Emulsifier, emulsion composition and method for producing same

Abstract

Provided is an emulsifier containing cellulose and a thickener, wherein the cellulose includes oxidized cellulose that is an oxide of a cellulosic raw material oxidized with hypochlorous acid or a salt thereof, and / or nanocellulose that is a defibrated product of the oxidized cellulose, and does not substantially include N-oxyl compounds.

Description

Emulsifiers, emulsifying compositions, and methods for producing the same

[0001] The present invention relates to emulsifiers, emulsifying compositions, and methods for producing the same.

[0002] Various technologies have been proposed for producing nanocellulose materials by oxidizing various cellulosic raw materials with an oxidizing agent and then micronizing the resulting oxidized cellulose.

[0003] For example, Patent Document 1 discloses a method for producing cellulose nanofibers, comprising the steps of: producing oxidized cellulose by oxidizing a cellulosic raw material using hypochlorous acid or a salt thereof with an effective chlorine concentration of 14 to 43% by mass; and defibrating the oxidized cellulose to nanofibers. Patent Document 2 also discloses a method for producing oxidized cellulose, comprising oxidizing a cellulosic raw material using hypochlorous acid or a salt thereof with an effective chlorine concentration of 6% to 14% by mass while adjusting the pH to a range of 5.0 to 14.0. In these methods, the oxidation treatment is performed without using N-oxyl compounds such as 2,2,6,6-tetramethyl-1-piperidine-N-oxyl radical (TEMPO), so no N-oxyl compounds remain in the cellulose fibers, thereby reducing the impact on the environment.

[0004] Patent Document 3 discloses oxidized cellulose, which is an oxide of a cellulosic raw material made from hypochlorous acid or a salt thereof, and which substantially does not contain N-oxyl compounds and has a degree of polymerization of 600 or less.

[0005] Patent Document 4 discloses nanocellulose, which is an oxide of a cellulosic raw material made of hypochlorous acid or a salt thereof, having an average fiber width of 1 nm or more and 200 nm or less, substantially free of N-oxyl compounds, and having a zeta potential of -30 mV or less.

[0006] Applications of cellulose include emulsifiers. For example, Patent Document 5 discloses an emulsifier containing a dried solid mixture of carboxymethylated cellulose nanofibers and a water-soluble polymer.

[0007] International Publication No. 2018 / 230354, International Publication No. 2020 / 027307, International Publication No. 2022 / 009979, International Publication No. 2022 / 009980, Japanese Patent Publication No. 2021-113301

[0008] To produce an emulsion using the carboxymethylated cellulose nanofibers described in Patent Document 5, it is necessary to mix the nanofibers with a water-soluble polymer and dry them to obtain a solid, then mix this solid with either water or oil, and then mix it with the other, which is a complicated procedure. Furthermore, there is room for improvement in the stability of the resulting emulsion.

[0009] The present invention aims to provide an emulsifier for producing an emulsified composition with excellent stability in the emulsified state, and an emulsified composition using the emulsifier.

[0010] The present inventors have found that the stability of an emulsified composition is improved by using a combination of oxidized cellulose, which is an oxide of a cellulosic raw material made from hypochlorous acid or a salt thereof, and / or nanocellulose, which is a defibrated product of said oxidized cellulose, and a thickening agent.

[0011] The present invention includes the following embodiments: [1] An emulsifier comprising cellulose and a thickening agent, wherein the cellulose comprises oxidized cellulose, which is an oxide of a cellulosic raw material by hypochlorous acid or a salt thereof, and / or nanocellulose, which is a defibration of the oxidized cellulose, and substantially free of N-oxyl compounds. [2] An emulsifier comprising cellulose and a thickening agent, wherein the cellulose comprises oxidized cellulose having a structure in which the hydroxyl groups at the 2nd and 3rd positions of the glucopyranose ring are oxidized and dicarboxyl groups are introduced, and / or nanocellulose, which is a defibration of the oxidized cellulose. [3] The emulsifier according to [1] or [2], wherein the thickening agent is a thickening polysaccharide. [3-1] The emulsifier according to [3], wherein the thickening polysaccharide comprises at least one selected from the group consisting of methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, guar gum, xanthan gum, locust bean gum, cassia gum, gellan gum, psyllium seed gum, tragacanth gum, karaya gum, gum arabic, ghati gum, tara gum, tamarind seed gum, carrageenan, pectin, pullulan, curdlan, starch, gelatin, agar, alginic acid, and soybean polysaccharides. [3-2] The emulsifier according to [3] or [3-1], wherein the thickening polysaccharide comprises at least one selected from the group consisting of methylcellulose and carboxymethylcellulose. [3-3] The emulsifier according to any one of [3] to [3-2], wherein the thickening polysaccharide comprises methylcellulose. [4] The emulsifier according to any one of [1] to [3-3] wherein the thickening agent has a hydrophobic region that can hydrophobically interact with the oxidized cellulose and / or the nanocellulose. [4-1] The emulsifier according to [4] wherein the hydrophobic region has a continuous cyclic structure, a chain-like hydrocarbon chain structure, a branched hydrocarbon chain structure, or a combination thereof. [4-2] The emulsifier according to [4-1] wherein the cyclic structure has an aromatic hydrocarbon structure or an alicyclic hydrocarbon structure. [4-3] The emulsifier according to [4-1] or [4-2] wherein the cyclic structure has a cycloalkane structure.[4-4] The emulsifier according to any one of [4-1] to [4-3], wherein the cyclic structure has a cyclohexane structure. [5] The emulsifier according to any one of [1] to [4-4], wherein the amount of the thickener is 0.1 to 40% by mass with respect to the mass (solids) of the oxidized cellulose and / or the nanocellulose. [5-1] The emulsifier according to any one of [1] to [5], wherein the amount of the thickener is 0.3 to 35% by mass with respect to the mass (solids) of the oxidized cellulose and / or the nanocellulose. [5-2] The emulsifier according to any one of [1] to [5-1], wherein the amount of the thickener is 0.5 to 30% by mass with respect to the mass (solids) of the oxidized cellulose and / or the nanocellulose. [5-3] The emulsifier according to any one of [1] to [5-2], wherein the amount of the thickener is 0.5 to 20% by mass with respect to the mass (solids) of the oxidized cellulose and / or the nanocellulose. [6] The emulsifier according to any one of [1] to [5-3], wherein the nanocellulose is cellulose nanofiber. [7] An emulsified composition comprising the emulsifier according to any one of [1] to [6], a continuous phase, and a dispersed phase. [8] The emulsified composition according to [7], wherein the continuous phase contains water. [8-1] The emulsified composition according to [8], wherein the amount of water is 60% by mass or more based on the mass of the continuous phase. [8-2] The emulsified composition according to [8] or [8-1], wherein the amount of water is 80% by mass or more based on the mass of the continuous phase. [8-3] The emulsified composition according to any one of [8] to [8-2], wherein the amount of water is 90% by mass or more based on the mass of the continuous phase. [9] The emulsified composition according to any one of [7] to [8-3], wherein the dispersed phase contains oil. [9-1] The emulsified composition according to [9], wherein the amount of oil is 60% by mass or more based on the mass of the dispersed phase. [9-2] The emulsified composition according to [9] or [9-1], wherein the amount of oil is 80% by mass or more based on the mass of the dispersed phase. [9-3] The emulsified composition according to any one of [9] to [9-2], wherein the amount of oil is 90% by mass or more based on the mass of the dispersed phase.[9-4] The emulsion composition according to any one of [9] to [9-3], wherein the oil comprises at least one selected from the group consisting of mineral oil, vegetable oil, animal oil, synthetic oil, and silicone oil. [9-5] The emulsion composition according to any one of [9] to [9-4], wherein the oil comprises at least one selected from the group consisting of mineral oil and vegetable oil. [9-6] The emulsion composition according to any one of [7] to [9-5], wherein the amount of the dispersed phase is 1 to 80% by mass based on the mass of the emulsion composition. [9-7] The emulsion composition according to any one of [7] to [9-6], wherein the amount of the dispersed phase is 5 to 60% by mass based on the mass of the emulsion composition.

[10] The emulsion composition according to any one of [7] to [9-7], wherein the amount of the dispersed phase is 10 to 40% by mass based on the mass of the emulsion composition. [10-1] The emulsified composition according to any one of [7] to

[10] , wherein the total amount (solid content) of the oxidized cellulose and / or the nanocellulose is 0.05 to 20% by mass, based on the mass of the emulsified composition. [10-2] The emulsified composition according to any one of [7] to [10-1], wherein the total amount (solid content) of the oxidized cellulose and / or the nanocellulose is 0.1 to 10% by mass, based on the mass of the emulsified composition. [10-3] The emulsified composition according to any one of [7] to [10-2], wherein the total amount (solid content) of the oxidized cellulose and / or the nanocellulose is 0.5 to 5% by mass, based on the mass of the emulsified composition. [10-4] The emulsified composition according to any one of [7] to [10-3], wherein the amount of the thickener is 0.005 to 2% by mass, based on the mass of the emulsified composition. [10-5] An emulsified composition according to any one of [7] to [10-4], wherein the amount of the thickener is 0.01 to 1% by mass, based on the mass of the emulsified composition. [10-6] An emulsified composition according to any one of [7] to [10-5], wherein the amount of the thickener is 0.05 to 0.5% by mass, based on the mass of the emulsified composition.

[11] A cosmetic product comprising the emulsified composition according to any one of [7] to [10-6]. [11-1] A food product comprising the emulsified composition according to any one of [7] to [10-6]. [11-2] A medical product comprising the emulsified composition according to any one of [7] to [10-6].[11-3] A paint comprising the emulsifying composition described in any of [7] to [10-6]. [11-4] An ink comprising the emulsifying composition described in any of [7] to [10-6].

[12] A method for producing an emulsifying composition, comprising the step of mixing an emulsifier described in any of [1] to [6], a liquid constituting a continuous phase, and a liquid constituting a dispersed phase. [12-1] The method for producing an emulsifier according to

[12] , comprising mixing the emulsifier, the liquid constituting the continuous phase, and the liquid constituting the dispersed phase at the same time and stirring.

[0012] The present invention can provide an emulsifier for producing an emulsified composition with excellent stability, and an emulsified composition using the emulsifier.

[0013] The embodiments of the present invention will be described in detail below, but the present invention is not limited to these, and various modifications are possible without departing from the spirit of the invention.

[0014] <Emulsifier> One embodiment of the present invention relates to an emulsifier comprising cellulose and a thickener, wherein the cellulose comprises oxidized cellulose, which is an oxide of a cellulosic raw material with hypochlorous acid or a salt thereof, and / or nanocellulose, which is a defibrated product of the oxidized cellulose, and substantially does not contain an N-oxyl compound.

[0015] One embodiment of the present invention relates to an emulsifier comprising cellulose and a thickening agent, wherein the cellulose comprises oxidized cellulose having a structure in which the hydroxyl groups at the 2nd and 3rd positions of the glucopyranose ring are oxidized and dicarboxyl groups are introduced, and / or nanocellulose which is a defibrillated product of the oxidized cellulose.

[0016] Hereinafter, the emulsifiers according to the two embodiments described above will be collectively referred to as the emulsifiers according to this embodiment.

[0017] The emulsifier according to this embodiment can significantly improve the stability of the emulsified composition.

[0018] The dispersion containing oxidized cellulose and / or nanocellulose in this embodiment tends to have a lower viscosity than the dispersion containing oxidized cellulose and / or nanocellulose obtained by other methods (e.g., TEMPO oxidation or mechanical fibrillation) (hereinafter also referred to as "comparative cellulose"). While the viscosity of the dispersion containing comparative cellulose does not increase easily when mixed with a thickening agent, the viscosity of the dispersion containing oxidized cellulose and / or nanocellulose in this embodiment increases significantly when mixed with a thickening agent.

[0019] Generally, emulsified compositions tend to be more stable the higher their viscosity. However, surprisingly, the emulsified composition using the emulsifier according to this embodiment exhibits significantly superior stability compared to other emulsified compositions with similar viscosity. This is presumed to be due to effects other than viscosity increase, such as interactions (preferably hydrophobic interactions) between cellulose and the thickener, but the present invention is not limited in any way by the aforementioned reasons.

[0020] Furthermore, the emulsifier according to this embodiment makes it possible to produce an emulsified composition with simple operations. That is, the emulsified composition can be produced simply by mixing and stirring all the components of the emulsified composition (including the emulsifier) ​​at once. Therefore, complicated operations such as those described in Patent Document 5 are not required.

[0021] The emulsifier according to this embodiment may be in the form of a dispersion or a solid. If the emulsifier is a dispersion, the dispersion medium preferably contains water, and more preferably contains only water. Furthermore, although the emulsifier according to this embodiment contains cellulose and a thickener as constituent components as described above, these constituent components may be present in a single system, or they may be combined and blended when adding these constituent components to the substance to be emulsified.

[0022] [Oxidized Cellulose] Unless otherwise specified, "oxidized cellulose" in this column refers to the oxide of cellulosic raw materials with hypochlorous acid or its salts, before fibrillation.

[0023] Examples of hypochlorous acid or its salts include hypochlorous acid water, sodium hypochlorite, potassium hypochlorite, calcium hypochlorite, and ammonium hypochlorite.

[0024] The amount of hypochlorous acid or its salt used is not particularly limited, but it is preferable to use it so that the effective chlorine concentration of the reaction system is 6 to 43% by mass. The effective chlorine concentration may be a low concentration of 6 to 14% by mass, or a high concentration of 14 to 43% by mass.

[0025] The definition of the effective chlorine concentration of hypochlorous acid or its salts is as described in International Publication No. 2022 / 009979.

[0026] Cellulosic raw materials are not particularly limited as long as they are primarily composed of cellulose, and examples include pulp, natural cellulose, and fine cellulose obtained by depolymerizing cellulose through mechanical treatment. Cellulosic raw materials preferably have a type I crystalline structure. Commercially available products such as crystalline cellulose made from pulp can be used as cellulose raw materials. Other unused biomass containing large amounts of cellulose, such as okara (soy pulp) or soybean hulls, may also be used as raw materials. Furthermore, cellulose raw materials may be pre-treated. For example, the cellulose raw material may be pre-treated with an appropriate concentration of alkali to facilitate the penetration of the oxidizing agent into the pulp. Note that the main component of plants is cellulose, and bundles of cellulose molecules are called cellulose microfibrils. Cellulose in cellulose raw materials is also contained in the form of cellulose microfibrils.

[0027] (N-oxyl compounds) It is preferable that oxidized cellulose is substantially free of N-oxyl compounds. By substantially free of N-oxyl compounds, the impact on the environment and the human body is sufficiently reduced, resulting in high safety. An example of an N-oxyl compound is 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO).

[0028] In this specification, "substantially free of N-oxyl compounds" means that N-oxyl compounds are not used in the production of oxidized cellulose, that N-oxyl compounds are not contained in the oxidized cellulose at all, or that the content of N-oxyl compounds is 2.0 ppm by mass or less, preferably 1.0 ppm by mass or less, relative to the total amount of oxidized cellulose. Furthermore, if the content of N-oxyl compounds is an increase from the cellulosic raw material, preferably 2.0 ppm by mass or less, more preferably 1.0 ppm by mass or less, it is also considered "substantially free of N-oxyl compounds."

[0029] The content of N-oxyl compounds can be measured by known means. Known means include using a trace total nitrogen analyzer (for example, the TN-2100H manufactured by Nitto Seiko Analytech Co., Ltd.).

[0030] (Carboxylate group content) The amount of carboxylate groups in oxidized cellulose is preferably 0.1 to 3.0 mmol / g, more preferably 0.2 to 2.0 mmol / g, even more preferably 0.3 to 1.5 mmol / g, particularly preferably 0.4 to 1.2 mmol / g, and most preferably 0.5 to 0.9 mmol / g.

[0031] The amount of carboxyl groups in oxidized cellulose can be measured by the method described in International Publication No. 2022 / 009979.

[0032] Oxidized cellulose preferably has a structure in which at least two of the hydroxyl groups of the glucopyranose ring constituting cellulose are oxidized, and more specifically, it is preferable that the hydroxyl groups at positions 2 and 3 of the glucopyranose ring are oxidized and a dicarboxyl group is introduced. Furthermore, it is preferable that the hydroxyl group at position 6 of the glucopyranose ring is not oxidized and remains as a hydroxyl group. Note that the position of the carboxyl group in the glucopyranose ring is solid. １３ It can be analyzed using C-NMR spectroscopy.

[0033] Rayon has the same chemical structure as cellulose, and its oxide (rayon oxide) is water-soluble. When rayon oxide is dissolved in heavy water, a one-dimensional solution is formed.１３ 13C-NMR measurements reveal a peak at 165–185 ppm attributed to the carboxyl group. In one embodiment of the cellulose-based raw material oxide due to hypochlorous acid or its salt, two signals appear within this chemical shift range. Furthermore, two-dimensional solution NMR measurements can determine that the carboxyl group is introduced at positions 2 and 3.

[0034] Solid oxide of cellulose-based raw materials using hypochlorous acid or its salts １３ In 1C-NMR, when the amount of carboxyl group introduced is large, two signals appear at 165-185 ppm, while when the amount of carboxyl group introduced is small, a very broad signal may appear. As can be seen from the results for rayon oxide, the signals of carboxyl group carbons introduced at positions 2 and 3 are close together, and the solid has low resolution. １３ In 1C-NMR, the separation of the two signals is insufficient. Therefore, when the amount of carboxyl group introduced is small, it is observed as a broad signal. In other words, solid １３ In the 1C-NMR spectrum, the introduction of carboxyl groups at positions 2 and 3 can be confirmed by evaluating the broadening of the peak appearing between 165 and 185 ppm.

[0035] In other words, solid １３ A baseline is drawn over the peaks in the 165 ppm to 185 ppm range in the C-NMR spectrum to determine the total area value. Then, the area value is vertically divided at the peak top to obtain the ratio of the two resulting peak area values ​​(larger area value / smaller area value). If this ratio is 1.2 or greater, the peak is considered broad. The presence or absence of the broad peak can also be determined by the ratio of the length L of the baseline in the 165 ppm to 185 ppm range to the length L' of the perpendicular line from the peak top to the baseline. That is, if the ratio L' / L is 0.1 or greater, a broad peak is considered to exist. The ratio L' / L may be 0.2 or greater, 0.3 or greater, 0.4 or greater, or 0.5 or greater. There is no particular upper limit to the ratio L' / L, but it is usually sufficient if it is 3.0 or less, 2.0 or less, or 1.0 or less.

[0036] The structure of the glucopyranose ring can also be determined by analyzing according to the method described in Sustainable Chem. Eng. 2020, 8, 48, 17800-17806.

[0037] (Viscosity-average degree of polymerization) The viscosity-average degree of polymerization of the oxidized cellulose is preferably 30 to 500, more preferably 60 to 300, still more preferably 70 to 150, and particularly preferably 80 to 130.

[0038] The viscosity-average degree of polymerization is the average degree of polymerization measured by the viscosity method. The viscosity-average degree of polymerization can be measured by the method described in International Publication No. 2022 / 009979.

[0039] [Method for producing oxidized cellulose] Oxidized cellulose can be produced by oxidizing a cellulose-based raw material with hypochlorous acid or a salt thereof. Specific production methods include, for example, the methods described in International Publication No. 2022 / 009979 and International Publication No. 2022 / 009980. Oxidized cellulose can also be obtained as a commercial product, for example, Aron Fibro (registered trademark) manufactured by Toagosei Co., Ltd., etc.

[0040] [Nanocellulose] Hereinafter, unless otherwise specified, "nanocellulose" in this column means an oxide of a cellulose-based raw material with hypochlorous acid or a salt thereof after fibrillation.

[0041] Nanocellulose represents a general term for refined cellulose, and includes microcrystalline cellulose fibers, cellulose nanocrystals (CNC), etc. Microcrystalline cellulose fibers are also called cellulose nanofibers (CNF). From the viewpoint of improving the stability of the emulsion composition, nanocellulose is preferably CNF. Nanocellulose preferably has an amorphous part. CNF has an amorphous part, while CNC does not have an amorphous part.

[0042] Nanocellulose preferably contains carboxyl groups. The carboxyl groups may be in the H form (—COOH) or in the salt form. The type of the salt is not particularly limited, and examples thereof include alkali metal salts such as lithium salt, sodium salt, and potassium salt; alkaline earth metal salts such as calcium salt and barium salt; other metal salts such as magnesium salt and aluminum salt; ammonium salt, organic amine salt, and the like.

[0043] Nanocellulose is an aggregate of single-unit fibers. When the nanocellulose contains carboxylated nanocellulose, it may contain at least one carboxylated nanocellulose, and it is preferable that the carboxylated nanocellulose is the main component. Here, when the carboxylated nanocellulose is the main component, it means that the ratio of the carboxylated nanocellulose in the total amount of the nanocellulose exceeds 50% by mass, preferably exceeds 70% by mass, more preferably exceeds 80% by mass. The upper limit of the above ratio is 100% by mass, but it may be 98% by mass or 95% by mass.

[0044] (N-oxyl compound) Nanocellulose preferably does not substantially contain an N-oxyl compound. The meaning of "nanocellulose does not substantially contain an N-oxyl compound" and the measurement method of the content of the N-oxyl compound shall follow the description in the column of (N-oxyl compound) of the above [oxidized cellulose].

[0045] (Amount of carboxyl group) The amount of carboxyl groups in the nanocellulose, the measurement method thereof, and the introduction position of the carboxyl groups shall follow the description in the column of (amount of carboxyl group) of the above [oxidized cellulose].

[0046] (Average fiber length) The average fiber length of the nanocellulose is preferably 50 to 700 nm, more preferably 50 to 500 nm, still more preferably 50 to 300 nm, even more preferably 60 to 300 nm, and particularly preferably 70 to 200 nm.

[0047] (Average fiber width) The average fiber width of nanocellulose is preferably 1 to 20 nm, more preferably 1 to 15 nm, even more preferably 1 to 10 nm, and particularly preferably 1 to 5 nm.

[0048] The average fiber width and average fiber length of nanocellulose can be measured by the method described in International Publication No. 2022 / 009980.

[0049] (Aspect Ratio) The aspect ratio (average fiber length / average fiber width) of nanocellulose is preferably 20 to 200, more preferably 30 to 190, and even more preferably 40 to 180.

[0050] (Zeta potential) The zeta potential of nanocellulose is preferably -30 mV or less, more preferably -90 mV to -30 mV, even more preferably -80 mV to -30 mV, even more preferably -70 mV to -30 mV, and particularly preferably -65 mV to -35 mV.

[0051] The zeta potential can be measured by the method described in International Publication No. 2022 / 009980.

[0052] (Light transmittance) Nanocellulose dispersions, in which nanocellulose is dispersed in a dispersion medium, exhibit high light transmittance due to reduced light scattering from cellulose fibers. Specifically, the light transmittance of a mixture obtained by mixing nanocellulose with water to a solid content concentration of 0.1% by mass is preferably 95% or higher, more preferably 96% or higher, even more preferably 97% or higher, and particularly preferably 99% or higher. The light transmittance is the value at a wavelength of 660 nm measured by a spectrophotometer.

[0053] Light transmittance can be measured by the method described in International Publication No. 2022 / 009979.

[0054] [Method for producing nanocellulose] Nanocellulose can be produced by defibrating the oxidized cellulose described above. Specific production methods include, for example, the methods described in International Publication No. 2022 / 009979 and International Publication No. 2022 / 009980. Nanocellulose can also be obtained by defibrating commercially available oxidized cellulose (for example, Aronfibro® manufactured by Toagosei Co., Ltd.).

[0055] [Thickener] The emulsifier according to this embodiment includes a thickener. By combining the oxidized cellulose and / or nanocellulose in this embodiment with the thickener, the stability of the emulsified composition can be significantly improved. The thickener may be used alone or in combination of two or more types.

[0056] The thickening agent is preferably a thickening polysaccharide. The thickening polysaccharide is preferably water-soluble. In this specification, "water-soluble" means that the amount that dissolves in 100 g of water at 20°C is 1 g or more. The amount that dissolves is preferably 3 g or more, more preferably 10 g or more, and even more preferably 20 g or more.

[0057] Examples of thickening polysaccharides include methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, guar gum, xanthan gum, locust bean gum, cassia gum, gellan gum, psyllium seed gum, tragacanth gum, karaya gum, gum arabic, ghati gum, tara gum, tamarind seed gum, carrageenan, pectin, pullulan, curdlan, starch, gelatin, agar, alginic acid, and soybean polysaccharides.

[0058] The thickening agent may be a thickening agent having a hydrophobic region that can hydrophobically interact with oxidized cellulose and / or nanocellulose in this embodiment (hereinafter referred to as "hydrophobic thickening agent").

[0059] Examples of hydrophobic regions in hydrophobic thickeners include continuous cyclic structures and chain-like or branched hydrocarbon chain structures.

[0060] Hydrophobic thickeners having a continuous cyclic structure can be obtained, for example, by polymerizing monomers having a cyclic structure. Examples of cyclic structures include aromatic hydrocarbon structures and alicyclic hydrocarbon structures. The cyclic structure is preferably a cycloalkane structure, and more preferably a cyclohexane structure. Since the aforementioned thickening polysaccharides generally have a continuous cyclohexane structure, they are included in the category of hydrophobic thickeners.

[0061] The amount of thickener can be adjusted as appropriate, but in this embodiment, it is preferably 0.1 to 40% by mass, more preferably 0.3 to 35% by mass, even more preferably 0.5 to 30% by mass, and particularly preferably 0.5 to 20% by mass, relative to the mass (solid content) of oxidized cellulose and / or nanocellulose. The emulsifier according to this embodiment can significantly improve the stability of the emulsified composition with a small amount of thickener.

[0062] <Emulsified Composition> One embodiment of the present invention relates to an emulsion composition comprising the emulsifier described above, a continuous phase, and a dispersed phase. The emulsion composition may be either an oil-in-water (O / W) emulsion composition or a water-in-oil (W / O) emulsion composition, but is preferably an oil-in-water (O / W) emulsion composition. The emulsion composition according to this embodiment also includes an emulsion composition comprising the cellulose described above, the thickener described above, a continuous phase, and a dispersed phase. That is, if the emulsion composition contains cellulose and a thickener, it is determined that the emulsion composition contains an emulsifier. Therefore, when manufacturing the emulsion composition, even if cellulose and a thickener are used separately instead of using an emulsifier that combines cellulose and a thickener, the emulsion composition ultimately obtained will be an emulsion composition according to this embodiment.

[0063] The emulsified composition according to this embodiment has excellent stability due to the inclusion of the emulsifier described above.

[0064] The continuous phase of the emulsified composition preferably contains water. The amount of water is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on the mass of the continuous phase.

[0065] The dispersed phase of the emulsified composition preferably contains oil. The amount of oil is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on the mass of the continuous phase.

[0066] There are no particular restrictions on the type of oil used; you can choose one as appropriate depending on the intended use.

[0067] Examples of oils include mineral oils, vegetable oils, animal oils, synthetic oils, and silicone oils.

[0068] Examples of mineral oils include paraffin, naphthenes, and petrolatum.

[0069] Examples of vegetable oils include lavender oil, rosemary oil, grapeseed oil, eucalyptus oil, rosehip oil, linseed oil, camellia oil, macadamia nut oil, corn oil, mink oil, olive oil, avocado oil, sasanqua oil, castor oil, safflower oil, jojoba oil, sunflower oil, almond oil, rapeseed oil, sesame oil, soybean oil, and peanut oil.

[0070] Examples of animal oils include squalene and squalane.

[0071] Examples of synthetic oils include alkane oils, ester oils, and artificial triglycerides.

[0072] Examples of silicone oils include organopolysiloxanes.

[0073] While not particularly limited, the oil is preferably a biocompatible (e.g., skin-compatible) oil. In this specification, "biocompatible" or "skin-compatible" means that it does not cause harmful effects on living organisms or skin.

[0074] The amount of the dispersed phase is preferably 1 to 80% by mass, more preferably 5 to 60% by mass, and even more preferably 10 to 40% by mass, based on the mass of the emulsified composition.

[0075] The total amount (solids) of oxidized cellulose and / or nanocellulose is preferably 0.05 to 20% by mass, more preferably 0.1 to 10% by mass, and even more preferably 0.5 to 5% by mass, based on the mass of the emulsified composition.

[0076] The amount of the thickening agent is preferably 0.005 to 2% by mass, more preferably 0.01 to 1% by mass, and even more preferably 0.05 to 0.5% by mass, based on the mass of the emulsified composition.

[0077] [Optional components] The emulsified composition according to this embodiment may contain further components (optional components).

[0078] The optional components can be appropriately selected depending on the intended use, but examples include resins, pigments, surfactants, defoamers, preservatives, plasticizers, stabilizers, and antioxidants. For example, when applying the emulsified composition according to this embodiment as a cosmetic in the uses described later, these optional components can be used, and pigments are preferably used.

[0079] [Applications] The applications of the emulsified composition according to this embodiment are not particularly limited, but examples include cosmetics, food products, medical products, paints, and inks. Examples of embodiments of the emulsified composition according to this embodiment include cosmetics, food products, medical products, paints, and inks, with cosmetics being preferred.

[0080] Cosmetics are a preferred embodiment of the emulsified composition according to this embodiment. Therefore, one embodiment of the present invention is the emulsified composition according to this embodiment as a cosmetic (hereinafter also simply referred to as "cosmetics of this embodiment"). One embodiment of the cosmetics of this embodiment relates to cosmetics in the form of an emulsified composition containing cellulose and a thickener, wherein the cellulose contains oxidized cellulose, which is an oxide of a cellulosic raw material by hypochlorous acid or a salt thereof, and / or nanocellulose, which is a defibrillated product of the oxidized cellulose, and substantially does not contain an N-oxyl compound. Another embodiment of the cosmetics of this embodiment relates to cosmetics in the form of an emulsified composition containing cellulose and a thickener, wherein the cellulose contains oxidized cellulose having a structure in which the hydroxyl groups at the 2nd and 3rd positions of the glucopyranose ring are oxidized and dicarboxyl groups are introduced, and / or nanocellulose, which is a defibrillated product of the oxidized cellulose. Examples of cosmetics of this embodiment include makeup cosmetics, hair cosmetics, skin cosmetics, perfumes, colognes, bath cosmetics, nail cosmetics, lip care cosmetics, and body powders.

[0081] Examples of makeup cosmetics include lip cosmetics such as lipstick and lip gloss; point makeup cosmetics such as eyeshadow, eyeliner, blush, and mascara; and base makeup cosmetics such as foundation, concealer, and powder.

[0082] Examples of hair care cosmetics include hair styling products, hair colorants (hair dyes), shampoos, and conditioners.

[0083] Examples of skin cosmetics include lotions, toners, creams, emulsions, sunscreens, sun protection products, aftercare lotions, cleansers, and face masks.

[0084] Examples of nail cosmetics include nail polish, pedicure polish, and nail polish remover.

[0085] The term "cosmetics" as used herein also includes quasi-drugs. In other words, products containing active ingredients for purposes such as prevention or hygiene are also included in the definition of cosmetics as used herein.

[0086] Furthermore, for example, hair colorants (hair dyes) fall under both cosmetics and quasi-drugs. Examples of hair colorants (hair dyes) include permanent hair dyes such as hair color and gray hair dye; decolorizing agents such as hair bleach; semi-permanent hair dyes such as hair manicure, color treatment, and color rinse; and temporary hair dyes such as hair mascara, hair color spray, hair marker, and hair foundation. These embodiments are included in the hair colorants (hair dyes) described herein.

[0087] <Method for Manufacturing an Emulsified Composition> One embodiment of the present invention relates to a method for manufacturing an emulsified composition, comprising a step of mixing the above-mentioned emulsifier, a liquid constituting a continuous phase, and a liquid constituting a dispersed phase (hereinafter also referred to as the "mixing step"). The manufacturing method according to this embodiment also includes a manufacturing method comprising a step of mixing the above-mentioned cellulose, the above-mentioned thickener, a liquid constituting a continuous phase, and a liquid constituting a dispersed phase. That is, if cellulose and a thickener are used in the mixing step, it is determined that an emulsifier is being used. Therefore, even if an emulsifier combining cellulose and a thickener is not used in the mixing step, and cellulose and a thickener are used separately, the manufacturing method according to this embodiment still applies.

[0088] Details of the manufacturing method according to this embodiment (for example, details of the emulsifying composition and its components) shall be as described in the sections <Emulsifier> and <Emulsifying Composition> above.

[0089] Since oxidized cellulose obtained by oxidation reaction with hypochlorous acid or its salt is readily defibrated, at least some of the oxidized cellulose is defibrated into nanocellulose even with gentle stirring for the production of emulsifiers or emulsifying compositions.

[0090] The operation of the mixing step in this embodiment is not particularly limited, and the components of the emulsified composition may be mixed and stirred in any way. The mixing and stirring of the components may be done in stages, but from the viewpoint of simple production, it is preferable to do it all at once (i.e., mixing and stirring all components at once).

[0091] The present invention will be described in more detail below using examples and comparative examples, but the technical scope of the present invention is not limited thereto.

[0092] The various values ​​in the examples may be preferred lower or upper limits in the embodiments of the present invention. Alternatively, two similar values ​​in the examples may be combined as appropriate to form a preferred numerical range.

[0093] [Manufacturing Example 1] Commercially available powdered cellulose was used as the cellulosic raw material. 350 g of sodium hypochlorite pentahydrate crystals with an effective chlorine concentration of 42% by mass was placed in a beaker, pure water was added and stirred to obtain a sodium hypochlorite aqueous solution with an effective chlorine concentration of 21% by mass. 35% by mass hydrochloric acid was then added and stirred to obtain an aqueous solution with a pH of 11.0. This sodium hypochlorite aqueous solution was heated to 30°C in a constant temperature water bath while being stirred at 200 rpm using a propeller-type stirring blade with a stirrer (Three One Motor, BL600) manufactured by Shinto Kagaku Co., Ltd., and then 50 g of the above powdered cellulose was added. After supplying the cellulosic raw material, the solution was kept at 30°C in the same constant temperature water bath, and the pH during the reaction was adjusted to 11.0 while adding 48% by mass sodium hydroxide. The solution was stirred at 200 rpm using a propeller-type stirring blade with the above stirrer for 30 minutes to carry out the oxidation reaction. After the reaction was complete, the product was separated into solid and liquid components by suction filtration using a PTFE membrane filter with a mesh size of 0.1 μm to obtain oxidized cellulose. The obtained oxidized cellulose was washed with pure water, and the amount of carboxyl groups in the filtered product (oxidized cellulose) after washing was measured to be 0.70 mmol / g. In addition, the nitrogen component derived from the N-oxyl compound in the oxidized cellulose was measured as nitrogen content using a trace total nitrogen analyzer (manufactured by Nitto Seikou Analytech Co., Ltd., instrument name: TN-2100H), and the increase from the raw pulp was calculated to be less than 1 ppm.

[0094] The effective chlorine concentration in the sodium hypochlorite aqueous solution was measured by the following method: (Measurement of effective chlorine concentration in sodium hypochlorite aqueous solution) 0.582 g of an aqueous solution prepared by adding sodium hypochlorite pentahydrate crystals to pure water was accurately weighed, 50 ml of pure water was added, 2 g of potassium iodide and 10 ml of acetic acid were added, and the container was immediately sealed and left in the dark for 15 minutes. After 15 minutes, the liberated iodine was titrated with a 0.1 mol / L sodium thiosulfate solution (indicator: starch solution), and the titration volume was 34.55 ml. A blank test was performed separately and corrected, and since 1 ml of 0.1 mol / L sodium thiosulfate solution corresponds to 3.545 mg Cl, the effective chlorine concentration in the sodium hypochlorite aqueous solution is 21% by mass.

[0095] The amount of carboxyl groups in oxidized cellulose was measured by the following method: (Measurement of carboxyl group amount) 60 ml of an aqueous dispersion of oxidized cellulose, adjusted to a concentration of 0.5% by mass, was mixed with a 0.1 M hydrochloric acid solution to adjust the pH to 2.5. Then, a 0.05 N sodium hydroxide solution was added dropwise, and the electrical conductivity was measured until the pH reached 11.0. The amount of carboxyl groups (mol / g) was calculated from the amount of sodium hydroxide (a) consumed during the neutralization stage of the weak acid, where the change in electrical conductivity was gradual, using the following formula: Amount of carboxyl groups = a (ml) × 0.05 / Mass of oxidized cellulose (g)

[0096] The solid sample obtained by freeze-drying the oxidized cellulose obtained in Production Example 1 and then leaving it at 23°C and 50% RH for 24 hours or more. １３ C-NMR measurements confirmed that both samples possessed a structure in which the hydroxyl groups at positions 2 and 3 of the glucopyranose ring were oxidized and carboxyl groups were introduced. (Solid) １３The measurement conditions for 13C-NMR are shown below. (1) Sample tube: Zirconia tube (4 mm diameter) (2) Magnetic field strength: 9.4 T (1H resonance frequency: 400 MHz) (3) MAS rotation speed: 15 kHz (4) Pulse sequence: CP-MAS method (5) Contact time: 3 ms (6) Waiting time: 5 s (7) Number of integrations: 10,000 to 15,000 times (8) Measuring device: JNM ECA-400 (manufactured by JEOL Ltd.). Also, that the obtained oxidized cellulose has a structure in which the hydroxyl groups at the 2nd and 3rd positions of the glucopyranose ring are oxidized and carboxyl groups are introduced was confirmed from the results of measuring two-dimensional NMR using a model molecule of the oxidized cellulose as a sample. Also, regarding the 6th position, no change in the spectral data between 13C-NMR and the solid of oxidized cellulose was observed, so it was determined that the hydroxyl group at the 6th position was not oxidized and remained as a hydroxyl group in the oxidized cellulose. １３ 13C-NMR and the solid of oxidized cellulose １３ Since no change in the spectral data between 13C-NMR and the solid of oxidized cellulose was observed, it was determined that the hydroxyl group at the 6th position was not oxidized and remained as a hydroxyl group in the oxidized cellulose.

[0097] [Example 1] The oxidized cellulose obtained in Production Example 1 was made into an aqueous dispersion (solid content: about 10% by mass), and distilled water was added thereto and diluted to a solid content of 5% by mass. In this state, stirring was performed at 10,000 rpm for 60 minutes using a homomixer (TOKUSHU KIKA ROBO MICS) to defibrate the oxidized cellulose into CNF. Separately, an aqueous solution with a concentration of 1% by mass of methylcellulose (MC) (manufactured by FUJIFILM Wako Pure Chemical Corporation) and distilled water were prepared. The CNF aqueous dispersion with a solid content of 5% by mass, the 1% by mass MC aqueous solution, distilled water, and liquid paraffin (manufactured by FUJIFILM Wako Pure Chemical Corporation) were mixed so that the ratio of CNF / MC / liquid paraffin / water was 1.0% by mass / 0.1% by mass / 20% by mass / 78.9% by mass, and stirring was performed for 1 minute using an ultrasonic homogenizer (manufactured by Hielscher) to prepare an emulsified composition. The obtained emulsified composition remained stable without separation even after standing for one month or more.

[0098] [Example 2] The same procedure as in Example 1 was followed, except that olive oil was used instead of liquid paraffin, to prepare an emulsified composition with CNF / MC / olive oil / water ratios of 1.0% by mass / 0.1% by mass / 20% by mass / 78.9% by mass. The obtained emulsified composition remained stable without separation even after being left to stand for more than one month.

[0099] [Example 3] The same procedure as in Example 1 was followed, except that lavender essential oil was used instead of liquid paraffin, to prepare an emulsified composition with CNF / MC / lavender essential oil / water ratios of 1.0% by mass / 0.1% by mass / 20% by mass / 78.9% by mass. The obtained emulsified composition remained stable without separation even after being left to stand for more than one month.

[0100] [Comparative Example 1] An emulsion composition was prepared using the same procedure as in Example 1, except that MC was not used, with a CNF / liquid paraffin / water ratio of 1.0% by mass / 20% by mass / 79% by mass. When the obtained emulsion composition was allowed to stand, separation occurred after 1 hour.

[0101] [Comparative Example 2] The same procedure as in Example 1 was performed, except that CNF was not used, to prepare an emulsion composition with an MC / liquid paraffin / water ratio of 1.0% by mass / 20% by mass / 79% by mass. When the obtained emulsion composition was allowed to stand, separation occurred after 1 day.

[0102] [Comparative Example 3] The same procedure as in Example 1 was followed, except that carbomer (manufactured by Lubrizol) was used instead of CNF and MC to prepare an emulsion composition with a carbomer / liquid paraffin / water ratio of 0.05% by mass / 20% by mass / 79.95% by mass. When the obtained emulsion composition was allowed to stand, separation occurred after 1 hour. The emulsion composition of Comparative Example 3 had the same viscosity as the emulsion composition of Example 1 when allowed to stand.

[0103]

Claims

1. An emulsifier comprising cellulose and a thickening agent, wherein the cellulose comprises oxidized cellulose, which is an oxide of a cellulosic raw material due to hypochlorous acid or a salt thereof, and / or nanocellulose, which is a defibrated product of the oxidized cellulose, and substantially free of N-oxyl compounds.

2. An emulsifier comprising cellulose and a thickening agent, wherein the cellulose comprises oxidized cellulose having a structure in which the hydroxyl groups at the 2nd and 3rd positions of the glucopyranose ring are oxidized and dicarboxyl groups are introduced, and / or nanocellulose which is a defibrillated product of the oxidized cellulose.

3. The emulsifier according to claim 1 or 2, wherein the thickening agent is a thickening polysaccharide.

4. The emulsifier according to claim 1 or 2, wherein the thickening agent has a hydrophobic region that can hydrophobically interact with the oxidized cellulose and / or the nanocellulose.

5. The emulsifier according to claim 1 or 2, wherein the amount of the thickening agent is 0.1 to 40% by mass with respect to the mass (solid content) of the oxidized cellulose and / or the nanocellulose.

6. The emulsifier according to claim 1 or 2, wherein the nanocellulose is cellulose nanofiber.

7. An emulsifying composition comprising the emulsifier according to claim 1 or 2, a continuous phase, and a dispersed phase.

8. The emulsifying composition according to claim 7, wherein the continuous phase contains water.

9. The emulsifying composition according to claim 7, wherein the dispersed phase contains oil.

10. The emulsified composition according to claim 7, wherein the amount of the dispersed phase is 10 to 40% by mass, based on the mass of the emulsified composition.

11. A cosmetic comprising the emulsifying composition described in claim 7.

12. A method for producing an emulsified composition, comprising the step of mixing an emulsifier according to claim 1 or 2, a liquid constituting a continuous phase, and a liquid constituting a dispersed phase.

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