Design water dispersion

Abstract

To provide a design material which is easily prepared, is excellent in handleability, can be easily defoamed when air bubbles are mixed, and can achieve both of viscosity capable of fixing a display object at a desired position and desired optical characteristics suitable for expression of a polar color or multi-light color space or the like for expressing a space such as water, atmosphere, sky, and outer space or a different dimensional space or the like, and to provide a device and a display object using properties of the design material.SOLUTION: The water dispersion for design is obtained by dispersing cellulose nanofibers in water and is used as a spatial expression of a display article.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an aqueous dispersion for decorative applications. [Background technology]

[0002] There is a need to enhance the diversity and realism of exhibits by depicting the underwater existence of various marine life such as submarines, submersibles, and other vessels that navigate the ocean, as well as various underwater creatures (fish, marine mammals (dolphins, whales, sea lions, sea lions, etc.), birds (penguins, cormorants, etc.), various other creatures (octopus, squid, jellyfish, shrimp, etc.), and extinct species (ichthyosaurs, sea dragons)). In such underwater exhibits, in order to position the exhibited objects in their designated locations, for example, the background of the exhibit is colored to evoke an underwater environment, and these models are either attached to support rods and placed on the ground, or hung from the ceiling or the top of the exhibit container by tying strings to the models. However, even if the support rods or strings are made thin or made of transparent materials, it is not possible to completely eliminate the presence of the support rods or strings, which results in the exhibit lacking realism and a loss of realism. Furthermore, when multiple exhibit objects are used, the positional relationships between the support rods and hanging strings become complicated, which may result in limitations on placement.

[0003] Instead of using support rods and hanging strings, a known method involves filling the exhibit with a curable transparent resin material and fixing (embedding) the exhibit in the transparent resin material, thereby enabling the exhibit to be positioned in the desired location without using support rods or hanging strings. Examples of such curable transparent resins include two-component curable transparent resins such as epoxy resin, silicone resin, and urethane resin, and one-component curable transparent resins such as moisture-curable acrylic resin and ultraviolet (UV)-curable acrylic resin. On the other hand, when creating an exhibit using a two-component curable transparent resin, the curing reaction begins as soon as the curing agent is added to the main material (base), making it impossible to prepare the main material and curing agent in a premixed state. Therefore, the main material and curing agent must be uniformly mixed in a specific ratio each time, which makes the process complicated. Furthermore, the use of two-component curable transparent resins requires considerable skill and experience, as their usable life is affected by temperature. When using one-component curable transparent resin, it is not suitable for preparing large cured objects due to the need to ensure the addition of humidity, which triggers curing, and the strength of the UV light that reaches the object. Also, when arranging multiple models at different heights, it is necessary to fill the resin up to the height at which the models will be placed, let it harden, then place the models after hardening, and then fill with more resin, a series of steps that must be repeated, which takes a considerable amount of time to complete the creation of the exhibit. Another common problem with the above-mentioned curable transparent resins is the high viscosity of the resin solution before hardening. High-viscosity resin solutions are difficult to fill into display cases, and they are prone to trapping air bubbles during filling, making them difficult to remove. If the resin hardens while retaining air bubbles, the exhibit loses its realism and significantly diminishes the sense of realism. Because the above-mentioned curable transparent resins cannot be redissolved after hardening, trapped air bubbles cannot be removed after hardening, and used models cannot be reused. Therefore, if a new exhibit without air bubbles is to be recreated, the model itself must be prepared (manufactured) again.

[0004] As a technology that can solve the above problems, for example, Patent Document 1 discloses an invention of a smectite aqueous dispersion for design use, which is a design material obtained by dispersing smectite in water. This smectite aqueous dispersion is a gel-like dispersion, and even after filling an exhibit, it allows display objects to be placed (moved) to their designated positions within the exhibit, and air bubbles can be easily removed. Furthermore, because the smectite is dispersed in the form of fine particles that remain sufficiently smaller than the incident wavelength, it is possible to produce a blue color due to Rayleigh scattering. This blue color due to Rayleigh scattering allows exhibits to be presented as if they are underwater, without the need to color the background of the exhibit, simply by using the dispersion. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-093307 Summary of the Invention [Problem to be solved by the invention]

[0006] No alternative has been found to date that exhibits properties equivalent to those of the design material described in Patent Document 1. The reason for this is that no material exists that exhibits the balance of viscosity required to fix exhibited objects in place, light transmittance sufficient to match the exhibit, and light scattering properties such as Rayleigh scattering required to achieve the water effect described above. For example, even aqueous dispersions that use gelatin (collagen) or agar (dietary fiber, etc.), which are known as common gelling agents, as dispersoids cannot achieve the balance of viscosity, light transmittance, and light scattering properties described above.

[0007] In addition to the underwater models and dioramas mentioned above, high levels of realism are also being demanded for exhibits that represent flying objects such as aircraft flying through the air, flying creatures such as birds, bats, insects, and ancient wyverns, as well as spaceships, rockets, artificial satellites, space robots that appear in anime, satellites, meteorites, and so on, all of which face the same problems as those related to water representations mentioned above. In addition to the above-mentioned methods of expressing the sea and sky, there is also a demand for design materials for exhibits that can express light using the brilliantly colored, multicolored flickering of light used in special effects, animation, movies, and dramas. Such special flickering of light is usually expressed using computer graphics (CG), and when creating an exhibit that uses such light expression, it is generally necessary to place a model or diorama in front of an LCD display that displays the computer graphics. This can result in the exhibit becoming larger, or there can be a physical separation between the exhibit and the display, making it difficult to achieve a sense of unity as an exhibit.

[0008] The present invention aims to provide a design material that is easy to prepare, has excellent handling properties, allows for simple degassing when air bubbles are mixed in, and has both viscosity that allows exhibit objects to be fixed in desired positions and desired optical properties that are suitable for expressing brilliantly colored or multicolored light spaces for expressing spaces such as water, atmosphere, sky, and outer space, or other dimensions, etc. Another objective of the present invention is to provide devices and exhibits that utilize the properties of the design material. [Means for solving the problem]

[0009] The present inventors conducted extensive research in light of the above-mentioned problems. As a result, they discovered that an aqueous dispersion of cellulose nanofibers (CNFs), which are cellulose fibers defibrated into extremely fine fibers, dispersed in water exhibits extremely high transparency and viscosity, and that, despite the fiber length of the cellulose nanofibers being longer than the incident wavelength, they can cause Rayleigh scattering of incident light, and further, when polarized light is used, can produce polarized color, which is a special fluctuation of light. The present invention was completed based on these findings.

[0010] The above-mentioned problems of the present invention have been solved by the following means. [1] A design aqueous dispersion made by dispersing cellulose nanofibers in water, intended for use as a spatial expression for exhibits. [2] The water dispersion for design use according to [1], wherein the spatial expression is a water expression, an atmospheric expression, a space expression, or an other-dimensional expression of an exhibit. [3] The aqueous dispersion for design purposes according to [1] or [2] above, wherein the cellulose nanofibers have a fiber width of 3 to 50 nm. [4] The aqueous dispersion for design purposes according to any one of [1] to [3] above, wherein the content of the cellulose nanofibers is 0.1 to 20% by mass. [5] An exhibit in which the decorative aqueous dispersion according to any one of [1] to [4] above is used as a spatial expression. [6] A multicolor light generating device comprising an aqueous dispersion in which cellulose nanofibers are dispersed in water, and a polarizing plate disposed on the front side of the aqueous dispersion, the device being used by irradiating polarized light onto the aqueous dispersion from the rear side. [7] The multicolor light generating device according to [6] above, wherein the cellulose nanofibers have a fiber width of 3 to 50 nm. [8] The multicolor light generating device according to [6] or [7] above, wherein the cellulose nanofiber content is 0.1 to 20% by mass. [9] The multicolor light generating device according to any one of [6] to [8] above, further comprising a polarizing plate disposed on the rear side of the aqueous dispersion. .

[10] The multi-color light generating device described in [9], wherein the angle of the polarization axis of the polarizing plate arranged on the front side of the water dispersion is different from the angle of the polarization axis of the polarizing plate arranged on the back side of the water dispersion.

[11] An exhibit comprising the multi-color light generating device according to any one of [6] to

[10] .

[12] An illumination device comprising the multicolor light generating device according to any one of [6] to

[10] above and a light source device.

[13] A dispersant containing cellulose nanofibers for spatial expression of exhibits.

[14] The dispersant for spatial expression according to

[13] above, wherein the cellulose nanofibers have a fiber width of 3 to 50 nm. [Effects of the Invention]

[0011] The aqueous dispersion for design purposes of the present invention is easy to prepare and has excellent handleability, and can be easily degassed when air bubbles are mixed in. Furthermore, it has both viscosity that allows an object to be displayed to be fixed in a desired position and desired optical properties that are suitable for expressing brilliantly colorful or multicolored light spaces for expressing spaces such as water, atmosphere, sky, and outer space, or other-dimensional spaces. Furthermore, it is possible to provide a multicolor light generating device and an exhibit using the properties of the above-mentioned aqueous dispersion for design purposes. [Brief explanation of the drawings]

[0012] [Figure 1] Fig. 1(a) is a photograph, used as a substitute for a drawing, showing the state when a white LED light is irradiated from above the diorama of Example 1. Fig. 1(b) is a photograph, used as a substitute for a drawing, showing the state when a polarizing plate is placed in front and behind the diorama of Example 1 and a white LED light is irradiated from the back side, as observed from the front side. [Figure 2] Fig. 2(a) is a photograph, used as a substitute for a drawing, showing the diorama of Example 5 when a white LED light is irradiated from above. Fig. 1(b) is a photograph, used as a substitute for a drawing, showing the diorama of Example 5 when polarizing plates are placed in front and behind it and a white LED light is irradiated from the back side, as observed from the front side. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present invention will be specifically described below, but the present invention is not limited to these embodiments except as defined in the present invention.

[0014] The cellulose nanofibers used in the present invention have high transparency when dispersed in water, moderate viscosity, and thixotropy. They also exhibit Rayleigh scattering and the Tyndall phenomenon, and transmit polarized light to produce a variety of polarized colors. It was previously unknown that aqueous dispersions of cellulose nanofibers exhibit both Rayleigh scattering and the Tyndall phenomenon, and it was previously unknown that these properties, combined with physical and optical properties such as thixotropy and the expression of polarized colors, make them suitable for use in designs (exhibits) with abundant visual variety. Each of the embodiments of the present invention described below utilizes previously unknown properties discovered by the inventors in the aqueous dispersions of cellulose nanofibers, and in this respect, they share a common technical feature. Each embodiment of the present invention will be described in detail below.

[0015] [Water dispersion for design purposes] One embodiment of the present invention is an aqueous dispersion for design purposes. The aqueous dispersion for design purposes of the present invention is an aqueous dispersion (aqueous dispersion) containing at least cellulose nanofibers and water, and is used for spatial expression of exhibits. In the aqueous dispersion for design purposes of the present invention, the cellulose nanofibers constitute the dispersoid, and the water constitutes the dispersion medium. In the present invention and this specification, "for design purposes" means appealing to human senses through their visual senses (such as a sense of reality (illusion) that makes something appear as if it were real, or a sense of beauty). In other words, the aqueous dispersion for design purposes is an aqueous dispersion that appeals to human senses through their visual senses when used to express the space of an exhibit. The aqueous dispersion itself may exhibit design properties, or the use of the aqueous dispersion may allow the entire exhibit to exhibit design properties.

[0016] The cellulose nanofibers maintain sufficient transparency (high light transmittance) in aqueous dispersions while gelling or increasing the viscosity of water, allowing display objects such as models to be held (fixed) in any desired position. Unlike cured products such as curable transparent resins, the aqueous dispersion for design purposes of the present invention is a thixotropic gel, making it easy to move, remove, or replace display objects placed in the aqueous dispersion for design purposes of the present invention. Furthermore, even if air bubbles are introduced during the preparation of the aqueous dispersion for design purposes of the present invention or when display objects are placed in the aqueous dispersion for design purposes, they can be easily removed using a dropper or similar. Furthermore, because the cellulose nanofibers can strongly retain water, they can be maintained in their original state for a long period of time by suppressing the rate of water evaporation. Furthermore, the aqueous dispersion for design purposes of the present invention has thixotropy, meaning that its fluidity can be temporarily increased (viscosity reduced) by stirring or the like, and then the fluidity is lost (viscosity returns to the original state) when it is left to stand. Therefore, when the fluidity is temporarily increased, the aqueous dispersion for design purposes of the present invention has excellent workability, and when the fluidity is lost, the risk of liquid leakage, etc. can be reduced.

[0017] In the water dispersion for design use of the present invention, the cellulose nanofibers are not dissolved in water but are dispersed in a fibrous form, and the cellulose nanofibers act as a dispersoid, resulting in special optical properties. By utilizing these optical properties, spatial expression of an exhibit can be realized. In this specification and the present invention, "spatial expression of an exhibit" means imparting or generating a different concept to the space or its surroundings by filling or applying the water dispersion for design use of the present invention to at least a partial area within the space of an exhibit. For example, by filling the space of an exhibit with the water dispersion for design use of the present invention, the filled space can be made to appear as if it were underwater. Examples of such spatial expression of an exhibit include water, atmosphere, space, and other-dimensional expressions of the exhibit. The water representations include underwater representations of oceans, lakes, rivers, ponds, and other areas from just below the surface to the deep sea. The atmospheric representations include representations of air (atmosphere), sky (blue sky, sunrise, sunset, etc.), light such as crepuscular rays, and imitation of weather such as cloudy skies, fog, storms, and dust storms. The space representations include representations of outer space as well as boundary regions with the atmosphere, such as the atmosphere. The other-dimensional representations include representations of other dimensions such as the fourth dimension, black holes, white holes, dimensional faults, the flow of space-time, warp navigation, time reversal, light-speed travel, the atmosphere of extraterrestrial planets, strong gravity fields, reincarnation, the afterlife, and various other states. The spatial representation of the exhibit may also be a combination of the above representations.

[0018] The spatial expression of the water dispersion for design use of the present invention can be appropriately selected and determined, for example, depending on the relationship between each component of the exhibit (exhibit object, background image, type of light source, etc.) and the optical properties of the water dispersion for design use of the present invention. Examples of such optical properties include Rayleigh scattering, Tyndall phenomenon, and optical interference.

[0019] -Rayleigh scattering- Rayleigh scattering is a phenomenon in which incident light is scattered by particles that are sufficiently small compared to the wavelength of the incident light. Cellulose nanofibers are generally nanofibers with a fiber length of 100 μm or less, and because their fiber length (average) is longer than the incident wavelength and they are not in the form of particles, it was expected that Rayleigh scattering would not occur in principle. However, the inventors' investigations have revealed that an aqueous dispersion in which cellulose nanofibers are dispersed exhibits Rayleigh scattering in the same way as particles, and that it is possible to achieve both viscosity and transparency sufficient to hold display objects. By efficiently generating Rayleigh scattering, it is possible to mimic the natural light (color) of the sky or sea that humans can perceive. By applying this, for example, the design water dispersion of the present invention can reproduce the color of highly transparent ocean water, the yellow color of looking directly at sunlight during the day, the blue color of a clear blue sky, the orange to red color of a sunrise or sunset, and the dim blue color of the boundary region between the atmosphere and space, such as the atmosphere. For example, when the design water dispersion of the present invention is irradiated with light (white light), the water dispersion itself exhibits a natural blue color due to Rayleigh scattering, making it possible to reproduce the blue light (color) unique to the sky or sea. Furthermore, by adjusting the fiber width and fiber length of the cellulose nanofibers contained in the design water dispersion of the present invention, it is possible to produce a cloudy white color (Mie scattering) that mimics the appearance of a cloudy day or a foggy sky during the day.

[0020] -Tyndall phenomenon- In nature, the Tyndall effect is observed when light is passed through dust-rich air. The Tyndall effect refers to the phenomenon in which light passing through a dispersion of fine particles is scattered by Mie scattering or other methods, resulting in the light path appearing to glow even when observed obliquely or from the side. Furthermore, in a true solution, such as saline, the particles are not large enough to cause the Tyndall effect when light is passed through the solution. In the water dispersion for design purposes of the present invention, it is believed that the Tyndall effect is caused by at least a portion of the cellulose nanofibers scattering the irradiated light. For example, by placing cotton or other materials resembling clouds on top of an exhibit and illuminating the exhibit from above, it is possible to create a crepuscular ray (angel's ladder) in which the light path entering through gaps in obstacles appears as scattered light. Furthermore, by forming an uneven surface on the water dispersion for design purposes of the present invention and illuminating the exhibit from above, it is possible to create an underwater ray of light in which streaks of light appear underwater.

[0021] -Light interference- By dispersing the cellulose nanofibers in water, the resulting aqueous dispersion for design purposes maintains a transparent to nearly transparent state while forming a nanofiber network structure within the aqueous dispersion. This network structure is believed to have a partial (region-specific) anisotropic structure and exhibits birefringence. Therefore, when incident light (preferably light that has passed through a polarizing plate) passes through the aqueous dispersion for design purposes, the polarization of the light changes with wavelength, and the intensity of the light passing through the polarizing plate on the observation side changes depending on the polarization, resulting in the appearance of brilliantly colorful interference colors (also known as "polychromatic light" or "polarized colors"). By utilizing these interference colors, it is possible to create other-dimensional expressions that cannot be achieved through anything other than computer graphics.

[0022] Each of the constituent materials of the aqueous dispersion for design use of the present invention will be described below.

[0023] (Cellulose nanofiber) Cellulose nanofibers are generally mechanically and / or chemically defibrated plant fibers primarily composed of cellulose. They are cellulose microfibrils (single nanofibers) consisting of crystalline, quasi-crystalline, and amorphous portions, or aggregates of these microfibrils torn longitudinally, tangled, or having a mesh-like structure. Cellulose nanofibers themselves are known and commercially available. There are no particular limitations on the type of plant from which cellulose nanofibers are made. Materials that have been subjected to surface modification, chemical modification, or other treatments to improve dispersion stability in water can also be used as the raw material. Furthermore, the aqueous dispersion for design purposes of the present invention can also be obtained by using an aqueous dispersion, dried powder, or wet cake of cellulose nanofibers as the cellulose nanofiber. Commercially available cellulose nanofibers include, for example, Cellenpia (registered trademark) TC-01A (1 wt% aqueous dispersion of cellulose nanofibers) and Cellenpia (registered trademark) CS-01 (dried powder of cellulose nanofibers) manufactured by Nippon Paper Industries Co., Ltd.

[0024] The content (concentration) of the cellulose nanofibers in the aqueous dispersion for design use of the present invention is not particularly limited and can be appropriately set depending on the purpose. For example, the content of the cellulose nanofibers in the aqueous dispersion for design use of the present invention is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more, from the viewpoint of exhibiting the desired viscosity and optical properties. Furthermore, from the viewpoint of maintaining high transparency, the content is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, even more preferably 1% by mass or less, and even more preferably 0.7% by mass or less. The above is shown as a preferred range, preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass, even more preferably 0.2 to 5% by mass, even more preferably 0.2 to 1% by mass, and even more preferably 0.3 to 0.7% by mass.

[0025] -Fiber width- The fiber width (average value) of the cellulose nanofibers used in the present invention is preferably 3 to 50 nm, more preferably 3 to 25 nm, and even more preferably 3 to 10 nm. By setting the fiber width to 50 nm or less, the occurrence of Mie scattering, which causes a decrease in transparency, can be suppressed, thereby improving the transparency of the water dispersion for design use of the present invention. Note that, for example, when the water dispersion for design use of the present invention is used to express fog in atmospheric expression or turbid water in water expression, cellulose nanofibers having a fiber width of more than 50 nm can be used alone or in combination with cellulose nanofibers having the above-mentioned preferred fiber width. The fiber width can be measured by a known and commonly used method using scanning electron microscope observation, transmission electron microscope observation, etc. When using commercially available cellulose nanofibers, values ​​disclosed by the manufacturers may be used.

[0026] -Fiber length- The fiber length (average value) of the cellulose nanofibers used in the present invention is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 10 μm or less. Furthermore, the fiber length (average value) is usually 500 nm or more, and may be 1 μm or more, or may be 5 μm or more. By keeping the fiber length 100 μm or less, the occurrence of Mie scattering can be suppressed, and the transparency of the aqueous dispersion for design use of the present invention can be maintained at a high level. The fiber length can be measured by a known and commonly used method using scanning electron microscope observation, transmission electron microscope observation, etc. When using commercially available cellulose nanofibers, values ​​disclosed by the manufacturers may be used.

[0027] -Aspect ratio- The aspect ratio (fiber length / fiber width) of the cellulose nanofibers used in the present invention is preferably at least 10, more preferably at least 20. By making the aspect ratio at least 10, it becomes easier to form a gel structure, and sufficient viscosity can be obtained to hold the display object at a specific position within the design aqueous dispersion.

[0028] (water) The water dispersion for design purposes of the present invention contains water as a dispersion medium. There are no particular limitations on the water used; in addition to ordinary tap water, purified water, such as distilled water or ion-exchanged water, from which ionic components have been removed, can also be used. The water used in the water dispersion for design purposes of the present invention is preferably highly transparent. For example, the transmittance of light at a wavelength of 500 nm passing through a distance of 1 cm is preferably 80% or more, more preferably 90% or more, even more preferably 95% or more, and even more preferably 99% or more. Light transmittance can be measured, for example, by the method described in the Examples. From a design perspective, if you want to express water with low transparency, such as mud or a swamp, or an atmosphere with low transparency, such as a storm, thick fog, or dust, you can use cloudy water or colored water as a dispersion medium.

[0029] There is no particular limitation on the pH of the aqueous dispersion for design use of the present invention. From the viewpoint of long-term storage of exhibit objects (models, etc.) and the safety of workers during installation of the exhibit objects, the pH of the aqueous dispersion for design use of the present invention is preferably adjusted to a range from weakly acidic to weakly alkaline, i.e., 4 to 11, at the temperature at which the exhibit objects will be placed.

[0030] From the viewpoint of fixing the position of an object to be exhibited, such as a model, in the aqueous dispersion for design use of the present invention, the aqueous dispersion for design use of the present invention preferably has a high viscosity within a certain range. -1 The viscosity measured at 200°C is preferably 200 to 10,000 mPa·s, more preferably 400 to 8,000 mPa·s, and even more preferably 800 to 6,000 mPa·s. By setting the viscosity of the aqueous dispersion for design use of the present invention within the above range, the display object can be fixed at any position in the display case, it can be easily transported to the display case, and any trapped air bubbles can be easily removed.

[0031] (Other ingredients) The aqueous dispersion for design use of the present invention may contain other components within the range that does not impair the effects of the present invention. For example, known and commonly used additives such as colorants such as dyes and pigments, dispersants, surfactants, antifoaming agents, and wetting agents may be used. The aqueous dispersion for design purposes of the present invention can also contain a water-swellable clay mineral (preferably smectite) as a dispersoid. By incorporating the clay mineral, the state of Rayleigh scattering and the state of manifestation of polarized color can be adjusted within a range that does not impair the effects of the present invention.

[0032] Furthermore, the aqueous dispersion for design purposes of the present invention can contain other solvents (solvents) as long as they do not impair the effects of the present invention. In the present invention, a mixture of water and a solvent other than water is used as a dispersion medium for cellulose nanofibers. This also applies to the aqueous dispersion in the multicolor light generating device described below. The inclusion of other solvents can change the viscosity and refractive index of the aqueous dispersion to adjust light scattering properties, increase the boiling point of the dispersion medium to suppress volatilization, or lower the freezing point to suppress freezing. Examples of such other solvents include solvents that are easily miscible with water, solvents with a refractive index higher than that of water, solvents with a high boiling point that are less likely to volatilize, solvents with a low freezing point that are less likely to freeze, highly transparent solvents, and solvents with low toxicity and odor. Specific examples include ethylene glycol, propylene glycol, glycerol, polyethylene glycol, polypropylene glycol, and various amine-based organic solvents. When the aqueous dispersion for design use of the present invention contains the other solvent, the content of the other solvent is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, of the total dispersion medium.

[0033] [Method for producing aqueous dispersion for design use] The aqueous dispersion for design use of the present invention can be produced by mixing cellulose nanofibers, which are dispersoids, with a dispersion medium containing water and dispersing them in the dispersion medium. There are no particular restrictions on the method for dispersing cellulose nanofibers in water, and dispersion can be carried out using a known, commonly used batch or continuous dispersion device, etc., as appropriate, taking into account the viscosity of the target dispersion. Furthermore, in this dispersion process, components other than the cellulose nanofibers described above can also be blended, if necessary. Furthermore, for example, when the cellulose nanofibers are already dispersed in a liquid medium, the dispersion can be mixed with a liquid medium containing water or diluted with a liquid medium containing water to obtain the aqueous dispersion for design purposes of the present invention in which the cellulose nanofibers are dispersed in the liquid medium at the desired content.

[0034] (Degassing process of aqueous dispersion for design) The water dispersion for design use of the present invention may be subjected to a degassing treatment to remove air bubbles. The degassing method is not particularly limited as long as it can remove air bubbles from the water dispersion for design use of the present invention. Examples include a method of degassing under reduced pressure while stirring, a method of degassing under stirring using a planetary mixer, and ultrasonic irradiation. The timing of the degassing step may be such that the dispersion after dispersing the cellulose nanofibers is degassed, or the water before dispersing the cellulose nanofibers may be degassed in advance by a reduced pressure treatment or the like to suppress the generation of air bubbles during the dispersion of the cellulose nanofibers.

[0035] [Polychromatic light generation device] Another embodiment of the present invention is a multicolor light generating device. An aqueous dispersion obtained by dispersing cellulose nanofibers in water can be used as a component of the multicolor light generating device. That is, the multicolor light generating device of the present invention comprises the aqueous dispersion and a polarizing plate disposed on the front side of the aqueous dispersion, and is used by irradiating the aqueous dispersion with polarized light from the rear side. By irradiating the multicolor light generating device with light from the rear side, the light that passes through the aqueous dispersion and the polarizing plate disposed on the front side in this order exhibits a variety of polarized colors (interference colors, polychromatic light). Each component of the multi-color light generating device of the present invention will be described below.

[0036] (Aqueous dispersion obtained by dispersing cellulose nanofibers in water) The aqueous dispersion used in the multi-color light generating device of the present invention is an aqueous dispersion obtained by dispersing cellulose nanofibers in water. The aqueous dispersion may have the same structure as the aqueous dispersion for design use of the present invention described above, except that its use is not limited to the spatial expression of exhibits. Furthermore, the aqueous dispersion used in the multi-color light generating device of the present invention can be obtained by the same manufacturing method as the aqueous dispersion for design use of the present invention described above. The aqueous dispersion may be filled in, for example, a highly transparent glass or plastic container, and may be placed so as to be in direct contact with a polarizing plate (for example, sandwiched between two polarizing plates).

[0037] (polarizing plate) The polarizing plate used in the multicolor light generating device of the present invention can be any polarizing plate having a polarization property that selectively transmits light having a specific vibration direction. Examples include an iodine-based polarizing plate in which an iodine compound is adsorbed onto a polyvinyl alcohol film and aligned, and a dye-based polarizing plate in which a dichroic dye or the like is used instead of the iodine compound. There is a trade-off between the single transmittance and the degree of polarization of a polarizing plate, with a high transmittance resulting in a low degree of polarization, and a low transmittance resulting in a high degree of polarization. Generally, a transmissive polarizing plate has a transmittance of 35 to 50% and a degree of polarization of about 70 to 100%, while a semi-transmissive polarizing plate has a transmittance of 5 to 25% and a degree of polarization of about 70 to 100%, both of which can be appropriately selected depending on the purpose of use of the present invention. The shape of the polarizing plate can be appropriately set depending on the size of the aqueous dispersion.

[0038] (polarization axis angle of polarizer) The multicolor light generating device of the present invention preferably includes a polarizing plate (front-side polarizing plate) disposed on the front side of the aqueous dispersion and a polarizing plate (rear-side polarizing plate) disposed on the rear side of the aqueous dispersion. In this preferred configuration, polarized light that has passed through the rear-side polarizing plate enters the rear side of the aqueous dispersion, exits the front side of the aqueous dispersion, and then passes through the front-side polarizing plate to generate multicolor light. The angle between the polarization axes (transmission axes) of these two polarizing plates (the angle between the polarization axis of the polarizing plate disposed on the rear side of the aqueous dispersion and the polarization axis of the polarizing plate disposed on the front side of the aqueous dispersion) is not particularly limited, and the polarization axes of the two polarizing plates can be arranged so that they have different angles. That is, the angle between the polarization axes of the polarizing plate and the polarizing plate can be set to between 0° (parallel Nicols) and 90° (crossed Nicols). From the viewpoint of achieving more vivid polarized colors, the angle is preferably greater than 0°. Furthermore, since the aspect of the polarized color changes depending on the angle, at least one of the polarizing plates may be moved or rotated at a constant speed, for example.

[0039] (light source) The type of light passing through (transmitting) the multicolor light generating device of the present invention is not particularly limited. For example, it may be natural light such as sunlight, or light from a light source such as an LED (light-emitting diode), fluorescent lamp, incandescent lamp, electroluminescent tube, organic electroluminescence (EL), or inorganic electroluminescence (EL). In particular, the light is preferably light from a white LED, from the viewpoint of high light intensity and beautiful expression of polarized colors. If the light contains polarized light, the multicolor light generating device of the present invention can be used as is. If the light does not contain polarized light, the multicolor light generating device of the present invention can be used with a polarizing plate provided on the back side of the aqueous dispersion. Furthermore, if the light is from a light source, for example, it is also preferable to place a white sheet made of light-scattering paper or plastic with a certain degree of transparency between the light source and the dispersion in order to uniformize the intensity of the irradiated light.

[0040] [Exhibits] Yet another embodiment of the present invention is an exhibit using the water dispersion for design use of the present invention or the multi-color light generating device of the present invention. The exhibit of the present invention may have an exhibit object arranged within it (the exhibit may have an exhibit object and a space in which the exhibit object is arranged, and this space may be represented using the water dispersion for design use of the present invention or the multi-color light generating device of the present invention), or it may be an exhibit without an exhibit object such as a model (the water dispersion for design use or the multi-color light generating device itself is the exhibit object). Furthermore, for example, by providing an uneven surface to the water dispersion for design use, it is possible to represent splashes of waves, ripples, and the like. The type of the exhibit object is not particularly limited and can be determined appropriately depending on the purpose of the exhibit. Examples include models or real objects such as aircraft, helicopters, balloons, airships, kites, drones, aquatic creatures, submarines, missiles, robots, space battleships, UFOs, birds, insects, clouds (cotton), leaves, the moon, and time machines. In the exhibit of the present invention, the liquid surface (upper surface) of the aqueous dispersion can be covered with a transparent material such as a transparent plastic plate or transparent film to prevent water from evaporating, allowing the exhibit to be displayed for a long period of time.

[0041] When the water dispersion for design purposes of the present invention is used as an exhibit for representing water, the atmosphere, or space, for example, the water dispersion for design purposes of the present invention can be poured into a container (display case) with at least one transparent surface, such as a plastic case or glass case, and an exhibit object such as a model placed therein can be placed in a realistic spatial representation. By adjusting the cellulose nanofiber concentration in the water dispersion for design purposes of the present invention within the preferred range described above, the water dispersion for design purposes of the present invention can be made into a highly thixotropic dispersion. Such highly thixotropic dispersions have the property of being easily pourable into containers by applying shear stress to the dispersion, such as by stirring, but becoming more viscous when left at rest. Therefore, by leaving the dispersion to stand for a certain period of time after pouring, a large model or the like can be fixed at any position in the water dispersion without the use of fixing devices. Furthermore, by ensuring that the layer thickness of the aqueous dispersion for design purposes of the present invention is at least a certain level, the light scattering properties unique to cellulose nanofibers can be used to make the aqueous dispersion appear to have a certain depth of water or a bluish color like the blue sky, without the need to color the aqueous dispersion. Furthermore, by adjusting the light path length, it is possible to create sunrises and sunsets. Furthermore, by irradiating the aqueous dispersion with light from a light-emitting diode, fluorescent lamp, incandescent lamp, or the like from the outside of the transparent container, light scattering occurs due to the cellulose nanofibers dispersed in the aqueous dispersion for design purposes of the present invention, and the light path of the irradiated light can be expressed, creating a phenomenon similar to crepuscular rays (angel's ladder).

[0042] When the decorative water dispersion of the present invention is used as an exhibit to create an other-dimensional expression, for example, the decorative water dispersion of the present invention can be poured into a container (display case) such as a plastic case or a glass case that has at least a portion that is transparent in the direction in which light passes, an object to be exhibited such as a model is placed therein, and a polarizing plate (front-side polarizing plate) is arranged on the front side of the decorative water dispersion, and preferably a polarizing plate (rear-side polarizing plate) is also arranged on the back side of the decorative water dispersion to create an exhibit. By irradiating the exhibit from the back side and passing the light through the back-side polarizing plate, the decorative water dispersion, and the front-side polarizing plate in this order, brilliantly colorful polarized colors appear, creating an other-dimensional expression.

[0043] When the multicolor light generating device of the present invention is used as an exhibit, for example, an object to be exhibited may be placed in the aqueous dispersion of the multicolor light generating device. Examples of the object to be exhibited include those described above. Polarized colors generated by the multicolor light generating device can also be projected onto a wall or the like.

[0044] [Lighting equipment] Yet another embodiment of the present invention is an illumination device using the multicolor light generating device of the present invention. The illumination device of the present invention is an illumination device comprising the multicolor light generating device of the present invention and the light source device. The light source device can be the same as the light source device described above. When the light emitted from the light source device is polarized (consisting only of light vibrating in a specific direction, or a high proportion of light vibrating in that direction), the light source device can be arranged so that the light can pass (transmit) through an aqueous dispersion of cellulose nanofibers and a polarizing plate arranged in front of the aqueous dispersion, in that order. When the light emitted from the light source device is unpolarized or natural light (light that does not vibrate in a specific direction but vibrates in random directions), the light source device is arranged so that the light can pass (transmit) through a polarizing plate arranged behind the aqueous dispersion, the aqueous dispersion, and a polarizing plate arranged in front of the aqueous dispersion, in that order.

[0045] [Dispersant for spatial expression of exhibits] The dispersant for spatial expression of exhibits of the present invention (hereinafter also referred to as the "dispersant of the present invention") contains cellulose nanofibers. The preferred form of this cellulose nanofiber is the same as the cellulose nanofiber described in the aqueous dispersion for design purposes of the present invention. The dispersant of the present invention may consist solely of cellulose nanofibers, or may contain components other than cellulose nanofibers. Examples of components other than cellulose nanofibers include the "other components" described above in the aqueous dispersion for design purposes of the present invention. Specifically, the dispersant may contain colorants, dispersants, surfactants, antifoaming agents, lubricants, etc. The dispersant may also contain a liquid medium such as water. When the dispersant of the present invention contains a liquid medium, the aqueous dispersion for design purposes of the present invention can be obtained by further diluting the dispersant of the present invention with a medium such as water. When the dispersant of the present invention does not contain a liquid medium, the aqueous dispersion for design purposes of the present invention can be obtained by mixing the dispersant of the present invention with a liquid medium containing water and dispersing cellulose nanofibers in the liquid medium. The content of cellulose nanofibers in the dispersant of the present invention is preferably 30% by mass or more, more preferably 40% by mass or more, also preferably 50% by mass or more, preferably 60% by mass or more, preferably 70% by mass or more, preferably 80% by mass or more, and may be 90% by mass or more. [Example]

[0046] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0047] Details of the materials used in this example are as follows: (Cellulose nanofiber) Cellenpia (registered trademark, sample name: TC-01A, 1 wt% aqueous dispersion of cellulose nanofiber, manufactured by Nippon Paper Industries Co., Ltd.) (hereinafter also referred to as "CNF1") Cellenpia (registered trademark, sample name: CS-01, dried powder of cellulose nanofiber, manufactured by Nippon Paper Industries Co., Ltd.) (hereinafter also referred to as "CNF2") The fiber widths of all the above cellulose nanofibers published by the manufacturers were 3 to 20 nm and fiber lengths were 0.5 to 1 μm. (clay minerals) Sumecton-SWN (product name: synthetic hectorite, manufactured by Kunimine Industries Co., Ltd., particle size: 70 nm) (others) Distilled water (ionic conductivity 0.5 μS / cm)

[0048] [Creating a diorama] Example 1 The above CNF1 and distilled water were placed in a 1 L container so that the total amount was 500 g, in the blending ratio (blending composition) shown in Table 1 below. The mixture was stirred for 30 minutes at 140 rpm using a Three-One Motor (manufactured by Shinto Scientific Co., Ltd.) equipped with an anchor blade, to obtain a transparent, viscous aqueous dispersion of cellulose nanofibers with a concentration of 0.67% by mass (aqueous dispersion for design purposes of the present invention). The resulting aqueous dispersion was shaken by hand to reduce viscosity and poured into a cylindrical transparent glass container (inner diameter 55 mm x height 150 mm) to a height of 130 mm. Cotton (to represent clouds) and two aircraft models (Japanese Army Type 100 heavy bomber, 1 / 700 scale, manufactured by Pit-Road Co., Ltd.) were then placed with tweezers in the positions shown in Figure 1. Any air bubbles that occurred during placement were removed with a dropper. The models could be easily sunk and remained in place even after the tweezers were removed. A transparent plastic plate was placed on top of the container to create the diorama of Example 1.

[0049] (Examples 2 and 3) Dioramas of Examples 2 and 3 were obtained in the same manner as in Example 1, except that the blending composition of the aqueous dispersion used for the diorama was set as shown in Table 1 below.

[0050] Example 4 The above CNF2 and distilled water were placed in a 1 L container at a total weight of 500 g in the blending ratio (blending composition) shown in Table 1. Using a TK Robomix (manufactured by Tokushu Kika Kogyo Co., Ltd.) equipped with a homogenizer blade, the mixture was run at 3000 rpm for 10 minutes, followed by a 5-minute stop cycle, for a total of three cycles, to obtain a transparent, viscous aqueous dispersion containing 1% by mass of cellulose nanofibers (aqueous dispersion for design purposes of the present invention). The resulting aqueous dispersion was shaken by hand to reduce viscosity and poured into a cylindrical transparent glass container (inner diameter 55 mm x height 150 mm) to a height of 130 mm. A dolphin figurine measuring 60 mm in length and 20 mm in diameter was then placed in the center of the liquid using tweezers. Any air bubbles that formed during placement were removed using a dropper. The figurine was easily sunk into the container, and remained fixed in place even after the tweezers were removed. A transparent plastic plate was placed on top of the container to create the diorama of Example 4.

[0051] Example 5 A diorama of Example 5 was obtained in the same manner as in Example 4, except that the blending composition of the aqueous dispersion used for the diorama was the blending composition shown in Table 1 below.

[0052] (Comparative Example 1) The base resin and curing agent (resin liquid) of Crystal Resin NEO (Ohashi Paint Co., Ltd., two-component curing epoxy resin) were placed in a sealed container at a mixing ratio of 2:1 and mixed as in Example 1. The resulting mixture (resin) was poured into a cylindrical transparent glass container (inner diameter 55 mm x height 150 mm) to a height of 70 mm, taking care to minimize air bubble inclusion, and allowed to cure. After the resin cured, the aircraft model (Japanese Army Type 100 Heavy Bomber, 1 / 700 scale, Pit Road Co., Ltd.) was placed in a central position on the cured resin. A mixture was prepared as described above, and the mixture was slowly poured into the transparent container to a height of 70 mm from the surface of the cured resin (140 mm from the bottom of the container). The mixture was then left to stand at room temperature for 48 hours to cure the resin. A transparent plastic plate was placed on top of the container to create a diorama for Comparative Example 1.

[0053] (Comparative Example 2) A diorama of Comparative Example 2 was obtained in the same manner as Comparative Example 1, except that NEW Modeling Water (product number: MW-01, modified silicone resin, manufactured by Koei-do Co., Ltd.) was used instead of the Crystal Resin NEO.

[0054] (Comparative Example 3) Realistic Water (product number 24-338, manufactured by Kato Corporation, one-component moisture-curing acrylic resin) was filled into the same transparent container as in Comparative Example 1 to a height of 10 mm from the bottom, and then left to stand for one hour to allow the curing reaction to proceed. This procedure was repeated six times to fill the container with Realistic Water to a height of 70 mm, and then an aircraft model (Japanese Army Type 100 heavy bomber, 1 / 700 scale, manufactured by Pit Road Co., Ltd.) was placed in the container as in Comparative Example 1. Realistic Water was filled into the container in 10 mm increments from the bottom to a height of 140 mm, as described above, and the container was left to stand at room temperature for 24 hours to allow the resin to cure. A transparent plastic plate was placed on top of the container to create a diorama for Comparative Example 3.

[0055] Comparative Example 4 A uniform, nearly transparent aqueous solution was obtained in the same manner as in Example 1, except that sodium salt of carboxymethylcellulose (product number: 1190, manufactured by Daicel Miraize Co., Ltd.) was used instead of cellulose nanofibers. Using this aqueous solution, cotton and an aircraft model (Japanese Army Type 100 heavy bomber, 1 / 700 scale, manufactured by Pit Road Co., Ltd.), which were the display objects, were submerged in the same positional relationship using tweezers in the same manner as in Example 1. A transparent plastic plate was placed on top of the container to obtain a diorama of Comparative Example 4.

[0056] [evaluation]

[0057] (Evaluation of light transmittance) The aqueous dispersions, aqueous solutions, or pre-cured resins used to prepare the dioramas in Examples 1 to 5 and Comparative Examples 1 to 4 were poured into 1 cm wide plastic cells. The resins used in Comparative Examples 1 to 3 were completely cured in the plastic cells by carrying out the same curing reaction as in Comparative Examples 1 to 3. The light transmittance (%) of these at a wavelength of 500 nm was measured using a spectrophotometer ASV11D-H (manufactured by AS ONE Corporation).

[0058] (presence or absence of bubbles) The number of large bubbles that were clearly visible to the naked eye was counted in the dioramas of Examples 1 to 5 and Comparative Examples 1 to 4, and the results were evaluated based on the following evaluation criteria. A large number of bubbles means that the design of the exhibit is inferior. -Evaluation criteria- ○: 4 or fewer visible bubbles △: Visible bubbles: 5 to 9 ×: 10 or more visible bubbles

[0059] (Evaluation of optical characteristics 1 (presence or absence of optical path generation)) White light was irradiated from above the dioramas of Examples 1 to 5 and Comparative Examples 1 to 4 using a clip light (product number: CLC40X01BK, manufactured by Yazawa Corporation) equipped with a 60W daylight white LED bulb as the light source. The light source was positioned approximately 5 cm above the top surface of the diorama, and white light was irradiated onto a certain area above the diorama. When each diorama was viewed from the front (front), the presence or absence of light streaks (light paths, Tyndall phenomenon) in the aqueous dispersion, resin, or aqueous solution was visually observed. The presence or absence of light paths was marked "Good" and the absence or presence of light streaks was marked "Poor."

[0060] (Evaluation of optical properties 2 (presence or absence of blue coloring)) Dark gray background paper was placed on the back of the dioramas of Examples 1 to 5 and Comparative Examples 1 to 4, and white light was irradiated onto the entire top of each diorama from above using a white LED light (product number: Light Up 300, manufactured by Suisaku Co., Ltd.) as a light source, and the color tone of the aqueous dispersion, resin, or aqueous solution was observed from the front (front). If a blue color was developed due to light scattering, it was marked as "Good", and if no color was developed, it was marked as "Poor". Photographs of the dioramas of Examples 1 and 5, when illuminated with white LED lights on the entire top surface, are shown in FIG. 1(a) and FIG. 2(a), respectively.

[0061] (Evaluation of optical properties 3 (presence or absence of polarization color)) A horizontally long white LED light (product number: Light Up 300, manufactured by Suisaku Co., Ltd.) was fixed to a cardboard approximately 1 mm thick as a support, with the long side facing the desk surface. Next, a light diffusion plate (0.75 mm white plastic plate, manufactured by Seria Co., Ltd., opaque PP sheet) was placed in contact with the light-emitting surface of the white LED light to form a light source device. Note that this light diffusion plate is a light-diffusing and light-transmitting plate that diffuses and transmits light. Furthermore, the light emitted from the LED light is not polarized, but rather light that vibrates in various directions. A rear polarizing plate (experimental polarizing plate D20-1883, manufactured by Narica Co., Ltd., 0.2 mm thick, 250 mm × 250 mm) was placed in front of the light source device (viewing side). Next, a diorama of each example and comparative example was placed in front of the rear polarizing plate, and a polarizing plate identical to the rear polarizing plate (front polarizing plate) was placed in front of the transparent container so that it was at a 90° angle (crossed Nicols) relative to the slit angle of the viewing polarizing plate, thereby forming a multicolor light generating device (illumination device). The LED light on the back was turned on, and the multicolor light generating device was visually observed from the front. If a polarized color was observed, it was evaluated as "Good", and if no polarized color was observed, it was evaluated as "Poor". Photographs of the dioramas of Examples 1 and 5 when the LED lights on the backside are turned on are shown in FIG. 1(b) and FIG. 2(b), respectively.

[0062] The results obtained are summarized in the following Tables 1 and 2. The amounts blended in the tables below are in parts by mass (mass ratio).

[0063] [Table 1]

[0064] [Table 2]

[0065] The dioramas in Comparative Examples 1 to 4, which used curable resin or aqueous solution of water-soluble resin, all had sufficient light transmittance. However, the dioramas in Comparative Examples 1 to 3, which used curable resin, had air bubbles that could not be removed, and there were more than 10 visible air bubbles. Furthermore, none of the dioramas in Comparative Examples 1 to 4 produced a light path when irradiated with light, and they did not exhibit blue coloring due to Rayleigh scattering or polarization. Furthermore, because curable resin was used in Comparative Examples 1 to 3, the models could not be recovered or reused once installed and cured. Furthermore, the curable resin used in Comparative Examples 1 to 3 did not allow cotton to be spread out like a cloud, making them unusable as exhibits. Even if cotton could be placed, the resin would have to be filled and cured three times, which was expected to result in poor workability.

[0066] In contrast, in the dioramas of Examples 1 to 5, which used the water dispersion for design purposes of the present invention, the light path was confirmed by light irradiation, and even though the water dispersion for design purposes was uncolored, it showed blue coloring due to light scattering and polarized color. Furthermore, the water dispersion for design purposes had a light transmittance of 85% or more, showing transparency equal to or greater than that of conventional cured resins. Furthermore, due to the manifestation of thixotropy, the positions of multiple models could be maintained at any desired position for a long period of time while left stationary, and air bubbles could be virtually eliminated by removing them. Furthermore, the material could be moved and recovered. By using the aqueous dispersion for design use of the present invention, it was possible to realize an atmospheric expression of blue sky in the dioramas of Examples 1 to 3 in which an aircraft model was installed, and an underwater expression of blue sky in the dioramas of Examples 4 and 5 in which a dolphin figure was installed. Furthermore, by placing polarizing plates in front of and behind the dioramas of Examples 1 to 5, it was possible to realize an expression in which an aircraft or a dolphin is placed in an other-dimensional space.

Claims

1. A design aqueous dispersion made by dispersing cellulose nanofibers in water, intended for use as a spatial expression for exhibits.

2. The water dispersion for design purposes according to claim 1 , wherein the spatial expression is a water expression, an atmospheric expression, a space expression, or an other-dimensional expression of an exhibit.

3. The aqueous dispersion for design purposes according to claim 2, wherein the cellulose nanofibers have a fiber width of 3 to 50 nm.

4. The aqueous dispersion for design purposes according to claim 3, wherein the content of the cellulose nanofibers is 0.1 to 20% by mass.

5. An exhibit in which the decorative aqueous dispersion according to any one of claims 1 to 4 is used as a spatial expression.

6. A multicolor light generating device comprising an aqueous dispersion in which cellulose nanofibers are dispersed in water, and a polarizing plate disposed on the front side of the aqueous dispersion, the device being used by irradiating polarized light onto the aqueous dispersion from the rear side.

7. The multi-color light generating device according to claim 6, wherein the cellulose nanofibers have a fiber width of 3 to 50 nm.

8. The multi-color light generating device according to claim 7, wherein the content of the cellulose nanofiber is 0.1 to 20% by mass.

9. 9. The multicolor light generating device according to claim 8, further comprising a polarizing plate disposed on the rear side of the aqueous dispersion.

10. The multi-color light generating device according to claim 9 , wherein the angle of the polarization axis of the polarizing plate arranged on the front side of the aqueous dispersion is different from the angle of the polarization axis of the polarizing plate arranged on the back side of the dispersion.

11. An exhibit comprising the multicolor light generating device according to any one of claims 6 to 10.

12. An illumination device comprising the multicolor light generating device according to any one of claims 6 to 10 and a light source device.

13. A dispersant containing cellulose nanofibers for spatial expression of exhibits.

14. The dispersant for spatial expression according to claim 13, wherein the cellulose nanofibers have a fiber width of 3 to 50 nm.

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