JPWO2020050153A1 - Composition - Google Patents

Abstract

It is a particle that has taken in an organic solvent, and has a sustained release property that allows the organic solvent to be released to the outside little by little over time, and when a certain pressure is applied, the outer shell breaks and the organic solvent is released. A composition containing particles that can be supplied to the outside and containing cellulose nanofibers (A), water (B), and an organic solvent (C), wherein the organic solvent (C) and cellulose are blended. The compounding amount ratio [(C) / (A)] with the nanofiber (A) is 0.05 to 45 in terms of mass ratio, and contains particles having an outer shell containing the cellulose nanofiber (A). A composition in which at least a part of the organic solvent (C) is incorporated into the particles.

Description

The present invention relates to compositions.

Cellulose raw fiber, which is one of the fibrous polysaccharides, is being studied for application to a wide range of applications such as agriculture, foods, cosmetics, pharmaceuticals, and filters. In particular, in recent years, cellulose nanofibers obtained by refining this cellulose raw fiber by various methods have been attracting attention as a new material.
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 attached to a breathable support at a predetermined ratio.
Patent Document 1 describes that the cellulose nanofibers used in the filter medium for an air filter have particle collection performance.

Japanese Unexamined Patent Publication No. 2017-177091

By the way, for example, in the fields of agriculture, food, cosmetics, pharmaceuticals, etc., it has the property of gradually releasing the organic solvent to the outside over time (sustained release property) while taking in the organic solvent, and has taken in the organic solvent. The formation of capsule-like particles may be required.
Further, in a composition containing such particles, the organic solvent is usually suppressed from being released to the outside, but the organic solvent is supplied to the outside by applying pressure when necessary to break the outer shell of the particles. Therefore, it can be applied to applications that require such characteristics.

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

The present invention is particles that have taken in an organic solvent and has a sustained release property that allows the organic solvent to be released to the outside little by little over time, and also has an outer shell when a constant or higher 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.

As a result of various studies, the present inventors have set the blending amount ratio of the organic solvent and the cellulose nanofibers within a predetermined range in the composition in which the cellulose nanofibers, water, and the organic solvent are blended. It was found that a composition containing particles having an outer shell containing cellulose nanofibers can be obtained by the preparation as described above.
The present invention has been completed based on this finding.

That is, the present invention relates to the following [1] to [12].
[1] A composition comprising cellulose nanofibers (A), water (B), and an organic solvent (C).
The compounding amount ratio [(C) / (A)] of the organic solvent (C) and the cellulose nanofibers (A) is 0.05 to 45 in terms of mass ratio.
Contains particles with an outer shell containing cellulose nanofibers (A),
A composition in which at least a part of the organic solvent (C) is incorporated into the particles.
[2] At least one of a state in which at least a part of the organic solvent (C) is contained 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].
[3] The composition according to the above [1] or [2], wherein the solid content in the composition is 80 to 100% by mass with respect to the total amount of the composition.
[4] The composition according to any one of the above [1] to [3], wherein the composition has a viscosity of 500 to 20000 mPa · s at 23 ° C. and 50 rpm.
[5] One of the above [1] to [4], wherein the TI value (viscosity at 5 rpm / viscosity at 50 rpm) of the composition at 23 ° C. is 1.2 to 20. The composition described.
[6] The composition according to any one of the above [1] to [5], wherein the average diameter (thickness) of the cellulose nanofibers (A) is 1 to 1000 nm.
[7] The composition according to any one of the above [1] to [6], wherein the average fiber length of the cellulose nanofibers (A) is 0.01 to 10 μm.
[8] The composition according to any one of the above [1] to [7], wherein the blending amount of the organic solvent (C) is 0.05 to 80% by mass with respect to the total amount of the composition. ..
[9] Of the above [1] to [8], the compounding amount ratio [(B) / (C)] of water (B) and the organic solvent (C) is 0.1 to 1000 in terms of mass ratio. The composition according to any one.
[10] The composition according to any one of the above [1] to [9], wherein the organic solvent (C) contains an organic solvent (C1) having less than 20 carbon atoms.
[11] The composition according to any one of the above [1] to [10], wherein the content of the surfactant is less than 10 parts by mass with respect to 100 parts by mass of the total amount of the cellulose nanofibers (A). thing.
[12] Any of the above [1] to [11], wherein the content of polysaccharides other than the cellulose nanofibers (A) is less than 10 parts by mass with respect to 100 parts by mass of the total amount of the cellulose nanofibers (A). The composition according to one.

The particles contained in the composition of the present invention are particles that have taken in an organic solvent, have a sustained release property that allows the organic solvent to be released to the outside little by little over time, and have a constant or longer release property. When the pressure of is applied, the outer shell is broken and the organic solvent can be supplied to the outside.

It is an image acquired when the composition prepared in Example 7 was observed with a digital microscope. It is a schematic diagram of a measurement sample for observing the compositions prepared in Examples and Comparative Examples with a digital microscope, (a) is a schematic plan view of a measurement sample in the process of preparation, and (b) is a schematic diagram of the measurement sample in the process of preparation. It is a front schematic diagram of the measured sample.

〔Composition〕
The composition of the present invention comprises a mixture of cellulose nanofibers (A), water (B), and an organic solvent (C), and comprises particles having an outer shell containing the cellulose nanofibers (A). contains. Hereinafter, the cellulose nanofibers (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 later was observed with a digital microscope.
As shown in FIG. 1, the composition of the present invention contains particles, and the particles 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 incorporated into the particles, specifically, a state of being contained in the particles and an outer shell of the particles. It is preferable that the state is at least one of the states of being adsorbed on the forming cellulose nanofibers (A).
Here, "a state in which the organic solvent (C) is contained in the particles" means that hollow particles are formed from an outer shell containing cellulose nanofibers (A), and the organic solvent (C) is formed in the hollow portion of the hollow particles. ) 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 aspect 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 of being. In the present specification, "the outer shell composed of cellulose nanofibers (A) adsorbs the organic solvent (C)" means that the organic solvent is contained in the network structure of the outer shell composed of cellulose nanofibers (A). It means that (C) exists.

Since the cellulose nanofibers (A) contained in the outer shell of the particles have a finer structure than general cellulose raw fibers such as pulp, the surface area per unit mass is large, and as a result, The amount of the organic solvent (C) attracted to the surface of the cellulose nanofibers (A) also increases.
Further, since a plurality of fibers of the cellulose nanofibers (A) are entangled with each other to form an outer shell, the force of attracting the organic solvent (C) to the surface is large, and the outer shell composed of the cellulose nanofibers (A) has a large force. It is easy to maintain the state in which the organic solvent (C) is incorporated into the network structure (that is, the state in which the organic solvent (C) is adsorbed).
Therefore, the organic solvent (C) is taken into the particles (that is, in the network structure of the outer shell) unless a constant or higher pressure is intentionally applied during the formation of the particles and for a while after the formation. In addition, the state in which the organic solvent (C) is present in the space inside the outer shell) is maintained, and a large amount of the organic solvent (C) is less likely to be released to the outside.

On the other hand, the organic solvent (C) incorporated in the particles is not completely sealed with the outside of the particles, and can be gradually released to the outside of the particles over time.
That is, the particles contained in the composition of the present invention include an outer shell containing cellulose nanofibers (A) as described above. Since the cellulose nanofibers (A) are fibrous, the outer shell containing the cellulose nanofibers (A) has a large number of voids. Then, the organic solvent (C) taken into the particles can be released from the voids to the outside of the particles over time.

From the above, it is difficult for the particles to be released to the outside in large quantities for a short period of time or when the organic solvent (C) taken in after formation is not loaded, but the organic solvent (C) is gradually released to the outside over time. It can be said that it has sustained release property, which is the property of solvent.

In addition, since the outer shell of the particles contains 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 constant or higher pressure, and the incorporated organic solvent (C) can be supplied to the outside at once.
In the composition of one aspect of the present invention, the 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 incorporated into the particles. In the stirring step at the time of forming the particles, a gas such as air is mixed in the composition, but it is also conceivable that the gas such as air is taken into the inside of the outer shell constituting the particles.

By the way, since the cellulose nanofiber (A) forms a hydrogen bond with water (B), it has a high affinity with 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 in which the organic solvent (C) is taken in and water (B) is held in 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) existing separately from the particles.
In addition, the particles having an outer shell containing cellulose nanofibers and the cellulose nanofibers which do not form the particles and are dispersed in water retain water so much that they interact with water molecules which are dispersion media. It is considered that the amount of the liquid composed of water (B), which exists separately from the cellulose nanofibers (A), is reduced because of the ease of use. From the viewpoint of preventing the sedimentation and aggregation of the particles by reducing the amount of the liquid existing apart from the particles, the larger the solid content in the composition is, the more preferable.
The solid content in the composition of one aspect of the present invention is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, still more preferably 95, based on the total amount (100% by mass) of the composition. It is ~ 100% by mass, more preferably 98-100% by mass.

In the present specification, the "solid content ratio" in the composition is the ratio of the solid content remaining on the tetron mesh after the composition is applied on the tetron mesh (# 200 mesh) and allowed to stand. Point, specifically, means a value measured by the method described in the examples.
The solid content remaining on the above-mentioned tetron mesh includes not only the cellulose nanofibers (A) but also the organic solvent (C) incorporated in the particles and the water retained in the outer shell of the particles ( 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 are also included.
Therefore, the composition having a high solid content means that it is at least one of the following [a] and [b].
[A] At least one of a large amount of water (B) and an organic solvent (C) is taken into the three-dimensional network structure of the outer shell composed of cellulose nanofibers (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 retained in the cellulose nanofibers (A) that are not involved in the formation of the outer shell of the particles.

The average particle size of the particles contained in the composition of one aspect of the present invention is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 7 μm or more, from the viewpoint of suppressing aggregation of particles in the composition. , 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, still more. It is preferably 35 μm or less, and particularly preferably 30 μm or less.

Further, the standard deviation of the particles with respect to the average particle size contained in the composition of one aspect of the present invention is incorporated into the particles when the outer shell of the particles is broken by applying a constant or higher pressure. From the viewpoint of stabilizing the amount of the organic solvent released to the outside, it is preferably 20 μm or less, more preferably 18 μm or less, further 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 are calculated from an image obtained when the target composition is observed with a digital microscope at a magnification of 500 to 1000 times. can do.
That is, the average value of the particle diameters (outer diameters of the outer shells constituting the particles) of 36 arbitrarily selected particles among the particles projected on the image can be set as the above-mentioned "average particle diameter". can. Further, 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 36 particle size values.

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

In the present specification, the thickness of the outer shell of the particles is the cross section of the coating film after the target composition is applied on a support material such as a polyethylene terephthalate film and dried to form a coating film. Can be calculated from the image acquired when observing with a scanning electron microscope (SEM) or the like.
That is, the average value of the outer shells of the particle sizes of 36 arbitrarily selected particles among the particles projected on the image can be defined as the above-mentioned "average thickness of the outer shells".

The viscosity of the composition of one aspect of the present invention at 23 ° C. and 50 rpm is preferably 500 mPa · s or more, more preferably 500 mPa · s or more, from the viewpoint of improving storage stability and suppressing sedimentation when stored in a container. It is 1000 mPa · s or more, more preferably 1200 mPa · s or more, and from the viewpoint of good stirring and removal from the container, it is preferably 20000 mPa · s or less, more preferably 15000 mPa · s or less, still more preferable. Is 12000 mPa · s or less.

Further, the TI value (viscosity at 5 rpm / viscosity at 50 rpm) of the composition of one aspect of the present invention improves 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, further preferably 3 or more, still more preferably 4 or more, and from the viewpoint of improving the ease of removal from the container, preferably 20 or less. It is more preferably 15 or less, still more preferably 10 or less, and even more preferably 8 or less.
Further, in the present specification, the viscosity of the composition means a value measured using a B-type viscometer in accordance with JIS Z 8803: 2011.

The pH of the composition of one aspect of the present invention 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 also preferably 10 or less, more preferably 9 or less, still more preferably 8 or less.
In this specification, the pH of the composition means a value measured based on the method described in Examples in an environment of 23 ° C. and 50% relative humidity.

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

The concentration of the active ingredient of the composition of one aspect of the present invention facilitates the formation of the particles with respect to the total amount (100% by mass) of the composition, and from the viewpoint of improving the film strength of the formed particles. It is preferably 0.5% by mass or more, more preferably 0.7% by mass or more, still more preferably 1.0% by mass or more, still more preferably 1.5% by mass or more, and it is easy to form the particles. From the viewpoint of appropriately adjusting the viscosity of the composition, it is preferably 50% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, still more preferably 10% by mass or less.
In addition, in this specification, an "active ingredient" means a component which excludes water (B) and an organic solvent (C) among the components contained in a composition, and specifically, a cellulose nanofiber (a cellulose nanofiber (a)). A), polysaccharides other than cellulose nanofibers (A), various additives, and the like. That is, it differs from the above-mentioned "solid content ratio" in that the masses of the organic solvent (C) and water (B) incorporated in the cellulose nanofibers (A) are not included.

The particles having an outer shell containing the cellulose nanofibers (A) and incorporating the organic solvent (C) are the blending amount of the cellulose nanofibers (A) to be blended, and the cellulose nanofibers (A) and the organic solvent (C). It can be made easier to form by appropriately adjusting the blending amount ratio, the type of the organic solvent (C), and the like.

By the way, in the composition of the present invention, the blending amount ratio [(C) / (A)] of the organic solvent (C) and the cellulose nanofibers (A) is set to 0.05 to 45 by mass ratio. By blending with, the particles are easily formed.
That is, when the blending amount ratio [(C) / (A)] is less than 0.05, the amount of the organic solvent (C) incorporated into the cellulose nanofibers (A) is too small, so that the particles are formed. The number is small, and the sustained release property of the entire composition tends to be insufficient.
Further, when the blending amount ratio [(C) / (A)] is more than 45, the amount of the organic solvent (C) is too large with respect to the cellulose nanofibers (A), so that the organic solvent (C) is added. It becomes difficult to stir the aqueous dispersion of the cellulose nanofibers (A), and it becomes difficult to form the particles. As a result, the sustained release properties of the entire composition tend to be insufficient.

From the above viewpoint, in the composition of one aspect of the present invention, the blending amount ratio [(C) / (A)] of the organic solvent (C) and the cellulose nanofibers (A) is 0.05 or more in terms of mass ratio. However, it is preferably 0.1 or more, more preferably 0.5 or more, still more preferably 0.75 or more, still more preferably 0.9 parts by mass or more, and 45 or less, preferably 45 or less. It is 40 or less, more preferably 35 or less.

In addition to adjusting the above-mentioned compounding amount ratio [(C) / (A)], the shape (diameter, fiber length, aspect ratio) of the cellulose nanofiber (A), water (B) and the organic solvent (C) ), The mixing amount ratio of water (B) and the organic solvent (C), and the like can be appropriately set to make it easier to form the particles.
Hereinafter, details of each component will be described with a focus on a specific method for forming the particles.

<Cellulose nanofiber (A)>
Examples of the raw material of the cellulose nanofiber (A) used in one embodiment of the present invention include wood-derived kraft pulp or sulfite pulp; powdered cellulose obtained by crushing kraft pulp or sulfite pulp with a high-pressure homogenizer, a mill, or the like; Microcrystalline cellulosic powder purified by chemical treatment such as acid hydrolysis; bast fiber pulp such as kozo, ganpi, and sansho; cellulosic raw material derived from plants such as cotton pulp, kenaf, hemp, rice, bacas, and bamboo; etc. Cellulose-based raw materials can be mentioned.

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 modifications, 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 can be mentioned.
In addition, these modification treatments may be performed either at the time of defibration of the cellulosic raw material or before and after defibration.

The above-mentioned cellulose-based raw material can be made into cellulose nanofibers by defibrating and converting into nanofibers.
As a specific method, a dispersion liquid containing cellulose nanofibers is prepared by preparing a dispersion liquid in which a cellulosic raw material is dispersed in a dispersion medium such as water, and then applying a shearing force to the cellulosic raw material. Can be mentioned.
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. 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, still more preferably 140 MPa or more.
From the viewpoint of applying a strong shearing force to the cellulosic raw material under such high pressure, it is preferable to use a wet high pressure or ultrahigh pressure homogenizer.

The average diameter (thickness) of the cellulose nanofibers (A) used in one aspect 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, still more preferably 2.5 nm or more, and preferably 1000 nm or less, more preferably 500 nm or less, still more preferably 200 nm or less. More preferably, it is 100 nm or less.

The average fiber length of the cellulose nanofibers (A) used in one aspect 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. More preferably 0.1 μm or more, still more preferably 0.2 μm or more, still more preferably 0.3 μm or more, and preferably 10 μm or less, more preferably 7.0 μm or less, still more preferably 5.0 μm or less. Even more preferably, it is 2.5 μm or less.

The average aspect ratio of the cellulose nanofibers (A) used in one aspect 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, preferably 10000 or less, more preferably 5000 or less, still more preferably 3000 or less, still more preferably 1000, and particularly preferably 500 or less.

The "aspect ratio" is the 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 nanofibers comes into contact with other cellulose nanofibers and it is difficult to determine the "length", only the part of the target cellulose nanofibers whose thickness can be measured. The length of the portion is measured, and the aspect ratio of the portion may be within the above range.
The diameter (thickness) and fiber length of the cellulose nanofibers (A) can be measured using a transmission electron microscope. For the average diameter (thickness) and fiber length of the cellulose nanofibers (A), the diameter (thickness) and fiber length of a plurality of arbitrarily selected cellulose nanofibers are measured, and the average value of each is calculated. Obtained by calculation. The average aspect ratio of the cellulose nanofibers (A) can be calculated by using the average diameter (thickness) thus obtained and the average fiber length. The diameter (thickness), fiber length, average value thereof, and average aspect ratio of the cellulose nanofiber (A) can be specifically calculated by the method shown in Examples.

In the composition of one aspect of the present invention, the blending amount of the cellulose nanofibers (A) facilitates the formation of the particles with respect to the total amount (100% by mass) of the composition, and the film of the formed particles. From the viewpoint of improving the strength, 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 also. From the viewpoint of appropriately adjusting the viscosity of the composition so as to facilitate the formation of the particles, the composition is preferably 15% by mass or less, more preferably 10% by mass or less, still more preferably 7% by mass or less, still more preferably. It is 5% by mass or less, particularly preferably 3% by mass or less.

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

In the composition of one aspect 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 the total amount (100% by mass) of the composition. ), 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 composition of one aspect 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) with respect to 100 parts by mass of the cellulose nanofibers (A). Is preferably 500 parts by mass or more, more preferably 1000 parts by mass or more, further preferably 2000 parts by mass or more, still more preferably 3000 parts by mass or more, and preferably 20000 parts by mass or less, more preferably 15000 parts by mass. Parts or less, more preferably 10,000 parts by mass or less.

The composition of one aspect of the present invention is preferably a composition obtained by blending an organic solvent (C) with an aqueous dispersion containing cellulose nanofibers (A) and water (B).
By preparing the aqueous dispersion in advance and then blending the organic solvent (C), the cellulose nanofibers (A) can easily take in the organic solvent (C), and the particles can be easily formed.
The aqueous dispersion is preferably prepared by blending each component so that the blending amount ratio of the cellulose nanofibers (A) and water (B) is within the above range.
Further, the aqueous dispersion may contain other components other than the components (A) to (C) together with the cellulose nanofibers (A) and water (B).

<Organic solvent (C)>
The organic solvent (C) used in one aspect of the present invention can be appropriately selected depending on the intended use of the composition, for example, heptane, n-hexadecane, toluene, cyclohexanone, methylethylketone, n-dodecane, tetrahydrofuran, xylene. , Butyl acetate, cyclohexane, 1,4-dioxane, styrene, normal hexane, gasoline, television oil, 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 in which two or more kinds are used in combination.

The organic solvent (C) used in one aspect 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 incorporated into the cellulose nanofibers (A), and the particles are easily formed.
That is, in an organic solvent having a large number of carbon atoms, the molecules of the organic solvent tend to gather together, and since the viscosity is high, it becomes difficult to form particles close to a true sphere. As a result, it is considered that such an organic solvent is not incorporated into the cellulose nanofibers (A) and remains on the outside of the particles in a large proportion.
The carbon number of the organic solvent (C1) is preferably less than 20, more preferably 1 to 18, and even 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, based on the total amount (100% by mass) of the organic solvent (C). As mentioned above, it is more preferably 50% by mass or more, and 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 preferable.
By containing these organic solvents (C2), the particles can be more easily formed.
From the viewpoint of facilitating the formation of the particles, the blending 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 35% by mass or more, further preferably 50% by mass or more, and even more preferably 70% by mass or more.

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

In the composition of one aspect of the present invention, from the viewpoint of facilitating the formation of the particles, the blending amount of the organic solvent (C) is preferably 0.05% by mass with respect to 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, still more preferably 0.8% by mass or more, and preferably 80% by mass or less, more preferably 60% by mass. % Or less, more preferably 45% by mass or less, still more preferably 42% by mass or less, still more preferably 40% by mass or less, still more preferably 38% by mass or less.

In the composition of one aspect of the present invention, from the viewpoint of facilitating the formation of the particles, the blending amount ratio [(B) / (C)] of water (B) and the organic solvent (C) is a mass ratio. It is preferably 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 1000 or less, more preferably 700 or less, still more preferably. It is 500 or less, more preferably 300 or less, and particularly preferably 100 or less.

<Ingredients other than ingredients (A) to (C)>
The composition of one aspect 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 depending on the use of the composition, and are, for example, colorants, antioxidants, pH adjusters, sweeteners, fragrances, preservatives, ultraviolet absorbers, and polymerization inhibitors. Examples thereof include agents, antibacterial agents, insecticides, defoamers, foaming agents, flocculants, thickeners, plasticizers, modifiers, flame retardants, flame retardants and the like.

In the composition of one aspect of the present invention, a surfactant may be contained.
However, when a composition containing a surfactant is used for applications that come into contact with the human body, the surfactant also serves as a penetrant and an irritating irritant, especially for users with sensitive skin. In addition, the composition containing a surfactant may affect the stability of the physical properties of the composition.
Therefore, in the composition of one aspect of the present invention, the smaller the content of the surfactant, the more preferable.
From the above viewpoint, in the composition of one aspect of the present invention, the content of the surfactant is preferably less than 10 parts by mass, more preferably 1 part by mass with respect to 100 parts by mass of the total amount of the cellulose nanofibers (A). Less than, more preferably less than 0.1 parts by mass, even more preferably less than 0.01 parts by mass, particularly preferably less than 0.001 parts by mass, most preferably 0 parts by mass.

Further, in the composition of one aspect of the present invention, a polysaccharide other than the cellulose nanofiber (A) may be contained, 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, in the composition of one aspect of the present invention, the content of the polysaccharide other than the cellulose nanofibers (A) is preferably less than 10 parts by mass with respect to 100 parts by mass of the total amount of the cellulose nanofibers (A). , More preferably less than 1 part by mass, still more preferably less than 0.1 parts by mass, even more preferably less than 0.01 parts by mass, and particularly preferably 0 parts by mass.

[Method for producing 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 cellulose nanofibers (A) and water (B).
-Step (2): A step of adding the organic solvent (C) to the aqueous dispersion obtained in the step (1).
The details of the components (A) to (C) used in the steps (1) and (2) are as described above.

<Process (1)>
Step (1) is a step of preparing an aqueous dispersion containing cellulose nanofibers (A) and water (B).
When a commercially available aqueous dispersion is used in this step, the step may be omitted, or cellulose nanofibers (A) or water (B) may be added to the commercially available aqueous dispersion to obtain a desired formulation. It may be prepared in an amount of an aqueous dispersion.

When other components other than the components (A) to (C) are blended, they may be blended at the time of preparing the aqueous dispersion in the step (1), and the steps (1) and (2) may be blended. It may be blended between and, during step (2), or after step (2).

The pH of the aqueous dispersion obtained in the step (1) is preferably from the viewpoint of suppressing the aggregation of the cellulose nanofibers (A) in the aqueous dispersion and reducing the variation 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, still more preferably 8 or less.

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

The stirring speed (rotational 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 1000 rpm or more, more preferably 1500 rpm or more, still more preferably 2000 rpm or more, and preferably 5000 rpm or less, more preferably 4500 rpm or less, more preferably 4000 rpm or less, still more preferably 3500 rpm or less, still more preferably 3000 rpm. It is as follows.

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 variations in the shape and size of the formed particles. It is more preferably 15 ° C. or higher, and from the viewpoint of suppressing volatilization of the added organic solvent (C), it is preferably 45 ° C. or lower, more preferably 40 ° C. or lower, still more preferably 35 ° C. or lower.

As a method of adding the organic solvent (C), a method of adding a fixed amount at regular intervals is preferable from the viewpoint of reducing variations in the shape and size of the formed particles.
Specifically, the amount of the organic solvent (C) added every 10 seconds to 100 parts by mass of the total amount of the aqueous dispersion 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, more preferably 5 parts by mass or more, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, still more preferably 10 parts by mass or less, still more preferably 7 parts by mass or less. be.

The stirring time from the start of addition of the organic solvent (C) is preferably 3 minutes or longer, more preferably 5 minutes or longer, still more preferably 10 minutes or longer, from the viewpoint of reducing the variation in the shape and size of the formed particles. It 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, 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 stirring. In order to sufficiently disperse the organic solvent (C) and promote the formation of particles, even after the addition of the required amount of the organic solvent (C) is completed, stirring is performed until the above time elapses from the start of the addition of the organic solvent (C). It is desirable to continue.

<Use of composition>
The particles contained in the composition of the present invention are particles containing an organic solvent, have a sustained release property that allows the organic solvent to be released to the outside little by little over time, and have a constant or longer release property. When the pressure of is applied, the outer shell is broken and the organic solvent can be supplied to the outside.
Compositions containing particles having such properties can be used in the fields of agriculture, foods, cosmetics, pharmaceuticals and the like.
Specifically, liquid fragrances supplied in response to pressurization, liquid fragrances supplied in response to temperature, foodstuffs whose taste changes on the tongue in response to temperature, and cooling materials released slowly in response to temperature. , Pressure-sensitive adhesives, drag delivery systems, etc.
More specifically, the active ingredients (fragrances, nutrients, functional substances, drugs, etc.) for each of the above-mentioned uses are mixed with an appropriate organic solvent and incorporated into the hollow particles composed of the outer shell containing the above-mentioned cellulose nanofibers. The prepared composition can be prepared and used for each application.

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 method for measuring the following physical property values is as follows.

(1) Average diameter (thickness), average length, and average aspect ratio of cellulose nanofibers Ten arbitrarily selected fibers using a transmissive electron microscope (manufactured by Karl Zeiss, product name "LEO912"). The diameter (thickness) and length of the cellulose nanofibers were measured, and the average value of 10 fibers was taken as the "average diameter (thickness)" and "average length" of the target cellulose nanofibers. In addition, "average length / average diameter (thickness)" was used as the average aspect ratio.
(2) pH of aqueous dispersion and 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.
(3) Viscosity of Organic Solvent According to JIS Z 8803: 2011, the measurement was carried out at 23 ° C. and a rotation speed of 5 rpm using a B-type viscometer.
(4) Viscosity of composition, TI value The viscosity of the composition at 23 ° C., rotation speed of 5 rpm and 50 rpm was measured using a B-type viscometer in accordance with JIS Z 8803: 2011. Further, the ratio of [viscosity at 5 rpm] / [viscosity at 50 rpm] was taken as the TI value.

Examples 1 to 13, Comparative Examples 1 to 2
In preparing the composition, an aqueous dispersion (1) or (2) containing the following commercially available cellulose nanofibers was used.
-Aqueous dispersion (1): Product name "BiNFi-s AMa 10002", manufactured by Sugino Machine Limited. An aqueous dispersion containing 2% by mass of machine-treated 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 nanofibers, and the pH of the aqueous dispersion (1) was 7.0.
-Aqueous dispersion (2): Product name "TEMPO Oxidized CNF", manufactured by Nippon Paper Industries, Ltd. 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.

The amount of the organic solvent shown in Table 1 added to the aqueous dispersion (1) or (2) with respect to 100 parts by mass of the cellulose nanofibers in the aqueous dispersion (1) or (2) is shown in Table 1. It was added so as to be.
Specifically, using 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, blade diameter 35 mm)), 23 ° C. The aqueous dispersion of No. 1 was stirred at a rotation speed of 3000 rpm. After the start of stirring, the organic solvent shown in Table 1 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 (1) or (2). Stirring was continued even after the addition of the organic solvent, and the stirring was terminated 10 minutes after the start of stirring to prepare a composition.

The viscosities (viscosities at 5 rpm and 50 rpm, TI values) were measured and calculated for the compositions prepared in Examples and Comparative Examples, and the following evaluations and measurements were carried out. These results are shown in Table 2.

(1) Measurement of solid content in composition Using a conical trapezoidal cup with a top bottom diameter of 7.2 cm, a bottom bottom diameter of 6.8 cm, and a height of 8 cm, a square with a side of 10 cm is used on the top bottom surface of the cup. A cut tetron mesh (# 200 mesh) was placed on the top, 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 was 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 formula.
-Solid content [mass%] = 100- (w [g] / 10 [g] x 100)

(2) Observation of the presence or absence of particles As shown in the schematic plan view shown in FIG. 2A, two strips of polyethylene terephthalate (PET) film 21 having a thickness of 125 μm are placed on the surface of the slide glass 11. 22 was placed in parallel so as to be separated by 5 cm in the horizontal direction, a gap 30 sandwiched between the 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 shown in FIG. 2B, another slide glass 12 is laminated so as to cover the two PET films 21 and 22 and the composition 40 filled in the gap 30 and measured. Sample 100 was prepared.
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 the evaluation was made according to the following criteria.
-A: The presence of the particles was confirmed.
-F: The presence of the particles could not be confirmed.
The following evaluations (3) to (5) were performed only on the compositions in which the particles could be confirmed.

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

(4) Confirmation of whether or not an organic solvent is incorporated into 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 to cover the surface of the composition. Using a digital microscope (manufactured by Keyence, product name "VHX-5000"), observe whether or not the particles break and the organic solvent is released when hit with a glass rod at a magnification of 500 times. However, it was confirmed and evaluated according to the following criteria.
-A: It was confirmed that the particles were broken and the organic solvent was released.
-F: No change occurred in the particles, and it was not confirmed that the organic solvent was released.

(5) Confirmation of Sustained Release 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. Further, 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 above-mentioned transparent container of the same type.
Then, the test sample and the comparative sample were allowed to stand at 23 ° C. and a relative humidity of 50% in a continuously operated draft for 6 hours without a lid.
Five evaluators confirmed the odor of the test sample and the comparative sample taken out from the draft after standing. Then, Table 2 shows the number of evaluators who judged that "the test sample smells better than the comparative sample". It can be said that the larger the number of the evaluators, the higher the certainty that the particles have sustained release properties.

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

Further, the compositions prepared in Examples 7 and 10 are applied onto the easy-adhesion layer surface of the PET film (Cosmo Shine (registered trademark) manufactured by Toyo Spinning Co., Ltd., product number "A4100", thickness: 50 μm) which is a support, respectively. Then, it was dried at 120 ° C. for 10 minutes to form a coating film having a thickness of 50 μm, and an image when the cross section of the coating film was observed with a scanning electron microscope (SEM) (S-4700 manufactured by Hitachi, Ltd.). Was acquired. Then, among the particles projected on the image, the thickness of the outer shell of 36 arbitrarily selected particles is measured, and the average value thereof is calculated as the above-mentioned "average thickness of the outer shell". bottom.
As a result, the average thickness of the outer shells 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 and 2, the presence of particles could not be confirmed.

Claims (12)

A composition comprising cellulose nanofibers (A), water (B), and an organic solvent (C).
The compounding amount ratio [(C) / (A)] of the organic solvent (C) and the cellulose nanofibers (A) is 0.05 to 45 in terms of mass ratio.
Contains particles with an outer shell containing cellulose nanofibers (A),
A composition in which at least a part of the organic solvent (C) is incorporated into the particles. At least a part of the organic solvent (C) is contained in the particles and is adsorbed on the cellulose nanofibers (A) forming the outer shell of the particles. The composition according to claim 1. The composition according to claim 1 or 2, wherein the solid content in the composition is 80 to 100% by mass with respect to the total amount of the composition. The composition according to any one of claims 1 to 3, wherein the composition has a viscosity at 23 ° C. and 50 rpm of 500 to 20000 mPa · s. The composition according to any one of claims 1 to 4, wherein the TI value of the composition at 23 ° C. (viscosity at 5 rpm / viscosity at 50 rpm) is 1.2 to 20. The composition according to any one of claims 1 to 5, wherein the average diameter (thickness) of the cellulose nanofibers (A) is 1 to 1000 nm. The composition according to any one of claims 1 to 6, wherein the average fiber length of the cellulose nanofibers (A) is 0.01 to 10 μm. The composition according to any one of claims 1 to 7, wherein the blending amount of the organic solvent (C) is 0.05 to 80% by mass with respect to the total amount of the composition. The invention according to any one of claims 1 to 8, wherein the compounding amount ratio [(B) / (C)] of water (B) and the organic solvent (C) is 0.1 to 1000 in terms of mass ratio. Composition. The composition according to any one of claims 1 to 9, 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 10, wherein the content of the surfactant is less than 10 parts by mass with respect to 100 parts by mass of the total amount of the cellulose nanofibers (A). The invention according to any one of claims 1 to 11, wherein the content of the polysaccharide other than the cellulose nanofiber (A) is less than 10 parts by mass with respect to 100 parts by mass of the total amount of the cellulose nanofiber (A). Composition.

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