WO2020050154A1

WO2020050154A1 - Composition

Info

Publication number: WO2020050154A1
Application number: PCT/JP2019/034045
Authority: WO
Inventors: 翔大高; 和恵上村; 高志阿久津; 宮田　壮
Original assignee: リンテック株式会社
Priority date: 2018-09-03
Filing date: 2019-08-30
Publication date: 2020-03-12
Also published as: JPWO2020050154A1

Abstract

A composition that contains particles into which an organic solvent has been taken in, and which are able to supply the organic solvent to the outside by having shells that are broken when a pressure of a predetermined value or higher is applied thereto, while having sustained release properties that enable the organic solvent to be released to the outside little by little over time. This composition is obtained by blending (A) cellulose nanofibers, (B) water and (C) an organic solvent; and the blending amount of the cellulose nanofibers (A) is 0.7% by mass or more relative to the total amount of the composition. This composition contains particles which are provided with shells that contain the cellulose nanofibers (A), and into which at least some of the organic solvent (C) has been taken in.

Description

Composition

The present invention relates to a composition.

Cellulose fibrils, one of the fibrous polysaccharides, have been studied for application to a wide range of uses such as agriculture, food, cosmetics, drugs, and filters. In particular, in recent years, cellulose nanofibers obtained by miniaturizing the cellulose fibrils by various methods have attracted attention as new materials.
For example, Patent Document 1 describes a filter medium for an air filter in which cellulose nanofibers having a number average fiber diameter of 1 to 50 nm are adhered at a predetermined ratio to a support having air permeability.
Patent Document 1 describes that the cellulose nanofiber used for the air filter material has a particle collecting performance.

JP 2017-177091 A

By the way, for example, in the fields of agriculture, food, cosmetics, pharmaceuticals, etc., the organic solvent has the property of gradually releasing the organic solvent to the outside with time (slow release) while taking in the organic solvent. The formation of capsule-like particles may be required.
In addition, the composition containing such particles generally supplies the organic solvent to the outside by suppressing the release of the organic solvent to the outside, and by applying pressure when necessary to break the outer shell of the particles. Therefore, the present invention can be applied to applications where such characteristics are required.

General cellulose fibrils have a function of replacing a surfactant and are amphiphilic materials having a hydrophilic group and a hydrophobic site. Therefore, it is possible to adsorb an organic solvent by using cellulose fibrils.
However, when an organic solvent is adsorbed using a general cellulose fibril, it does not have a property of gradually releasing the adsorbed organic solvent to the outside over time, that is, a sustained release property. Further, the organic solvent is in a state of being adsorbed on the surface of the fibrous material of the cellulose fibrils, and particles such as capsules incorporating the organic solvent are not formed.

The present invention is a particle incorporating an organic solvent, has a sustained release property that can gradually release the organic solvent to the outside over time, and the outer shell when a certain or more pressure is applied It is an object of the present invention to provide a composition containing particles that can be broken to supply an organic solvent to the outside.

The present inventors have conducted various studies and found that, in a composition comprising cellulose nanofibers, water, and an organic solvent, the blending amount of cellulose nanofibers is adjusted to be within a predetermined range. Thus, it was found that a composition containing particles having an outer shell containing cellulose nanofibers could be obtained.
The present invention has been completed based on this finding.

That is, the present invention relates to the following [1] to [13].
[1] A composition comprising a cellulose nanofiber (A), water (B), and an organic solvent (C),
The compounding amount of the cellulose nanofiber (A) is 0.7% by mass or more based on the total amount of the composition,
Containing particles having an outer shell containing cellulose nanofibers (A),
A composition in which at least a part of the organic solvent (C) is in a state of being incorporated in the particles.
[2] The composition according to the above [1], wherein a mixing ratio of water (B) to the organic solvent (C) [(B) / (C)] is from 0.1 to 1000 in terms of mass ratio. .
[3] At least one of a state in which at least a part of the organic solvent (C) is included in the particles and a state in which the organic solvent (C) is adsorbed on the cellulose nanofibers (A) forming the outer shell of the particles. The composition according to the above [1] or [2], which is:
[4] The composition according to any one of [1] to [3], wherein a solid content in the composition is 80 to 100% by mass based on the total amount of the composition.
[5] The composition according to any one of [1] to [4], wherein the composition has a viscosity at 23 ° C. and 50 rpm of 500 to 20,000 mPa · s.
[6] The composition according to any one of [1] to [5], wherein the composition has a TI value at 23 ° C. (viscosity at a rotation speed of 5 rpm / viscosity at a rotation speed of 50 rpm) of 1.2 to 20. A composition as described.
[7] The composition according to any one of [1] to [6], wherein the average of the diameter (thickness) of the cellulose nanofiber (A) is 1 to 1000 nm.
[8] The composition according to any one of [1] to [7] above, wherein the average fiber length of the cellulose nanofiber (A) is 0.01 to 10 μm.
[9] The composition according to any one of [1] to [8] above, wherein the amount of the organic solvent (C) is 0.05 to 80% by mass based on the total amount of the composition. .
[10] The composition according to any one of [1] to [9], wherein the blending amount of the cellulose nanofiber (A) is 0.7 to 15% by mass based on the total amount of the composition. object.
[11] The composition according to any one of [1] to [10], wherein the organic solvent (C) contains an organic solvent (C1) having less than 20 carbon atoms.
[12] The composition according to any one of the above [1] to [11], wherein the content of the surfactant is less than 10 parts by mass relative to 100 parts by mass of the total amount of the cellulose nanofiber (A). object.
[13] Any of the above [1] to [12], wherein the content of the polysaccharide other than the cellulose nanofiber (A) is less than 10 parts by mass based on 100 parts by mass of the total amount of the cellulose nanofiber (A). A composition according to any one of the preceding claims.

The particles contained in the composition of the present invention are particles incorporating an organic solvent, have a sustained release property of gradually releasing the organic solvent to the outside over time, and maintain a constant or higher pressure. When applied, the outer shell is broken and the organic solvent can be supplied to the outside.

9 is an image obtained when the composition prepared in Example 7 was observed with a digital microscope. It is a schematic diagram of the measurement sample for observing the composition prepared by the Example and the comparative example with a digital microscope, (a) is a schematic plan view of the measurement sample in the middle of manufacture, (b) is the manufacture FIG. 5 is a schematic front view of a measurement sample obtained.

〔Composition〕
The composition of the present invention comprises cellulose nanofiber (A), water (B), and an organic solvent (C), and comprises particles having an outer shell containing cellulose nanofiber (A). contains. Hereinafter, the cellulose nanofiber (A), water (B), and organic solvent (C) may be collectively referred to as “components (A) to (C)”.
FIG. 1 is an image obtained when the composition prepared in Example 7 described below was observed with a digital microscope.
As shown in FIG. 1, the composition of the present invention contains particles, which are composed of an outer shell containing cellulose nanofibers (A).
In the composition of the present invention, at least a part of the organic solvent (C) is in a state of being taken in by the particles, and specifically, in a state of being included in the particles, and in an outer shell of the particles. It is preferable that at least one of the state in which the cellulose nanofiber (A) is adsorbed is present.
Here, "the state in which the organic solvent (C) is included in the particles" means that hollow particles are formed from the outer shell containing the cellulose nanofiber (A), and the organic solvent (C) is formed in the hollow portion of the hollow particles. ) Means the state is taken in. At this time, the organic solvent (C) is separated from the outside of the hollow particles by the outer shell constituting the hollow particles.

In the composition of one embodiment of the present invention, the particles contain the organic solvent (C), and the cellulose nanofibers (A) constituting the outer shell of the particles adsorb the organic solvent (C). It may be in the state where it is. In this specification, "the outer shell composed of the cellulose nanofiber (A) adsorbs the organic solvent (C)" means that the organic solvent is contained in the network structure of the outer shell composed of the cellulose nanofiber (A). (C) means that it exists.

Cellulose nanofibers (A) contained in the outer shell of the particles have a fine structure as compared with general cellulose fibrils such as pulp, and therefore have a large surface area per unit mass. The amount of the organic solvent (C) attracted to the surface of the cellulose nanofiber (A) also increases.
Further, the cellulose nanofiber (A) has a large force to attract the organic solvent (C) to the surface because a plurality of fibers are entangled with each other to form an outer shell. It is easy to maintain the state where the organic solvent (C) is taken into the network structure (that is, the state where the organic solvent (C) is adsorbed).
Therefore, during and for a while after the formation of the particles, the organic solvent (C) is incorporated into the particles (ie, within the network structure of the outer shell, unless intentionally applying a constant or higher pressure). In addition, the state in which the organic solvent (C) is present in the space inside the outer shell) is maintained, and it becomes difficult for a large amount of the organic solvent (C) to be released to the outside.

On the other hand, the organic solvent (C) taken in the particles is not completely sealed with the outside of the particles, but can be gradually released to the outside of the particles over time.
That is, the particles contained in the composition of the present invention have the outer shell containing the cellulose nanofiber (A) as described above. Since the cellulose nanofiber (A) is a fibrous material, the outer shell containing the cellulose nanofiber (A) has many voids. Then, the organic solvent (C) taken into the particles can be released to the outside of the particles over time from the void.

From the above, it is difficult for the particles to release a large amount of the organic solvent (C) taken in after the formation in a short period of time or in a state where no load is applied, but the particles gradually release the organic solvent (C) to the outside over time. It can be said that it has a sustained release property.

In addition, since the outer shell of the particles contains the cellulose nanofibers (A), the film strength is high, and it is difficult to break under normal conditions of no load or low load. On the other hand, the particles can be easily broken by applying a certain or more pressure, and the captured organic solvent (C) can be supplied to the outside at once.
Note that in the composition of one embodiment of the present invention, an organic solvent (C) that is not incorporated into the particles may be present.

Further, water (B) may be incorporated into the particles together with the organic solvent (C).
Further, a gas such as air may be taken into the particles. In the stirring step at the time of the formation of the particles, a gas such as air is mixed into the composition, but it is conceivable that a gas such as air is taken into the inside of the outer shell constituting the particles.

By the way, the cellulose nanofiber (A) forms a hydrogen bond with water (B), and thus has a high affinity for water (B).
Therefore, the outer shell containing the cellulose nanofibers (A) of the particles may be in a state of adsorbing water (B). That is, the particles may be in a state where the organic solvent (C) is taken in and the water (B) is adsorbed on the outer shell.

In the composition of the present invention, the larger the amount of the organic solvent (C) incorporated into the particles, the smaller the amount of the liquid composed of the organic solvent (C) present separately from the particles.
Further, the particles having the outer shell containing the cellulose nanofibers, and the cellulose nanofibers that do not form the particles and are dispersed in water, retain water so that the water interacts with a large number of water molecules as a dispersion medium. Therefore, it is considered that the amount of liquid composed of water (B) present separately from the cellulose nanofiber (A) is reduced. From the viewpoint of preventing the particles from settling or aggregating by reducing the amount of the liquid existing apart from the particles, the solid content ratio in the composition is preferably as large as possible.
The solid content in the composition of one embodiment of the present invention is preferably from 80 to 100% by mass, more preferably from 90 to 100% by mass, and still more preferably from 95 to 100% by mass, based on the total amount (100% by mass) of the composition. -100% by mass, more preferably 98-100% by mass.

In the present specification, the “solid content ratio” in the composition refers to the ratio of the solid content remaining on the tetron mesh after the composition is applied on a tetron mesh (# 200 mesh) and allowed to stand. And specifically, a value measured by the method described in Examples.
The solid content remaining on the tetron mesh described above includes not only the cellulose nanofiber (A), but also the organic solvent (C) incorporated in the particles, and the water ( B), and the mass of water (B) and the like retained in the cellulose nanofibers (A) that are not involved in the formation of the outer shell of the particles.
Therefore, a composition having a high solid content means at least one of the following [A] and [B].
[A] A large amount of at least one of water (B) and the organic solvent (C) is taken into the three-dimensional network structure of the outer shell constituted by the cellulose nanofiber (A) and the space inside the outer shell. ing.
[B] At least one of a large amount of water (B) and an organic solvent (C) is held in the cellulose nanofiber (A) which is not involved in the formation of the outer shell of the particles.

The average particle diameter of the particles contained in the composition of one embodiment of the present invention is preferably 1 μm or more, more preferably 5 μm or more, and still more preferably 7 μm or more, from the viewpoint of suppressing aggregation of the particles in the composition. And still more preferably 10 μm or more, particularly preferably 15 μm or more, and from the viewpoint of suppressing the floating of particles in the composition, preferably 60 μm or less, more preferably 50 μm or less, still more preferably 40 μm or less, and even more. Preferably it is 35 μm or less, particularly preferably 30 μm or less.

Further, the standard deviation with respect to the average particle diameter of the particles contained in the composition of one embodiment of the present invention is such that when a constant pressure is applied to break the outer shell of the particles, the organic solvent incorporated in the particles is used. From the viewpoint of stabilizing the release amount of, the thickness is preferably 20 µm or less, more preferably 18 µm or less, further preferably 15 µm or less, more preferably 12 µm or less, and usually 1 µm or more.

In this specification, the average particle size of the particles and the standard deviation with respect to the average particle size are calculated from images obtained when the target composition is observed at a magnification of 500 to 1000 using a digital microscope. can do.
In other words, the average value of the particle diameters (outer diameters of the outer shells constituting the particles) of the 36 particles arbitrarily selected among the particles displayed in the image is defined as the “average particle diameter”. it can. 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. In the above calculation, the standard deviation is calculated for all 36 particle size values.

The average thickness of the outer shell of the particles contained in the composition of one embodiment of the present invention is preferably 10 nm or more, more preferably 50 nm or more, and still more preferably, from the viewpoint of improving the shape stability of the particles. Is 75 nm or more, and from the viewpoint of easily breaking the outer shell of the particle by applying a constant or more pressure, preferably 2000 nm or less, more preferably 1750 nm or less, still more preferably 1500 nm or less, even more preferably It is 1250 nm or less.

In the present specification, the thickness of the outer shell of the particles, the target composition, after coating and drying on a support material such as a polyethylene terephthalate film to form a coating, the cross-section of the coating Can be calculated based on an image obtained when observed using a scanning electron microscope (SEM) or the like.
In other words, the average value of the outer shells of the particle diameters of the 36 particles arbitrarily selected among the particles shown in the image can be the above-mentioned “average of outer shell thickness”.

The viscosity of the composition of one embodiment of the present invention at 23 ° C. and a rotation speed of 50 rpm is preferably 500 mPa · s or more, and more preferably, from the viewpoint of improving storage stability and suppressing sedimentation when stored in a container. 1000 mPa · s or more, more preferably 1200 mPa · s or more, and from the viewpoint of improving the ease of stirring and taking out of the container, preferably 20,000 mPa · s or less, more preferably 15000 mPa · s or less, and still more preferably. Is 12000 mPa · s or less.

The TI value of the composition of one embodiment of the present invention at 23 ° C. (viscosity at a rotation speed of 5 rpm / viscosity at a rotation speed of 50 rpm) indicates good storage stability and suppresses sedimentation when stored in a container. From the viewpoint, it is preferably 1.2 or more, more preferably 2 or more, still more preferably 3 or more, and still more preferably 4 or more, and preferably 20 or less from the viewpoint of improving the removability from the container. It is more preferably 15 or less, further preferably 10 or less, and still more preferably 8 or less.
In this specification, the viscosity of the composition means a value measured using a B-type viscometer according to JIS Z 8803: 2011.

The pH of the composition of one embodiment of the present invention is preferably 4 or more, more preferably 5 or more, and still more preferably 6 or more, from the viewpoint that the formed particles are stable and the dispersion state is easily maintained in the composition. And preferably 10 or less, more preferably 9 or less, and still more preferably 8 or less.
In addition, in this specification, the pH of a composition means the value measured based on the method of an Example in 23 degreeC and 50% of relative humidity environment.

The composition of one embodiment of the present invention may contain components other than the above components (A) to (C).
However, in the composition of one embodiment of the present invention, the total content of the cellulose nanofiber (A), water (B), and organic solvent (C) is preferably based on the total amount of the composition (100% by mass). Is from 60 to 100% by mass, more preferably from 65 to 100% by mass, further preferably from 70 to 100% by mass, even more preferably from 80 to 100% by mass.

The active ingredient concentration of the composition of one embodiment of the present invention is preferably such that the particles are easily formed and the film strength of the formed particles is improved with respect to the total amount of the composition (100% by mass). It is preferably at least 0.5% by mass, more preferably at least 0.7% by mass, still more preferably at least 1.0% by mass, and still more preferably at least 1.5% by mass. From the viewpoint of appropriately adjusting the viscosity of the composition, the content is preferably 50% by mass or less, more preferably 20% by mass or less, further preferably 15% by mass or less, and further more preferably 10% by mass or less.
In addition, in this specification, "active ingredient" means the component except water (B) and organic solvent (C) among the components contained in a composition, and specifically, a cellulose nanofiber ( A), polysaccharides other than cellulose nanofiber (A), and various additives. In other words, it differs from the above-mentioned “solid content” in that the mass of the organic solvent (C) and water (B) taken into the cellulose nanofiber (A) is not included.

In the composition of the present invention, by setting the blending amount of the cellulose nanofiber (A) within a predetermined range, particles having the outer shell containing the cellulose nanofiber (A) and incorporating the organic solvent (C) are formed. Making it easier.
In addition, in addition to the above, the shape (diameter, fiber length, aspect ratio) of the cellulose nanofiber (A), the blending amount of water (B) and the organic solvent (C), the water (B) and the organic solvent (C) The particles can be formed more easily by appropriately setting the compounding ratio of the particles.
Hereinafter, each component will be described in detail, focusing on a specific method for forming the particles.

<Cellulose nanofiber (A)>
As a raw material of the cellulose nanofiber (A) used in one embodiment of the present invention, for example, wood-derived kraft pulp or sulfite pulp; powdered cellulose obtained by grinding kraft pulp or sulfite pulp with a high-pressure homogenizer or a mill; Microcrystalline cellulose powder obtained by purifying pulp by chemical treatment such as acid hydrolysis; bast fiber pulp such as mulberry, ganpi, mitsumata, etc .; cellulosic raw material derived from plants such as cotton pulp, kenaf, hemp, rice, bacas, bamboo; Cellulose-based raw materials.

If a large amount of lignin remains in these raw materials, the oxidation reaction of the raw materials may be hindered. Therefore, a cellulose-based raw material obtained by removing lignin from these raw materials is preferable.
Further, the above-mentioned cellulose-based raw material may be used as finely divided by a high-speed rotation type, colloid mill type, high pressure type, roll mill type, ultrasonic type or other dispersing device, wet type high pressure or ultra high pressure homogenizer, or the like.

In addition, these cellulosic raw materials may be those having improved functionality by chemical modification and / or physical modification. Here, the chemical modification includes acetylation, carboxylation, carboxysodiumation, esterification, cyanoethylation, acetalization, etherification, arylation, alkylation, acryloylation, addition of a functional group by isocyanation, etc. And a method in which an inorganic substance such as silicate or titanate is compounded or coated by a chemical reaction, a sol-gel method, or the like.
In addition, as the physical modification, a metal or ceramic raw material is subjected to a physical vapor deposition method (PVD method) such as vacuum deposition, ion plating, and sputtering, a chemical vapor deposition method (CVD method), and a plating method such as electroless plating and electrolytic plating. Surface coating.
These modification treatments may be performed either at the time of defibrating the cellulose-based material or before or after defibrating.

The above-mentioned cellulose-based material can be made into cellulose nanofibers by defibrating and forming nanofibers.
As a specific method, after preparing a dispersion in which the cellulose-based material is dispersed in a dispersion medium such as water, a shear force is applied to the cellulose-based material to obtain a dispersion containing cellulose nanofibers. Is mentioned.
As a method of applying a shearing force to the cellulosic material, after adding the cellulosic material to a dispersion medium such as water, using a high-speed rotation type, a colloid mill type, a high pressure type, a roll mill type, an ultrasonic type or the like, The method of preparation is preferred.
At this time, the pressure applied to the dispersion is preferably 50 MPa or more, more preferably 100 MPa or more, and still more preferably 140 MPa or more.
From the viewpoint of applying a strong shearing force to the cellulosic material under such a high pressure, it is preferable to use a wet high-pressure or ultra-high-pressure homogenizer.

The average of the diameter (thickness) of the cellulose nanofiber (A) used in one embodiment of the present invention is preferably 1. from the viewpoint of facilitating the formation of the particles and improving the film strength of the formed particles. 0 nm or more, more preferably 1.5 nm or more, still more preferably 2.0 nm or more, even more preferably 2.5 nm or more, and preferably 1000 nm or less, more preferably 500 nm or less, and still more preferably 200 nm or less. More preferably, it is 100 nm or less.

The average of the fiber length of the cellulose nanofiber (A) used in one embodiment of the present invention is preferably 0.01 μm or more from the viewpoint of facilitating the formation of the particles and improving the film strength of the formed particles. It is more preferably at least 0.1 μm, further preferably at least 0.2 μm, even more preferably at least 0.3 μm, and preferably at most 10 μm, more preferably at most 7.0 μm, even more preferably at most 5.0 μm, Even more preferably, it is 2.5 μm or less.

The average aspect ratio of the cellulose nanofiber (A) used in one embodiment of the present invention is preferably 5 or more, more preferably 5 or more, from the viewpoint of facilitating the formation of the particles and improving the film strength of the formed particles. It is 10 or more, more preferably 15 or more, and preferably 10,000 or less, more preferably 5,000 or less, further preferably 3,000 or less, still more preferably 1,000 or less, and particularly preferably 500 or less.

The “aspect ratio” is a ratio of the length to the thickness of the target cellulose nanofiber [length / thickness], and the “length” of the cellulose nanofiber is the most of the cellulose nanofiber. Refers to the distance between two distant points.
If a part of the target cellulose nanofiber is in contact with another cellulose nanofiber and it is difficult to determine the “length”, only the part of the target cellulose nanofiber whose thickness can be measured can be used. Is measured, and the aspect ratio of the portion may be within the above range.

The composition of the present invention is prepared so that the blending amount of the cellulose nanofiber (A) is 0.7% by mass or more based on the total amount (100% by mass) of the composition.
If the blending amount of the cellulose nanofiber (A) is less than 0.7% by mass, it is difficult to form the particles, and the film strength tends to be poor.
From the above viewpoint, the blending amount of the cellulose nanofiber (A) is preferably 0.8% by mass or more, more preferably 1.0% by mass or more, and still more preferably, based on the total amount (100% by mass) of the composition. Is 1.2% by mass or more.
The diameter (thickness) and fiber length of the cellulose nanofiber (A) can be measured using a transmission electron microscope. The average of the diameter (thickness) and the average of the fiber length of the cellulose nanofibers (A) are obtained by measuring the diameter (thickness) and the fiber length of a plurality of arbitrarily selected cellulose nanofibers, and calculating the average value of each. It is obtained by calculating. The average aspect ratio of the cellulose nanofiber (A) can be calculated using the thus obtained average of the diameter (thickness) and the average of the fiber length. The diameter (thickness), fiber length, average value, and average aspect ratio of the cellulose nanofiber (A) can be specifically calculated by the methods described in Examples.

In the composition of one embodiment of the present invention, from the viewpoint of appropriately adjusting the viscosity of the composition so that the particles are easily formed, the blending amount of the cellulose nanofiber (A) is determined based on the total amount of the composition. (100% by mass), 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% by mass or less, particularly preferably 3% by mass or less. .

<Water (B)>
In the composition of one embodiment of the present invention, most of the water (B) is adsorbed on the outer shell of the particle, or is present outside the particle.
However, a part of the water (B) may be included together with the organic solvent (C) inside the particles.

In the composition of one embodiment of the present invention, from the viewpoint of preparing a composition having an appropriate viscosity and facilitating the formation of the particles, the blending amount of water (B) is determined based on the total amount of the composition (100% by mass). ), 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 composition of one embodiment of the present invention, from the viewpoint of preparing a composition having an appropriate viscosity and facilitating the formation of the particles, the mixing ratio of water (B) to 100 parts by mass of the cellulose nanofiber (A) Is preferably 500 parts by mass or more, more preferably 1000 parts by mass or more, still more preferably 2000 parts by mass or more, still more preferably 3000 parts by mass or more, and preferably 20,000 parts by mass or less, more preferably 15,000 parts by mass. Parts by mass, more preferably 10,000 parts by mass or less.

Note that the composition of one embodiment of the present invention is preferably formed by mixing an organic solvent (C) with an aqueous dispersion containing cellulose nanofibers (A) and water (B).
By preparing the aqueous dispersion in advance and blending the organic solvent (C), the cellulose nanofiber (A) can easily take in the organic solvent (C), and the particles can be easily formed.
It is preferable that the aqueous dispersion is prepared by blending the respective components such that the blending ratio of the cellulose nanofiber (A) and the water (B) is within the above range.
Further, the aqueous dispersion may contain components other than the components (A) to (C) together with the cellulose nanofiber (A) and the water (B).

<Organic solvent (C)>
The organic solvent (C) used in one embodiment of the present invention can be appropriately selected depending on the use of the composition. For example, heptane, n-hexadecane, toluene, cyclohexanone, methyl ethyl ketone, n-dodecane, tetrahydrofuran, xylene Butyl acetate, cyclohexane, 1,4-dioxane, styrene, normal hexane, gasoline, turpentine, phenol and the like.
The organic solvent (C) used in the composition of the present invention may be used alone or as a mixed solvent using two or more kinds.

The organic solvent (C) used in one embodiment of the present invention preferably contains an organic solvent (C1) having less than 20 carbon atoms.
The organic solvent (C1) having less than 20 carbon atoms is easily taken into the cellulose nanofiber (A), and the particles are easily formed.
That is, in an organic solvent having a large number of carbon atoms, molecules of the organic solvent are likely to collect with each other, and since the viscosity is high, it is difficult to form particles close to a true sphere. As a result, it is considered that such an organic solvent is not taken into the cellulose nanofiber (A), but remains at a higher rate outside the particles.
In addition, the carbon number of the organic solvent (C1) is preferably less than 20, more preferably 1 to 18, and still more preferably 1 to 16.

From the above viewpoint, the blending ratio of the organic solvent (C1) in the organic solvent (C) is preferably 20% by mass or more, more preferably 35% by mass or more based on the total amount (100% by mass) of the organic solvent (C). , More preferably 50% by mass or more, even more preferably 70% by mass or more.

Further, among the organic solvents (C1), one or more organic solvents (C2) selected from heptane, n-hexadecane, toluene, cyclohexanone, methyl ethyl ketone, and n-dodecane are preferred.
By including these organic solvents (C2), the particles can be more easily formed.
From the viewpoint of facilitating the formation of the particles, the mixing ratio of the organic solvent (C2) in the organic solvent (C) is preferably 20% by mass or more based on the total amount (100% by mass) of the organic solvent (C). It is more preferably at least 35% by mass, further preferably at least 50% by mass, even more preferably at least 70% by mass.

In the composition of one embodiment of the present invention, from the viewpoint of facilitating the formation of the particles, the viscosity of the organic solvent (C) at 25 ° C is preferably 0.1 mPa · s or more, more preferably 0.15 mPa · s. s or more, more preferably 0.2 mPa · s or more, even more preferably 0.25 mPa · s or more, and preferably 30 mPa · s or less, more preferably 10 mPa · s or less, and still more preferably 6.0 mPa · s or less. s or less, more preferably 2.8 mPa · s or less.

In the composition of one embodiment of the present invention, from the viewpoint of facilitating the formation of the particles, the amount of the organic solvent (C) is preferably 0.05% by mass based on the total amount (100% by mass) of the composition. % Or more, more preferably 0.1% by mass or more, still more preferably 0.5% by mass or more, even more preferably 0.8% by mass or more, and preferably 80% by mass or less, more preferably 60% by mass. %, More preferably 45% by mass or less, further preferably 42% by mass or less, further preferably 40% by mass or less, and still more preferably 38% by mass or less.

In the composition of one embodiment of the present invention, from the viewpoint of facilitating the formation of the particles, the compounding ratio [(C) / (A)] of the organic solvent (C) and the cellulose nanofiber (A) is expressed by mass ratio , Preferably 0.01 or more, more preferably 0.05 or more, more preferably 0.1 or more, further preferably 0.5 or more, further preferably 0.75 or more, and still more preferably 0.9 parts by mass. It is preferably at most 60, more preferably at most 45, even more preferably at most 40, even more preferably at most 35.

In the composition of one embodiment of the present invention, from the viewpoint of facilitating the formation of the particles, the blending ratio [(B) / (C)] of water (B) and the organic solvent (C) is expressed by mass ratio, It is preferably at least 0.1, more preferably at least 0.5, further preferably at least 1.0, even more preferably at least 1.5, and preferably at most 1,000, more preferably at most 700, still more preferably It is at most 500, more preferably at most 300, particularly preferably at most 100.

<Other components other than components (A) to (C)>
The composition of one embodiment of the present invention 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 according to the use of the composition, and include, for example, a colorant, an antioxidant, a pH adjuster, a sweetener, a flavor, a preservative, an ultraviolet absorber, and a polymerization inhibitor. Agents, fungicides, insecticides, defoamers, foaming agents, flocculants, thickeners, plasticizers, modifiers, flame retardants, flame retardants and the like.

In the composition of one embodiment of the present invention, a surfactant may be contained.
However, when the composition containing a surfactant is used for the purpose of touching the human body, the surfactant also becomes a penetrant and an irritating irritant, especially for users with sensitive skin. Further, there is a concern that the composition containing a surfactant may affect the stability of physical properties of the composition.
Therefore, in the composition of one embodiment of the present invention, the content of the surfactant is preferably as small as possible.
From the above viewpoint, in the composition of one embodiment of the present invention, the content of the surfactant 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 the cellulose nanofiber (A). Less than 0.1 part by mass, more preferably less than 0.01 part by mass, particularly preferably less than 0.001 part by mass, and most preferably 0 part by mass.

Further, the composition of one embodiment of the present invention may contain a polysaccharide other than the cellulose nanofiber (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 better.
From the above viewpoint, in the composition of one embodiment of the present invention, the content of the polysaccharide other than the cellulose nanofibers (A) is preferably less than 10 parts by mass relative to 100 parts by mass of the total amount of the cellulose nanofibers (A). , More preferably less than 1 part by mass, further preferably less than 0.1 part by mass, still more preferably less than 0.01 part by mass, particularly preferably 0 part by mass.

(Production method of the composition)
The method for producing the composition of the present invention is not particularly limited, but a method having the following steps (1) and (2) is preferable from the viewpoint of facilitating the formation of the particles.
Step (1): a step of preparing an aqueous dispersion containing the cellulose nanofiber (A) and water (B).
Step (2): a step of adding an organic solvent (C) to the aqueous dispersion obtained in Step (1).
The details of the components (A) to (C) used in the steps (1) and (2) are as described above.

<Step (1)>
Step (1) is a step of preparing an aqueous dispersion containing cellulose nanofibers (A) and water (B).
In the case where a commercially available aqueous dispersion is used in this step, the step may be omitted. In addition, the cellulose nanofiber (A) or water (B) is added to the commercially available aqueous dispersion, and a desired blending is performed. It may be prepared in a volume of aqueous dispersion.

When components other than the components (A) to (C) are blended, they may be blended in the preparation of the aqueous dispersion in the step (1), and the steps (1) and (2) May be added during the step (2), may be added during the step (2), or may be added after the step (2).

The pH of the aqueous dispersion obtained in the step (1) is preferably from the viewpoint of suppressing aggregation of the cellulose nanofibers (A) in the aqueous dispersion and reducing variations in the shape and size of the formed particles. It is 4 or more, more preferably 5 or more, still more preferably 6 or more, and preferably 10 or less, more preferably 9 or less, and still more preferably 8 or less.

<Step (2)>
Step (2) is a step of adding an organic solvent (C) to the aqueous dispersion obtained in step (1).
In this step, it is preferable to add the organic solvent (C) while stirring the aqueous dispersion using a stirrer equipped with a stirring blade such as a homodisper, a mixer, or a paddle blade.

The stirring speed (rotation speed) when stirring the aqueous dispersion is preferably 500 rpm or more, from the viewpoint of suppressing aggregation of the cellulose nanofibers (A) and reducing variations in the shape and size of the formed particles. It is preferably at least 1,000 rpm, more preferably at least 1500 rpm, even more preferably at least 2,000 rpm, and preferably at most 5,000 rpm, more preferably at most 4,500 rpm, more preferably at most 4,000 rpm, further preferably at most 3,500 rpm, even more preferably at 3,000 rpm. It is as follows.

In addition, the temperature of the aqueous dispersion is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, from the viewpoint of suppressing aggregation of the cellulose nanofibers (A) and reducing the variation in the shape and size of the formed particles. It is more preferably at least 15 ° C, and from the viewpoint of suppressing the volatilization of the added organic solvent (C), preferably at most 45 ° C, more preferably at most 40 ° C, even more preferably at most 35 ° C.

As a method of adding the organic solvent (C), a method of adding the organic solvent (C) in a constant amount at regular time intervals is preferable from the viewpoint of reducing the variation in the shape and size of the formed particles.
Specifically, the addition amount of the organic solvent (C) every 10 seconds is preferably at least 0.1 part by mass, more preferably at least 1 part by mass, further preferably at least 3 parts by mass based on 100 parts by mass of the total amount of the aqueous dispersion. It is at least 5 parts by mass, more preferably at least 5 parts by mass, and preferably at most 20 parts by mass, more preferably at most 15 parts by mass, further preferably at most 10 parts by mass, even more preferably at most 7 parts by mass. .

The stirring time from the start of the addition of the organic solvent (C) is preferably 3 minutes or more, more preferably 5 minutes or more, and still more preferably 10 minutes or more, from the viewpoint of reducing the variation in the shape and size of the formed particles. In addition, the time is preferably 180 minutes or less, more preferably 120 minutes or less, further preferably 60 minutes or less, still more preferably 40 minutes or less, and particularly preferably 20 minutes or less. The stirring time refers to the time from the addition of the organic solvent (C) to the end of the stirring. In order to sufficiently disperse the organic solvent (C) and promote the formation of particles, after the addition of the required amount of the organic solvent (C) is completed, stirring is continued until the above-mentioned time from the start of the addition of the organic solvent (C) has elapsed. It is desirable to continue.

<Use of composition>
The particles contained in the composition of the present invention are particles containing an organic solvent, and have a sustained release property that is capable of gradually releasing the organic solvent to the outside over time, and at least a certain amount or more. When the pressure is applied, the outer shell is broken and the organic solvent can be supplied to the outside.
A composition containing particles having such properties can be used in the fields of agriculture, food, cosmetics, medicine, and the like.
Specifically, a liquid fragrance supplied according to the pressure, a liquid fragrance supplied according to the temperature, a foodstuff whose taste changes on the tongue according to the temperature, a coolant gradually released according to the temperature , A pressure-sensitive adhesive, a drug delivery system, and the like.
More specifically, a mixture of the active ingredients (flavors, nutrients, functional substances, drugs, etc.) for each of the above uses in an appropriate organic solvent is incorporated into the hollow particles formed of the outer shell containing the cellulose nanofibers described above. The composition can be prepared and used for each application.

The present invention will be described specifically with reference to the following examples, but the present invention is not limited to the following examples. The methods for measuring the following physical properties are as follows.

(1) Average of diameter (thickness), average of length, average aspect ratio of cellulose nanofiber 10 randomly selected 10 pieces using a transmission electron microscope (manufactured by Carl Zeiss, product name "LEO912") The diameter (thickness) and length of the cellulose nanofiber were measured, and the average value of the ten fibers was defined as the “average diameter (thickness)” and “average length” of the target cellulose nanofiber. The “average length / average diameter (thickness)” was defined as the average aspect ratio.
(2) 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 (product name “LAQUAtwin pH-22B” manufactured by HORIBA Advanced Techno Co., Ltd.) under an environment of 23 ° C. and 50% relative humidity. After the measurement, the sample was dropped and measured so as to cover the entire flat sensor.
(3) Viscosity of Organic Solvent It was measured at 23 ° C. and 5 rpm using a B-type viscometer in accordance with JIS Z 8803: 2011.
(4) Viscosity and TI value of composition According to JIS Z 8803: 2011, the viscosity of the composition was measured using a B-type viscometer at 23 ° C, rotation speed of 5 rpm and 50 rpm. The ratio of [viscosity at 5 rpm] / [viscosity at 50 rpm] was defined as the TI value.

Examples 1 to 13 and Comparative Examples 1 to 3
In preparing the composition, an aqueous dispersion (1) or (2) containing the following commercially available cellulose nanofiber was used.
Aqueous dispersion (1): Product name "BiNFi-s AMa 10002", manufactured by Sugino Machine Co., Ltd. An aqueous dispersion containing 2% by mass of mechanically processed cellulose nanofibers 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 4900 parts by mass of water with respect to 100 parts by mass of the cellulose nanofiber, and the pH of the aqueous dispersion (1) was 7.0.
-Aqueous dispersion (1 '): an aqueous dispersion containing 5000 parts by mass of water further mixed with the above-mentioned aqueous dispersion (1) and containing 9,900 parts by mass of water with respect to 100 parts by mass of cellulose nanofiber. The pH of the aqueous dispersion (1 ′) was 7.0.
-Aqueous dispersion (2): Product name "TEMPO oxidized CNF", manufactured by Nippon Paper Industries. An aqueous dispersion containing 1% by mass of chemically treated cellulose nanofibers having an average diameter (thickness) of 3.8 nm, an average length of 0.7 μm, and an average aspect ratio of 184.
The aqueous dispersion (2) contained 9900 parts by mass of water with respect to 100 parts by mass of the cellulose nanofibers, and the pH of the aqueous dispersion (2) was 7.0.
-Aqueous dispersion (2 '): An aqueous dispersion containing 10,000 parts by mass of water further mixed with the above-mentioned aqueous dispersion (2), and containing 19,900 parts by mass of water with respect to 100 parts by mass of cellulose nanofiber. The pH of the aqueous dispersion (2 ′) was 7.0.

An organic solvent of the type shown in Table 1 was added to any of the above aqueous dispersions so as to have a blending amount shown in Table 1 with respect to 100 parts by mass of the cellulose nanofibers in the aqueous dispersion.
Specifically, at 23 ° C. using an ultra-high-speed multi-stirring system (manufactured by Primix Corporation, product name “Lab-Ruution (registered trademark)”, stirring blade: homodisper (manufactured by the company, blade diameter 35 mm)). Was stirred at 3000 rpm. After the start of the stirring, the organic solvents shown in Table 1 were added at a rate of 5 parts by mass every 10 seconds to 100 parts by mass of the aqueous dispersion (1) or (2). Stirring was continued after the addition of the organic solvent, and the stirring was stopped 10 minutes after the start of stirring to prepare a composition.

粘性 The compositions prepared in Examples and Comparative Examples were measured and calculated for viscosity (viscosity at 5 rpm and 50 rpm, TI value), and evaluated and measured as follows. Table 2 shows the results.

(1) Measurement of solid content ratio in composition Using a truncated conical cup having a diameter of 7.2 cm on the upper bottom, a diameter of 6.8 cm on the lower bottom, and a height of 8 cm, a square with a side of 10 cm on the upper bottom of the cup The tetron mesh (# 200 mesh) cut into pieces was placed, and the edge of the cup and the tetron mesh were fixed with a clip to prepare a measuring container.
10 g of the compositions prepared in Examples and Comparative Examples were spread thinly on the tetron mesh of this measuring container, and allowed to stand for 1 minute. Then, the mass w [g] of the liquid in the composition dropped into the measuring container was measured, and the solid content in the composition was calculated from the following equation.
・ Solid content [mass%] = 100− (w [g] / 10 [g] × 100)

(2) Observation of Presence or Absence of Particles As shown in the schematic plan view of FIG. 2A, two strip-shaped polyethylene terephthalate (PET) films 21 each having a thickness of 125 μm 22 were placed in parallel with each other at a distance of 5 cm in the horizontal direction, a gap 30 sandwiched between two

PET films

21 and 22 was provided, and about 0.06 ml of the prepared composition was dropped into the gap 30.
Then, as shown in the schematic front view of FIG. 2B, another slide glass 12 is laminated so as to cover the two

PET films

21 and 22 and the composition 40 filling the gap 30, and the measurement is performed. Sample 100 was produced.
Using the above measurement sample, a digital image was obtained when the composition was observed at a magnification of 500 times using a digital microscope (manufactured by KEYENCE CORPORATION, product name "VHX-5000"). Then, the presence of particles having an outer shell containing cellulose nanofibers was confirmed from the digital image, and evaluated based on the following criteria.
A: The presence of the particles was confirmed.
F: The presence of the particles could not be confirmed.
In addition, the following evaluations (3) to (5) were performed only for the composition in which the particles were confirmed.

(3) Calculation of the average particle diameter of the particles and the standard deviation of the average particle diameter of the particles From the digital image obtained in the above (2), the particle diameters of arbitrarily selected 36 particles (excluding the particles constituting the particles) The outer diameter of the shell was measured, and the average particle diameter of the particles and the standard deviation with respect to the average particle diameter of the particles were calculated.

(4) Confirmation of whether or not an organic solvent is incorporated in the particles In an environment of 23 ° C. and 50% RH (relative humidity), the prepared composition is dropped on the surface of a glass plate, and the surface of the composition is cleaned. Using a digital microscope (manufactured by KEYENCE CORPORATION, product name "VHX-5000"), the state of whether or not the particles were broken and the organic solvent was released when hit with a glass rod was observed at a magnification of 500 times. While checking, the evaluation was made according to the following criteria.
A: It was confirmed that the particles were cracked and the organic solvent was released.
-F: No change occurred in the particles, and no appearance of the organic solvent could be confirmed.

(5) Confirmation of sustained release properties of particles A test sample was prepared by putting 100 g of the prepared composition in a cylindrical transparent glass container having a diameter of 4.2 cm. A comparative sample was prepared by putting an organic solvent having a mass contained in 100 g of the composition to be measured in the same type of transparent container as described above.
Then, the test sample and the comparative sample were left uncovered at 23 ° C. and a relative humidity of 50%, and allowed to stand in a continuously operated draft for 6 hours.
Five evaluators confirmed the odor of the test sample and the comparative sample taken out of the draft after standing still. Table 2 shows the number of evaluators who judged that the test sample smelled better than the comparative sample. It can be said that the larger the number of the evaluators, the more the particles have a sustained release property.

FIG. 1 is an image obtained when the composition of Example 7 was observed with a digital microscope, and it can be seen that particles were present. In the compositions of Examples 1 to 6 and 8 to 13, the presence of similar particles was confirmed. And it was also confirmed that these particles have a sustained release property.
The composition of Example 7 had a pH of 7.0.

Each of the compositions prepared in Examples 7 and 10 was applied onto the surface of an easily adhesive layer of a PET film (Cosmoshine (registered trademark) manufactured by Toyobo Co., Ltd., product number “A4100”, thickness: 50 μm) as a support material. And dried at 120 ° C. for 10 minutes to form a coating film having a thickness of 50 μm, and an image obtained by observing a cross section of the coating film with a scanning electron microscope (SEM) (S-4700 manufactured by Hitachi, Ltd.) I got Then, among the particles projected on the image, the thicknesses of the outer shells of 36 particles arbitrarily selected are measured, and the average value thereof is calculated as the above-mentioned “average of outer shell thickness”. did.
As a result, the average of the outer shell thickness of the particles in the composition was “1202 nm” in Example 7 and “93 nm” in Example 10.

On the other hand, in the compositions prepared in Comparative Examples 1 to 3, the presence of particles could not be confirmed.

Claims

A composition comprising a cellulose nanofiber (A), water (B), and an organic solvent (C),
The compounding amount of the cellulose nanofiber (A) is 0.7% by mass or more based on the total amount of the composition,
Containing particles having an outer shell containing cellulose nanofibers (A),
A composition in which at least a part of the organic solvent (C) is in a state of being incorporated in the particles.
2. The composition according to claim 1, wherein the blending ratio [(B) / (C)] of the water (B) and the organic solvent (C) is from 0.1 to 1000 in terms of mass ratio.
At least one of a state in which at least a part of the organic solvent (C) is included in the particles and a state in which the organic solvent (C) is adsorbed on the cellulose nanofibers (A) forming the outer shell of the particles. The composition according to claim 1.
(4) The composition according to any one of (1) to (3), wherein the solid content in the composition is 80 to 100% by mass based on the total amount of the composition.
The composition according to any one of claims 1 to 4, wherein the composition has a viscosity at 23 ° C and 50 rpm of 500 to 20,000 mPa · s.
The composition according to any one of claims 1 to 5, wherein the composition has a TI value at 23 ° C (viscosity at a rotation speed of 5 rpm / viscosity at a rotation speed of 50 rpm) of 1.2 to 20.
The composition according to any one of claims 1 to 6, wherein the average of the diameter (thickness) of the cellulose nanofiber (A) is 1 to 1000 nm.
The composition according to any one of claims 1 to 7, wherein the average fiber length of the cellulose nanofiber (A) is 0.01 to 10 µm.
The composition according to any one of claims 1 to 8, wherein the amount of the organic solvent (C) is 0.05 to 80% by mass based on the total amount of the composition.
The composition according to any one of claims 1 to 9, wherein the blending amount of the cellulose nanofiber (A) is 0.7 to 15% by mass based on the total amount of the composition.
(11) The composition according to any one of (1) to (10), wherein the organic solvent (C) contains an organic solvent (C1) having less than 20 carbon atoms.
The composition according to any one of claims 1 to 11, wherein the content of the surfactant is less than 10 parts by mass relative to 100 parts by mass of the total amount of the cellulose nanofiber (A).
13. The method according to claim 1, wherein the content of the polysaccharide other than the cellulose nanofiber (A) is less than 10 parts by mass based on 100 parts by mass of the total amount of the cellulose nanofiber (A). Composition.