JP2021007905A - Structure, and production method of structure - Google Patents

Abstract

To provide a structure that is able to contain more substances to be included and has high ability for holding the substances to be included, and a production method of the structure.SOLUTION: There are provided a structure that includes a film containing cellulose nanofiber and a closed space formed by the film and contains substances to be included in the closed space, and a production method of the structure.SELECTED DRAWING: Figure 1

Description

The present invention relates to a structure and a method for manufacturing the structure.

It has been proposed to hold a substance that performs a specific function in a retainer and use it for various purposes. For example, in order to meet the demand for energy saving, a heat insulating material containing a heat storage substance is being studied as a heat insulating material used for building materials and interior materials. In addition, a soundproof / vibration-proof material in which a material having a soundproofing or vibration-proofing function is held by a holding body has also been proposed.

For example, Patent Document 1 describes a heat storage sheet obtained by impregnating a fiber base material with a heat storage material composition containing paraffin and a polymer binder component and being solid in a temperature range of 100 ° C. or lower. Further, Patent Document 2 describes that felt impregnated with asphalt is used as a soundproofing material.

Japanese Unexamined Patent Publication No. 2014-125626 Japanese Patent No. 6376543

However, there are various problems in the conventionally proposed retainer that retains a substance that fulfills a specific function. For example, since the heat storage sheet described in Patent Document 1 is produced by impregnating cloth or paper with paraffin, there is a problem that paraffin flows and bleeds out from the heat storage sheet to contaminate the surroundings. The soundproofing material described in Patent Document 2 has a similar problem. That is, when the substance to be retained exhibits fluidity in the usage environment, there is a problem that it becomes difficult to maintain the substance.
Further, in the conventionally proposed retainer holding a substance that fulfills a specific function, the content of the substance is increased to enhance the desired performance or the sensitivity of the desired performance. There is room for improvement in terms of doing so. For example, the conventional heat storage sheet has room for improvement in that the content of the heat storage substance is increased to improve the heat storage property and the heat storage response is improved.

The present invention has been made in view of the above problems, and provides a structure and a method for producing a structure, which can contain a larger amount of the encapsulated substance and have high retention of the encapsulated substance. The task is to do.

As a result of diligent studies to solve the above problems, the present inventors have obtained a structure including a membrane containing cellulose nanofibers and a closed space composed of the membrane, and the structure is covered in the closed space. The present invention has been completed by finding that the above-mentioned problems can be solved by a structure having an inclusion substance.
That is, the present invention provides the following [1] to [15].
[1] A structure including a membrane containing cellulose nanofibers and a closed space composed of the membrane, and having an encapsulated substance in the closed space.
[2] The structure according to [1], wherein the encapsulated substance is a liquid or a solid at normal temperature and pressure.
[3] The structure according to the above [1] or [2], wherein the inclusion substance has a melting point of −100 ° C. to + 90 ° C.
[4] The first surface of the film faces the contained substance, and the second surface opposite to the first surface of the film is a substance, gas, or solid having the same composition as the contained substance. The structure according to any one of the above [1] to [3], which is in contact with at least one of them.
[5] The structure according to any one of the above [1] to [4], wherein the content of the contained substance is 30 to 98% by mass with respect to the total volume of the structure.
[6] The structure according to any one of the above [1] to [5], which has a plurality of the closed spaces.
[7] The structure according to the above [6], wherein a set of adjacent closed spaces among the plurality thereof share the membrane.
[8] The structure according to the above [6] or [7], wherein the structure has a sheet shape.
[9] The structure according to the above [8], wherein the structure has a thickness of 0.5 to 300 μm.
[10] The structure according to the above [8] or [9], which is self-supporting by itself.
[11] The structure according to any one of [6] to [10] above, wherein the average of the maximum ferret diameters of the plurality of closed spaces of the structure is 1 μm to 60 μm.
[12] A structure with a support, wherein the structure according to any one of the above [1] to [11] is provided on the support.
[13] The method for producing a structure according to any one of the above [1] to [12].
The inclusion substance is added to the dispersion liquid in which the cellulose nanofibers are dispersed, and the inclusion substance is added.
The dispersion liquid to which the encapsulated substance is added is stirred at a temperature at which the encapsulated substance becomes liquid, and at least a part of the encapsulated substance is in a space surrounded by an outer shell containing the cellulose nanofibers. A method for producing a structure, which comprises producing the particles incorporated in the structure to obtain the structure.
[14] The method for producing a structure according to the above [13], wherein the encapsulated substance is heated to change the phase from a solid to a liquid, and then added to the dispersion.
[15] The dispersion liquid containing the particles is applied onto the support to form a coating layer.
The method for producing a structure according to the above [13] or [14], wherein the coating layer is dried to form the structure.

According to the present invention, it is possible to provide a structure and a method for producing a structure, which can contain a larger amount of the encapsulated substance and have high retention of the encapsulated substance.

It is a schematic diagram which shows the structural example of the sheet-like structure which is one Embodiment of the structure of this invention. FIG. 1A is an external view of a configuration example of a sheet-like structure. FIG. 1B is a partially enlarged view of the surface of the sheet-like structure of FIG. 1A. It is an enlarged schematic diagram which shows the manufacturing method of a structure. FIG. 2A is a schematic side view showing a state in which the substance-encapsulating particle-containing composition is applied onto the support. FIG. 2B is an enlarged plan view of a coating layer of the substance-encapsulating particle-containing composition formed on the support. FIG. 2C is an enlarged plan view of the substance-encapsulating layer obtained by drying the coating layer of the substance-encapsulating particle-containing composition.

<Structure of structure>
The structure according to the embodiment of the present invention is a structure including a membrane containing cellulose nanofibers (hereinafter, abbreviated as “CNF”) and a closed space composed of the membrane, and is contained in the closed space. It is a structure having an encapsulated substance.
As used herein, the term "closed space composed of a membrane containing CNF" means a closed space surrounded by a membrane containing CNF in all directions such as above, below, and sideways. As will be described later, the film containing CNF is a dense film but has fine voids. Therefore, if the space surrounded by the membrane containing CNF does not lead to an opening having a size exceeding the fine voids, it corresponds to "a closed space composed of a membrane containing CNF".
The shape of the structure is not particularly limited, and for example, a dispersion liquid after producing particles incorporating a substance to be encapsulated in a closed space composed of a membrane containing CNF (hereinafter, "material-encapsulating particle-containing composition"). ”) Can be made into an arbitrary shape by a method such as putting it in a molding die and drying it. The composition containing substance-encapsulating particles will be described in detail later.
A preferred embodiment of the structure of the present invention is a sheet-like structure. The sheet-like structure can be easily produced in large quantities by applying the substance-encapsulating particle-containing composition to the support and drying it, and can be used for a wide range of purposes.
In the following description, the "material-encapsulating particle-containing composition" may be simply referred to as "composition".
Hereinafter, the structure according to the embodiment of the present invention will be specifically described with reference to the sheet-like structure as an example. Note that FIGS. 1 and 2 used in the following description are schematic views and are exaggerated for ease of understanding. The number and size of the enclosed spaces, the thickness of the structure, and the like are also schematically shown, and these are not limited by the drawings.

FIG. 1 is a schematic view showing a configuration example of a sheet-like structure according to an embodiment of the structure of the present invention. FIG. 1A is an external view of a configuration example of a sheet-like structure. FIG. 1B is an enlarged plan view of a part of FIG. 1A.
As shown in FIG. 1 (A), in the above configuration example, the substance inclusion layer 31 having a plurality of closed spaces and having an encapsulated substance in each closed space is laminated on one surface of the support 40. ing. The substance inclusion layer 31 is also a sheet-like structure. Then, in the example shown in FIG. 1 (A), the support 40 and the substance inclusion layer 31 constitute the structure 50 with the support. In FIG. 1A, the thickness of the sheet-like structure 31 is indicated by reference numeral L.
As will be described later, the support 40 may not be provided. When there is no support 40, it becomes a single sheet-like structure 31.

FIG. 1 (B) is an enlarged view of a part of the surface of the substance-encapsulating layer 31, which is indicated by reference numeral P in FIG. 1 (A). As shown by a broken line in FIG. 1B, the structure 31 according to the present embodiment is a structure including a membrane 35 containing a CNF and a plurality of closed spaces 33 composed of the membrane. Then, the encapsulated substance 36 is contained in the closed space 33. From the viewpoint of retaining a larger amount of encapsulated substance, a structure having a plurality of such closed spaces is preferable.
The first surface (inner surface) of the film 35 faces the inclusion material 36, and the second surface (outer surface) of the film 35 opposite to the first surface is the surrounding atmosphere (that is, the surrounding atmosphere). , Gas), support 40 (ie, solid), and at least one of the substances having the same composition as the contained substance facing the first surface, which is contained in the adjacent closed space. ing. Specifically, the film existing on the most surface side of the substance inclusion layer 31 (the surface side opposite to the surface on which the support exists) is in contact with the surrounding atmosphere. Further, the film existing on the most back surface side (the surface side where the support is present) of the substance inclusion layer 31 is in contact with the support. Further, the film 35 existing inside the substance inclusion layer 31 (the region between the surface on the side where the support exists and the surface on the opposite side) and shared by a pair of adjacent closed spaces is one of the films 35. A surface is in contact with an encapsulated substance or air existing in one enclosed space, and the other surface is in contact with an encapsulated substance or air existing in the other enclosed space.
As described above, it is preferable to dispose only at least one of the inclusion substance, the solid and the gas around the membrane containing CNF. By doing so, it is possible to prevent a highly fluid liquid from being present around the film, and as a result, it becomes easy to improve the shape retention of the structure.

The CNF-containing film 35 formed by the manufacturing method described later is considered to be a network-like or fibrous dense film formed by arranging or entwining a plurality of CNFs. Therefore, the encapsulated substance can be held in the closed space 33 surrounded by the membrane 35 containing the CNF. Further, since the membrane 35 containing CNF is a dense membrane of CNF, it has a certain strength without thickening the membrane, and constitutes an enclosed space capable of holding the encapsulated substance inside. be able to. Therefore, elements other than the membrane containing CNF, such as a binder component, are not always required inside the structure, and the abundance ratio of the space in the structure is increased, and the content ratio of the encapsulated substance is increased. Can be done.
Further, if a liquid or a fluid substance is used as the encapsulated substance and this substance is enclosed in a closed space surrounded by a membrane containing CNF, the entire structure can be treated as a solid. Therefore, it becomes easy to carry and handle liquids and fluid substances.

Although it is possible to prepare a CNF porous body by freeze-drying, the production method using freeze-drying has a complicated process and the obtained porous body has a so-called open cell structure. Have. The porous body having such an open cell structure has a problem in the retention of the substance, and there is a problem that the substance to be retained at the time of use bleeds out or contaminates the surroundings.

Further, as shown in FIG. 1 (B), in the sheet-like structure 31, a film 35a containing a CNF is shared between a set of adjacent closed spaces 33a and 33b. In one aspect of the structure of the present invention, from the viewpoint of increasing the sheet strength, it is preferable that a set of adjacent closed spaces among the plurality of closed spaces share at least one membrane as in the structure 31.

In this way, since the encapsulated substance is held in the closed space, for example, when a heat storage substance is used as the encapsulated substance, the heat storage substance stores the amount of heat received from the outside by the structure, thereby storing heat by the structure. Is done. Then, when the temperature of the surrounding environment of the structure becomes low, the amount of heat stored in the structure is released to the outside. The details of the materials used for the membrane 35 and the inclusion substance 36 will be described later.

[Inclusive substances]
The encapsulated substance used in the present invention is a target substance to be retained in a structure, and is, for example, a liquid or solid substance at normal temperature and pressure. Such substances are used for various purposes such as heat storage, heat insulation, heat retention, sound insulation, sound insulation, vibration isolation, high dielectric constant, strain detection, and liquid retention (fragrances, fuels, dangerous substances, cosmetics, drugs, foods, etc.). Used.
As the inclusion substance, a substance having a melting point of −100 ° C. to + 90 ° C. can be used. The melting point of the inclusion material is preferably −100 ° C. or higher, more preferably −75 ° C. or higher, still more preferably −50 ° C. or higher, still more preferably -25 ° C. or higher, still more preferably 0 ° C. or higher, still more preferably. Is + 25 ° C. or higher, particularly preferably + 40 ° C. or higher, and preferably + 90 ° C. or lower, more preferably + 85 ° C. or lower, still more preferably + 80 ° C. or lower, still more preferably + 70 ° C. or lower. When the melting point of the encapsulated substance is in the above temperature range, when the structure is used for heat storage, the structure having the heat storage temperature in a wide temperature range from low temperature to high temperature can be easily manufactured. Further, when the melting point of the contained substance is in the above temperature range, the substance is not significantly separated from the environmental temperature in actual use, so that the substance can be easily contained and retained, and the structure can be easily manufactured.

Examples of substances having a melting point of -100 ° C to + 90 ° C include hydrocarbon-based oily components, natural animal and vegetable fats and oils and semi-synthetic fats and oils, lubricating oils and lubricant compositions, fuel oils, and poorly water-soluble organic solvents. At least one oil content selected from is mentioned.
Hydrocarbon-based oily components include liquid paraffin, light liquid isoparaffin, heavy liquid isoparaffin, vaseline, n-paraffin, isoparaffin, isododecane, isohexadecane, polyisobutylene, hydride polyisobutylene, polybutene, ozokerite, ceresin, and microcrystalin wax. , Paraffin wax, polyethylene wax, polyethylene / polypyrropylene wax, squalane, squalane, pristane, polyisoprene, wax and the like.
Natural animal and vegetable fats and oils and semi-synthetic fats and oils include avocado oil, flaxseed oil, almond oil, sardine oil, eno oil, olive oil, cacao fat, capok wax, kaya oil, carnauba wax, liver oil, candelilla wax, beef fat, beef leg fat, etc. Beef bone fat, hardened beef fat, lanolin oil, whale wax, hardened oil, wheat germ oil, sesame oil, rice germ oil, rice bran oil, sugar cane, southern ka oil, saflower oil, shea butter, lanolin oil, cinnamon oil, jojobaro , Olive squalane, celac resin, turtle oil, soybean oil, brown seed oil, camellia oil, evening primrose oil, corn oil, pork fat, rapeseed oil, Japanese millet oil, lanolin, germ oil, horse fat, persic oil, palm oil, Palm kernel oil, sunflower oil, hardened sunflower oil, sunflower oil fatty acid methyl ester, sunflower oil, grape oil, baby wax, jojoba oil, hydrogenated jojoba ester, macadamia nut oil, honey wax, minced oil, cotton seed oil, cotton wax, lanolin, lanolin kernel Oil, Montan wax, palm oil, hardened palm oil, tri-palm oil fatty acid glyceride, sheep fat, peanut oil, lanolin, liquid lanolin, reduced lanolin, lanolin alcohol, hard lanolin, lanolin acetate, lanolin fatty acid isopropyl, POE (polyoxyethylene) lanolin Examples thereof include alcohol ether, POE lanolin alcohol acetate, lanolin fatty acid polyethylene glycol, POE hydrogenated lanolin alcohol ether, and egg yolk oil.

Lubricating oils used in engine oils, drive train oils, hydraulic hydraulic oils, turbine oils, compressor oils, machine tool lubricants, cutting oils, gear oils, fluid bearing oils, rolling bearing oils, spindle oils, etc. The base oil (base oil) used in the agent composition can be used. In addition, synthetic lubricating oils such as silicone oil, PFPE oil, CTFE oil, and PTFE oil can also be used.
Examples of the base oil include mineral oils obtained from crude oils, chemically synthesized ester oils, fluorine oils, polyα-olefin oils, and mixtures thereof.
The lubricant composition includes the above base oil or a mixture thereof, a flow point lowering agent, a viscosity index improver, a metal cleaning agent, a dispersant, an abrasion resistant agent, an extreme pressure agent, an antioxidant, an antifoaming agent, and the like. Examples thereof include those containing various additives such as a friction modifier, a rust preventive, and a metal inactivating agent. A commercially available lubricant composition can also be used as the engine oil.
Examples of fuel oil include naphtha, gasoline, kerosene, and light oil.
Examples of the poorly water-soluble organic solvent include benzene, toluene, xylene, chlorobenzene, saturated aliphatic hydrocarbons having 6 to 18 carbon atoms, methylene chloride and the like.

The inclusion substance may be a substance obtained by dissolving a solid oil component at room temperature in a liquid oil component at room temperature. Further, the encapsulated substance may be composed entirely of various oils as described above, or may be obtained by dissolving these oils in an organic solvent. In the latter case, for example, at least one component selected from the group consisting of the above-mentioned hydrocarbon-based oily components, natural animal and vegetable fats and oils, and semi-synthetic fats and oils is dissolved in a soluble organic solvent. It can be used as an inclusion substance.
When the inclusion substance contains an organic solvent capable of dissolving oil, the content of the organic solvent is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, based on the total mass of the oil and the organic solvent. %, More preferably 40 to 60% by mass.

The inclusion material used in the structure of one aspect of the present invention preferably has 6 or more carbon atoms, more preferably 7 or more carbon atoms, still more preferably 8 or more carbon atoms, still more preferably 10 or more carbon atoms, and further. It is preferably a hydrocarbon having 12 or more carbon atoms, more preferably 16 or more carbon atoms, and particularly preferably 20 or more carbon atoms. In addition, it is usually 40 or less hydrocarbons.
Hydrocarbons having 6 or more carbon atoms include the above-mentioned various oils, hexane, heptane, octane, nonan, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecan, icosan, liquid paraffin, and paraffin. Examples include wax and paraffin oil.

It is also possible to use an aqueous solvent or a hydrophilic substance as the inclusion substance. Examples of the aqueous solvent include methanol, ethanol, 1-propanol, 2-propanol, diethylene glycol, glycerin, and pyrrolidone-based solvents. Examples of the hydrophilic substance include polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyacrylamide, poly (N-isopropylamide), starch, ethylene glycol and the like, and among these. Examples thereof include a mixture of at least one and water, or a mixture of two or more of these.

The encapsulated substance may be used alone or in combination of two or more.

The content of the inclusion substance is preferably 30% by mass or more, more preferably 50% by mass or more, still more preferably 75% by mass or more, and preferably 99% by mass or less, based on the mass of the entire structure. It is preferably 98% by mass or less. When the content of the encapsulated substance is 30% by mass or more with respect to the mass of the entire structure, it becomes easy to sufficiently secure the desired performance. Further, when the content of the encapsulated substance is 98% by mass or less with respect to the mass of the entire structure, the encapsulated substance can be easily encapsulated in the outer shell made of a membrane containing CNF.

[Cellulose nanofibers (CNF) and other ingredients]
As the material and shape of the CNF constituting the structure, those described in CNF blended in the substance-encapsulating particle-containing composition are directly applicable. Further, as for the polysaccharides other than CNF and the substance and other components that can be contained in the structure, the components blended in the substance-encapsulating particle-containing composition are directly applicable. Therefore, detailed description of these will be omitted here.
When the above structure is produced by the production method described later, a substance-encapsulating particle-containing composition containing particles having an outer shell containing CNF can be produced without using a dispersant such as a surfactant. By using the substance-encapsulating particle-containing composition, the CNF content in the structure can be increased. The content of the surfactant in the structure is preferably less than 10 parts by mass, more preferably less than 1 part by mass, still more preferably less than 0.1 parts by mass, still more preferably 0.01 parts by mass with respect to 100 parts by mass of CNF. Less than parts, particularly preferably less than 0.001 parts by mass, most preferably 0 parts by mass.
Further, the above structure may contain a polysaccharide other than CNF, but the content thereof is from the viewpoint of facilitating the desired performance (for example, in the case of a heat storage substance, the intended heat storage performance). With respect to 100 parts by mass of the total amount of CNF, preferably less than 10 parts by mass, more preferably less than 1 part by mass, further preferably less than 0.1 parts by mass, still more preferably less than 0.01 parts by mass, particularly preferably. It is 0 parts by mass.
As a method for measuring the content of the surfactant in the structure, the surfactant is extracted with a solvent, and the chemical composition is identified by a high performance liquid chromatograph mass spectrometer (LC-MS), a nuclear magnetic resonance apparatus (NMR), or the like. There is a method of performing quantification. Polysaccharides can also be identified and quantified in the same procedure as surfactants.

[Maximum ferret diameter in closed space]
In FIG. 1B, the maximum ferret diameter of the closed space is indicated by the symbol df for one specific closed space contained in the substance inclusion layer 31. Since the closed space can take various shapes, the size of the closed space is represented by the maximum ferret diameter in the present specification (the size of the closed space does not include the thickness of the membrane including CNF). In the structure according to the embodiment of the present invention, the average of the maximum ferret diameters of the plurality of closed spaces is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more, still more preferably 15 μm or more, particularly. It is preferably 20 μm or more. The average of the maximum ferret diameters of the plurality of closed spaces is preferably 100 μm or less, more preferably 90 μm or less, still more preferably 80 μm or less, still more preferably 70 μm or less.
When the maximum ferret diameter is 1 μm or more, it is possible to prevent the sensitivity of the target performance (for example, the heat storage response speed in the case of a heat storage substance) from becoming too low. Further, when the maximum ferret diameter is 100 μm or less, it is possible to prevent the strength of the structure from becoming too low.
Here, the "maximum ferret diameter" of a certain figure means the maximum distance of the figure sandwiched between two parallel lines. In the present specification, in the observation image of the surface of the structure including the closed space composed of the membrane containing CNF, the figure corresponding to the closed space is specified, and the maximum of this figure sandwiched between two parallel lines. The maximum ferret diameter of the closed space is calculated by measuring the distance.
In the present specification, the "average of the maximum ferret diameters of the plurality of closed spaces" is the average value of the maximum ferret diameters of the plurality of closed spaces in the observation image of the surface of the structure. In the present specification, in the structure, any 36 closed spaces are selected, the maximum ferret diameter of each is measured, and the average value thereof is defined as "the average of the maximum ferret diameters of a plurality of closed spaces". If the closed space cannot be observed from the surface of the structure due to the provision of another layer on the structure, the structure is arbitrarily cut, and the cut surface thereof is the same as described above. In the procedure, the average of the maximum ferret diameters of a plurality of closed spaces may be obtained.

When the average of the maximum ferret diameters of the plurality of closed spaces of the structure according to the embodiment of the present invention is in the above range, the size of the closed spaces is generally small. Therefore, a large number of films containing CNF are present inside the structure, and the strength of the structure can be increased. Therefore, it becomes easy to obtain a structure having excellent shape retention against pressure and the like. Further, as a result of increasing the strength of the structure, it also works favorably for holding the encapsulated substance in the closed space for a long time. Further, since the size of the enclosed space is small, the encapsulated substance can be individually held in many closed spaces, and the retention of the encapsulated substance can be enhanced.
Further, as shown in FIG. 1 (B), since the strength of the structure is increased by sharing the membrane with a plurality of closed spaces, a self-retaining membrane (self-supporting membrane) can be provided without adding a binder component. Can be made. This self-supporting membrane does not necessarily require a binder component, and can increase the space for holding the encapsulated substance, for example, as compared with a capsule in which a plurality of capsules having an internal space are bound with a binder.
It is preferable that the sheet-like structure alone has self-supporting property. In the present specification, "having independence" means a state in which the structure has self-supporting property and can maintain its shape by itself even if it is not held by another support or the like. Whether or not the structure is self-supporting by itself can be determined by using a plunger with a tip diameter of 1 mm on a single structure having a sheet shape at an approach speed of 0.5 mm / sec and a depth of up to 15 mm. It can be judged by performing a creep test by pressing and measuring the maximum load at that time. When the maximum load is 0.10 N / 1 mmΦ or more, it can be determined that the structure has sufficient sheet strength and is self-supporting.
The maximum load is preferably 0.20 N / 1 mmΦ or more from the viewpoint of further increasing the sheet strength. The upper limit of the maximum load is not particularly limited, but is usually 100 N / 1 mmΦ or less.

The size of the enclosed space in the structure can be adjusted, for example, by changing the size of the particles having an outer shell containing CNF in the material-encapsulating particle-containing composition. Thereby, the maximum ferret diameter of the closed space can be adjusted, and the average of the maximum ferret diameters of the plurality of closed spaces can be set within the above-mentioned numerical range. Further, by keeping the average of the maximum ferret diameters of the plurality of closed spaces within the above-mentioned numerical range, it becomes easy to improve the independence of the sheet-like structure.

[Shape of closed space]
The shape of the closed space is arbitrary, but when a structure is manufactured by using the manufacturing method described later, a set of adjacent closed spaces form a membrane containing CNF as described above due to the manufacturing method. Each closed space has a polyhedral shape surrounded by a plurality of flat membranes in order to facilitate a shared structure.

[Structure thickness]
When the structure is sheet-shaped or strip-shaped, the thickness L of the structure (see FIG. 1 (A)) is preferably 0.5 μm or more, more preferably 1.0 μm or more, still more preferably 3.5 μm or more. It is even more preferably 5.0 μm or more, particularly preferably 7.5 μm or more, and preferably 300 μm or less, more preferably 250 μm or less, still more preferably 200 μm or less. When the thickness of the structure is 300 μm or less, it is possible to avoid a long drying time and poor drying, and as a result, the variation in the shape and size of the closed space is suppressed, and the structure is formed. It is easy to prevent problems such as deterioration of the quality. Further, when the thickness of the structure is 0.5 μm or more, it is easy to prevent the strength of the structure from being insufficient and the amount of substances that can be held in the closed space from being reduced.
When the structure has a sheet shape or a strip shape, the area of the structure and the size in the longitudinal direction are not particularly limited, and any size can be used as long as the manufacturing equipment can be prepared. Even when the structure has a shape other than a sheet shape or a strip shape, for example, a lump shape, the maximum diameter of the structure is preferably 1 mm or more, more preferably 5 mm or more, from the same viewpoint as described above. Further preferably 1 cm or more, further preferably 2.5 cm or more, particularly preferably 5 cm or more, and preferably 5 m or less, more preferably 3 m or less, still more preferably 1 m or less, still more preferably 50 cm or less, particularly preferably. Is 10 cm or less.

[Support]
In one aspect of the present invention, the structure includes a support, such as the sheet-like structure 50 with a support. When the support is provided, the structure and the support may be integrated, or the structure may be separated from the support after the structure is formed. That is, a sheet-like structure may be formed on a holding body that is temporarily used, such as a release material.
In the former case, the surface of the support to which the substance-encapsulating particle-containing composition is applied is preferably subjected to an easy-adhesion treatment. As the easy-adhesion treatment, for example, corona discharge treatment, plasma treatment, ozone treatment and the like can be used. Further, for example, an easy-adhesion layer can be provided by using an acrylic resin, an ester resin, a urethane resin, or the like. In the latter case, a material having a release layer formed on the surface to which the substance-encapsulating particle-containing composition is applied may be used, or a support whose entire support is made of a material that easily peels off the structure is used. You may.
The support is appropriately selected according to the application of the sheet-like structure, and is, for example, a paper base material such as high-quality paper, art paper, coated paper, and glassin paper; a thermoplastic resin such as polyethylene is laminated on these paper base materials. Laminated paper; Metal foils such as aluminum foil, copper foil and iron foil; Porous materials such as non-woven fabrics: Polyethylene resin such as polyethylene resin and polypropylene resin, polyester resin such as polybutylene terephthalate resin and polyethylene terephthalate resin, acetate resin, Examples thereof include a resin film or sheet containing one or more kinds of resins such as ABS resin, polystyrene resin, and vinyl chloride resin.
The support may be a single-layer film or sheet, or may be a multi-layer film or sheet which is a laminated body of two or more layers.
Further, the resin film or sheet may be unstretched, or may be stretched in a uniaxial direction or a biaxial direction such as vertical or horizontal.
Further, the resin film or sheet may contain an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a slip agent, an anti-blocking agent, a colorant and the like in addition to the above-mentioned resin.
The thickness of the support is appropriately selected depending on the use of the sheet-like structure, but is preferably 10 μm or more, more preferably 15 μm or more, still more preferably 20 μm or more, and preferably 250 μm or less, more preferably. Is 200 μm or less, more preferably 150 μm or less. When the thickness of the support is 10 μm or more, it becomes easy to avoid troubles such as tearing when a strong tension is applied during coating. When the thickness of the support is 250 μm or less, it is easy to wind it into a roll, and it is easy to secure good productivity.
The type and thickness of the holder can be the same as that of the support described above.

<Manufacturing method of structure>
In a structure having a closed space composed of a film containing CNF, a substance to be encapsulated is added to a dispersion in which CNF is dispersed in a liquid dispersion medium, and the substance adds the substance to the dispersion. It can be produced by a production method in which at least a part of the substance is agitated at a temperature to become a liquid to generate particles incorporated in a space surrounded by an outer shell containing CNF to obtain a structure.

In one aspect of the method for producing the structure, as described below, the step of adding the substance to be included in the dispersion liquid dispersed in the liquid dispersion medium by CNF (addition step (step (1))), the substance to be included is A step of applying the added dispersion to one surface of the support (coating step (step (2))) and a step of drying the coating layer formed on the support (drying step (step (3))). ))including. Hereinafter, a sheet-like structure is supplied on a support with a dispersion liquid (material-encapsulating particle-containing composition) containing substance-encapsulating particles, which is particles in which a substance to be contained in a space surrounded by an outer shell containing CNF is incorporated. The method for producing the structure will be specifically described by taking an example of producing the above.

FIG. 2A shows one process during the manufacturing process, and is a schematic view showing how the substance-encapsulating particle-containing composition 30 is applied onto the surface (coating surface) 40a of the support 40. When the substance-encapsulating particle-containing composition 30 prepared in the step (1) is applied onto the coating surface 40a of the support 40, as shown in FIGS. 2A and 2B, the outside containing CNF is contained. It contains particles 32 having a shell and a medium 34 mainly composed of a liquid dispersion medium. Further, the particle 32 contains a substance mainly composed of a substance. After that, in the drying step, the medium 34 is removed by drying, and as shown in FIG. 2C, a large number of closed spaces 33 formed by the membrane 35 containing CNF are formed, and the encapsulated substance 36 is formed in each closed space 33. A substance inclusion layer 31 (see FIG. 1 (A)) containing the substance is formed on the support 40.

[Addition step (step (1))]
When adding a substance to be included in the dispersion liquid dispersed in the liquid dispersion medium by CNF, it is preferable to supply the substance to be included in the dispersion liquid little by little while stirring the dispersion liquid. Hereinafter, the step of adding the substance to be included in the dispersion liquid is referred to as "addition step" or "step (1)".
In a state where CNF is uniformly dispersed in the liquid dispersion medium, a substance to be further encapsulated is added, and this substance is also uniformly dispersed, so that the liquid dispersion medium does not use a dispersant such as a surfactant. CNF gathers at the interface between the substance and the substance to form particles having an outer shell containing CNF. The process of forming particles having an outer shell containing CNF is not limited to this, but one of them is presumed to be due to the following mechanism. That is, since CNF is an amphipathic insoluble material, it is present at the interface between the liquid dispersion medium such as the aqueous solvent used for emulsification and the substance to be included, thereby creating an energetically stable state. In addition, since CNF is insoluble and film-forming, it forms an irreversible independent phase as a result of localization to the interface. In this way, it is considered that the outer shell containing the CNF is provided and the particles containing the encapsulated substance are formed in the space surrounded by the outer shell.
When a substance to be included in the dispersion liquid containing the uniformly dispersed CNF is added, the particles generated by localizing the CNF at the interface are considered to have relatively high stability. Therefore, it is considered that the change to the large-diameter capsule is unlikely to occur due to the bonding between the produced capsules, and the dispersion liquid to which the above-mentioned substance is added is sufficiently agitated to obtain particles having a small diameter and uniform diameter. As a result, unless an excessive stimulus is applied or a constant pressure is intentionally applied, the particles do not disappear for several months or more and are considered to be stable particles.
Since the substance-encapsulating particle-containing composition is a dispersion of particles encapsulating the substance, the composition itself has the desired performances such as heat storage, heat insulation, heat retention, soundproofing, and vibration-proofing. Have. Therefore, it can be said that the substance-encapsulating particle-containing composition is a structure containing a liquid dispersion medium. Further, it can be said that the step of preparing the substance-encapsulating particle-containing composition is also a method for producing a structure. Further, for example, by encapsulating the substance-encapsulating particle-containing composition in a container, the container containing the substance-encapsulating particle-containing composition can be made into a structure.

In the step (1), from the viewpoint of preventing the substance containing the CNF from being phase-separated from the liquid dispersion medium without forming particles having an outer shell containing CNF, the total amount of the dispersion liquid is 100 parts by mass. The amount of the substance added every 10 seconds is preferably 0.1 part by mass or more, more preferably 1 part by mass or more, still more preferably 3 parts by mass or more, particularly preferably 5 parts by mass or more, and preferably. A substance to be included is added so as to be 20 parts by mass or less, more preferably 15 parts by mass or less, further preferably 10 parts by mass or less, and particularly preferably 7 parts by mass or less. The substance may be continuously supplied, or the substance may be supplied intermittently. In any case, by stirring while adding a limited amount of the above substance to the dispersion liquid, the substances to be included are uniformly dispersed in the dispersion liquid, and as a result, the particles having an outer shell containing CNF are satisfactorily dispersed. Can be generated.

In the step (1), from the viewpoint of facilitating uniform dispersion of the substance to be included, it is preferable to heat the substance to change the phase from solid to liquid and then add the substance to the dispersion. If the substance to be included is a substance that is liquid at room temperature, it is not always necessary to heat it. Even if the substance to be included is a substance that is solid at room temperature, if it is a substance that is liquid at room temperature or a substance that dissolves in a specific organic solvent, it is not always necessary to heat it when using it in a state of being dissolved in them. ..

In the step (1), it is preferable to add a substance to be included while stirring the dispersion liquid by using a stirring device equipped with a stirring blade such as a homodisper, a mixer, or a paddle blade. By bringing the stirring blade into contact with the dispersion liquid and stirring the particles, particles having an outer shell containing CNF can be efficiently generated.

The stirring speed (rotational speed) when stirring the dispersion is preferably 500 rpm or more, more preferably 1,000 rpm or more, from the viewpoint of suppressing the aggregation of CNF and reducing the variation in the shape and size of the formed particles. , More preferably 1,500 rpm or more, still more preferably 2,000 rpm or more, and preferably 5,000 rpm or less, more preferably 4,500 rpm or less, still more preferably 4,000 rpm or less, still more preferably 3. , 500 rpm or less, particularly preferably 3,000 rpm or less.

The stirring time is preferably 3 minutes or longer, more preferably 5 minutes or longer, still more preferably 10 minutes or longer, from the viewpoint of making the shape and size of the particles having the outer shell containing CNF uniform. Further, the upper limit of the stirring time is preferably 180 minutes or less, more preferably 120 minutes or less, still more preferably 60 minutes or less, still more preferably 40 minutes or less, particularly from the viewpoint of preventing the production time from becoming too long. It is preferably 20 minutes or less.

The temperature of the liquid dispersion medium varies depending on the type of the liquid dispersion medium used, the surrounding environmental conditions such as pressure, and the like, but it is desirable that the temperature of the substance to be included can maintain the liquid state. For example, when water is used as the liquid dispersion medium (B), the temperature is preferably higher than 0 ° C and 100 ° C or lower. From the viewpoint of suppressing the aggregation of CNF and reducing the variation in the shape and size of the formed particles, the temperature is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, still more preferably 15 ° C. or higher, and the above-mentioned addition. From the viewpoint of uniformly dispersing the substance, the temperature is preferably 95 ° C. or lower, more preferably 70 ° C. or lower, still more preferably 50 ° C. or lower, still more preferably 40 ° C. or lower.

The step (1) is preferably carried out at 80 kPa or more, more preferably 90 kPa or more, further preferably 95 kPa or more, and preferably 120 kPa or less, more preferably 110 kPa or less, further preferably 105 kPa or less, and particularly preferably large. Perform under atmospheric pressure. By preparing the composition containing substance-encapsulating particles under conditions close to atmospheric pressure, the composition can be prepared in a short time, and the production equipment can be simplified. Further, the step (1) may be performed in an atmosphere of air or an inert gas. In an air atmosphere, the manufacturing equipment can be simplified, and in an inert gas atmosphere, deactivation of the substance-encapsulating particle-containing composition can be easily suppressed. By preparing a substance-encapsulating particle-containing composition in a sheet-like structure in an atmosphere of a specific type of gas, the gas may be encapsulated together with the encapsulating substance in the generated particles.
These temperature conditions, pressure conditions, and atmosphere conditions also apply to the steps (2-1) and (2-2) described later.

[Composition obtained in step (1) and constituent material of composition]
The substance-encapsulating particle-containing composition prepared by the step (1) is a mixture of CNF (A), a liquid dispersion medium (B), and a substance (C) to be included, and is composed of CNF (A). Contains particles with an outer shell containing. In the present specification, the CNF (A), the liquid dispersion medium (B) and the substance (C) may be collectively referred to as components (A) to (C).
In the above composition, at least a part of the substance (C) is in a state of being incorporated into the particles, and specifically, a state of being contained in the CNF (A) forming the outer shell of the particles. , And at least one of the states of being adsorbed by the CNF (A) forming the outer shell of the particles.
Here, "a state in which the substance (C) is contained in the outer shell containing CNF (A)" means that the outer shell containing CNF (A) forms hollow particles, and the substance is contained in the hollow portion of the hollow particles. It means a state in which (C) is taken in. At this time, the substance (C) is separated from the outside of the hollow particles by the outer shell constituting the hollow particles.
In the substance-encapsulating particle-containing composition prepared by the addition step, the particles contain the substance (C), and the CNF (A) constituting the outer shell of the particles contains the substance (C). It may be in a state of being adsorbed. In the present specification, "the outer shell composed of CNF (A) adsorbs the substance (C)" means that the substance (C) exists in the network structure of the outer shell composed of CNF (A). Means that.

In the composition containing particles containing substances, a substance (C) that is not incorporated into the particles may be present.

(Average particle size of particles having an outer shell containing CNF in the composition)
In order to make the average of the maximum ferret diameters of the closed space of the structure within the above-mentioned numerical range, the average particle diameter of the particles having an outer shell containing CNF in the material-encapsulated particle-containing composition should be set to an appropriate range. It is preferable to set it.
The average particle size of the particles contained in the material-encapsulating particle-containing composition is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 7 μm or more, still more preferably 10 μm or more, and particularly preferably 15 μm or more. Further, it is preferably 60 μm or less, more preferably 50 μm or less, still more preferably 40 μm or less, still more preferably 35 μm or less, and particularly preferably 30 μm or less.
When the average particle diameter of the particles is 1 μm or more, it becomes easy to suppress the aggregation of the particles, and it becomes easy to prevent the closed space of the structure from becoming too small.
Further, when the average particle diameter of the particles is 60 μm or less, it becomes easy to prevent the particles from being unevenly distributed on the surface of the composition due to the floating of the particles.

In addition, the standard deviation of the particles contained in the substance-encapsulating particle-containing composition with respect to the average particle size suppresses the proportion of the substance contained in the particles from fluctuating among the particles, and tries to impart it to the structure. From the viewpoint of avoiding non-uniformity of the desired performance, it is preferably 20 μm or less, more preferably 18 μm or less, still more preferably 15 μm or less, still more preferably 12 μm or less, and usually 1 μm or more.
In the present specification, the average particle size of the particles and the standard deviation with respect to the average particle size were obtained when the target composition was observed with a digital microscope at a magnification of 500 to 1,000 times. It can be calculated from the image.
That is, the average value of the particle diameters (outer diameters) of 36 arbitrarily selected particles among the particles projected on the image can be defined as the above-mentioned "average particle diameter". In addition, the "standard deviation with respect to the average particle size" can be calculated from the value of the particle size of each of the 36 particles. The standard deviation is the standard deviation of the population, and in the above calculation, the standard deviation is calculated for all the values of the 36 particle sizes.

The viscosity of the material-encapsulating particle-containing composition at 23 ° C. and 50 rpm is preferably 500 mPa · s or more, more preferably from the viewpoints of ease of removal from the container, ease of stirring, inhibition of sedimentation, and the like. Is 1,000 mPa · s or more, more preferably 1,200 mPa · s or more, preferably 20,000 mPa · s or less, more preferably 15,000 mPa · s or less, still more preferably 12,000 mPa · s or less. Is.
In the step (2-2) described later, in order to enable the composition to be satisfactorily applied to the support, the viscosity of the material-encapsulating particle-containing composition is increased at the temperature at which the composition is applied to the support. It is preferable to select the material so as to be within the above numerical range.

In addition, the TI value (viscosity at 5 rpm / viscosity at 50 rpm) of the material-encapsulating particle-containing composition at 23 ° C. indicates storage stability, inhibitory property of sedimentation when stored in a container, and from the container. From the viewpoint of ease of removal, the amount is preferably 1.2 or more, more preferably 2 or more, still more preferably 3 or more, still more preferably 4 or more, and preferably 20 or less, more preferably 15 or less. It is even more preferably 10 or less, and even more preferably 8 or less.
Further, in the present specification, the viscosity of the substance-encapsulating particle-containing composition means a value measured using a B-type viscometer in accordance with JIS Z 8803: 2011.

The pH of the material-encapsulating particle-containing composition is preferably 4 or more, more preferably 5 or more, still more preferably 6 or more, from the viewpoint that the particles to be formed are stable and the dispersed state can be easily maintained in the composition. It is preferably 10 or less, more preferably 9 or less, still more preferably 8 or less.

The substance-encapsulating particle-containing composition may contain components other than the above components (A) to (C).
However, in the substance-encapsulating particle-containing composition, the total content of CNF (A), the liquid dispersion medium (B) and the substance (C) is preferably 60% by mass with respect to the total amount (100% by mass) of the composition. % Or more, more preferably 65% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, and preferably 100% by mass or less.

The concentration of the active ingredient of the material-encapsulating particle-containing composition is preferably 0.5% by mass or more, more preferably 0.7% by mass or more, still more preferably 1. It is 0% by mass or more, more preferably 1.5% by mass or more, and preferably 50% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less.
In the present specification, the “active ingredient” refers to a component contained in the composition containing particles containing substances, excluding the liquid dispersion medium (B).

The particles having an outer shell containing CNF (A) and incorporating the substance (C) include the amount of CNF (A) to be blended, the blending amount ratio of CNF (A) to the substance (C), and the substance (C). ) Can be formed by appropriately adjusting the type and the like.

In the material-encapsulating particle-containing composition, as described later, the particles are formed by blending the substance (C) with the dispersion liquid in which CNF (A) is dispersed in the liquid dispersion medium (B). The composition is prepared in. In addition to the above, the shape (diameter, fiber length, aspect ratio) of CNF (A), the blending amount of the liquid dispersion medium (B) and the substance (C), and the liquid dispersion medium (B) and the substance (C) The composition can be prepared so as to facilitate the formation of the particles by appropriately setting the blending amount ratio and the like.

(Cellulose Nanofiber (CNF) (A))
As a raw material of CNF (A) used in the structure of one aspect of the present invention and the method for producing the same, for example, kraft pulp or sulphite pulp derived from wood; kraft pulp or sulphite pulp is pulverized with a high-pressure homogenizer, a mill or the like. Powdered cellulose; Microcrystalline cellulose powder obtained by purifying powdered cellulose by chemical treatment such as acid hydrolysis; Bast fiber pulp such as Kozo, Ganbari, Sansho; Cotton pulp, Kenaf, hemp, rice, bacas, bamboo, etc. Cellulose-based raw materials; Since the plant-derived CNF has a high crystallinity, a linear structure, and a large aspect ratio, the strength of the outer shell can be increased and it is easily available.

If a large amount of lignin remains in these raw materials, the oxidation reaction of the raw materials may be inhibited. Therefore, cellulosic raw materials obtained by removing lignin from these raw materials are preferable.
Further, it is also possible to use the above-mentioned cellulosic raw material finely divided by a disperser such as a high-speed rotary type, a colloid mill type, a high pressure type, a roll mill type, an ultrasonic type, or a wet high pressure or ultra high pressure homogenizer.

Further, these cellulosic raw materials may be chemically modified and / or physically modified to enhance their functionality. Here, as chemical modification, addition of a functional group by acetylation, carboxylation, carboxysolation, esterification, cyanoethylation, acetalization, etherification, arylation, alkylation, acryloylation, isocyanatement, etc. In addition, inorganic substances such as silicates and titanates may be compounded or coated by a chemical reaction, a solgel method, or the like.
In addition, as physical modification, a metal or ceramic raw material is vapor-deposited, ion-plated, sputtering or other physical vapor deposition method (PVD method), chemical vapor deposition method (CVD method), electroless plating, electrolytic plating or other plating method, etc. Surface coating may be mentioned.
In addition, these modification treatments may be performed at the time of defibrating the cellulosic raw material or before and after defibrating.

The above-mentioned cellulosic raw material can be made into CNF by defibrating it into nanofibers.
As a specific method, a method is used in which a dispersion liquid in which a cellulosic raw material is dispersed in a dispersion medium such as water is prepared, and then a shearing force is applied to the cellulosic raw material to prepare a dispersion liquid containing CNF. be able to.
As a method of applying a shearing force to a cellulosic raw material, after adding the cellulosic raw material to a dispersion medium such as water, a device such as a high-speed rotary type, a colloid mill type, a high pressure type, a roll mill type, or an ultrasonic type is used. It is preferable to adopt the method of preparation.
At this time, the pressure applied to the dispersion is preferably 50 MPa or more, more preferably 100 MPa or more, still more preferably 140 MPa or more.
From the viewpoint of applying a strong shearing force to the cellulosic raw material under such a high pressure, it is preferable to apply the shearing force using a high-pressure device, and it is preferable to use a wet high-pressure or ultra-high-pressure homogenizer.

The average diameter (thickness) of the CNF is preferably 1.0 nm or more, more preferably 1.5 nm or more, still more preferably, from the viewpoint of facilitating the formation of the particles and improving the film strength of the formed particles. Is 2.0 nm or more, more preferably 2.5 nm or more, and preferably 1,000 nm or less, more preferably 500 nm or less, still more preferably 200 nm or less, still more preferably 100 nm or less.

The average fiber length of CNF is preferably 0.01 μm or more, more preferably 0.1 μm or more, still more preferably 0., from the viewpoint of facilitating the formation of the particles and improving the film strength of the formed particles. It is 2 μm or more, more preferably 0.3 μm or more, preferably 10 μm or less, more preferably 7.0 μm or less, still more preferably 5.0 μm or less, still more preferably 2.5 μm or less.

The average aspect ratio of CNF (A) is preferably 5 or more, more preferably 10 or more, still more preferably 15 or more, from the viewpoint of facilitating the formation of the particles and improving the film strength of the formed particles. Further, it is preferably 10,000 or less, more preferably 5,000 or less, still more preferably 3,000 or less, still more preferably 1,000 or less, and particularly preferably 500 or less.

The "aspect ratio" is the ratio of the length to the thickness of the target CNF [length / thickness], and the "length" of the CNF is between the two most distant points of the CNF. Refers to the distance.
If a part of the target CNF comes into contact with another CNF and it is difficult to determine the "length", measure the length of only the part of the target CNF whose thickness can be measured. , The aspect ratio of the relevant portion may be in the above range.

In the production method of the present embodiment, when the composition containing substance-encapsulating particles is prepared, excessive stress is not applied to the CNF. Therefore, the fiber diameter and fiber length of the CNF before compounding are set to a sheet-like structure. It is maintained almost as it is. Therefore, the numerical ranges for the fiber diameter, fiber length, and aspect ratio of the CNF described above include the CNF before the composition is prepared, the CNF after the composition is prepared, and the structure prepared by using the composition described later. This applies as is to any of the CNFs in.

(Content of CNF in composition)
The content of CNF (A) in the material-encapsulating particle-containing composition is a viewpoint of facilitating the formation of the particles and improving the film strength of the formed particles with respect to the total amount (100% by mass) of the composition. Therefore, it is preferably 0.7% by mass or more, more preferably 0.8% by mass or more, still more preferably 1.0% by mass or more, still more preferably 1.2% by mass or more, and form the particles. From the viewpoint of appropriately adjusting the viscosity of the material-encapsulating particle-containing composition so as to facilitate, preferably 15% by mass or less, more preferably 10% by mass or less, still more preferably 7% by mass or less, still more preferably 5. It is mass% or less, particularly preferably 3 mass% or less.

(Liquid dispersion medium (B))
In the material-encapsulating particle-containing composition, most of the liquid dispersion medium (B) is either adsorbed on the outer shell of the particles or exists outside the particles.
However, a part of the liquid dispersion medium (B) may be encapsulated together with the substance (C) inside the particles.
As the liquid dispersion medium (B), an aqueous dispersion medium or an organic solvent can be used. In particular, an aqueous dispersion medium is preferable from the viewpoint of affinity with CNF (A). Specific examples thereof include aqueous solvents such as water, methanol, ethanol, 1-propanol, 2-propanol, diethylene glycol, glycerin, pyrrolidone-based solvents, and mixtures of two or more of these. In particular, water is preferable because the substance-encapsulating capsule (X) has good dispersibility.
As will be described later, when water or an aqueous solvent is used as the substance (C), it is also possible to use an organic solvent that is difficult to be compatible with water or the aqueous solvent as the liquid dispersion medium (B).
In any case, the liquid dispersion medium (B) and the substance (C) form a phase independent of the substance (C) when the substance (C) is mixed with the liquid dispersion medium (B), and It is preferable to use a combination that can temporarily take an emulsified state by stirring. With this combination, particles having an outer shell containing CNF can be generated without using a dispersant such as a surfactant.

The content of the liquid dispersion medium (B) is the total amount (100% by mass) of the composition from the viewpoint of preparing a composition having an appropriate viscosity in the substance-encapsulating particle-containing composition and facilitating the formation of the particles. ), More preferably 15% by mass or more, more preferably 30% by mass or more, still more preferably 50% by mass or more, still more preferably 60% by mass or more, and preferably 99% by mass or less, more preferably. Is 98.7% by mass or less, more preferably 98.5% by mass or less.

In the material-encapsulating particle-containing composition, the content ratio of the liquid dispersion medium (B) to 100 parts by mass of CNF (A) is determined from the viewpoint of preparing a composition having an appropriate viscosity and facilitating the formation of the particles. It is preferably 500 parts by mass or more, more preferably 1,000 parts by mass or more, further preferably 2,000 parts by mass or more, still more preferably 3,000 parts by mass or more, and preferably 20,000 parts by mass or less. , More preferably 15,000 parts by mass or less, still more preferably 10,000 parts by mass or less.

When a substance-encapsulating particle-containing composition is produced by using a substance (C) that becomes liquid at a temperature higher than the melting point of the liquid dispersion medium (B) and lower than the boiling point of the liquid dispersion medium (B). In addition, the substance (C) is likely to be uniformly dispersed throughout the composition, and is easily encapsulated in the thermal substance-encapsulating capsule (X). Therefore, the substance (C) is preferably selected in consideration of the melting point and boiling point of the liquid dispersion medium (B) to be used. In other words, in the liquid dispersion medium (B), the temperature at which the substance (C) becomes liquid is higher than the melting point of the liquid dispersion medium (B) in consideration of the temperature characteristics of the substance (C) used. It is preferable to select one having a temperature lower than the boiling point of B).

(Dispersion)
As the dispersion liquid containing CNF and the liquid dispersion medium, as described above, the aqueous dispersion liquid obtained by dispersing the cellulosic raw material in, for example, an aqueous solvent and then applying a shearing force to the cellulosic raw material is used as the dispersion liquid as it is. Can be used. A commercially available aqueous dispersion of CNF can also be used.
The pH of the dispersion is preferably 4 or more, more preferably 5 or more, still more preferably 5 or more, from the viewpoint of suppressing the aggregation of CNF (A) in the dispersion and reducing the variation in the shape and size of the formed particles. It is 6 or more, preferably 10 or less, more preferably 9 or less, still more preferably 8 or less.

(Content of inclusion substance in composition)
From the viewpoint of facilitating the formation of the particles in the material-encapsulating particle-containing composition, the content ratio of the substance (C) with respect to 100 parts by mass of CNF (A) is preferably 1 part by mass or more, more preferably 5 parts by mass or more. , More preferably 10 parts by mass or more, still more preferably 50 parts by mass or more, still more preferably 75 parts by mass or more, still more preferably 90 parts by mass or more, and preferably 6,000 parts by mass or less, more preferably 6,000 parts by mass or more. It is 4,500 parts by mass or less, more preferably 4,000 parts by mass or less, and even more preferably 3,500 parts by mass or less.

In the material-encapsulating particle-containing composition, the content of the substance (C) is preferably 0.05% by mass or more with respect to the total amount (100% by mass) of the composition from the viewpoint of facilitating the formation of the particles. , More preferably 0.1% by mass or more, still more preferably 0.5% by mass or more, still more preferably 0.8% by mass or more, and preferably 80% by mass or less, more preferably 60% by mass or less. It is more preferably 45% by mass or less, still more preferably 42% by mass or less, still more preferably 40% by mass or less, and particularly preferably 38% by mass or less.
When a substance is dissolved in an organic solvent, the entire solution is referred to as oil in the substance-encapsulating particle-containing composition.

(Ratio of liquid dispersion medium (B) and substance (C))
In the substance-encapsulating particle-containing composition, the content ratio [(B) / (C)] of the liquid dispersion medium (B) to the substance (C) is preferably a mass ratio from the viewpoint of facilitating the formation of the particles. Is 0.1 or more, more preferably 0.5 or more, still more preferably 1.0 or more, still more preferably 1.5 or more, and preferably 1,000 or less, more preferably 700 or less, even more preferably. Is 500 or less, more preferably 300 or less, and particularly preferably 100 or less.

(Other ingredients)
The material-encapsulating particle-containing composition may contain components other than the components (A) to (C) as long as the effects of the present invention are not impaired.
Such other components are appropriately selected depending on the intended use of the composition, and are, for example, colorants, antioxidants, pH adjusters, gelling agents, ultraviolet absorbers, preservatives, and fungicides. , Antibacterial agents, fluorescent agents, water repellents, sweeteners, flavors and the like.

The material-encapsulating particle-containing composition may contain a surfactant.
However, when a structure prepared using a composition containing a surfactant is used for applications that come into contact with the human body, the surfactant is a penetrant and an irritating stimulant, especially for users with sensitive skin. It also becomes. In addition, the composition containing the surfactant may affect the stability of the physical properties of the composition. Further, the surfactant may affect the stability of the physical properties of the structure, and the retention of the encapsulated substance may be impaired.
Therefore, in the substance-encapsulating particle-containing composition of one aspect of the present invention, the smaller the content of the surfactant, the more preferable. By reducing the content of the surfactant in the composition, it becomes easy to suppress the mixing of the surfactant into the encapsulated substance in the structure.
From the above viewpoint, the content of the surfactant in the substance-encapsulating particle-containing composition is preferably less than 10 parts by mass, more preferably less than 1 part by mass, still more preferably, with respect to 100 parts by mass of the total amount of CNF (A). Is less than 0.1 parts by mass, more preferably less than 0.01 parts by mass, particularly preferably less than 0.001 parts by mass, and most preferably 0 parts by mass. By adjusting the content of the surfactant in the composition in this way, the content of the surfactant in the structure can be kept within the above range.

Further, the substance-encapsulating particle-containing composition may contain a polysaccharide other than CNF (A), but from the viewpoint of improving the thermal stability of the particles and facilitating the formation of the particles. The smaller the content of the polysaccharide, the more preferable.
From the above viewpoint, the content of the polysaccharide other than CNF (A) in the substance-encapsulating particle-containing composition is preferably less than 10 parts by mass, more preferably 1 part by mass, based on 100 parts by mass of the total amount of CNF (A). Less than parts, more preferably less than 0.1 parts by mass, even more preferably less than 0.01 parts by mass, particularly preferably 0 parts by mass. By adjusting the content of the polysaccharide other than CNF (A) in the material-encapsulating particle-containing composition in this way, the content of the polysaccharide other than CNF (A) in the structure is within the above-mentioned range. be able to.

[Applying step (step (2)) and drying step (step (3))]
When a sheet-like structure is produced as in this example, a substance-encapsulating particle-containing composition is applied onto a support to form a coating film, and the coating film is dried to obtain a sheet-like structure. In the coating step (2), from the viewpoint of avoiding excessive stress on the particles having an outer shell containing CNF in the composition prepared in the step (1), the composition is preferably first supported. It is fed onto (step (2-1)) and then the composition on the support is uniformly applied (step (2-2)).
(Step (2-1): Step of supplying the composition to one surface of the support)
In step (2-1), for example, the composition is placed on the support by tilting the container containing the substance-encapsulating particle-containing composition and gradually moving the composition from the container to the support by its own weight. Supply. Further, the above composition may be supplied onto the support by using a pump or the like.
The temperature condition, pressure condition, and atmosphere condition in the step (2-1) may be set in the same manner as described in the step (1).

(Step (2-2): Step of applying the composition to the support)
In the step (2-2), the substance-encapsulating particle-containing composition supplied on the support in the step (2-1) is applied onto the support using, for example, a coating device.
Here, the coating gap when forming the coating film forms a sufficient number of closed spaces composed of a film containing CNF in a good shape, and takes a long time to dry or heats at a relatively high temperature. From the viewpoint of preventing some particles in the composition after coating from breaking or disappearing as a result, preferably 30 μm or more, more preferably 100 μm or more, still more preferably 150 μm or more. It is more preferably 200 μm or more, preferably 1,250 μm or less, more preferably 1,000 μm or less, still more preferably 750 μm or less, and even more preferably 500 μm or less.

Examples of the coating method of the composition include spin coating method, spray coating method, bar coating method, knife coating method, roll coating method, roll knife coating method, blade coating method, die coating method, gravure coating method, and air knife coating method. , Dip coat method and the like. Of these, the knife coating method and the gravure coating method are preferable.
In step (2-2), a jig capable of forming a gap larger than the diameter of the particles in the composition is used from the viewpoint of preventing the particles having an outer shell containing CNF from being broken by coating. Is preferable. In this case, the gap formed by the jig is preferably 1 times or more, more preferably 2 times or more, still more preferably 3 times or more, and preferably 10 times the diameter of the particles having an outer shell containing CNF. It is doubled or less, more preferably 9 times or less, still more preferably 8 times or less.

In step (2-2), the liquid dispersion medium is prevented from volatilizing and it becomes difficult to apply the composition, and the substance is volatilized when a substance having a low melting point is used as the inclusion substance. From the viewpoint of preventing the desired performance from being lost, the composition is applied in an environment where the temperature of the composition is preferably 45 ° C. or lower, more preferably 40 ° C. or lower, and further preferably 35 ° C. or lower. .. Further, from the viewpoint of preventing the composition from becoming too viscous to form a uniform coating layer and damaging the particles having an outer shell containing CNF, the temperature is preferably 5 ° C. or higher, more preferably 10. The coating is performed in an environment of ° C. or higher, more preferably 15 ° C. or higher.
The pressure condition and the atmosphere condition in the step (2-2) may be set in the same manner as described in the step (1).

It is also possible to use a coating device such as a die coater to supply the composition to the support and apply the composition at the same time (that is, the steps (2-1) and (2-2) are performed at the same time). However, in this case, it is preferable to adjust the injection conditions and the like so that excessive stress is not applied to the particles having the outer shell containing CNF in the composition.

(Drying step (step (3)))
The layer of the substance-encapsulating particle-containing composition applied on the support is dried by heating or the like, for example, to form a plurality of closed spaces composed of a film containing CNF and a substance contained in each closed space ( It becomes a substance inclusion layer including C). Specifically, the layer of the substance-encapsulating particle-containing composition coated on the support is dried by a heater or the like, and the liquid dispersion medium is evaporated from the layer of the composition to form a film containing CNF. It is provided with a plurality of closed spaces, and a substance-encapsulated layer containing an encapsulated substance is formed in each closed space.
In step (3), the mechanism by which the closed space composed of the membrane containing CNF containing the encapsulated substance is formed is not necessarily limited to this, but is presumed as follows. That is, in the process of volatilizing the liquid dispersion medium from the layer of the substance-encapsulating particle-containing composition, some of the particles are fixed to each other or some of the particles move to a more stable position. The gaps between the particles gradually disappear, while the CNF collected at the interface between the encapsulated substance and the liquid dispersion medium is stably present, so that the film containing the CNF is not destroyed, and finally the above substance. It is presumed that a dense closed space containing the above is formed three-dimensionally.

In the step (3), the temperature is preferably 90 ° C. or higher, more preferably 100 ° C. or higher, further preferably 110 ° C. or higher, and preferably 150 ° C. or lower, more preferably 140 ° C. or lower, still more preferably 130 ° C. or lower. Dry with. By drying at 90 ° C. or higher, the liquid dispersion medium is quickly removed, and it becomes easy to form a well-shaped closed space. By drying at 150 ° C. or lower, it becomes easy to prevent the shape and size of the closed space from becoming uneven and the support from being deformed.
The pressure condition and the atmosphere condition in the step (3) may be set in the same manner as described in the step (1).

In the step (3), from the viewpoint of preventing the liquid dispersion medium from remaining without being removed and deforming the shape of the closed space, it is preferably 10 seconds or longer, more preferably 30 seconds or longer, and further preferably 1 minute. Above, more preferably 5 minutes or more, particularly preferably 10 minutes or more, preferably 2 hours or less, more preferably 1 hour or less, still more preferably 30 minutes or less.

In the above-mentioned example, the composition containing the substance-encapsulating particles is applied onto the support and then dried, but the step of applying the composition to the support can be omitted. For example, by spraying the composition into particles by a spraying device such as a spray and drying each of the formed particles, there is no liquid dispersion medium on the outer surface (in other words, the surface is in a dry state). ) You may try to obtain a particulate structure. In this case, each particle formed by spraying may be dried while it is present in the air so that each particle becomes a dry individual particle, or the particles are sprayed toward a support or the like. A structure composed of agglomerates of a plurality of particles may be obtained, in which the outer surface is dried in a state where a plurality of particles are bonded by drying after the composition or by putting the composition in a mold and then drying.

The present invention will be specifically described with reference to the following examples, but the present invention is not limited to the following examples. The physical property values in the following production examples and examples are values measured by the following methods.

<Average diameter (thickness) of CNF, average length, average aspect ratio>
Using a transmission electron microscope (manufactured by Karl Zeiss, product name "LEO912"), the diameter (thickness) and length of 10 arbitrarily selected CNFs were measured, and the average value of 10 was used as the target. The "average diameter (thickness)" and "average length" of the CNFs are used. In addition, "average length" / "average diameter (thickness)" was defined as "average aspect ratio".
<Aqueous dispersion, pH of composition>
Two-point calibration of pH 4.01 standard solution and pH 6.86 standard solution using a compact pH meter (manufactured by HORIBA Advanced Techno Co., Ltd., product name "LAQUAtwin pH-22B") in an environment of 23 ° C. and 50% relative humidity. After that, a sample was dropped so as to cover the entire plane sensor for measurement.
<Melting point>
Using a differential scanning calorimeter (DSC) (manufactured by TA Instruments Japan Co., Ltd., product name "DSC Q2000"), the melting point of the sample [° C.] according to JIS K 7121: 2012 under the following conditions. ] Was measured.
-Measurement conditions: In the atmosphere, heating rate 10 ° C / min, measurement temperature range -85 ° C to + 100 ° C
More specifically, first, the temperature lowering rate is 10 ° C./min, the temperature is lowered from room temperature to -85 ° C., the heating rate is 10 ° C./min, the temperature is raised from -85 ° C. to + 100 ° C., and the temperature lowering rate is 10 ° C./min. Reduce to 85 ° C again. After that, a DSC curve is created when the temperature is raised to + 100 ° C. again at a heating rate of 10 ° C./min, and the temperature at the peak top of the largest endothermic peak is set as the melting point.

(Example 1)
1. 1. Preparation of Material Encapsulating Particle-Containing Composition E1 In preparing the substance-encapsulating particle-containing composition E1, the following commercially available aqueous dispersion containing CNF (1) and commercially available paraffin wax (1) were used.
-Aqueous dispersion (1) Product name "BiNFi-s AMa10002", manufactured by Sugino Machine Limited. An aqueous dispersion containing 2% by mass of a machine-treated CNF having an average diameter (thickness) of 76.8 nm, an average length of 1.4 μm, and an average aspect ratio of 18.2. The aqueous dispersion (1) contained 4,900 parts by mass of water with respect to 100 parts by mass of CNF, and the pH of the aqueous dispersion (1) was 7.0.
-Paraffin wax (1): Product name "Paraffin Wax-115", manufactured by Nippon Seiro Co., Ltd. The melting point was 48.9 ° C.
Water dispersion (1) 5,000 parts by mass (CNF 100 parts by mass) is put into a container, and an ultra-high-speed multi-stirring system (manufactured by Primix Corporation, product name "Lab Solution (registered trademark)", stirring blade: homodisper (Manufactured by the same company, wing diameter 35 mm)) was used to stir the aqueous dispersion at 90 ° C. at a rotation speed of 2,000 rpm. After the start of stirring, the paraffin wax (1) previously melted at 90 ° C. was added at a rate of 5 parts by mass every 10 seconds to 100 parts by mass of the total amount of the aqueous dispersion. With respect to 5,000 parts by mass (100 parts by mass of CNF) of the aqueous dispersion, the paraffin wax (1) was mixed with paraffin wax (1) until it became 500 parts by mass (CNF: paraffin wax = 1: 5 in terms of solid content ratio). The addition was continued, and after 20 minutes had passed from the start of stirring, stirring was terminated to prepare a substance-encapsulating particle-containing composition E1 containing a substance-encapsulating capsule having an outer shell containing CNF.

2. 2. Preparation of sheet-like structure E1 Material-encapsulating particle-containing composition E1 was applied to the easy-adhesion layer surface of a polyethylene terephthalate film with a thickness of 50 μm (Cosmo Shine (registered trademark) manufactured by Toyobo Co., Ltd., product number “A4100”, thickness: 50 μm). The film was placed gently, and the composition 1 was applied to the film using an applicator (coating gap: 254 μm (10 mil)). Further, the sheet-like structure E1 with a support was produced by heating at 120 ° C. for 10 minutes and drying.
All the steps from the preparation of the composition E1 to the coating were carried out in an air atmosphere under atmospheric pressure and at 23 ° C.

(Example 2)
A substance-encapsulating particle-containing composition E2 containing a substance-encapsulating capsule was prepared in the same manner as in Example 1 except that the following commercially available paraffin wax (2) was used instead of the paraffin wax (1).
-Paraffin wax (2): Product name "Paraffin Wax-135", manufactured by Nippon Seiro Co., Ltd. The melting point was 59.6 ° C.
Then, a sheet-like structure E2 with a support was produced by the same procedure as in Example 1 except that the composition E2 was used instead of the composition E1.

(Example 3)
A substance-encapsulating particle-containing composition E3 containing a substance-encapsulating capsule was prepared in the same manner as in Example 1 except that the following commercially available paraffin wax (3) was used instead of the paraffin wax (1).
-Paraffin wax (3): Product name "Paraffin Wax-155", manufactured by Nippon Seiro Co., Ltd. The melting point was 68.9 ° C.
Then, a sheet-like structure E3 with a support was produced by the same procedure as in Example 1 except that the composition E3 was used instead of the composition E1.

(Examples 4 and 5)
The substance-encapsulating particle-containing compositions E4 and E5 containing the substance-encapsulating capsule were prepared in the same procedure as in Example 2 except that the total amount of paraffin wax (2) added was changed to 100 parts by mass and 3,000 parts by mass, respectively. Prepared. Then, sheet-like structures E4 and E5 with a support were produced in the same procedure as in Example 2 except that the compositions E4 and E5 were used instead of the composition E2, respectively.

(Example 6)
A substance-encapsulating particle-containing composition E6 containing a substance-encapsulating capsule in the same manner as in Example 1 except that the following commercially available aqueous dispersion (2) containing CNF was used instead of the aqueous dispersion (1). Was prepared.
-Aqueous dispersion (2): Product name "TEMPO Oxidized CNF", manufactured by Nippon Paper Industries, Ltd. An aqueous dispersion containing 1% by mass of a chemically treated CNF having an average diameter (thickness) of 3.8 nm, an average length of 0.7 μm, and an average aspect ratio of 184. It contained 9,900 parts by mass of water with respect to 100 parts by mass of CNF, and the pH was 7.0.
Then, a sheet-like structure E6 with a support was produced by the same procedure as in Example 1 except that the composition E6 was used instead of the composition E1.

(Examples 7 and 8)
Compositions E7 and E8 containing substance-encapsulating capsules were prepared in the same manner as in Example 6 except that paraffin wax (2) and paraffin wax (3) were used instead of paraffin wax (1), respectively. Then, sheet-like structures E7 and E8 with a support were produced in the same procedure as in Example 6 except that the substance-encapsulating particle-containing compositions E7 and E8 were used instead of the composition E6, respectively.

(Example 9)
Instead of the paraffin wax (1), the following commercially available engine oil is used, and the temperature of the engine oil and the aqueous dispersion (1) at the time of adding the engine oil to the aqueous dispersion (1) is set to 23 ° C., and stirring is performed. A substance-encapsulating particle-containing composition E9 containing a substance-encapsulating capsule was prepared in the same manner as in Example 1 except that it was performed without heating.
-Engine oil: Product name "Audi genuine engine oil 5W-30", manufactured by Audi. The melting point was -14.5 ° C.
Then, a sheet-like structure E9 with a support was produced by the same procedure as in Example 1 except that the composition E9 was used instead of the composition E1.

(Example 10)
A substance-encapsulating particle-containing composition containing a substance-encapsulating capsule in the same manner as in Example 1 except that the following commercially available lanolin (1) 3,000 parts by mass was used instead of the paraffin wax (1) 500 parts by mass. E10 was prepared.
-Lanolin (1): Product name "Purified lanolin", manufactured by Sankei Sangyo Co., Ltd. The melting point was 45 ° C.
Then, a sheet-like structure E10 with a support was produced by the same procedure as in Example 1 except that the composition E10 was used instead of the composition E1.

(Example 11)
A substance-encapsulating particle-containing composition E11 containing a substance-encapsulating capsule was prepared in the same manner as in Example 6 except that lanolin (1) was used in an amount of 3,000 parts by mass instead of 500 parts by mass of paraffin wax (1). ..
Then, a sheet-like structure E11 with a support was produced by the same procedure as in Example 1 except that the composition E11 was used instead of the composition E1.

(Example 12)
Instead of the aqueous dispersion (1), the following commercially available aqueous dispersion (3) containing CNF is used, and instead of the paraffin wax (1), the following commercially available liquid paraffin (1) is used, and water is used. Same as in Example 1 except that the temperature of the liquid paraffin (1) and the aqueous dispersion (3) at the time of adding the liquid paraffin (1) to the dispersion liquid (3) was set to 23 ° C. and stirring was performed without heating. To prepare a substance-encapsulating particle-containing composition E12 containing a substance-encapsulating capsule.
-Aqueous dispersion (3): An aqueous dispersion prepared to contain 2% by mass of carboxymethylated CNF (CM-modified CNF) manufactured by Nippon Paper Industries, Ltd. under the product name "CM-modified CNF powder product". The average diameter (thickness) is 50 nm, the average length is about 2 μm, the average aspect ratio is about 40, and 100 parts by mass of CNF contains 4,900 parts by mass of water, and pH = 7. It was .0.
-Liquid paraffin (1) Product name "Moresco White P-350" manufactured by MORESCO Co., Ltd. The melting point was -16.2 ° C.
Then, a sheet-like structure E12 with a support was produced by the same procedure as in Example 1 except that the composition E12 was used instead of the composition E1.

(Comparative Example 1)
The comparative composition C1 was prepared in the same manner as in Example 1 except that the paraffin wax (1) was not blended.
Then, the support CE1 on which the CNF layer was formed was prepared by the same procedure as in Example 1 except that the comparative composition CE1 was used instead of the composition E1.

(Comparative Example 2)
Example 1 except that the blending amount of paraffin wax (2) was changed from 500 parts by mass to 100 parts by mass, and the method was changed to mix each component by hand using a spatula without using a stirrer. In the same manner, the comparative composition CE2 was prepared.
Then, a sheet-like structure CE2 with a support was produced by the same procedure as in Example 2 except that the comparative composition CE2 was used instead of the composition E1.

Table 1 summarizes the components used in Examples 1 to 12 and Comparative Examples 1 and 2 and their blending amounts.
Next, the following evaluations were performed on the structures produced in each example. The evaluation results are shown in Table 2.

[Maximum ferret diameter and average of closed space of structure]
The surface of each sheet-like structure is observed with a digital microscope at a magnification of 500 times, 36 closed spaces are arbitrarily selected from the obtained images, the maximum ferret diameter of each is measured, and the average value thereof is calculated. By doing so, the average maximum ferret diameter was used.

[Structure thickness]
The thickness of the sheet-like structure is measured by measuring the thickness of the entire sheet-like structure with the support using a constant-pressure film thickness meter, and the thickness of the known base material is reduced to reduce the thickness of the sheet-like structure (FIG. 1 (A)). Corresponds to the symbol L of) was calculated.

[Sheet strength]
Regarding the sheet-like structure with the support of Examples 1 to 12, the structure is peeled off from each support to form a single sheet-like structure, and the approach speed is 0 by using a plunger having a tip diameter of 1 mm. A creep test was performed by pressing to a depth of 15 mm at 5.5 mm / sec, and the maximum load at that time was taken as the sheet strength of the structure.
When the sheet strength is 0.10 N / 1 mmΦ or more, it is judged that the structure has self-supporting property, and when the sheet strength is less than 0.10 N / 1 mmΦ, the structure is insufficiently self-supporting. I decided.

[Surface condition of sheet-like structure]
At room temperature (23 ° C.), the surface material of each sheet-like structure and its dry state were confirmed by visual inspection and tactile sensation of the evaluator.
-When the encapsulated substance is not deposited and the outermost surface is a film formed of CNF: A
・ When the encapsulated substance is partially precipitated and there is a tactile sensation such as roughness or stickiness: B
・ When the inclusion substance is precipitated: F

[Retention of inclusion substances]
Each sheet-like structure was held at a temperature equal to or higher than the melting point of each encapsulated substance for 3 minutes, and the surface condition thereof was visually confirmed. Specific temperatures are Example 1, 6:55 ° C., Example 2, 4, 5, 7: 65 ° C., Example 3, 8:75 ° C., Example 10, 11:50 ° C., Example 9, The temperature was 12:23 ° C. If there was no leakage of the encapsulated substance from the sheet-like structure, it was evaluated as good "A", and if there was leakage, it was evaluated as bad "F".

As shown in Table 2, each of the sheet-like structures of Examples 1 to 12 has a closed space composed of a membrane containing CNF, and the closed space has an encapsulated substance. Was confirmed. Further, it can be seen that each sheet-like structure contains a large amount of encapsulated substance of 50% by mass or more. Further, it can be seen that the sheet-like structures of Examples 1 to 3 and 5 to 12 contain a larger amount of the encapsulated substance exceeding 83% by mass. Further, it can be seen that the structures of Examples 5, 10 and 11 contain a larger amount of the inclusion substance exceeding 95% by mass. Further, it can be seen that the structures of Examples 1 to 12 all have a sheet strength of 0.10 N / 1 mmΦ or more and have self-supporting property. The structures of Examples 1 to 8 have a higher sheet strength of 0.15 N / 1 mmΦ or more, and the structures of Examples 1, 3 to 5, 7, and 8 have a higher sheet strength. There is. Further, in the structures of Examples 1 to 12, no encapsulated substance is precipitated on the surface of the structure at room temperature, and even if the structure is held at a temperature equal to or higher than the melting point of the encapsulated substance for 3 minutes, the encapsulated substance is not deposited. Can be seen to be held inside the structure.

On the other hand, in Comparative Example 1, since the substance to be included was not blended, a self-supporting structure could not be obtained, and the obtained structure was clogged with a membrane containing CNF. The space could not be formed.
Further, in Comparative Example 2, although paraffin wax (2), which is a substance to be included, is used, phase separation occurs during the preparation of the composition, and a closed space composed of a membrane containing CNF is formed. It was not formed and no capsule containing paraffin wax (2) was formed. Further, for this reason, it was not possible to properly coat the support, and in addition, the paraffin wax (2) was eluted when the temperature was raised.

30: Material-encapsulating particle-containing composition 31: Material-encapsulating layer (sheet-like structure) having a plurality of closed spaces
32: Particles having an outer shell containing CNF 33, 33a, 33b: Closed space 34: Medium mainly containing a liquid dispersion medium 35: Film containing CNF 35a: Membrane shared by a set of adjacent closed spaces 36: Encapsulating substance 40: Support 40a: Coating surface 50: Sheet-like structure with support df: Maximum ferret diameter of closed space P: Partial region of surface of sheet-shaped structure L: Having a plurality of closed spaces Thickness of material inclusion layer (sheet-like structure)

Claims (15)

A structure including a membrane containing cellulose nanofibers and a closed space composed of the membrane.
A structure having an encapsulated substance in the enclosed space. The structure according to claim 1, wherein the encapsulated substance is a liquid or a solid at normal temperature and pressure. The structure according to claim 1 or 2, wherein the inclusion substance has a melting point of −100 ° C. to + 90 ° C. The first surface of the film faces the inclusion material, and the second surface opposite to the first surface of the film is at least one of a substance, gas, and solid having the same composition as the inclusion material. The structure according to any one of claims 1 to 3, which is in contact with. The structure according to any one of claims 1 to 4, wherein the content of the inclusion substance is 30 to 98% by mass with respect to the volume of the entire structure. The structure according to any one of claims 1 to 5, which has a plurality of the closed spaces. The structure according to claim 6, wherein a set of adjacent closed spaces among the plurality of objects share the membrane. The structure according to claim 6 or 7, wherein the structure has a sheet shape. The structure according to claim 8, wherein the structure has a thickness of 0.5 to 300 μm. The structure according to claim 8 or 9, which is self-supporting by itself. The structure according to any one of claims 6 to 10, wherein the average of the maximum ferret diameters of the plurality of closed spaces of the structure is 1 μm to 60 μm. A structure with a support, wherein the structure according to any one of claims 1 to 11 is provided on the support. The method for manufacturing a structure according to any one of claims 1 to 12.
The inclusion substance is added to the dispersion liquid in which the cellulose nanofibers are dispersed, and the inclusion substance is added.
The dispersion liquid to which the encapsulated substance is added is stirred at a temperature at which the encapsulated substance becomes liquid, and at least a part of the encapsulated substance is in a space surrounded by an outer shell containing the cellulose nanofibers. A method for producing a structure, which comprises producing the particles incorporated in the structure to obtain the structure. The method for producing a structure according to claim 13, wherein the encapsulated substance is heated to change the phase from a solid to a liquid, and then added to the dispersion. The dispersion liquid containing the particles is applied onto the support to form a coating layer, and the coating layer is formed.
The method for producing a structure according to claim 13 or 14, wherein the coating layer is dried to form the structure.