic diol-based compound. The acetylenic diol-based compound may include an acetylenic diol compound or a derivative thereof. As a specific example, the acetylenic diol-based compound may be 2,4,7,9-tetramethyl-5-decyn-4,7-diol. Since the acetylenic diol-based compound does not have ethylene oxide repeating units in the structure of the emulsifier, it can relatively reduce van der Waals interaction with fluorinated liquid crystals compared to an emulsifier having ethylene oxide repeating units.
[0083] The above acetylenic diol-based compound may have a Hydrophile Lipophile Balance (HLB) value of 2 to 5, or 3 to 4. Generally, in order to make a stable oil-in-water emulsion using a conventional emulsifier, it is necessary for the emulsifier to adsorb to the aqueous / oil phase interface to form a liquid crystal, and to this end, the Hydrophile Lipophile Balance (HLB) value of the emulsifier to be used must be carefully adjusted according to the polarity of the oil phase.
[0084] The above polysorbate-based compound may include both polysorbate and derivative compounds thereof. The above polysorbate refers to a sorbitan ester containing a polyoxyalkylene repeating unit structure within the molecule. The above polysorbate-based compound may be one or more compounds selected from the group consisting of polysorbate 20, polysorbate 40, polysorbate 60, and polysorbate 80. That is, the above polysorbate-based compound may be one type of polysorbate 20, one type of polysorbate 40, one type of polysorbate 60, one type of polysorbate 80, or a mixture thereof.
[0085] The above polysorbate-based compound may have a molar mass of 1225 g / mol or more, or 1300 g / mol or more, or 1500 g / mol or less, or 1225 g / mol to 1500 g / mol, or 1300 g / mol to 1500 g / mol.
[0086] More specifically, the polysorbate-based compound may be a polysorbate 20 having a molar mass of 1225 g / mol to 1300 g / mol, or 1225 g / mol to 1250 g / mol.
[0087] In addition, the polysorbate-based compound may be a polysorbate 80 having a molar mass of 1300 g / mol to 1500 g / mol, or 1305 g / mol to 1350 g / mol.
[0088] Meanwhile, with respect to 100 parts by weight of the liquid crystal, the emulsifier content may 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 1 to 20 parts by weight, or 5 to 11 parts by weight. If the emulsifier content is excessively reduced with respect to 100 parts by weight of the liquid crystal, the vertical alignment of the liquid crystal by the emulsifier is induced, which has a limitation in that it is difficult to sufficiently induce a high transmittance variability even at lower voltages. In addition, if the emulsifier content is excessively increased with respect to 100 parts by weight of the liquid crystal, an excess amount of emulsifier may form colloidal micelles, causing a problem in which the surface tension of the solution drops sharply.
[0089] Meanwhile, the core may further include an anisotropic dye. The anisotropic dye is not particularly limited as long as it is a dopable anisotropic dye, and specifically may be S-428, M-483, M412 (Mitsui FineChemical), etc.
[0090] Meanwhile, the core may further include a siloxane-based additive. The siloxane-based additive is an additive capable of lowering the interfacial tension of the liquid crystal. Accordingly, a liquid crystal capsule containing the siloxane-based additive and the liquid crystal together in the core can sufficiently lower the surface anchoring energy of the liquid crystal within the capsule.
[0091] The above siloxane-based additive may have a molar mass of 500 g / mol or less, or 100 g / mol to 500 g / mol. The above siloxane-based additive may include a trisiloxane-based compound. The above trisiloxane-based compound may include a trisiloxane compound or a derivative thereof. As a specific example, the above siloxane-based additive may be octamethyltrisiloxane or hexamethylcyclotrisiloxane.
[0092] In particular, with respect to 100 parts by weight of the liquid crystal, the content of the siloxane-based additive may 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. If the content of the siloxane-based additive is excessively reduced with respect to 100 parts by weight of the liquid crystal, the effect of lowering the surface tension of the liquid crystal by the siloxane-based additive is not sufficiently realized, and there is a limitation in that the surface anchoring energy of the liquid crystal within the capsule cannot be sufficiently lowered. In addition, if the content of the siloxane-based additive is excessively increased with respect to 100 parts by weight of the liquid crystal, a problem may occur in which the liquid crystal state (mesophase state) changes into an isotropic liquid phase.
[0093] Meanwhile, the liquid crystal capsule of the above 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 or a multi-layer shell made of different polymer materials to achieve improved mechanical properties and particle uniformity. Accordingly, the uniformity of the liquid crystal particles can be improved, and the problem of contamination by dye can be improved at the same time.
[0094] The material forming the shell has the same refractive index as the matrix polymer in which the liquid crystal composite is dispersed, and while specific examples are not particularly limited, it may be selected from polyvinyl alcohol, polyurea, polyacrylic, polyurethane, polyamide including nylon, polyacetal, and polyester.
[0095] However, to give a specific example, the polymer shell formed on the surface of the core may be made of polyvinyl alcohol (PVA) resin crosslinked with glyoxal. There are no particular restrictions on the type of PVA, and various types of PVA with different molecular weights or saponification rates may be appropriately selected depending on the purpose. Glyoxal is used as the crosslinking agent for crosslinking the PVA.
[0096] Meanwhile, the average diameter of the liquid crystal capsule may be 100 nm to 300 nm. If the average diameter of the liquid crystal capsule is reduced excessively, there is a problem that the driving voltage increases and power consumption increases. In addition, if the average diameter of the liquid crystal capsule is increased excessively, there is a problem that visible light is scattered and haze increases.
[0097] The liquid crystal capsule may be a group of individual particles having an average diameter of 100 nm to 300 nm, and the individual particles included in this group may have an average diameter of 100 nm to 300 nm. More specifically, 60% or 80% of the individual particles included in the group may have a diameter of 100 nm to 300 nm.
[0098] The present application also provides uses for the liquid crystal capsule. The liquid crystal capsule of the present application can be used in various optical modulation devices applicable to liquid crystals. Accordingly, the present application provides an optical modulation device having a substrate; and a liquid crystal layer formed on one surface of the substrate and comprising the liquid crystal capsule. The manufacturing method and type of the optical modulation device are well known in the art and can be manufactured using known manufacturing methods without limitation. The optical modulation device includes, but is not limited to, a smart window, an isotropic film, a polarization control film, or a flexible LCD, etc.
[0099] The method for manufacturing the above liquid crystal capsule is not significantly limited, and various conventional methods for manufacturing liquid crystal capsules can be applied without limitation. However, for example, the method includes: (1) a process of preparing a mixed solution by mixing a mixed material containing liquid crystal, an emulsifier, and polyvinyl alcohol (PVA) in a solvent; (2) a process of forming a droplet from the mixed solution; (3) a process of placing polyvinyl alcohol (PVA) around the droplet; and (4) a process of manufacturing a liquid crystal capsule containing liquid crystal in a polymer shell by cross-linking the polyvinyl alcohol (PVA) using glyoxal to form a polymer shell surrounding the liquid crystal.
[0100] In the process of preparing a mixed solution by mixing the above (1) liquid crystal, emulsifier, and polyvinyl alcohol (PVA) with a solvent, the solvent is not particularly limited and can be appropriately selected according to the purpose, and examples include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, or ultrapure water. If necessary, additional additives may be added.
[0101] In the process of preparing a mixed solution by mixing the above (1) liquid crystal, emulsifier, and polyvinyl alcohol (PVA) with a solvent, examples of methods for mixing the liquid crystal, emulsifier, polyvinyl alcohol (PVA), and additive with the solvent are not significantly limited, and various methods used in conventional emulsification reactions can be applied without limitation.
[0102] In the process of forming droplets from the above (2) mixed solution, the droplets are dispersed in a dispersion medium, and more specifically, the droplets are dispersed in a dispersion medium in a state where an emulsifier covers the liquid crystal.
[0103] One method for preparing the above droplets is to produce droplets using a dispersion-type emulsification device.
[0104] As for the dispersion-type emulsification device, there are no particular restrictions as long as droplets of the desired particle size are obtained, and it can be appropriately selected according to the purpose; for example, a homomixer, which is a device for mixing liquids, or a homogenizer, which is a device for finely and uniformly grinding particles, can be used. Furthermore, there are no particular restrictions on the dispersion method; for example, any dispersion method such as stirring, ultrasound, or high pressure can be used.
[0105] In the present invention, as a dispersion emulsification device, various dispersion emulsification devices such as a high-speed homogenizer, an ultrasonic homogenizer, a high-pressure homogenizer, and a homo mixer may be used.
[0106] In addition, a more preferred embodiment of the droplet preparation process may include 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 smaller than the particle size obtained in the first preparation process using a second dispersion emulsification device.
[0107] As for the first and second dispersion emulsification devices, there are no particular restrictions as long as droplets of the desired particle size are obtained, and various dispersion emulsification devices such as the high-speed homogenizer, ultrasonic homogenizer, high-pressure homogenizer, and homo mixer described above can be appropriately combined and used.
[0108] In the process of placing polyvinyl alcohol (PVA) around the above (3) droplets, coacervation can proceed in which the PVA gathers around the liquid crystal composition under a droplet dispersion at a predetermined temperature. For example, it is preferable to set the solution temperature of the droplet dispersion in the coacervation process to room temperature or higher.
[0109] In the process of manufacturing a liquid crystal capsule containing a liquid crystal within a polymer shell by cross-linking polyvinyl alcohol (PVA) using the above (4) glyoxal to form a polymer shell surrounding the liquid crystal, the cross-linking reaction is preferably carried out under acidic conditions. As for the acidic conditions, it is preferable that the pH be in the range of 1 to 5, and more preferable that the pH be about 3.
[0110]
[0111] 2. Capsule solution
[0112] Meanwhile, according to another embodiment of the invention, a capsule solution comprising a liquid crystal capsule of the first embodiment or another embodiment and a solvent may be provided. The details regarding the liquid crystal capsule include the details described above regarding the first embodiment and other embodiments.
[0113] The above solvent is not particularly limited and can be appropriately selected according to the purpose, and examples include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, or ultrapure water.
[0114] The above capsule solution contains liquid crystal capsules dispersed in a solvent. That is, the above capsule solution may be a liquid crystal capsule dispersion. The above capsule solution may also be used as a coating solution for forming a liquid crystal layer. For example, a liquid crystal layer is formed by applying the capsule solution onto a support substrate to form a film.
[0115]
[0116] 3. Optical film
[0117] Meanwhile, according to another embodiment of the invention, an optical film may be provided comprising a binder resin and liquid crystal domains dispersed in the binder resin, wherein the haze is 10% or less when voltage is applied, and the threshold voltage, which is the voltage at 10% transmittance of the maximum transmittance when voltage is applied, is 60 V or less.
[0118] Specifically, the optical film may include a binder resin. The binder resin may act as a binder that fixes the liquid crystal domains while dispersing them within the optical film.
[0119] The content regarding the binder resin above is not particularly limited, but for example, the binder resin may be any of the various transparent materials widely used in the field of optical films without limitation. Specific examples of the binder resin above are not particularly limited, but may be selected from, for example, polyvinyl alcohol, polyurea, polyurethane, polyamide including nylon, polyacetal, and polyester.
[0120] Meanwhile, the optical film may include liquid crystal domains dispersed in the binder resin. The liquid crystal domain refers to an area within the optical film that contains liquid crystal. As the optical film forms a domain in which the liquid crystal is trapped within a certain area, the liquid crystal domain is more stably dispersed in the binder resin and can have durability during the film formation process. This is because the liquid crystal domain is derived from a liquid crystal capsule comprising a core containing liquid crystal and a polymer shell formed on the surface of the core.
[0121] The above liquid crystal domains may be contained in two or more, and each of the two or more liquid crystal domains may have an independent region. 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. Accordingly, the liquid crystal domains are dispersed more stably in the binder resin and can have durability during the film formation process.
[0122] The liquid crystal domain may include a liquid crystal and an emulsifier. The contents regarding the liquid crystal and the emulsifier may include all the contents described above in the above embodiment.
[0123] Specifically, the liquid crystal domain comprises a liquid crystal and an emulsifier, the emulsifier comprises a sorbitan ester-based compound, the sorbitan ester-based compound has a molar mass of 1220 g / mol or less, and the sorbitan ester-based compound may comprise intramolecular carbon-in-carbon double bonds. That is, the optical film of the other embodiment comprises a core containing a liquid crystal and an emulsifier; and a polymer shell formed on the surface of the core; the emulsifier comprises a sorbitan ester-based compound, the sorbitan ester-based compound has a molar mass of 1220 g / mol or less, and the sorbitan ester-based compound may be derived from a liquid crystal capsule comprising intramolecular carbon-in-carbon double bonds.
[0124] Additionally, the liquid crystal domain comprises a liquid crystal and an emulsifier, the emulsifier comprises a sorbitan ester-based compound, and the emulsifier may further comprise one or more second emulsifiers selected from the group consisting of acetylenic diol-based compounds and polysorbate-based compounds. That is, the optical film of the other embodiment comprises a core containing a liquid crystal and an emulsifier; and a polymer shell formed on the surface of the core; and the emulsifier may be derived from a liquid crystal capsule comprising a sorbitan ester-based compound and one or more second emulsifiers selected from the group consisting of acetylenic diol-based compounds and polysorbate-based compounds.
[0125] Meanwhile, the liquid crystal domain may further include an anisotropic dye. The details regarding the anisotropic dye may include all the details described above in the above embodiment.
[0126] In addition, the liquid crystal domain may further include a siloxane-based additive. The details regarding the siloxane-based additive may include all the details described above in the above embodiment.
[0127] The average diameter of the liquid crystal domain may be 100 nm to 300 nm. That is, the liquid crystal domain may be a liquid crystal nanodomain. If the average diameter of the liquid crystal domain is reduced excessively, there is a problem that the driving voltage increases and power consumption increases. In addition, if the average diameter of the liquid crystal domain is increased excessively, there is a problem that visible light is scattered and haze increases.
[0128] The liquid crystal domain may be a group of individual particles having an average diameter of 100 nm to 300 nm, and the individual particles included in this group may have an average diameter of 100 nm to 300 nm. More specifically, 95% or 99% of the individual particles included in the group may have a diameter of 100 nm to 300 nm.
[0129] The above liquid crystal domain may be derived from the liquid crystal capsule of one embodiment or the liquid crystal capsule liquid of another embodiment.
[0130] For a more specific example, the optical film may be formed by applying the capsule liquid of the other embodiment onto a supporting substrate to form a film.
[0131] Additionally, when voltage is applied, the optical film may have a haze of 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 numerical ranges.
[0132] The haze of the optical film when the above voltage is applied refers to the haze value measured when voltage is applied to the optical film. More specifically, examples of the applied voltage are not significantly limited, and a voltage of 1V to 100V can be applied.
[0133] To give a more specific example, haze at an applied voltage of 100V on This may 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 numerical ranges.
[0134] In addition, the optical film is haze at an applied voltage of 0V. off It may 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 numerical ranges.
[0135] As the above optical film has a haze within the range described above, it can achieve more transparent optical characteristics when voltage is applied and when it is not. The method for measuring the haze is not limited, and various methods widely known in the field of conventional liquid crystal-containing optical devices can be applied without limitation. However, for example, it can be measured using a haze meter (Nippon Denshoku, NDH7000) while applying voltage through a function generator.
[0136] The above optical film may have a threshold voltage, which is the voltage at 10% transmittance of the maximum transmittance when voltage is applied, of 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 above threshold voltage refers to the voltage at 10% transmittance of the maximum transmittance, and as the optical film has a threshold voltage within the range described above, it may be possible to drive it at a lower voltage. The method for measuring the above threshold voltage is not limited, and various methods widely known in the field of conventional liquid crystal-containing optical devices may be applied without limitation. However, for example, voltage can be applied through a function generator and measured using a haze meter (Nippon Denshoku, NDH7000).
[0137] Specific details regarding the above optical film can be applied without limitation to various conventionally known optical films. For example, regarding the structure, composition, manufacturing method, physical properties, and applications of the optical film, various details widely known in the conventional film field can be applied without limitation.
[0138] However, for example, the above optical film can be used in a transmittance variable film.
[0139]
[0140] 4. Optical device
[0141] Meanwhile, according to another embodiment of the invention, an optical device comprising an optical film of the other embodiment may be provided. The details regarding the optical film include the details described above regarding the other embodiment.
[0142] The content regarding the above optical device can be applied without limitation to various conventionally known optical devices. For example, regarding the specific structure, size, manufacturing method, physical properties, and applications of the optical device, various contents widely known in the conventional display field can be applied without limitation.
[0143] However, for example, the optical device may be a light modulation device including an optical film of the other embodiment. Specific examples of the light modulation device are not particularly limited, but may include, for example, a smart window, an isotropic film, a polarization control film, or a liquid crystal display, an organic electroluminescent display, etc.
[0144] More specifically, examples of the above optical device include a liquid crystal display element having a set of opposing substrates, an electrode formed on one or both opposing surfaces of each of the set of substrates, a liquid crystal layer formed by applying a liquid crystal capsule liquid of the present invention disposed between the substrates, and a means for applying an electric field to the liquid crystal capsule of the present invention in the liquid crystal layer through the electrode.
[0145] The above optical device may have a threshold voltage of 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 above threshold voltage refers to the voltage at 10% transmittance of the maximum transmittance, and as the optical device has a threshold voltage within the range described above, the optical device may be able to operate at a lower voltage. The method for measuring the above threshold voltage is not limited, and various methods widely known in the field of conventional liquid crystal-containing optical devices may be applied without limitation. However, for example, voltage can be applied through a function generator and measured using a haze meter (Nippon Denshoku, NDH7000).
[0146] In addition, the optical device may have a contrast of 10 or more, or 15 or more, or 17 or more, or 18 or more, or 20 or more, or 30 or more, or 33 or more, 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. The contrast refers to the ratio between the transmittance at a voltage of 100 V and the transmittance at a voltage of 0 V, and as the optical device has a contrast within the range described above, the optical device can achieve an excellent transmittance variability even at lower voltages. The method for measuring the contrast is not limited, and various methods widely known in the field of conventional liquid crystal-containing optical devices may be applied without limitation. However, for example, voltage can be applied through a function generator and measured using a haze meter (Nippon Denshoku, NDH7000).
[0147] In addition, the optical device has haze at an applied voltage of 100V. on This may 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 numerical ranges. Additionally, the optical device has a haze at an applied voltage of 0V. off It may 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 numerical ranges.
[0148] As the optical device has a haze within the range described above, the optical device can achieve more transparent optical characteristics when voltage is applied and when it is not. The method for measuring the haze is not limited, and various methods widely known in the field of conventional liquid crystal-containing optical devices can be applied without limitation. However, for example, voltage can be applied through a function generator while measuring using a haze meter (Nippon Denshoku, NDH7000).
[0149]
[0150] 5. Variable transmittance device
[0151] Meanwhile, according to another embodiment of the invention, a transmittance variable device comprising an optical film of the other embodiment may be provided. Details regarding the optical film include details described above regarding the other embodiment.
[0152] Regarding the above variable transmittance device, various conventionally known variable transmittance devices can be applied without limitation. For example, regarding the specific structure, size, manufacturing method, physical properties, and applications of the variable transmittance device, various contents widely known in the field of conventional liquid crystal capsules can be applied without limitation. However, as an example, the variable transmittance device may include a transparent electrode layer and a variable transmittance layer, and the variable transmittance layer may include an optical film of the above embodiment. More specifically, the variable transmittance layer may be located between two transparent electrode layers, and voltage may be applied to the variable transmittance layer using a voltage application means. The contents regarding the voltage application means are not particularly limited, and any conventionally known technical contents can be applied without limitation.
[0153] The transmittance variable device of the present application can be applied to any device to which transmittance variation can be applied. For example, the transmittance variable device of the present application can be applied to a sunroof, automotive glass, goggles, sunglasses, or helmet, etc., to provide a transmittance variable device. As long as the transmittance variable device includes the transmittance variable device of the present application, other parts or structures, etc., are not particularly limited, and all contents known in the art may be appropriately applied.
[0154] According to the present invention, a liquid crystal capsule capable of inducing a high transmittance variability even at a lower voltage, and a capsule liquid, an optical film, an optical device, and a transmittance variability device using the same may be provided.
[0155] The invention is described in more detail in the following examples. However, the following examples are merely illustrative of the invention, and the scope of the invention is not limited by the following examples.
[0156]
[0157] <Examples and Comparative Examples: Preparation of Liquid Crystal Capsules and Capsule Solutions>
[0158] Polyvinyl alcohol (PVA), water, an emulsifier, a liquid crystal containing an anisotropic dye, and additives were mixed and stirred as described in the composition in Table 1 below. Subsequently, emulsification was carried out at 18,000 rpm using an IKA homogenizer T25. Afterward, secondary emulsification was carried out at 10,000 psi using a microfluidizer to form droplets.
[0159] Afterwards, the solution was heated to 40°C under stirring and PVA was adsorbed onto the droplet surface for 18 hours.
[0160] Subsequently, the adsorbed PVA was crosslinked using a 40% aqueous glyoxal solution as a crosslinking agent at 40°C for 18 hours under pH 3 conditions.
[0161] 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.
[0162]
[0163] Composition Classification of Examples and Comparative Examples PVA Water Liquid Emulsifier (Type / Amount Added) Additive Example 1 1.3g 89g 9.2g E1 0.5g - Example 2 1.3g 89g 9.2g E2 0.5g - Example 3 1.3g 89g 9.2g E1 0.25g E3 0.25g - Example 4 1.3g 93.6g 4.6g E1 0.225g E4 0.025g - Example 5 1.3g 93.6g 4.6g E2 0.25g E3 0.25g - Example 6 1.3g 89g 9.2g E1 0.5g E3 0.5g A1 0.09g Comparative Example 11.3g 93.6g 4.6g E5 0.25g-Comparative Example 21.3g 93.6g 4.6g E6 0.25g-Comparative Example 31.3g 93.6g 4.6g E4 0.25g-Comparative Example 41.3g 93.6g 4.6g E7 0.75g-
[0164] E1 : Sorbitan monooleate (Molar mass: 428.61 g / mol, HLB: 4.3)
[0165] E2: Sorbitan sesquioleate (a 1:1 molar ratio mixture of sorbitan monooleate (molar mass: 428.61 g / mol) and sorbitan dioleate (molar mass: 693 g / mol), HLB: 3.7)
[0166] E3 : 2,4,7,9-tetramethyl-5-decyn-4,7-diol (2,4,7,9-tetramethyl-5-decyn-4,7-diol, HLB : 3)
[0167] E4 : Polysorbate 20 (Molar mass: 1226 g / mol)
[0168] E5 : Sorbitan monostearate
[0169] E6: Sorbitan Tristearate
[0170] E7 : Polysorbate 80 (Molar mass: 1309.65 g / mol)
[0171] A1 : Octamethyltrisiloxane
[0172]
[0173] <Experimental Example>
[0174] For the liquid crystal capsules or capsule liquids obtained in the above examples and comparative examples, physical properties were measured by the following method, and the results are shown in Table 2.
[0175]
[0176] 1. Physical properties of liquid crystal capsule films
[0177] (1) Thickness (㎛)
[0178] A liquid crystal capsule film was prepared by coating the capsule solution onto the ITO of a PET-ITO film using a film applicator and drying it at 70°C for 2 hours. The thickness of the liquid crystal capsule film was measured using an Alpha step (KLA TENCOR).
[0179] (2) T off (%), Haze off (%), Haze on (%), critical voltage (V), CR
[0180] After laminating the ITO surface of a PET-ITO film (GMP EXCELAM-SMART 655) onto the upper surface of the liquid crystal capsule film, an electrode tape was attached to the ITO surface.
[0181] T, which is the transmittance of a liquid crystal capsule film to which no voltage is applied (transmittance at an applied voltage of 0V). off , and Haze of a liquid crystal capsule film with no applied voltage (haze at an applied voltage of 0V) off It was measured using a haze meter (Nippon Denshoku, NDH7000).
[0182] And, while applying voltage through the function generator, the threshold voltage, which is the voltage at 10% transmittance of the maximum transmittance, and the haze, which is the applied voltage of 100V.on and transmittance at a voltage of 100 V and transmittance at a voltage of 0 V The contrast (CR), which is the ratio between them, was measured using a haze meter (Nippon Denshoku, NDH7000).
[0183]
[0184] Measurement results of experimental examples of examples and comparative examples, classification of thickness (㎛) T off (%)Haze off (%)Haze on (%) Critical Voltage (V) CR @100V Example 1 14.7 1.2 17.1 1.0 20 23.4 Example 2 11.8 1.2 26.3 1.4 25 18.8 Example 3 13.2 0.9 21.1 2.5 40 33.2 Example 4 13.4 1.7 30.8 7.5 55 17.3 Example 5 11.7 2.2 25.7 7.8 35 15.2 Example 6 12.8 0.9 15.5 2.7 45 30.6 Comparative Example 1 11.0 5.2 6 2.6 5 2.5 45 4.1 Comparative Example 2 13.8 2.8 6 3.4 5 3.8 55 4.1 Comparative Example 3 14.2 1.0 39.8 20.1 45 16.1 Comparative Example 4 Measurement impossible due to inability to manufacture film
[0185] As shown in Table 1 above, the liquid crystal capsule of the example has 1) a critical voltage of 60V or less, 2) a CR of 10 or more, and 3) haze on This simultaneously satisfied the condition of less than 10%. Accordingly, it was confirmed that excellent transmittance variability and optical characteristics can be realized while enabling operation at low voltage.
[0186] On the other hand, the liquid crystal capsules obtained in Comparative Examples 1 and 2 showed a CR of less than 10, confirming that the transmittance variability was poor compared to the Examples. In addition, the liquid crystal capsule obtained in Comparative Example 3 is haze on It was confirmed that the optical properties were poor compared to the example, exceeding 10%. Meanwhile, it was confirmed that the liquid crystal capsule obtained in Comparative Example 4 could not be manufactured into a film, making it impossible to measure its physical properties.
Claims
A core containing liquid crystal and an emulsifier; and A polymer shell formed on the surface of the core; comprising The above emulsifier includes a sorbitan ester-based compound, and The above sorbitan ester-based compound has a molar mass of 1220 g / mol or less, and The above sorbitan ester-based compound is a liquid crystal capsule containing intramolecular carbon-carbon double bonds. In paragraph 1, The above sorbitan ester compound is a reaction product of sorbitan and a carboxylic acid containing intramolecular carbon double bonds, and the carboxylic acid containing intramolecular carbon double bonds has 10 to 30 carbon atoms, liquid crystal capsule. In paragraph 1, The above sorbitan ester-based compound is a liquid crystal capsule having a molar mass of 800 g / mol or less. In paragraph 3, The above sorbitan ester compound is a liquid crystal capsule, which is sorbitan monooleate. In paragraph 1, A liquid crystal capsule in which the above-mentioned sorbitan ester compound is a mixture of two or more sorbitan ester compounds having different molar masses. In paragraph 5, A liquid crystal capsule in which a mixture of two or more sorbitan ester compounds having different molar masses is sorbitan sesquioleate. A core containing liquid crystal and an emulsifier; and A polymer shell formed on the surface of the core; comprising The above emulsifier includes a sorbitan ester-based compound, and A liquid crystal capsule comprising one or more second emulsifiers selected from the group consisting of acetylenic diol-based compounds and polysorbate-based compounds. In Paragraph 7, A liquid crystal capsule having a weight ratio of 1 to 1,000 parts by weight of a second emulsifier per 100 parts by weight of the above sorbitan ester-based compound. In Paragraph 7, The above acetylenic diol-based compound is a liquid crystal capsule having an HLB value of 2 to 5. In Paragraph 7, The above polysorbate-based compound is a liquid crystal capsule having a molar mass of 1225 g / mol or more. In Paragraph 7, The above sorbitan ester-based compound has a molar mass of 1220 g / mol or less, and The above sorbitan ester-based compound is a liquid crystal capsule containing intramolecular carbon-carbon double bonds. In either Article 1 or Article 7, The above core is a liquid crystal capsule further comprising a siloxane-based additive. A capsule solution comprising a liquid crystal capsule and a solvent according to either claim 1 or claim 7. It comprises a binder resin and liquid crystal domains dispersed in the binder resin, and When voltage is applied, the haze is 10% or less, and An optical film having a threshold voltage of 60 V or less, which is the voltage at 10% transmittance of maximum transmittance when voltage is applied. In Paragraph 14, The above liquid crystal domain includes a liquid crystal and an emulsifier, and The above emulsifier includes a sorbitan ester-based compound, and The above sorbitan ester-based compound has a molar mass of 1220 g / mol or less, and The above sorbitan ester-based compound is an optical film comprising intramolecular carbon-carbon double bonds. In Paragraph 14, The above liquid crystal domain includes a liquid crystal and an emulsifier, and The above emulsifier includes a sorbitan ester-based compound, and An optical film comprising one or more second emulsifiers selected from the group consisting of acetylenic diol-based compounds and polysorbate-based compounds. An optical device comprising the optical film of claim 14. A transmittance variable device comprising the optical film of claim 14.