Cosmetic containing chemically modified cellulose fine fibers

Abstract

Provided is a cosmetic comprising components (A)-(D): (A) anion-modified cellulose fine fibers; (B) a polyvalent metal salt; (C) (C1) an aminocarboxylic acid or a salt thereof and / or (C2) a hydroxycarboxylic acid or a salt thereof; and (D) water. This cosmetic has an excellent feel as aggregation of cellulose fine fibers is suppressed even in a system in which a polyvalent metal salt is blended.

Description

Cosmetics containing chemically modified cellulose microfibers

[0001] The present invention relates to a cosmetic preparation. More specifically, the present invention relates to a cosmetic preparation containing chemically modified cellulose fine fibers, particularly anionically modified cellulose fine fibers, a polyvalent metal salt, an aminocarboxylic acid or hydroxycarboxylic acid and its salt, and water.

[0002] It is known that cellulose microfibers, which are cellulose fibers reduced to nano-size, are used as thickeners, dispersants, and emulsifiers in cosmetics. Cellulose microfibers have low spinnability and a clean, pleasant texture, and are also characterized by suspension stability, emulsion stability, and thickening stability. Conventionally, cosmetics have sometimes used formulations containing salts, such as inorganic salts and organic salts, but even in such cases, it is preferable to maintain the aforementioned characteristics.

[0003] However, it is known that, particularly in a medium containing a polyvalent metal salt, the cellulose fine fibers aggregate, resulting in a decrease in suspension stability and emulsion stability, and various studies have been conducted to address this issue. For example, Patent Document 1 describes that cellulose fine fibers can be stably dispersed even in a liquid containing a salt by mixing the cellulose fine fibers with a water-soluble polymer under specific conditions.

[0004] International Publication No. 2016 / 060120

[0005] In the case of the method of using a water-soluble polymer in combination as in Patent Document 1, there is a problem that the water-soluble polymer causes a sticky feeling, resulting in a poor feel when used. In addition, when cellulose fine fibers aggregate in a system in which polyvalent metal ions derived from a polyvalent metal salt are present, there is a problem that lumps and granules form in the cosmetic, resulting in a poor feel when used. Therefore, an object of the present invention is to provide a cosmetic that suppresses aggregation of cellulose fine fibers and has an excellent feel when used, even in a system in which a polyvalent metal salt is blended.

[0006] The present invention provides the following: [1] A cosmetic comprising the following components (A) to (D): (A) anion-modified cellulose fine fibers, (B) a polyvalent metal salt, (C) a (C1) aminocarboxylic acid or a salt thereof and / or a (C2) hydroxycarboxylic acid or a salt thereof, and (D) water. [2] The cosmetic according to [1], wherein the (A) anion-modified cellulose fine fibers are carboxyalkylated cellulose fine fibers. [3] The cosmetic according to [1] or [2], wherein the (C) comprises an aminocarboxylic acid (C1), and the (C1) aminocarboxylic acid is one or more selected from ethylenediaminetetraacetic acid, ethylenediaminedisuccinic acid, glutamic acid diacetic acid, and pentetic acid. [4] The cosmetic according to any one of [1] to [3], wherein the (C) comprises a hydroxycarboxylic acid (C2), and the (C2) hydroxycarboxylic acid is hydroxyethylethylenediaminetriacetic acid. [5] The cosmetic preparation according to any one of [1] to [4], wherein the metal ions constituting the polyvalent metal salt (B) are one or more selected from calcium ions, magnesium ions, and zinc ions.

[0007] The cosmetic of the present invention is an aqueous cosmetic containing a polyvalent metal salt, and by mixing chemically modified cellulose fine fibers with an aminocarboxylic acid or its salt and / or a hydroxycarboxylic acid or its salt, aggregation of the cellulose fine fibers is suppressed, resulting in an excellent feeling when used.

[0008] The cosmetic of the present invention will now be described.

[0009] The present invention relates to a cosmetic preparation comprising chemically modified cellulose fine fibers, particularly anionically modified cellulose fine fibers, a polyvalent metal salt, an aminocarboxylic acid or a salt thereof and / or a hydroxycarboxylic acid or a salt thereof, and water.

[0010] (A: Chemically Modified Cellulose Fine Fibers) The chemically modified cellulose fine fibers used in the present invention are fine fibers made from cellulose and can be obtained by defibrating a chemically modified cellulose raw material to reduce its fiber diameter. An example of a chemically modified cellulose fine fiber is anion-modified cellulose fine fiber. The average fiber diameter of the chemically modified cellulose fine fiber is not particularly limited, but is approximately 3 nm to 500 nm. The average fiber diameter is preferably 3 nm to 100 nm, more preferably 3 nm to 50 nm. This range is preferred because it provides a smoother feel when used in cosmetics. The average fiber diameter and average fiber length of the chemically modified cellulose fine fiber can be obtained by averaging the fiber diameters and fiber lengths obtained from observations of each fiber using a fiber tester manufactured by ABB Corporation, a fractionator manufactured by Valmet, a scanning electron microscope (SEM), an atomic force microscope (AFM), or a transmission electron microscope (TEM) appropriately selected depending on the fiber diameter. When measuring nanoscale fiber diameters, it is preferable to measure the cross-sectional height of a fiber shape image observed using an atomic force microscope (AFM). The average fiber diameter can be determined by measuring the fiber diameters of 50 randomly selected fibers using the method described above and calculating the length-weighted average fiber diameter. Furthermore, when measuring the fiber length of nanoscale fibers, it is preferable to use an atomic force microscope (AFM). The average fiber length can be determined by measuring the fiber lengths of 200 randomly selected fibers using the method described above and calculating the length-weighted average fiber length.

[0011] The aspect ratio of the chemically modified cellulose fine fibers is preferably 10 to 1000, more preferably 10 to 500, and even more preferably 10 to 200. The aspect ratio can be calculated by the following formula: Aspect ratio = average fiber length (nm) / average fiber diameter (nm).

[0012] The cellulose raw material used to produce the chemically modified cellulose fine fibers is not particularly limited as long as it contains cellulose, and examples thereof include those derived from plants, animals (e.g., ascidians), algae, and microorganisms (e.g., acetic acid bacteria (Acetobacter)). Examples of plant-derived materials include wood, bamboo, hemp, jute, kenaf, agricultural waste, cloth, and pulp (softwood unbleached kraft pulp (NUKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), hardwood bleached kraft pulp (LBKP), softwood unbleached sulfite pulp (NUSP), softwood bleached sulfite pulp (NBSP), thermomechanical pulp (TMP), softwood dissolving pulp, hardwood dissolving pulp, recycled pulp, waste paper, etc.). Cellulose powder obtained by pulverizing the above-mentioned cellulose raw materials may also be used. Any one or a combination of these may be used as the cellulose raw material, but cellulose fibers derived from plants or microorganisms are preferred, cellulose fibers derived from plants are more preferred, and wood pulp is even more preferred.

[0013] (Chemical Modification) Cellulose has three hydroxy groups per glucose unit and can be chemically modified in various ways. From the viewpoint of promoting the progress of defibration, it is preferable to use chemically modified cellulose fine fibers obtained by defibrating the cellulose raw material (chemically modified cellulose fibers) obtained by chemical modification.

[0014] A preferred chemical modification is anionic modification, which introduces anionic groups into cellulose. Specifically, anionic modification refers to the introduction of anionic groups into the pyranose rings of cellulose by substitution or oxidation. Examples of types of anionic modification include, but are not limited to, carboxyalkylation, which ether-links a carboxyalkyl group such as a carboxymethyl group (hereinafter, "carboxymethyl" will be referred to as "CM") to the cellulose chain; oxidation (also referred to as carboxylation), which introduces carboxy groups into the cellulose chain; and phosphate esterification, which introduces phosphate groups into the cellulose chain. Among these, carboxyalkylation is preferred, and CM modification is most preferred.

[0015] Examples of chemically modified cellulose fine fibers include anion-modified cellulose fine fibers such as carboxymethyl cellulose fine fibers, carboxyalkylated cellulose fine fibers, TEMPO-oxidized cellulose fine fibers, ozone-oxidized cellulose fine fibers, phosphate-esterified cellulose fine fibers, phosphite-esterified cellulose fine fibers, sulfonated cellulose fine fibers, and xanthated cellulose fine fibers, with carboxymethyl cellulose fine fibers and oxidized cellulose fine fibers being particularly preferred.

[0016] Chemically modified cellulose fine fibers such as anion-modified cellulose fine fibers may have an anionic group such as a carboxyl group, a CM group, or a phosphate group having a metal ion such as a sodium ion or a potassium ion as a counter ion (this form is called a "salt form"), or may have an anionic group having a proton as a counter ion (this form is called a "hydrogen form").

[0017] Chemically modified cellulose fibers, which are the raw material for chemically modified cellulose microfibers, maintain at least a portion of the fibrous shape of cellulose even when dispersed in water. That is, when an aqueous dispersion of chemically modified cellulose fibers is observed with an electron microscope or the like, a fibrous substance can be observed, and when measured by X-ray diffraction, a peak of cellulose type I crystals can be observed. The crystallinity of cellulose in chemically modified cellulose fibers or chemically modified cellulose microfibers is preferably 40% or more, more preferably 50% or more, of cellulose type I crystals. The crystallinity of cellulose can be controlled by the degree of chemical modification. There is no particular upper limit to the crystallinity of cellulose type I. In practice, the upper limit is thought to be around 90%. The crystallinity of cellulose type I is measured as follows: A sample is placed in a glass cell and measured using an X-ray diffraction measurement device (product name: LabX XRD-6000, manufactured by Shimadzu Corporation). The degree of crystallinity is calculated using the method of Segal et al., using the diffraction intensity in the range of 2θ=10° to 30° in the X-ray diffraction pattern as a baseline, and is calculated from the diffraction intensity of the 002 plane at 2θ=22.6° and the diffraction intensity of the amorphous portion at 2θ=18.5° using the following formula: Xc=(I002c-Ia) / I002c×100, where Xc = crystallinity of type I cellulose (%) I002c: diffraction intensity of the 002 plane at 2θ=22.6° Ia: diffraction intensity of the amorphous portion at 2θ=18.5°.

[0018] In order to obtain chemically modified cellulose fibers having a peak of cellulose type I crystallinity, it is preferable to use a cellulose raw material having a high degree of crystallinity of cellulose type I. The degree of crystallinity of cellulose type I of the cellulose raw material is preferably 40% or more, more preferably 50% or more.

[0019] (Carboxyalkylation, carboxymethylation) Carboxyalkylated cellulose fine fibers, preferably carboxymethylated cellulose fine fibers, which are an example of chemically modified cellulose fine fibers and an example of anionically modified cellulose fine fibers, can be obtained by defibrating carboxyalkylated cellulose fibers, preferably carboxymethylated cellulose fibers, obtained by a known method. The degree of carboxyalkyl substitution per anhydroglucose unit of cellulose is preferably 0.01 to 0.50. The upper limit is preferably 0.40 or less. If the degree of carboxyalkyl substitution exceeds 0.50, the cellulose becomes more susceptible to dissolution in water, making it impossible to maintain a fibrous form in water. To obtain the effects of carboxyalkylation, a certain degree of substitution is necessary. For example, if the degree of substitution is less than 0.02, the benefits of introducing a carboxyalkyl group may not be obtained depending on the application. Therefore, the degree of carboxyalkyl substitution is preferably 0.02 or more, more preferably 0.05 or more, and even more preferably 0.10 or more. The degree of carboxyalkyl substitution can be adjusted by controlling the amount of carboxyalkylating agent added to the reaction, the amount of mercerizing agent, the composition ratio of water to organic solvent, etc.

[0020] In this specification, anhydroglucose unit refers to each anhydroglucose (glucose residue) constituting cellulose. The degree of carboxyalkyl substitution (also referred to as the degree of etherification) refers to the proportion of hydroxy groups in the glucose residues constituting cellulose that are substituted with carboxyalkyl ethers (the number of carboxyalkyl ethers per glucose residue). The degree of carboxyalkyl substitution is sometimes abbreviated as DS.

[0021] The method for measuring the degree of carboxyalkyl substitution is as follows: Approximately 2.0 g of sample is weighed out and placed in a 300 mL Erlenmeyer flask with a stopper. 100 mL of nitric acid methanol (a solution of 1000 mL of methanol and 100 mL of special-grade concentrated nitric acid) is added and the mixture is shaken for 3 hours to convert the salt-type carboxyalkylated cellulose fiber to hydrogen-type carboxyalkylated cellulose fiber. 1.5 to 2.0 g of hydrogen-type carboxyalkylated cellulose fiber (bone dry) is weighed out and placed in a 300 mL Erlenmeyer flask with a stopper. The mixture is moistened with 15 mL of 80% methanol, 100 mL of 0.1 N NaOH is added, and the mixture is shaken at room temperature for 3 hours. Phenolphthalein is used as an indicator, and the 0.1 N NaOH is added. ２ SO ４ The excess NaOH is back-titrated with 0.01% NaOH, and the degree of carboxyalkyl substitution (DS) is calculated by the following formula: A = [(100 × F' - 0.1N - H ２ SO ４ (mL) × F) × 0.1] / (bone dry mass (g) of hydrogen-type carboxyalkylated cellulose fiber) Degree of carboxyalkyl substitution (DS) = 0.162 × A / (1-0.058 × A) F': 0.1N-H ２ SO ４ F: Factor of 0.1N NaOH.

[0022] The DS of the carboxyalkylated cellulose fibers is usually the same as the DS of the carboxyalkylated cellulose fine fibers obtained by defibrating the carboxyalkylated cellulose.

[0023] As an example of a method for producing carboxyalkylated cellulose fibers, an example of producing carboxymethyl cellulose fibers will be described below.

[0024] First, the cellulose raw material is mixed with a solvent and a mercerizing agent, and the cellulose raw material is mercerized at a reaction temperature of 0 to 70°C, preferably 10 to 60°C, for a reaction time of 15 minutes to 8 hours, preferably 30 minutes to 7 hours. Next, a mercerization agent is added in an amount of 0.05 to 10.0 times the moles per glucose residue, and mercerization is carried out at a reaction temperature of 30 to 90°C, preferably 40 to 80°C, for a reaction time of 30 minutes to 10 hours, preferably 1 hour to 4 hours.

[0025] The solvent can be 3 to 20 times by mass of water or an organic solvent, or a mixture thereof. Examples of organic solvents include, but are not limited to, alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, isobutanol, and tertiary butanol; ketones such as acetone, diethyl ketone, and methyl ethyl ketone; and dioxane, diethyl ether, benzene, and dichloromethane. Among these, monohydric alcohols having 1 to 4 carbon atoms are preferred due to their excellent compatibility with water, and monohydric alcohols having 1 to 3 carbon atoms are more preferred. As the mercerizing agent, it is preferable to use an alkali metal hydroxide, specifically sodium hydroxide or potassium hydroxide, in an amount of 0.5 to 20 times the molar amount per anhydrous glucose residue of the cellulose raw material. Examples of mercerizing agents include monochloroacetic acid, sodium monochloroacetate, methyl monochloroacetate, ethyl monochloroacetate, and isopropyl monochloroacetate. Of these, monochloroacetic acid or sodium monochloroacetate is preferred due to the ease of raw material availability. The amount of carboxymethylation agent used is not particularly limited, but is preferably added in the range of 0.5 to 1.5 mol per anhydroglucose unit of cellulose. The lower limit of the above range is more preferably 0.6 mol or more, even more preferably 0.7 mol or more, and the upper limit is more preferably 1.3 mol or less, even more preferably 1.1 mol or less. The carboxymethylation agent may be added to the reactor as, for example, a 5 to 80 mass % aqueous solution, more preferably 30 to 60 mass %, but is not limited thereto, or may be added in powder form without being dissolved in a solvent such as water.

[0026] When mercerizing a cellulose raw material, there are generally two methods for carrying out both mercerization and CM in a solvent primarily composed of water (aqueous medium method), and two methods for carrying out both mercerization and CM in a mixed solvent of water and an organic solvent (solvent method), either of which may be used. Alternatively, a solvent primarily composed of water may be used for mercerization, and a mixed solvent of an organic solvent and water may be used for CM. By doing so, it is possible to economically obtain mercurized cellulose in which CM groups have been introduced uniformly, rather than locally, even when the degree of crystallinity of type I cellulose is maintained at 50% or higher.

[0027] A solvent primarily containing water (a water-based solvent) refers to a solvent containing water at a ratio of more than 50% by mass. The water content in the water-based solvent is preferably 55% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. A particularly preferred water-based solvent is 100% by mass (i.e., water). The higher the water content during mercerization, the more advantageously CM groups are introduced more uniformly into cellulose. The solvent other than water in the water-based solvent (used in a mixture with water) can be the organic solvent described above. The amount of organic solvent in the water-based solvent is preferably 45% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, even more preferably 20% by mass or less, even more preferably 10% by mass or less, even more preferably 5% by mass or less, and more preferably 0% by mass.

[0028] It is preferable to add an organic solvent or an aqueous solution of an organic solvent to the reactor simultaneously with the addition of the carboxylation agent, or before or immediately after the addition of the carboxylation agent, or to appropriately reduce the organic solvents other than water used in the mercerization treatment by reducing the pressure, etc., to form a mixed solvent of water and an organic solvent, and then to allow the carboxylation reaction to proceed in this mixed solvent of water and an organic solvent. The timing of adding or reducing the organic solvent is not particularly limited as long as it is between the end of the mercerization reaction and immediately after the addition of the carboxylation agent, but is preferably within 30 minutes before or after the addition of the carboxylation agent, for example.

[0029] The proportion of organic solvent in the mixed solvent during carboxymethylation is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, even more preferably 45% by mass or more, and particularly preferably 50% by mass or more, of the total of water and organic solvent. The higher the proportion of organic solvent, the more likely it is that uniform CM group substitution will occur, thereby stabilizing the quality of the resulting carboxymethyl cellulose fiber. The upper limit of the proportion of organic solvent is not limited and may be, for example, 99% by mass or less. Considering the cost of the organic solvent to be added, the proportion is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, and even more preferably 70% by mass or less.

[0030] The reaction medium for carboxymerization (a cellulose-free mixed solvent of water, organic solvent, etc.) preferably has a lower proportion of water (in other words, a higher proportion of organic solvent) than the reaction medium for mercerization. By satisfying this range, it becomes easier to maintain a high degree of crystallinity of the resulting carboxymerized cellulose fiber. Furthermore, when the reaction medium for carboxymerization has a lower proportion of water (a higher proportion of organic solvent) than the reaction medium for mercerization, there is also the advantage that, when transitioning from the mercerization reaction to the carboxymerization reaction, a mixed solvent for the carboxymerization reaction can be formed by the simple means of adding a desired amount of organic solvent to the reaction system after the mercerization reaction is completed.

[0031] Oxidized cellulose fine fibers (also called "carboxylated cellulose fine fibers"), which are an example of chemically modified cellulose fine fibers and an example of anionically modified cellulose fine fibers, can be obtained by defibrating oxidized cellulose fibers obtained by oxidizing (carboxylating) the above-mentioned cellulose raw material using a known method. The amount of carboxy groups is preferably 0.1 to 2.5 mmol / g, more preferably 0.6 mmol / g to 2.5 mmol / g, and even more preferably 1.0 mmol / g to 2.0 mmol / g, based on the bone dry mass of the oxidized cellulose fiber. The amount of carboxy groups in oxidized cellulose fiber can be measured by the following method: 60 mL of a 0.5 mass% slurry (aqueous dispersion) of oxidized cellulose fiber is prepared, and 0.1 M aqueous hydrochloric acid is added to adjust the pH to 2.5. After that, 0.05 N aqueous sodium hydroxide is added dropwise and the electrical conductivity is measured until the pH reaches 11. The amount of carboxy groups is calculated using the following formula from the amount of sodium hydroxide (a) consumed in the neutralization stage of a weak acid, where the change in electrical conductivity is gradual: Amount of carboxy groups [mmol / g oxidized cellulose fiber] = a [mL] × 0.05 / mass of oxidized cellulose fiber [g].

[0032] The amount of carboxy groups in the oxidized cellulose fibers is usually the same as the amount of carboxy groups in the oxidized cellulose fine fibers obtained by defibrating the oxidized cellulose fibers.

[0033] An example of the oxidation method is a method in which a cellulose raw material is oxidized in water using an oxidizing agent in the presence of an N-oxyl compound and a compound selected from the group consisting of bromides, iodides, and mixtures thereof. This oxidation reaction selectively oxidizes the primary hydroxyl group at the C6 position of the glucopyranose ring on the surface of the cellulose, leaving aldehyde groups and carboxyl groups (-COOH) or carboxylate groups (-COO) on the surface. － The concentration of the cellulose raw material during the reaction is not particularly limited, but is preferably 5% by mass or less.

[0034] An N-oxyl compound refers to a compound capable of generating a nitroxy radical. Any compound that promotes the target oxidation reaction can be used as the N-oxyl compound. Examples include 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) and its derivatives (e.g., 4-hydroxyTEMPO). The amount of the N-oxyl compound used is not particularly limited, as long as it is a catalytic amount that can oxidize the cellulose raw material. For example, 0.01 to 10 mmol is preferred, 0.01 to 1 mmol is more preferred, and 0.05 to 0.5 mmol is even more preferred, per 1 g of bone-dry cellulose raw material. The concentration of the N-oxyl compound in the reaction system is preferably about 0.1 to 4 mmol / L.

[0035] Bromides are compounds containing bromine, examples of which include alkali metal bromides that can dissociate and ionize in water. Iodides are compounds containing iodine, examples of which include alkali metal iodides. The amount of bromide or iodide used can be selected within a range that can promote the oxidation reaction. The total amount of bromide and iodide is, for example, preferably 0.1 to 100 mmol, more preferably 0.1 to 10 mmol, and even more preferably 0.5 to 5 mmol, per 1 g of bone-dry cellulose raw material.

[0036] Known oxidizing agents can be used, such as halogens, hypohalous acids, halous acids, perhalogen acids or their salts, halogen oxides, and peroxides. Among these, sodium hypochlorite is preferred because it is inexpensive and has a low environmental impact. The appropriate amount of oxidizing agent used is, for example, preferably 0.5 to 500 mmol, more preferably 0.5 to 50 mmol, even more preferably 1 to 25 mmol, and most preferably 3 to 10 mmol, per 1 g of bone-dry cellulose raw material. Furthermore, for example, 1 to 40 mol is preferred per 1 mol of the N-oxyl compound.

[0037] The oxidation process of cellulose raw materials can proceed efficiently even under relatively mild conditions. Therefore, the reaction temperature is preferably 4 to 40°C, or may be room temperature, about 15 to 30°C. As the reaction proceeds, carboxyl groups are generated in the cellulose chains, resulting in a decrease in the pH of the reaction solution. To efficiently proceed with the oxidation reaction, it is preferable to add an alkaline solution such as an aqueous sodium hydroxide solution to maintain the pH of the reaction solution at about 8 to 12, preferably about 10 to 11. Water is preferred as the reaction medium because of its ease of handling and the low occurrence of side reactions. The reaction time in the oxidation reaction can be appropriately set depending on the degree of oxidation progress, and is usually about 0.5 to 6 hours, for example, about 0.5 to 4 hours.

[0038] Alternatively, the oxidation reaction may be carried out in two stages. For example, the oxidized cellulose obtained by filtration after the completion of the first-stage reaction can be oxidized again under the same or different reaction conditions, thereby enabling efficient oxidation without reaction inhibition by sodium chloride produced as a by-product in the first-stage reaction.

[0039] Another example of an oxidation method is a method in which the cellulose raw material is oxidized by contacting an ozone-containing gas with the raw material. This oxidation reaction oxidizes at least the hydroxy groups at positions 2 and 6 of the glucopyranose ring, and decomposes the cellulose chain. The ozone concentration in the ozone-containing gas is 50 to 250 g / m. ３ It is preferable that the density is 50 to 220 g / m ３It is more preferable that the ozone addition amount relative to the cellulose raw material is preferably 0.1 to 30 parts by mass, and more preferably 5 to 30 parts by mass, based on 100 parts by mass of the solids content of the cellulose raw material. The ozone treatment temperature is preferably 0 to 50°C, and more preferably 20 to 50°C. The ozone treatment time is not particularly limited, but is approximately 1 to 360 minutes, and preferably approximately 30 to 360 minutes. When the ozone treatment conditions are within these ranges, excessive oxidation and decomposition of the cellulose raw material can be prevented, resulting in a good yield of oxidized cellulose fiber. After the ozone treatment, a further oxidation treatment may be performed using an oxidizing agent. The oxidizing agent used in the further oxidation treatment is not particularly limited, but examples include chlorine-based compounds such as chlorine dioxide and sodium chlorite, oxygen, hydrogen peroxide, persulfuric acid, and peracetic acid. For example, the further oxidation treatment can be performed by dissolving these oxidizing agents in water or a polar organic solvent such as alcohol to prepare an oxidizing agent solution, and then immersing the cellulose raw material in the solution. The amount of carboxy groups in the oxidized cellulose fibers can be adjusted by controlling the reaction conditions, such as the amount of oxidizing agent added and the reaction time.

[0040] (Phosphate Esterification) Phosphate-esterified cellulose fine fibers, which are an example of chemically modified cellulose fine fibers and an example of anionically modified cellulose fine fibers, can be obtained by defibrating phosphate-esterified cellulose fibers. Phosphate-esterified cellulose fibers may be commercially available, or may be produced by phosphate-esterifying the above-mentioned cellulose raw material using a known method. The degree of phosphate substitution per glucose unit of the phosphate-esterified cellulose fiber is preferably 0.001 or more and less than 0.40. The degree of phosphate substitution in the phosphate-esterified cellulose fiber and the degree of phosphate substitution in the phosphate-esterified cellulose fine fibers obtained by defibrating the phosphate-esterified cellulose fiber are usually the same.

[0041] Examples of methods for phosphate esterification include mixing a powder or aqueous solution of a compound having a phosphate group with a cellulose raw material, or adding an aqueous solution of a compound having a phosphate group to a slurry of the cellulose raw material. Examples of compounds having a phosphate group include phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium phosphite, potassium phosphite, sodium hypophosphite, potassium hypophosphite, sodium pyrophosphate, sodium metaphosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, potassium metaphosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, and ammonium metaphosphate. Phosphate groups can be introduced into the cellulose raw material by using one or more of these compounds in combination. Among these compounds, phosphoric acid, sodium salts of phosphoric acid, potassium salts of phosphoric acid, and ammonium salts of phosphoric acid are preferred from the viewpoints of high efficiency of phosphate group introduction and ease of industrial application. Sodium dihydrogen phosphate and disodium hydrogen phosphate are particularly preferred. Furthermore, it is desirable to use the compound having a phosphate group in the form of an aqueous solution, as this allows the reaction to proceed uniformly and increases the efficiency of phosphate group introduction. The pH of the aqueous solution of the compound having a phosphate group is preferably 7 or less because this increases the efficiency of introducing the phosphate group, but from the viewpoint of suppressing hydrolysis of the fiber, a pH of 3 to 7 is preferred. When reacting the compound having a phosphate group, a basic compound (for example, a compound having an amino group that exhibits basicity, such as urea, methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, or hexamethylenediamine) may be further added to the reaction system.

[0042] The following method can be given as a specific example of a method for producing phosphated cellulose fibers. A compound having a phosphate group is added to a suspension of a cellulose raw material having a solids concentration of 0.1 to 10% by mass while stirring, to introduce phosphate groups into the cellulose. When the cellulose raw material is taken as 100 parts by mass, the amount of the compound having a phosphate group added is preferably 0.2 to 500 parts by mass, more preferably 1 to 400 parts by mass, in terms of elemental phosphorus.

[0043] After the resulting suspension of phosphated cellulose fibers is dehydrated, from the viewpoint of suppressing hydrolysis of cellulose, it is preferably heat-treated at 100 to 170° C. Furthermore, it is preferable that the suspension be heated at 130° C. or lower, preferably 110° C. or lower, while water is contained during the heat treatment, and then be heat-treated at 100 to 170° C. after the water has been removed.

[0044] (Defibrillation) Chemically modified cellulose raw material (chemically modified cellulose fibers) or anionically modified cellulose fibers can be defibrillated to obtain chemically modified cellulose fine fibers or anionically modified cellulose fine fibers. The chemical modification makes the cellulose fibers more easily fine. The device used for defibrillation is not particularly limited, and examples that can be used include devices capable of applying strong shearing forces, such as high-pressure, high-speed rotation, colloid mill, roll mill, ultrasonic, and cavitation types, as well as devices such as disk-type, conical-type, and cylinder-type refiners, high-pressure homogenizers, colloid mills, high-pressure jet dispersers, beaters, PFI mills, kneaders, and dispersers.

[0045] Defibration is preferably performed in a wet manner (i.e., in the form of a dispersion in which water or the like is used as a dispersion medium). When performing wet defibration, first, a dispersion of chemically modified cellulose fibers is prepared. The solids concentration in the dispersion to be subjected to defibration is preferably 0.1% by mass or more, more preferably 0.5% by mass or more. The upper limit of the concentration is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 10% by mass or less, and even more preferably 8% by mass or less. The dispersion medium is preferably water.

[0046] The chemically modified cellulose fine fibers may be dried and solidified after defibration. The dried solid matter of the chemically modified cellulose fine fibers is preferably diluted with a dispersing medium to a solid content of 1.0 to 5.0 mass % to form a dispersion, and the dispersion is preferably used as a raw material for cosmetics. The dispersing medium is preferably water.

[0047] (Viscosity) The Brookfield viscosity of the dispersion of chemically modified cellulose fine fibers is not particularly limited, but the viscosity measured with a Brookfield viscometer under the conditions described below is preferably 100,000 mPa s or less, more preferably 50,000 mPa s or less, and even more preferably 10,000 mPa s or less. The lower limit is preferably 10 mPa s or more, more preferably 50 mPa s or more, and even more preferably 100 mPa s or more.

[0048] The B-type viscosity of the dispersion of chemically modified cellulose fine fibers was measured by preparing an aqueous dispersion containing 1.0% by mass of chemically modified cellulose fine fibers, stirring the dispersion in a Homodisper (3,000 rpm, 1 minute), and then measuring the viscosity after 3 minutes at 25°C and 60 rpm using a B-type viscometer (manufactured by Eiko Seiki Co., Ltd.).

[0049] The amount of chemically modified cellulose fine fibers blended into the cosmetic is preferably 0.01 to 2 parts by mass in terms of solid content per 100 parts by mass of the entire cosmetic. Within this range, the thickening and dispersing effects of the chemically modified cellulose fine fibers are exerted in the cosmetic.

[0050] (B: Polyvalent Metal Salt) The polyvalent metal salt is a salt consisting of a divalent or higher metal ion and its counter ion. Any divalent or higher metal ion is sufficient, with calcium ion, magnesium ion, and zinc ion being particularly preferred. The polyvalent metal salt is preferably water-soluble. In systems containing polyvalent metal ions derived from polyvalent metal salts, there is usually a problem that the polyvalent metal ions crosslink the modifying groups of the chemically modified cellulose fine fibers, which tends to cause aggregation of the cellulose fine fibers. However, aggregation can be suppressed by adding an aminocarboxylic acid or a salt thereof, and / or a hydroxycarboxylic acid or a salt thereof, which will be described later.

[0051] The amount of polyvalent metal salt to be added can be adjusted appropriately depending on the type of salt and the purpose of addition. For example, the amount can be 0.01 to 1,000 parts by mass, more preferably 0.1 to 500 parts by mass, per 100 parts by mass of the chemically modified cellulose fine fibers.

[0052] (C1: Aminocarboxylic Acid or Salt thereof) Aminocarboxylic acids or salts thereof are organic compounds having both an amino group and a carboxy group in the molecule. Examples of aminocarboxylic acids include ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid, ethylenediaminedisuccinic acid, glutamic acid diacetate, pentetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraaminehexaacetic acid, 1,3-propanediaminetetraacetic acid, glycol ether diaminetetraacetic acid, tetrasodium L-glutamic acid diacetate, (S,S)-ethylenediaminedisuccinic acid, and 1,2-cyclohexanediaminetetraacetic acid, with ethylenediaminetetraacetic acid (EDTA) and pentetic acid being particularly preferred. Examples of aminocarboxylic acid salts include sodium salts, potassium salts, ammonium salts, and amine salts, with EDTA-2Na, EDTA-3Na, EDTA-4Na, and pentetic acid-5Na being particularly preferred.

[0053] The amount of aminocarboxylic acid or its salt can be adjusted as appropriate, and is preferably 0.01 mol to 10 mol, more preferably 0.1 mol to 5 mol, per mol of polyvalent metal salt. Within this range, aggregation of cellulose fine fibers due to the polyvalent metal salt can be further suppressed.

[0054] (C2: Hydroxycarboxylic Acid or Salt Thereof) Hydroxycarboxylic acid or its salt is an organic compound having both a hydroxy group and a carboxy group in the molecule. Examples of hydroxycarboxylic acid include hydroxyethylethylenediaminetriacetic acid, hydroxyethyliminodiacetic acid, dihydroxyethylglycine, 1,3-diamino-2-hydroxypropanetetraacetic acid, and gluconic acid, with hydroxyethylethylenediaminetriacetic acid (HEDTA) being particularly preferred. Examples of salts of hydroxycarboxylic acid include sodium salts, potassium salts, ammonium salts, and amine salts, with HEDTA-3Na being particularly preferred.

[0055] The aminocarboxylic acid or its salt and the hydroxycarboxylic acid or its salt may be used either alone or in combination of two or more thereof.

[0056] (D: Water) The cosmetic of the present invention contains water. The amount of water is not particularly limited, but is, for example, 0.01 to 90% by mass, preferably 1 to 70% by mass, relative to the total mass of the cosmetic.

[0057] (Cosmetics) The cosmetic of the present invention is resistant to polyvalent metal ions derived from polyvalent metal salts and can therefore be suitably used in a variety of applications. The cosmetic may be for makeup, skin care, or for hair or scalp treatment. The specific form of the cosmetic may be, but is not limited to, a solution, emulsion, suspension, cream, aerosol, or the like. The cosmetic may also contain various components acceptable for use in cosmetics in addition to the cosmetic of the present invention. Examples of such components include surfactants, pH adjusters, chelating agents, antioxidants, fragrances, colorants, pigments, powders, emulsifiers, preservatives, plant extracts, and functional components such as UV absorbers and whitening agents. More specific examples of the components include purified water, polyethylene glycol, propylene glycol, ethanol, glycerin, citrate, vitamin C or a vitamin C derivative, vitamin E, and the like.

[0058] The viscosity of the cosmetic of the present invention is not particularly limited, but the viscosity measured with a Brookfield viscometer at 25° C. and 60 rpm is preferably 100,000 mPa·s or less, and more preferably 50,000 mPa·s or less.

[0059] When the cosmetic of the present invention is a transparent liquid or gel cosmetic, high transparency of the cosmetic is an indicator of the stable dispersion of the chemically modified cellulose microfibers in the cosmetic. The transparency of such a cosmetic can be expressed as the transmittance of light with a wavelength of 660 nm at an optical path length of 10 mm. The transparency of such a cosmetic is preferably 20.0% or more, more preferably 30.0% or more, and even more preferably 46.0% or more, and is preferably 100% or less, more preferably 96.0% or less, and even more preferably 94.0% or less.

[0060] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these. Unless otherwise specified, parts and % represent parts by mass and % by mass.

[0061] <Production of carboxymethylated cellulose fine fibers> 130 parts of water and a solution of 20 parts of sodium hydroxide dissolved in 100 parts of water were added to a twin-screw kneader adjusted to 100 rpm, and 100 parts of hardwood pulp (LBKP, manufactured by Nippon Paper Industries Co., Ltd.) was added (dry mass: 100 parts after drying at 100°C for 60 minutes). The mixture was stirred and mixed at 30°C for 90 minutes to prepare mercerized cellulose. Further, 230 parts of isopropanol (IPA) and 60 parts of sodium monochloroacetate were added with stirring, and after stirring for 30 minutes, the mixture was heated to 70°C and subjected to a carboxymethylated cellulose reaction for 90 minutes. The concentration of IPA in the reaction medium during the carboxymethylated cellulose reaction was 50%. After completion of the reaction, the mixture was neutralized, deliquored, dried, and pulverized to obtain carboxymethylated cellulose fibers (sodium salt type) with a carboxymethylated cellulose substitution degree of 0.31 and a crystallinity of cellulose type I of 58%.

[0062] The resulting sodium salt of carboxymethyl cellulose was dispersed in water to prepare a 2% aqueous dispersion. This was then processed five times with a high-pressure homogenizer at 150 MPa to obtain an aqueous dispersion of carboxymethyl cellulose fine fibers. The resulting carboxymethyl cellulose fine fibers had an average fiber diameter of 3 nm and an aspect ratio of 40.

[0063] <Production of Oxidized Cellulose Fine Fibers 1> 500 g (bone-dry) of bleached, unbeaten kraft pulp (brightness 85%) derived from coniferous trees was used as the cellulose raw material. 500 g of the cellulose raw material, TEMPO (Sigma-Aldrich) (0.025 mmol relative to the cellulose raw material), and sodium bromide (1.0 mmol / g relative to the cellulose raw material) were added to 20 L of aqueous solution and stirred until the pulp was uniformly dispersed. A commercially available low-salt aqueous sodium hypochlorite solution (effective chlorine concentration 12% by mass, sodium chloride content 4% by mass or less) was added to the reaction system to achieve an effective chlorine concentration of 5.2 mmol / g relative to the cellulose raw material, initiating the oxidation reaction. As the reaction progressed, the pH of the system decreased, so 3 M aqueous sodium hydroxide solution was gradually added to adjust the pH to 10. The reaction was terminated when the pH no longer decreased. Hydrochloric acid was added to the reaction mixture to a pH of 2.4 or less, and the pulp was separated by filtration through a glass filter. The pulp was dispersed again in ion-exchanged water, and then hydrochloric acid was added to adjust the pH to 2.5 or less. The pulp was then separated by filtration through a glass filter, and this procedure was repeated to remove excess salts and impurities. The pulp was then thoroughly washed with water to remove excess hydrochloric acid, yielding carboxyl-introduced pulp (oxidized cellulose fibers). The carboxyl group content of the oxidized cellulose fibers was 1.4 mmol / g.

[0064] The obtained oxidized cellulose fibers were dispersed in water to prepare a 2% aqueous dispersion, which was then treated three times with a high-pressure homogenizer at 150 MPa to obtain an aqueous dispersion of oxidized cellulose fine fibers 1. The obtained oxidized cellulose fine fibers 1 had an average fiber diameter of 3 nm and an aspect ratio of 250.

[0065] <Production of Oxidized Cellulose Fine Fibers 2> 500 g (bone-dry) of bleached softwood-derived dissolving kraft pulp (DKP, manufactured by Buckeye) was added to 50 L of an aqueous solution containing 7.8 g (0.05 mol) of TEMPO (Sigma-Aldrich) and 75.5 g (0.74 mol) of sodium bromide, and the mixture was stirred until the pulp was uniformly dispersed. 1.6 L of a 2 M aqueous sodium hypochlorite solution was added to the reaction system, and the oxidation reaction was initiated (oxidation treatment). The pH of the system decreased during the reaction, but was adjusted to pH 10 by the sequential addition of a 3 M aqueous sodium hydroxide solution. After the reaction time of 2 hours, the mixture was filtered through a glass filter and thoroughly washed with water to obtain oxidized cellulose fibers.

[0066] The obtained oxidized cellulose fibers were dispersed in water to form a 5% slurry. Hydrogen peroxide was added to this at 2% relative to the oxidized cellulose fibers, and the pH was adjusted to 11.3 with 3 M sodium hydroxide. This slurry was left at 80°C for 2 hours to carry out hydrolysis. This was then adjusted to 5% with water and treated five times with an ultra-high pressure homogenizer (20°C, 140 MPa) to obtain an aqueous dispersion of oxidized cellulose fine fibers 2. The obtained oxidized cellulose fine fibers 2 had a carboxyl group content of 1.7 mmol / g, an average fiber diameter of 3 nm, and an aspect ratio of 117.

[0067] <Production of Cosmetic> Phenoxyethanol (preservative) was added to the 2.0% aqueous dispersion of anion-modified cellulose fine fibers (A) obtained above to a concentration of 0.5%, and the mixture was uniformly mixed (X). Calcium chloride was prepared as the polyvalent metal salt (B), and the aminocarboxylate or hydroxycarboxylate salt (C) shown in Tables 1 and 2 were prepared and dissolved in water. The mixture was then uniformly mixed while adjusting the pH to 9 using a 10% aqueous sodium hydroxide solution (Y). In each Example and Comparative Example, Y was added to X, and water was added as needed, so that the concentrations of (A), (B), and (C) would be the values ​​shown in Tables 1 and 2 when the final cosmetic was 100 parts by mass. The mixture was then uniformly mixed using a homodisper for 15 minutes. In Comparative Examples 6 to 8, a water-soluble cellulose polymer (carboxymethyl cellulose, brand: FS350HC-4, DS: 0.92) was used instead of the anion-modified cellulose fine fibers (A).

[0068] <Evaluation Method> (Transparency) The transparency of each Example and Comparative Example refers to the linear light transmittance (%) measured using an ultraviolet-visible spectrophotometer U-3000 (manufactured by Hitachi High-Technologies Corporation) under conditions of 25°C, a wavelength of 660 nm, and a cell length of 10 mm. The results are shown in Tables 1 and 2.

[0069] (Texture, Feeling in Use) The cosmetics prepared by the above method were spread on the back of the hand, observed, and evaluated according to the following criteria. The results are shown in Table 1. (Rating) (Contents) 5: Very good (no roughness at all, no stickiness, etc.) 4: Fairly good 3: Average 2: Fairly bad 1: Very bad

[0070]

[0071] Table 1 shows that the skin cosmetics obtained in each Example had higher transparency and better texture than those in each Comparative Example. In this cosmetic, high transparency indicates that aggregation of the anion-modified cellulose fine fibers was suppressed and the dispersion was more stable. Comparative Examples 6 to 8, in which a cellulose-based water-soluble polymer was used instead of the cellulose fine fibers, had high transparency and were not rough, but were sticky and were evaluated as having very poor overall texture and usability.

Claims

1. A cosmetic comprising the following components (A) to (D): (A) anion-modified cellulose fine fibers, (B) a polyvalent metal salt, (C) (C1) an aminocarboxylic acid or a salt thereof and / or (C2) a hydroxycarboxylic acid or a salt thereof, and (D) water.

2. The cosmetic according to claim 1, wherein the anion-modified cellulose fine fibers (A) are carboxyalkylated cellulose fine fibers.

3. A cosmetic preparation according to claim 1 or 2, wherein (C) contains (C1) an aminocarboxylic acid, and (C1) the aminocarboxylic acid is one or more selected from ethylenediaminetetraacetic acid, ethylenediaminedisuccinic acid, glutamic acid diacetic acid, and pentetic acid.

4. A cosmetic according to claim 1 or 2, wherein (C) comprises a (C2) hydroxycarboxylic acid, and the (C2) hydroxycarboxylic acid is hydroxyethylethylenediaminetriacetic acid.

5. A cosmetic preparation according to claim 1 or 2, wherein the metal ions constituting the polyvalent metal salt (B) are one or more selected from calcium ions, magnesium ions, and zinc ions.

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