Composition for artificial nail

Abstract

Provided is a composition for an artificial nail, the composition being capable of exhibiting favorable peelability. Provided are: a composition for an artificial nail, the composition comprising a cellulose microfiber such as a chemically modified cellulose microfiber; an artificial nail comprising a cured layer thereof; and a method for forming an artificial nail. The chemical modification is preferably anionic modification and more preferably oxidation. The composition may further comprise an adhesive component like a water-soluble polymer such as polyvinyl alcohol or gelatin.

Description

Composition for artificial nails

[0001] This invention relates to a composition for artificial nails, and more particularly to a composition for artificial nails containing cellulose microfibers and its applications.

[0002] Cosmetic products for artificial nails, such as manicures and pedicures, have traditionally been used for the decoration and protection of fingertips. However, in recent years, various types of artificial nails have been developed from the perspective of nail art and other decorative and cosmetic purposes. Examples include so-called gel nails, which involve applying a gel-like nail coating material to the nail and hardening it with ultraviolet light, and so-called nail tips, which are attached to the nail and then decorated on their surface.

[0003] As a technique to improve the adhesion to nails, for example, Patent Document 1 describes that an artificial nail compound containing a compound having at least one radically polymerizable unsaturated double bond in its molecule, an acidic phosphorus compound having the bond, and a radical polymerization initiator can improve adhesion and suppress peeling and detachment. Patent Document 2 describes that a composition containing an acrylamide compound and a polyfunctional compound such as dipentaerythritol hexa(meth)acrylate in a predetermined ratio has high adhesion and can be removed with an acidic aqueous solution with a pH of 3.5 or lower, so it can be used as a gel nail.

[0004] Japanese Patent Publication No. 2010-53097 Japanese Patent Publication No. 2020-23662

[0005] However, in conventional technologies such as those described in Patent Documents 1 and 2, removing artificial nails involves using chemicals such as nail polish remover, which can damage the nail surface tissue. In particular, with gel nails, it is necessary to file down to the base layer and then use organic solvents such as acetone to soften and peel off the primer layer. This process, involving organic solvents and filing, can thin or damage the nails and cause dryness of the surrounding skin, potentially harming the user's health. Furthermore, the removal process is time-consuming, and it is often not possible to perform the next treatment immediately after removal (usually a period of about a week is required between removal and the next treatment), which places a significant burden on both the practitioner and the user of the artificial nails. Moreover, the use of organic solvents is undesirable from an environmental perspective.

[0006] In view of the above-mentioned problems, the present invention aims to provide a composition for artificial nails that exhibits good peelability.

[0007] As a result of diligent research by the inventors, we discovered that using cellulose microfibers as a material when applying artificial nails makes it easier to remove the artificial nails after use, and thus completed the present invention.

[0008] The present invention includes the following: [1] A composition for artificial nails comprising cellulose microfibers and satisfying the following conditions: Condition A: The B-type viscosity (6 rpm) of the artificial nail composition is 2,300 mPa·s or more and 100,000 mPa·s or less. Condition B: The three-dimensional surface roughness (Sa) of the coating film of the artificial nail composition is 130 nm or less. [2] The composition according to [1], wherein the cellulose microfibers include chemically modified cellulose microfibers. [3] The composition according to [1], wherein the cellulose microfibers include anionically modified cellulose microfibers. [4] The composition according to [1], wherein the cellulose microfibers include oxidized cellulose microfibers. [5] The composition according to any one of [1] to [4], further comprising an adhesive component. [6] The composition according to [5], wherein the adhesive component is an aqueous polymer. [7] The composition according to [6], wherein the aqueous polymer is polyvinyl alcohol or gelatin. [8] A composition according to any one of [1] to [7] for use with gel nails. [9] A composition according to any one of [1] to [8] for use as a primer between an artificial nail and a real nail.

[10] An artificial nail comprising a hardened layer of the composition according to any one of [1] to [9].

[11] A method for forming an artificial nail, comprising applying the composition according to any one of [1] to [9] to the surface of a nail and hardening it.

[12] A method for removing an artificial nail, comprising subjecting the artificial nail according to

[10] to underwater vibration treatment or steam treatment irradiation and removing the artificial nail from the real nail.

[0009] The artificial nail composition of the present invention contains cellulose microfibers exhibiting predetermined physical properties, and therefore can exhibit good peelability, as well as good adhesion and applicability.

[0010] In the following explanation, the notations "XX or greater and YY or less" or "XX to YY" that represent numerical ranges mean a numerical range that includes the lower and upper limits, unless otherwise specified. When numerical ranges are described in steps, the upper and lower limits of each numerical range can be combined in any way.

[0011] [1. Artificial Nail Composition] The artificial nail composition of the present invention contains cellulose microfibers. The cellulose microfibers can contribute to the adhesion and peelability of the composition. The mechanism of these effects is presumed to be as follows: The cellulose microfibers can disperse the peeling stress between the artificial nail and the natural nail, and suppress deformation of the coating film during peeling, thereby improving adhesion. Furthermore, when peeling the artificial nail from the natural nail, it is thought that the cellulose fibers vibrate due to underwater vibration treatment or steam treatment, making it easier for water to penetrate between the fibers, and as a result, it can be easily peeled off.

[0012] [1.1 Cellulose Microfibers] The cellulose microfibers used in the present invention are microfibers made from cellulose, and can be obtained by defibrating the cellulose raw material to reduce its fiber diameter. The average fiber diameter of the cellulose microfibers is not particularly limited, but is about 2 nm to 10 μm. Preferably, the average fiber diameter is 2 nm to 1 μm, more preferably 2 nm to 500 nm, even more preferably 2 nm to 100 nm, and even more preferably 3 nm to 50 nm. The average fiber length (length-weighted average fiber length) of the cellulose microfibers is usually 50 to 2,000 nm, preferably 100 to 1,000 nm. It is preferable that the average fiber diameter and average fiber length of the cellulose microfibers are within these ranges because the surface irregularities when formed into a coating film become finer, and the effect of suppressing the adhesion of contaminants is enhanced. The average fiber diameter and average fiber length of cellulose microfibers can be obtained by averaging the fiber diameter and fiber length obtained from observing each fiber using an ABB fiber tester, a Valmet fractionator, a scanning electron microscope (SEM), an atomic force microscope (AFM), or a transmission electron microscope (TEM), selected appropriately according to the fiber diameter. When measuring nanoscale fiber diameter, it is preferable to determine it by measuring the cross-sectional height of the fiber shape image observed using an atomic force microscope (AFM). The average fiber diameter can be determined by measuring the fiber diameter 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 length of 200 randomly selected fibers using the method described above and calculating the length-weighted average fiber length.

[0013] The aspect ratio of the cellulose microfibers is preferably 10 to 1000, more preferably 10 to 500, and even more preferably 10 to 300. The aspect ratio can be calculated using the following formula: Aspect ratio = average fiber length (nm) / average fiber diameter (nm).

[0014] The cellulose raw material used to produce cellulose microfibers is not particularly limited as long as it contains cellulose, but examples include those derived from plants, animals (e.g., sea squirts), algae, and microorganisms (e.g., Acetobacter). Examples of plant-derived materials include wood, bamboo, hemp, jute, kenaf, agricultural waste, cloth, and pulp (unbleached softwood kraft pulp (NUKP), bleached softwood kraft pulp (NBKP), unbleached hardwood kraft pulp (LUKP), bleached hardwood kraft pulp (LBKP), unbleached softwood sulfite pulp (NUSP), bleached softwood sulfite pulp (NBSP), thermomechanical pulp (TMP), softwood soluble pulp, hardwood soluble pulp, recycled pulp, waste paper, etc.). Cellulose powder obtained by crushing 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 preferably it is cellulose fiber derived from plants or microorganisms, more preferably it is cellulose fiber derived from plants, and even more preferably it is woody pulp.

[0015] [1.2 Chemically Modified Cellulose Microfibers] Cellulose has three hydroxyl groups per glucose unit, and various chemical modifications can be performed on it. As an example of cellulose microfibers, it is preferable to use chemically modified cellulose microfibers obtained by defibrating a cellulose raw material (chemically modified cellulose fiber) obtained by chemical modification, from the viewpoint of promoting the progress of defibration.

[0016] As for chemical modification, anionic modification, which involves introducing anionic groups into cellulose, is preferred. Specifically, anionic modification involves introducing anionic groups into the pyranose ring of cellulose by substitution or oxidation reactions. The types of anionic modification are not limited to these, but examples include carboxyalkylation, which involves ether linking a carboxyalkyl group such as a carboxymethyl group (hereinafter, "carboxymethyl" will be referred to as "CM") to the cellulose chain; oxidation (also called carboxylation), which involves introducing a carboxyl group into the cellulose chain; and phosphate esterification, which involves introducing a phosphate group into the cellulose chain. Among these, carboxymethylation or oxidation is preferred, and oxidation is particularly preferred.

[0017] Examples of chemically modified cellulose microfibers include CM-modified cellulose microfibers, carboxyalkylated cellulose microfibers, oxidized cellulose microfibers, TEMPO-oxidized cellulose microfibers, ozone-oxidized cellulose microfibers, phosphate-esterified cellulose microfibers, phosphite-esterified cellulose microfibers, cationized cellulose microfibers, sulfonated cellulose microfibers, xantate-modified cellulose microfibers, and the like. CM-modified cellulose microfibers and oxidized cellulose microfibers are particularly preferred.

[0018] Chemically modified cellulose microfibers, such as anionic modified cellulose microfibers, can take the form of anionic groups such as carboxyl groups, CM groups, and phosphate groups having metal ions such as sodium ions or potassium ions as counterions (this form is called the "salt form"). Alternatively, they can take the form of anionic groups having protons as counterions (this form is called the "hydrogen form").

[0019] Chemically modified cellulose fibers, which are the raw materials for chemically modified cellulose microfibers, maintain at least a portion of their fibrous structure even when dispersed in water. That is, when an aqueous dispersion of chemically modified cellulose fibers is observed with an electron microscope, fibrous material can be observed, and when measured by X-ray diffraction, peaks of type I cellulose crystals can be observed. The degree of crystallinity of cellulose in chemically modified cellulose fibers or chemically modified cellulose microfibers is preferably 40% or more of type I crystals, and more preferably 50% or more. The crystallinity of cellulose can be controlled by the degree of chemical modification. There is no particular upper limit to the degree of crystallinity of type I cellulose. In reality, it is considered that the upper limit is around 90%. The method for measuring the degree of crystallinity of type I cellulose is as follows: The sample is placed on a glass cell and measured using an X-ray diffraction measuring device (product name: LabX XRD-6000, manufactured by Shimadzu Corporation). The degree of crystallinity is calculated using methods such as Segal's, with the diffraction intensity of the X-ray diffraction pattern from 2θ = 10° to 30° as the baseline. It is calculated from the diffraction intensity of the 002 plane at 2θ = 22.6° and the diffraction intensity of the amorphous region at 2θ = 18.5° using the following formula: Xc = (I002c - Ia) / I002c × 100 Xc = degree of crystallinity of type I cellulose (%) I002c: diffraction intensity of the 002 plane at 2θ = 22.6° Ia: diffraction intensity of the amorphous region at 2θ = 18.5°.

[0020] To obtain chemically modified cellulose fibers having peaks of type I cellulose crystals, it is preferable to use a cellulose raw material with a high degree of crystallinity of type I cellulose. The degree of crystallinity of type I cellulose in the cellulose raw material is preferably 40% or more, and more preferably 50% or more.

[0021] -Oxidation- Oxidized cellulose microfibers (also called "carboxylated cellulose microfibers"), which are an example of chemically modified cellulose microfibers, can be obtained by oxidizing (carboxylating) the above-mentioned cellulose raw material by a known method and then defibrating the oxidized cellulose fibers. The amount of carboxyl 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, relative to the oven-dry mass of oxidized cellulose. The amount of carboxyl groups in oxidized cellulose fibers can be measured by the following method: Prepare 60 mL of a 0.5% by mass slurry (aqueous dispersion) of oxidized cellulose fibers, add 0.1 M hydrochloric acid aqueous solution to adjust the pH to 2.5, then add 0.05 N sodium hydroxide aqueous solution dropwise until the pH becomes 11, and measure the electrical conductivity. From the amount of sodium hydroxide consumed in the neutralization stage of the weak acid, where the change in electrical conductivity is gradual (a), calculate the amount of carboxyl groups using the following formula: Amount of carboxyl groups [mol / g oxidized cellulose fiber] = a [mL] × 0.05 / Mass of oxidized cellulose fiber [g].

[0022] The amount of carboxyl groups in oxidized cellulose fibers and the amount of carboxyl groups in oxidized cellulose fine fibers obtained by defibrating oxidized cellulose fibers are usually the same. One example of an oxidation method is to oxidize the cellulose raw material in water using an oxidizing agent in the presence of an N-oxyl compound and a compound selected from the group consisting of bromide, iodide, and mixtures thereof. This oxidation reaction selectively oxidizes the primary hydroxyl group at the C6 position of the glucopyranose ring on the cellulose surface, resulting in the formation of an aldehyde group and a carboxyl group (-COOH) or carboxylate group (-COOH) on the surface. － A cellulose raw material (oxidized cellulose fiber) having the following properties can be obtained. The concentration of the cellulose raw material during the reaction is not particularly limited, but 5% by mass or less is preferred.

[0023] An N-oxyl compound is a compound capable of generating a nitroxyl radical. Any compound that promotes the desired 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 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, more preferably 0.01 to 1 mmol, and even more preferably 0.05 to 0.5 mmol per 1 g of oven-dried cellulose raw material. Also, about 0.1 to 4 mmol / L of the reaction system is preferable.

[0024] Bromides are compounds containing bromine, and examples include alkali metal bromides that can dissociate and ionize in water. Iodides are compounds containing iodine, and examples 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 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 oven-dried cellulose raw material.

[0025] As an oxidizing agent, known substances can be used, such as halogens, hypohalous acids, halogenous acids, perhalous acids or their salts, halogen oxides, peroxides, etc. Among these, sodium hypochlorite is preferred because it is inexpensive and has a low environmental impact. The appropriate amount of oxidizing agent to use is, for example, 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 oven-dried cellulose raw material. Also, for example, 1 to 40 mol per 1 mol of N-oxyl compound is preferred.

[0026] 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, and can also be room temperature of about 15 to 30°C. As the reaction progresses, carboxyl groups are generated in the cellulose chain, so a decrease in the pH of the reaction solution is observed. In order to efficiently carry out 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 8 to 12, preferably 10 to 11. Water is preferred as the reaction medium due to its ease of handling and the low likelihood of side reactions. The reaction time in the oxidation reaction can be appropriately set according to the degree of oxidation, and is usually 0.5 to 6 hours, for example, about 0.5 to 4 hours.

[0027] Furthermore, the oxidation reaction may be carried out in two stages. For example, by filtering out the oxidized cellulose after the first stage of the reaction and then oxidizing it again under the same or different reaction conditions, the oxidation can be carried out efficiently without being inhibited by the salt produced as a by-product in the first stage of the reaction.

[0028] Another example of oxidation is the method of bringing cellulose raw material into contact with an ozone-containing gas. This oxidation reaction oxidizes at least the hydroxyl groups at positions 2 and 6 of the glucopyranose ring, and also causes decomposition of the cellulose chain. The ozone concentration in the ozone-containing gas is 50 to 250 g / m³. ３ Preferably, it is 50 to 220 g / m². ３It is more preferable that the following conditions are met. The amount of ozone added to the cellulose raw material is preferably 0.1 to 30 parts by mass, and more preferably 5 to 30 parts by mass, when the solid content of the cellulose raw material is 100 parts by mass. 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 about 1 to 360 minutes, and is preferably about 30 to 360 minutes. When the ozone treatment conditions are within these ranges, it is possible to prevent the cellulose raw material from being excessively oxidized and decomposed, and the yield of oxidized cellulose fibers is improved. After ozone treatment, a follow-up oxidation treatment may be performed using an oxidizing agent. The oxidizing agent used for the follow-up oxidation treatment is not particularly limited, but examples include chlorine compounds such as chlorine dioxide and sodium chlorite, as well as oxygen, hydrogen peroxide, persulfuric acid, and peracetic acid. For example, these oxidizing agents can be dissolved in water or a polar organic solvent such as alcohol to prepare an oxidizing agent solution, and the follow-up oxidation treatment can be performed by immersing the cellulose raw material in the solution.

[0029] The amount of carboxyl groups in oxidized cellulose fibers can be adjusted by controlling the reaction conditions, such as the amount of oxidizing agent added and the reaction time.

[0030] -Carboxyalkylation, CM formation- Carboxyalkylated cellulose microfibers, preferably CM-formed cellulose microfibers, which are an example of chemically modified cellulose microfibers, can be obtained by defibrating carboxyalkylated cellulose fibers, preferably CM-formed cellulose fibers, obtained by known methods. The degree of carboxyalkylation per anhydrous glucose unit of cellulose is preferably 0.01 to 0.50. The upper limit is preferably 0.40 or less. If the degree of carboxyalkylation exceeds 0.50, dissolution in water becomes more likely, and the fiber form cannot be maintained in water. In order to obtain the effects of carboxyalkylation, it is necessary to have a certain degree of substitution. For example, if the degree of substitution is less than 0.02, the advantages of introducing carboxyalkyl may not be obtained depending on the application. Therefore, the degree of carboxyalkylation is preferably 0.02 or more, more preferably 0.05 or more, and even more preferably 0.10 or more. The degree of carboxyalkylation can be adjusted by controlling the amount of carboxyalkylating agent added, the amount of mercerizing agent, and the composition ratio of water and organic solvent.

[0031] In this specification, anhydrous glucose unit refers to individual anhydrous glucose (glucose residues) that constitute cellulose. Furthermore, the degree of carboxyalkyl substitution (also called the degree of etherification) indicates the proportion of hydroxyl 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.

[0032] The method for measuring the carboxyalkyl degree of substitution is as follows: Accurately weigh approximately 2.0 g of a sample, and place it in a 300 mL conical flask with a ground glass stopper. Add 100 mL of methanolic nitric acid (a solution prepared by adding 100 mL of special-grade concentrated nitric acid to 1000 mL of methanol), and shake for 3 hours to convert salt-type carboxyalkylated cellulose fibers into hydrogen-type carboxyalkylated cellulose fibers. Accurately weigh 1.5 to 2.0 g of absolutely dry hydrogen-type carboxyalkylated cellulose fibers, and place them in a 300 mL conical flask with a ground glass stopper. Wet the fibers with 15 mL of 80% methanol, add 100 mL of 0.1 N NaOH, and shake the mixture for 3 hours at room temperature. Using phenolphthalein as an indicator, excess NaOH is back-titrated with 0.1 N H ２ SO ４ , and the carboxyalkyl degree of substitution (DS) is calculated by the following formula. A = [(100 × F' - 0.1 N-H ２ SO ４ (mL) × F) × 0.1] / (absolutely dry mass of hydrogen-type carboxyalkylated cellulose fibers (g)) Carboxyalkyl degree of substitution (DS) = 0.162 × A / (1 - 0.058 × A) F': Factor of 0.1 N-H ２ SO ４ F: Factor of 0.1 N-NaOH.

[0033] The DS in carboxyalkylated cellulose fibers is generally the same as the DS in carboxyalkylated cellulose microfibers obtained by defibrating carboxyalkylated cellulose.

[0034] As an example of the method for producing carboxyalkylated cellulose fibers, a production example of CM-modified cellulose fibers is described below. First, a cellulose raw material is mixed with a solvent and a mercerizing agent, and mercerization of the cellulose raw material is performed at a reaction temperature of 0 to 70°C, preferably 10 to 60°C, and a reaction time of 15 minutes to 8 hours, preferably 30 minutes to 7 hours. Next, a CM-modifying agent is added in an amount of 0.05 to 10.0 times the molar amount per glucose residue, and CM modification is performed at a reaction temperature of 30 to 90°C, preferably 40 to 80°C, and a reaction time of 30 minutes to 10 hours, preferably 1 hour to 4 hours.

[0035] As a solvent, 3 to 20 times the mass of water or an organic solvent or a mixture thereof can be used. Examples of organic solvents, though not limited to these, include 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. Of these, monohydric alcohols with 1 to 4 carbon atoms are preferred due to their excellent compatibility with water, and monohydric alcohols with 1 to 3 carbon atoms are even more preferred. As a mercing agent, it is preferable to use 0.5 to 20 times the molar amount of alkali metal hydroxide per anhydrous glucose residue of the cellulose raw material, specifically sodium hydroxide and potassium hydroxide. Examples of CM agents include monochloroacetic acid, sodium monochloroacetate, methyl monochloroacetate, ethyl monochloroacetate, and isopropyl monochloroacetate. Of these, monochloroacetic acid or sodium monochloroacetate are preferred due to the availability of the raw materials. The amount of CM agent used is not particularly limited, but it is preferable to add it in the range of 0.5 to 1.5 moles per anhydrous glucose unit of cellulose. The lower limit of the above range is more preferably 0.6 moles or more, even more preferably 0.7 moles or more, and the upper limit is more preferably 1.3 moles or less, even more preferably 1.1 moles or less. The CM agent is not limited to these, but may be added to the reactor as an aqueous solution of 5 to 80% by mass, more preferably 30 to 60% by mass, or it may be added in powder form without dissolving in a solvent such as water.

[0036] The molar ratio of mercelling agent to CM agent (mercelling agent / CM agent) is generally between 0.90 and 2.45 when monochloroacetic acid or sodium monochloroacetic acid is used as the CM agent. This is because a ratio below 0.90 may result in an insufficient CM reaction, potentially leading to waste due to unreacted monochloroacetic acid or sodium monochloroacetic acid. Conversely, a ratio exceeding 2.45 may lead to side reactions between the excess mercelling agent and monochloroacetic acid or sodium monochloroacetic acid, potentially generating alkali metal glycolate salts, which can be uneconomical.

[0037] When performing mercellation and CM conversion of cellulose raw materials, there are generally two methods: one in which both mercellation and CM conversion are carried out under a water-based solvent (water-based method), and another in which both mercellation and CM conversion are carried out under a mixed solvent of water and an organic solvent (solvent method). Either method may be used. Alternatively, a water-based solvent may be used for mercellation, and a mixed solvent of an organic solvent and water may be used for CM conversion. By doing so, even when the crystallinity of the cellulose is maintained at 50% or higher, CM-converted cellulose in which CM groups are introduced uniformly rather than locally can be obtained economically.

[0038] Using water as the main solvent (water-based solvent) refers to a solvent containing water in a proportion higher than 50% by mass. The amount of water in a 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. Particularly preferable is a water-based solvent in which water is 100% by mass (i.e., water). The higher the proportion of water during mercellation, the more uniformly the CM group is introduced by the cellulose, which is an advantage. As a solvent other than water in a water-based solvent (used in mixture with water), the organic solvents mentioned above can be used. The amount of organic solvent in a water-based solvent is preferably 45% by mass or less, even 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 even more preferably 0% by mass.

[0039] It is preferable to add an organic solvent or an aqueous solution of an organic solvent to the reactor at the same time as, or before or immediately after, the addition of the CM agent, or to appropriately reduce the amount of organic solvents other than water during the mercerization process by reducing the pressure, etc., to form a mixed solvent of water and an organic solvent, and to proceed with the CM reaction under this mixed solvent of water and an organic solvent. The timing of adding or reducing the organic solvent can be anytime between the completion of the mercerization reaction and immediately after the addition of the CM agent, and is not particularly limited, but for example, it is preferable to do so within 30 minutes before or after the addition of the CM agent.

[0040] During carboxymethylation, the proportion of the organic solvent in the mixed solvent is preferably 20% by mass or more, more preferably 30% by mass or more, still more preferably 40% by mass or more, further preferably 45% by mass or more, and particularly preferably 50% by mass or more, based on the total amount of water and the organic solvent. A higher proportion of the organic solvent facilitates uniform substitution of carboxymethyl groups, thereby stabilizing the quality of the obtained carboxymethylated cellulose. The upper limit of the proportion of the organic solvent is not limited, and may be, for example, 99% by mass or less. In consideration of the cost of the added organic solvent, it is preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 80% by mass or less, and further preferably 70% by mass or less. Therefore, in a preferred embodiment, the proportion of the organic solvent in the mixed solvent during carboxymethylation is preferably 20 to 99% by mass or 30 to 90% by mass, more preferably 40 to 85% by mass or 45 to 80% by mass, and still more preferably 50 to 70% by mass.

[0041] The reaction medium for carboxymethylation (a mixed solvent of water and an organic solvent etc., excluding cellulose) preferably has a lower proportion of water (in other words, a higher proportion of the organic solvent) than the reaction medium for mercerization. Satisfying this range makes it easy to maintain the crystallinity of the obtained carboxymethylated cellulose. Further, when the reaction medium for carboxymethylation has a lower proportion of water (higher proportion of the organic solvent) than the reaction medium for mercerization, there is also an advantage that when shifting from the mercerization reaction to the carboxymethylation reaction, the mixed solvent for the carboxymethylation reaction can be formed by a simple means of adding a desired amount of the organic solvent to the reaction system after completion of the mercerization reaction.

[0042] -Difference between CM-modified cellulose microfibers and carboxymethyl cellulose- It is preferable that at least part of the fibrous shape of CM-modified cellulose microfibers is maintained even when dispersed in water (they are water-insoluble). Carboxyalkylated cellulose fibers are distinguished from carboxymethyl cellulose, which is a type of water-soluble polymer that dissolves in water and imparts viscosity. When an aqueous dispersion of carboxyalkylated cellulose fibers is observed with an electron microscope, fibrous substances can be observed. On the other hand, even when an aqueous dispersion of carboxymethyl cellulose, which is a type of water-soluble polymer, is observed, no fibrous substance is observed. In addition, anion-modified cellulose fibers have crystallinity, and a peak of cellulose type I crystal can be observed when measured by X-ray diffraction, whereas when carboxymethyl cellulose powder, which is a water-soluble polymer, is measured in the same manner, cellulose type I crystals are usually not observed.

[0043] -Phosphate esterification- Phosphate esterified cellulose microfibers, which are an example of chemically modified cellulose microfibers, can be obtained by defibrating phosphate esterified cellulose fibers. As the phosphate esterified cellulose fibers, commercially available products may be used, or they may be produced by subjecting the above cellulose raw material to phosphate esterification by a known method. The degree of phosphate group substitution per glucose unit of the phosphate esterified cellulose fiber is preferably 0.001 to 2.0 mmol / g. The degree of phosphate group substitution in phosphate esterified cellulose fibers is generally the same as the degree of phosphate group substitution in phosphate esterified cellulose microfibers obtained by defibrating phosphate esterified cellulose fibers.

[0044] Methods for phosphate esterification include mixing a cellulose raw material with a powder or aqueous solution of a compound having a phosphate group, or adding an aqueous solution of a compound having a phosphate group to a slurry of cellulose raw materials. 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. One or more of these can be used in combination to introduce a phosphate group into the cellulose raw material. Of these, from the viewpoint of high efficiency in introducing a phosphate group and ease of industrial application, phosphoric acid, sodium salts of phosphoric acid, potassium salts of phosphoric acid, and ammonium salts of phosphoric acid are preferred, and ammonium dihydrogen phosphate, sodium dihydrogen phosphate, and disodium hydrogen phosphate are preferred. Furthermore, it is desirable to use the compounds having a phosphate group as aqueous solutions so that the reaction can proceed uniformly and the efficiency of introducing a phosphate group is high. The pH of the aqueous solution of the compound having a phosphate group is preferably 7 or less because it increases the efficiency of phosphate group introduction, but a pH of 3 to 7 is preferred from the viewpoint of suppressing hydrolysis of fibers. When reacting the compound having a phosphate group, a basic compound (for example, a basic compound having an amino group such as urea, methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine, etc.) may be added to the reaction system.

[0045] The following method is a specific example of a method for producing phosphate-esterified cellulose fibers. A compound having a phosphate group is added to a suspension of cellulose raw material with a solid content concentration of 0.1 to 10% by mass while stirring to introduce a phosphate group into the cellulose. When the cellulose raw material is 100 parts by mass, the amount of compound having a phosphate group added is preferably 0.2 to 500 parts by mass, and more preferably 1 to 400 parts by mass, in terms of the amount of phosphorus element.

[0046] After dehydrating the suspension of phosphate-esterified cellulose fibers obtained, it is preferable to heat-treat it at 100 to 170°C from the viewpoint of suppressing hydrolysis of cellulose. Furthermore, it is preferable to heat at 130°C or lower, preferably 110°C or lower, while water is present during the heat treatment, and then heat-treat at 100 to 170°C after the water has been removed. After heating, it is preferable to perform a washing treatment such as washing with cold water. This allows for efficient defibrillation. Washing can be performed by adding water and then dehydrating (e.g., filtration), and may be repeated two or more times. It is preferable to continue washing until the electrical conductivity of the filtrate decreases. For example, it can be continued until the electrical conductivity is preferably 200 μS / cm or lower, more preferably 150 μS / cm or lower, and even more preferably 120 μS / cm or lower. In addition, neutralization treatment may be performed after washing as needed. Neutralization treatment can be performed, for example, by adding alkali (e.g., sodium hydroxide). After neutralization, washing and / or dehydration may be performed again.

[0047] - Phosphite Esterification - Phosphite-phosphorylated cellulose fibers typically have a structure in which at least one carbon atom constituting the cellulose molecular chain (for example, the carbon atom at position C6 that has a primary hydroxyl group constituting the glucopyranose unit) is phosphorylated. The degree of substitution of phosphite groups per glucose unit in phosphite-esterified cellulose fibers (hereinafter simply referred to as "degree of phosphite substitution") is preferably 0.001 to 2.0 mmol / g. This makes electrical repulsion between cellulose molecules easier, facilitating nanofibrillation. The degree of substitution of phosphite groups can be measured using the same method as for measuring the degree of phosphate group substitution. The degree of phosphite substitution can be adjusted by controlling reaction conditions such as the amount of phosphite or its salt added, and, if necessary, the amount of alkali metal ion-containing substances, urea or its derivatives added.

[0048] One method for esterifying phosphorous acid is to react unmodified cellulose fibers with phosphorous acid or its metal salt (preferably sodium hydrogen phosphite) to introduce an ester group of phosphorous acid.

[0049] Examples of phosphorous acid and its metal salts include phosphorous acid compounds such as phosphorous acid, sodium hydrogen phosphite, ammonium hydrogen phosphite, potassium hydrogen phosphite, sodium dihydrogen phosphite, sodium phosphite, lithium phosphite, potassium phosphite, magnesium phosphite, calcium phosphite, triethyl phosphite, triphenyl phosphite, and pyrophosphorous acid, and combinations of two or more selected from these, with sodium hydrogen phosphite being preferred. This also allows alkali metal ions to be introduced into the cellulose fibers. The amount of phosphorous acid or its metal salt added is preferably 1 to 10,000 g, more preferably 100 to 5,000 g, and even more preferably 300 to 1,500 g per 1 kg of unmodified cellulose fiber. In addition to phosphorous acid and its metal salt, alkali metal ion-containing substances (e.g., hydroxides, metal sulfates, metal nitrates, metal chlorides, metal phosphates, metal carbonates) may be further added to the reaction system.

[0050] Furthermore, urea or its derivatives may be added to the reaction system. This allows carbamate groups to be introduced into the cellulose fibers. Examples of urea and urea derivatives include urea, thiourea, biuret, phenylurea, benzylurea, dimethylurea, diethylurea, tetramethylurea, and two or more combinations selected from these, with urea being preferred. The amount of urea and urea derivative added is preferably 0.01 to 100 mol, more preferably 0.2 to 20 mol, and even more preferably 0.5 to 10 mol, per 1 mol of phosphorous acid or its metal salt.

[0051] The reaction temperature is preferably 100 to 200°C, more preferably 100 to 180°C, and even more preferably 100 to 170°C. During the heat treatment, it is preferable to heat at 130°C or below (preferably 110°C or below) while water is present, and then, after removing the water, to heat-treat at 100 to 170°C. The reaction time is usually about 10 to 180 minutes, more preferably 30 to 120 minutes. It is preferable to wash the phosphite-esterified cellulose fibers before defibration. The degree of substitution of phosphite groups per glucose unit is preferably 0.01 to 2.0 mmol / g.

[0052] [1.3 Defibration] Cellulose microfibers or chemically modified cellulose microfibers can be obtained by defibrating the above-mentioned cellulose raw material or chemically modified cellulose raw material (chemically modified cellulose fiber). The apparatus used for defibration is not particularly limited, and for example, apparatus that can apply strong shear force such as high-pressure type, high-speed rotation type, colloid mill type, roll mill type, ultrasonic type, cavitation type, etc., as well as apparatus such as disc type, conical type, or cylinder type refiners, high-pressure homogenizers, colloid mills, high-pressure jet dispersers, beaters, PFI mills, kneaders, and dispersers can be used.

[0053] Defibration is preferably carried out wet (i.e., in the form of a dispersion with water or the like as the dispersion medium). When performing defibration wet, first, a dispersion of cellulose raw material or chemically modified cellulose fibers is prepared. The solid content concentration in the dispersion to be defibrated is preferably 0.1% by mass or more, and 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, more preferably 10% by mass or less, and more preferably 8% by mass or less. The dispersion medium is preferably water. Therefore, in a preferred embodiment, the solid content concentration in the dispersion to be defibrated is preferably 0.1 to 40% by mass or 0.1 to 30% by mass, more preferably 0.5 to 10% by mass, and even more preferably 0.5 to 8% by mass.

[0054] [1.4 Physical Properties of Cellulose Microfibers] Cellulose microfibers preferably satisfy the following physical properties: - Viscosity - When fine cellulose fibers are dispersed in an aqueous solution, it is preferable that the viscosity of the aqueous solution is low. This makes it possible to create a material with good handling properties despite being fibrillated. For example, the B-type viscosity (25°C, 60 rpm) of an aqueous solution with a solid content of 1% by mass is usually 6,000 mPa·s or less or 5,000 mPa·s or less, preferably 4,500 mPa·s or less, and more preferably 4,000 mPa·s or less. The lower limit is preferably 10 mPa·s or more, more preferably 20 mPa·s or more, even more preferably 50 mPa·s or more, 100 mPa or more, 500 mPa or more, 1,000 mPa or more, or 2,000 mPa or more. Therefore, in a preferred embodiment, the B-type viscosity (25°C, 60 rpm) of a 1% by mass aqueous dispersion of solids is typically 10 to 6,000 mPa or 20 to 6,000 mPa, preferably 50 to 5,000 mPa or 100 to 5,000 mPa, more preferably 500 to 4,500 mPa or 1,000 to 4,500 mPa, and even more preferably 2,000 to 4,000 mPa. Also, for example, the B-type viscosity (25°C, 6 rpm) of a 1% by mass aqueous dispersion of solids is typically 25,000 mPa·s or less or 20,000 mPa·s or less, preferably 18,000 mPa·s or less, and more preferably 15,000 mPa·s or less. The lower limit is preferably 100 mPa·s or more, more preferably 500 mPa·s or more, even more preferably 1,000 mPa·s or more, 2,000 mPa or more, 3,000 mPa or more, 4,000 mPa or more, or 5,000 mPa or more. Therefore, in a preferred embodiment, the B-type viscosity (25°C, 6 rpm) of a 1% solids aqueous dispersion is usually 100 to 25,000 mPa or 500 to 25,000 mPa, preferably 1,000 to 20,000 mPa or 2,000 to 20,000 mPa, more preferably 3,000 to 18,000 mPa or 4,000 to 18,000 mPa, and even more preferably 5,000 to 15,000 mPa. The B-type viscosity can be measured, for example, by the following method.After fibrillation (e.g., defibrillation), the mixture is allowed to stand for at least one day, then diluted as needed, and stirred with a homodisperser (e.g., 3000 rpm, 5 min). After stirring, viscosity is measured (viscosity is measured after 60 rpm, 3 minutes of rotation). -Transparency- The transparency of an aqueous dispersion of cellulose microfibers with a solid content of 1.0 mass% is usually 1% or more, preferably 3% or more, more preferably 10% or more, and even more preferably 50% or more. There is no particular upper limit; it is acceptable as long as it is 100% or less. The transparency of an aqueous dispersion of cellulose microfibril (MFC) with a solid content of 1.0 mass% is usually 1% or more, preferably 5% or more. The upper limit is 50% or less. Therefore, in a preferred embodiment, the transparency of an aqueous dispersion of cellulose microfibril (MFC) with a solid content of 1.0 mass% is preferably 1 to 50%, more preferably 5 to 50%. Transparency can be measured as the transmittance of 660 nm light using a visible light photometer.

[0055] [1.5 Cellulose Microfiber Content] The content of cellulose microfibers in the composition (100% by mass of solids) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 18% by mass or more, even more preferably 20% by mass or more, and particularly preferably 23% by mass or more. This increases the effect of vibration of cellulose fibers due to vibration application or steam treatment during artificial nail peeling, further improving peelability. There is no particular upper limit, but for example it is 95% by mass or less, 90% by mass or less, or 85% by mass or less. Therefore, in a preferred embodiment, the content of cellulose microfibers in the composition (100% by mass of solids) is preferably 10 to 95% by mass or 15 to 95% by mass, more preferably 18 to 90% by mass or 20 to 90% by mass, and even more preferably 23 to 85% by mass.

[0056] [1.6 Adhesive Components] The compositions of the present invention typically contain adhesive components. The adhesive components are preferably highly transparent, low viscosity, highly polar, capable of forming a highly hard coating film when dried, and satisfying the safety requirements for cosmetics. Furthermore, it is preferable that the sodium acetate content is 1.5% or less and the viscosity measured by a B-type viscometer is 1 to 100 mPa·s. Within these ranges, the formation of aggregates can be avoided, and as a result, the formation of pinholes in the coating film can be suppressed. The adhesive components are preferably water-based polymers. Examples of aqueous polymers include cellulose derivative polymers (e.g., carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, or ethylcellulose or their salts (e.g., sodium salts)), other polysaccharide polymers (e.g., corn starch, starch (potato starch, tapioca starch, positive starch, phosphorylated starch, starch-polyacrylic acid copolymer, other starches), potato starch, kudzu starch, dextrin, dextran, polydextrose, pullulan, guar gum, cationized guar gum, locust bean gum, gum arabic, karaya gum, pectin (HM (high methoxyl) pectin, acid-treated LM (low methoxyl) pectin, alkali-treated LM pectin), peptone, konjac mannan, soybean polysaccharides, other plant-based gums, carrageenan (kappa-carrageenan, iota-carrageenan, rum) Dakaraginan), gelatin, agar, alginic acid and alginic acid ester derivatives and their salts, xanthan gum, cationized xanthan gum, gellan gum (HA (high acyl group-containing) gellan gum, LA (acyl group-removed) gellan gum), tamarind gum, gellan gum, succinoglucan, xyloglucan, chitin, water-soluble chitin, chitosan), protein polymers (e.g., casein, albumin, globulin, soy protein lysate), acrylic acid polymers (e.g., polyacrylic acid, polyacrylic acid ester, acrylic acid copolymer, alkyl acrylate copolymer, acrylic acid / alkyl methacrylate copolymer, styrene-acrylic acid copolymer, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer, vinyl acetate-acrylic acid copolymer, acrylic acid-acrylic acid copolymer, styrene-acrylic acid copolymer,This refers to styrene-butadiene copolymers and their salts, acrylamide resins, vinylpyrrolidone resins, polyvinyl alcohol, vinyl alcohol-modified resins, vinyl acetate resins, amino acid resins, lactic acid resins, malic acid resins, glycerin resins, latex resins, rosin-based sizing agents, petroleum resin-based sizing agents, urea-based resins, melamine resins, ethylene-vinyl alcohol copolymers, epoxy resins, resins, amide resins, amine resins, amide-amine copolymers, ethyleneimine resins, ethylene oxide resins, synthetic rubber resins, vinyl chloride resins and vinylidene chloride resins, olefin resins, alkylred resins, polyurethane resins, other hydrophilic crosslinked polymers and colloidal silica, and mixtures of two or more of these. Of these, polyvinyl alcohol and gelatin are preferred, and polyvinyl alcohol is more preferred. In the case of polyvinyl alcohol resins, the degree of saponification is preferably 72 to 99.5 mol%.

[0057] The content of the adhesive component in the composition (100% by mass of solids) is preferably 1% by mass or more, more preferably 2% by mass or more, and more preferably 3% by mass or more. The upper limit is preferably 70% by mass or less, more preferably 65% ​​by mass or less, and even more preferably 60% by mass or less. Therefore, in a preferred embodiment, the content of the adhesive component in the composition (100% by mass of solids) is preferably 1 to 70% by mass, more preferably 2 to 65% by mass, and even more preferably 3 to 60% by mass. The ratio of the content of the adhesive component to the cellulose microfibers (adhesive component / cellulose microfibers) is not particularly limited, but in the case of polyvinyl alcohol, it is usually 30% by mass or less, preferably 15% by mass or less, more preferably 13% by mass or less, and even more preferably 10% by mass or less. This provides adequate adhesive strength and avoids situations where the artificial nail becomes difficult to remove after use. The lower limit is preferably 5% by mass or more, more preferably 6% by mass or more, and even more preferably 7% by mass or more. Therefore, in a preferred embodiment, the ratio of the adhesive component to the cellulose microfibers (adhesive component / cellulose microfiber) is typically 5 to 30% by mass, preferably 6 to 15% by mass or 6 to 13% by mass, and more preferably 7 to 10% by mass. This allows the strength of the coating film to be maintained within an appropriate range and prevents the occurrence of pinholes in the coating film when the composition is applied and cured. The occurrence of pinholes can lead to an excessive increase in adhesive strength with other layers, potentially making it difficult to remove the artificial nail, but this situation can be avoided by staying within the above range.

[0058] Commercially available adhesive components can be used, such as Mitsubishi Chemical's Gosenol EG-05C (polyvinyl alcohol resin), Kuraray's Poval 8-88 (polyvinyl alcohol resin), or Poval 4-88LV (polyvinyl alcohol resin). The degree of saponification of the polyvinyl alcohol resin is preferably 72 to 99.5 mol%. This suppresses the formation of aggregates and prevents the formation of pinholes in the coating film.

[0059] [1.7 Wetting Agents] When the adhesive component is gelatin, it is preferable that the composition further contains a wetting agent. This can improve the dispersibility of the gelatin. Examples of wetting agents include glycerin, sorbitol, and polyhydric alcohols (e.g., polyethylene glycol).

[0060] [1.8 Solvent] The composition may further contain a solvent (dispersion medium). This allows for adjustment of the viscosity of the composition and stabilization of the cellulose microfibers. Examples of solvents include water, lower alcohols (e.g., ethanol, butanol, isopropyl alcohol (IPA)), and mixed solvents thereof, with water or a mixed solvent containing water (a solvent with water as the main component) being preferred. In a solvent with water as the main component, it is preferable that the water content is 60% by mass or more, 70% by mass or more, and more preferably 80% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, 99% by mass or more, or 100% by mass. Preferably, it is 60 to 100% by mass, more preferably 70 to 100% by mass, even more preferably 80 to 100% by mass, and particularly preferably 90 to 100% by mass. The water may be deionized water, distilled water, tap water, soft water, hard water, etc. The solvent may be added externally or added as a component in the formulation of each component. The solvent content can be adjusted as appropriate depending on the viscosity of the composition, but is preferably such that the solid content of the composition is 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more. This suppresses dripping during application due to a decrease in viscosity, suppresses unevenness in the thickness of the coating film due to the edges of the applied surface becoming thicker, thereby making it easier to ensure stable adhesive strength and suppressing peeling in daily life. The upper limit is preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 5% by mass or less, and even more preferably 3% by mass or less. This allows the viscosity to be adjusted to an appropriate range, suppresses the occurrence of irregularities in the coating film when the composition is applied to the nail, and consequently suppresses the occurrence of pinholes in the coating film, and also allows for easy mixing of raw materials, improving workability in the production of the composition. Therefore, in a preferred embodiment, the solvent content is such that the solid content of the composition is preferably 0.01 to 10% by mass, more preferably 0.1 to 8% by mass, even more preferably 0.3 to 5% by mass, and particularly preferably 0.5 to 3% by mass. When a hydrophilic organic solvent (e.g., ethanol or IPA) is used as the dispersion medium of the composition, it is preferable that the proportion of the hydrophilic organic solvent in the total dispersion medium, including water, be 50% or less.This reduces the formation of aggregates of cellulose microfibers.

[0061] [1.9 Preservatives] The composition may further contain preservatives. This can improve the shelf life of the composition. Examples of preservatives include sorbic acid or its salts (e.g., potassium sorbate), benzoic acid, benzoates, alkyldiaminoethylglycine hydrochloride, photosensitizer, chlorcresol, chlorobutanol, salicylic acid and its salts, sorbic acid and its salts, dehydroacetic acid and its salts, trichlorohydroxydiphenyl ether, phenoxyethanol, phenol, sodium lauryldiaminoethylglycine, resorcinol, zinc-ammonia-silver complex substituted zeolite, pantothenyl ethyl ether benzoate, isopropylmethylphenol, cetylpyridinium chloride, benzalkonium chloride, benzethonium chloride, chlorhexidine hydrochloride, orthophenylphenol, sodium orthophenylphenol, silver-copper zeolite, chlorhexidine gluconate, and cresol. Examples include chloramine T, chloroxylenol, chlorphenesin, chlorhexidine, 1,3-dimethylol-5,5-dimethylhydantoin, alkylisoquinolinium bromide, thianthol, thymol, trichlorocarbanilide, parachlorophenol, halocarban, hinokitiol, zinc pyrithione, piroctone olamine, iodide propynyl butylcarbamate, polyaminopropyl biguanide, methylisothiazolinone, methylchloroisothiazolinone / methylisothiazolinone solution, N,N''-methylenebis[N'-(3-hydroxymethyl-2,5-dioxo-4-imidazolidinyl)urea], iodide paradimethylaminostyrylheptylmethylthiazolium, parabens (parahydroxybenzoic acid esters) and their salts (e.g., sodium salts). The preservative content per 100% by mass of the composition solids is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, and even more preferably 0.01% by mass or more. The upper limit is not particularly limited, but for example, it is 40% by mass or less, 35% by mass or less, or 30% by mass or less. Therefore, in a preferred embodiment, the preservative content per 100% by mass of the composition solids is preferably 0.0001 to 40% by mass, more preferably 0.001 to 35% by mass, and even more preferably 0.01 to 30% by mass.

[0062] [1.10 Optional Components] The compositions of the present invention may contain optional components other than those listed above. Optional components are not limited to these, but include, for example, oils, surfactants, thickeners, excipients, disinfectants, antioxidants, chelating agents, pH adjusters, humectants, deodorants, cooling agents, anti-inflammatory agents, plant extracts, colorants, and fragrances.

[0063] [1.11 Physical Properties of the Composition] The composition of the present invention preferably exhibits the following physical properties.

[0064] - Viscosity (Condition A) - In the present invention, the viscosity (B6) and (B60) of the composition are affected by the degree of chemical modification of the cellulose microfibers contained in the composition. The viscosity (B6) of the composition is usually 2,300 mPa·s or more, preferably 3,000 mPa·s or more, and more preferably 4,000 mPa·s or more. This suppresses dripping during application, maintains dispersibility, and exhibits high adhesion. The upper limit is not particularly limited, but for example, it is 100,000 mPa·s or less, and 90,000 mPa·s or less. This improves coatability. Therefore, in a preferred embodiment, the viscosity (B6) of the composition is preferably 2,300 to 100,000 or 3,000 to 100,000 mPa·s, and more preferably 4,000 to 90,000 mPa. The viscosity (B6) of the composition can be measured with a B-type viscometer at a rotation speed of 6 rpm and 25°C. The viscosity (B60) of the composition is usually 800 mPa·s or more, preferably 1,000 mPa·s or more, and more preferably 1,200 mPa·s or more. This suppresses dripping during application, maintains dispersibility, and exhibits high adhesion. The upper limit is not particularly limited, but for example, it is 13,000 mPa·s or less, 12,000 or less, or 11,000 mPa·s or less. Therefore, in a preferred embodiment, the viscosity (B60) of the composition is preferably 800 to 13,000 mPa, more preferably 1,000 to 12,000 mPa, and even more preferably 1,200 to 11,000 mPa. The viscosity (B60) of the composition can be measured with a B-type viscometer at a rotation speed of 60 rpm and 25°C.

[0065] - Three-dimensional surface roughness (Condition B) - In the present invention, the three-dimensional surface roughness (Sa) and three-dimensional maximum height (Peak) of the coating film of the composition are influenced by the degree of chemical modification of the cellulose microfibers contained in the composition and the viscosity (B6) and (B60) of the composition as described above. The three-dimensional surface roughness (Sa) of the coating film of the composition is usually 130 nm or less, preferably 120 nm or less, more preferably 100 nm or less, and even more preferably 90 nm or less. This suppresses the occurrence of pinholes in the coating film and allows for good adhesion and peelability. The lower limit is not particularly limited, but for example, it is 5 nm or more and 10 nm or more. Therefore, in a preferred embodiment, the three-dimensional surface roughness (Sa) of the coating film of the composition is preferably 5 nm to 130 nm or 5 nm to 120 nm. The three-dimensional surface roughness of the coating film of each composition can be measured by, for example, manually applying each composition onto a glass plate with a 40-grit bar, placing the glass plate in a constant temperature test chamber at a set temperature of 100°C for 2 minutes to allow it to dry almost completely and form a coating film, and then measuring the surface of the coating film using a white light interference microscope or similar with a 10x objective lens within a field of view of 559 μm × 558 μm, and analyzing the image with image analysis software to calculate Sa. The average value of Sa measured at 10 locations on the hand-applied coating film was used for the calculation.

[0066] -Maximum 3D Surface Height- The maximum 3D height (Peak) of the coating film of the composition is usually 3,000 nm or less, preferably 2,500 nm or less, more preferably 2,000 nm or less, and even more preferably 1,900 nm or less. This suppresses the occurrence of pinholes in the coating film and allows for good adhesion and peelability. The lower limit is not particularly limited, but for example, it is 100 nm or more, or 200 nm or more. Therefore, in a preferred embodiment, the maximum 3D height (Peak) of the coating film of the composition is preferably 100 to 3,000 nm or 100 to 2,500 nm, more preferably 200 nm to 2,000 nm, and even more preferably 200 to 1,900 nm. The maximum 3D surface height can be measured, similar to the 3D surface roughness, by measuring the surface of the coating film of each composition using a white light interference microscope or the like with a 10x objective lens within a field of view area of ​​559 μm × 558 μm, and then calculating it by analyzing the image with image analysis software. Similar to the 3D surface roughness, it was calculated as the average of the peak values ​​measured at 10 locations on the hand-applied coating.

[0067] -pH- The pH of the composition is preferably 3.5 or higher. This suppresses the formation of aggregates and prevents the formation of pinholes in the coating film. The upper limit is preferably 11 or lower, more preferably 10 or lower, and even more preferably 9 or lower. This suppresses the decrease in viscosity of cellulose microfibers during long-term storage, etc., and prevents dripping. Therefore, the pH of the composition is preferably 3.5 to 11, more preferably 3.5 to 10, and even more preferably 3.5 to 9. The pH can be adjusted as appropriate using reagents such as hydrochloric acid and sodium hydroxide.

[0068] [1.12 Dosage Form of Composition] The dosage form of the composition of the present invention is not particularly limited and may be, for example, a liquid (e.g., liquid, gel, lotion, emulsion, cream, spray), a solid (e.g., ointment, stick, powder), etc., but a liquid is preferred. The composition of the present invention may also be impregnated into a sheet-like substrate, or it may be filled into a roll-on type container.

[0069] [1.13 Method for Producing the Composition] The method for producing the composition of the present invention is not particularly limited, and for example, it can be prepared by stirring each raw material. When stirring, equipment such as a mixer can be used.

[0070] [2. Uses and Methods of Use of the Composition] The composition of the present invention can be used for artificial nails and can be used as a primer layer for artificial nails. In this specification, a primer layer is, for example, a so-called undercoat layer formed between the artificial nail and the nail. For example, when the artificial nail is a gel nail, a base layer (base coat: adhesion between the nail and the color layer), a color layer (color coat: design, aesthetics, color development), a clear layer (clear coat: strength improvement), and a top layer (top coat: gloss, protection) are applied in order from the nail side, and the composition of the present invention can be used to form a primer layer between the base layer and the nail.

[0071] The composition of the present invention can be applied to the nail using an applicator such as a brush. If necessary, the application surface of the nail may be smoothed (sanded) before application. By drying the composition on the surface of the nail, a primer layer can be formed. Drying may be performed using drying equipment such as a hair dryer or infrared heater, or by natural drying. After the primer layer is formed, other artificial nail cosmetics such as gel nails, manicures, pedicures, and nail tips can be applied, layered, and adhered according to conventional methods. In the case of gel nails, a base coat, color coat, clear coat, and top coat are applied sequentially according to conventional methods. The composition of the base coat, color coat, clear coat, and top coat is not particularly limited, and commercially available products can be used.

[0072] When removing an artificial nail containing the composition of the present invention from a natural nail, it is preferable to use underwater vibration treatment or steam treatment. This allows for quick and easy removal, reducing the burden on the user and avoiding the retention of artificial nail fragments on the nail surface after removal. Furthermore, it allows for safe removal without the use of chemicals. For vibration treatment, it is preferable to use ultrasound in water. The frequency of the ultrasound is preferably 1,000 Hz or higher, more preferably 3,000 Hz or higher, even more preferably 5,000 Hz or higher, and even more preferably 6,000 Hz or higher. The upper limit is preferably 100,000 Hz or lower, and more preferably 80,000 Hz or lower. Therefore, in a preferred embodiment, the frequency of the ultrasound is preferably 1,000 to 100,000 Hz or 3,000 to 100,000 Hz, more preferably 5,000 to 80,000 Hz, and even more preferably 6,000 to 80,000 Hz. Ultrasonic treatment may be performed using simple devices such as an ultrasonic eyeglass cleaner (vibration treatment at approximately 40,000 Hz) or an electric toothbrush (vibration treatment at approximately 6,000 Hz). Steam treatment is a process in which the artificial nail is exposed to a steam atmosphere, and the exposure time is preferably 1 second to 5 minutes, more preferably 3 seconds to 3 minutes, even more preferably 5 seconds to 2 minutes, and even more preferably 7 seconds to 1 minute. Steam treatment may be performed using a commercially available steam-off machine. Before and after treatment, it is preferable to lightly poke the edge of the artificial nail with a pusher or the like to prepare a small gap for the steam to penetrate.

[0073] The composition of the present invention can be contained in a container suitable for the dosage form and intended use and used as a cosmetic.

[0074] The present invention will be described more specifically below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, parts and % refer to parts by mass and mass %.

[0075] <Production of Oxidized Cellulose Fine Fibers> 500 g (absolutely dry) bleached, unbeaten kraft pulp (whiteness 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 the mixture was stirred until the pulp was uniformly dispersed. A commercially available low-sodium sodium hypochlorite aqueous solution (effective chlorine concentration 12% by mass, sodium chloride content 4% by mass or less) was added to the reaction system so that the effective chlorine concentration was 5.2 mmol / g relative to the cellulose raw material, and the oxidation reaction was started. As the reaction progressed, the pH in the system decreased, so 3 M sodium hydroxide aqueous solution was added sequentially to adjust the pH to 10. The reaction was stopped when the pH stopped decreasing. Hydrochloric acid was added to the mixture after the reaction to adjust the pH to 2.4 or less, and the pulp was separated by filtration with a glass filter. The mixture was again dispersed in deionized water, hydrochloric acid was added to lower the pH to 2.5 or below, and the pulp was separated by filtration using a glass filter. This process was repeated to remove excess salt and impurities. Subsequently, the pulp was thoroughly washed with water to remove excess hydrochloric acid, yielding pulp with introduced carboxyl groups (oxidized cellulose fibers). The amount of carboxyl groups in the oxidized cellulose was 1.38 mmol / g.

[0076] The obtained oxidized cellulose fibers were dispersed in water to obtain a 1% (w / v) aqueous dispersion. This was treated three times in a 150 MPa high-pressure homogenizer to obtain an aqueous dispersion of oxidized cellulose microfibers. The obtained oxidized cellulose microfibers had an average fiber diameter of 3 nm, an aspect ratio of 250, a crystallinity of 60.2%, a transparency of 91.2%, and a B-type viscosity of 3120 mPa·s at 60 rpm with a solid content concentration of 1 wt%.

[0077] <Production of Carboxymethylated Cellulose Fine Fibers> In a 5L twin-screw kneader adjusted to a rotation speed of 100 rpm, 1089 parts of isopropanol (IPA) and a solution of 31 parts sodium hydroxide dissolved in 121 parts of water were added. 200 parts of hardwood pulp (manufactured by Nippon Paper Industries Co., Ltd., LBKP), based on its dry mass after drying at 100°C for 60 minutes, were charged. The mixture was stirred and mixed at 30°C for 60 minutes to prepare mercerized cellulose. Further stirring was performed, and 117 parts of sodium monochloroacetate were added. After stirring at 30°C for 30 minutes, the temperature was raised to 70°C over 30 minutes, and the carboxymethylation reaction was carried out at 70°C for 60 minutes. The proportion of water in the reaction medium during both the mercerization and carboxymethylation reactions was 10% by mass. After the reaction was complete, the mixture was neutralized, washed with 65% aqueous methanol, dehydrated, dried, and pulverized to obtain a sodium salt of carboxymethylated cellulose with a carboxymethyl substitution degree of 0.27 and a cellulose type I crystallinity of 64%. The obtained sodium salt of carboxymethylated cellulose was dispersed in water to obtain a 1% (w / v) aqueous dispersion. This was treated three times in a 150 MPa high-pressure homogenizer to obtain a dispersion of carboxymethylated cellulose fine fibers.

[0078] <Production of Phosphate-Esterified Cellulose Fine Fibers> As the raw material pulp, bleached, unbeaten kraft pulp derived from coniferous trees manufactured by Nippon Paper Industries Co., Ltd. was disintegrated and used (Canadian Standard CSF of 700 mL as measured in accordance with JIS P 8121). To 100 parts by mass (oven-dry mass) of the above raw material pulp, a mixed aqueous solution of ammonium dihydrogen phosphate and urea was added to adjust the mixture to 45 parts by mass of ammonium dihydrogen phosphate, 120 parts by mass of urea, and 150 parts by mass of water to obtain chemically impregnated pulp. Next, the obtained chemically impregnated pulp was heated in a hot air dryer at 165°C for 200 seconds to introduce phosphate groups into the cellulose in the pulp and obtain phosphorylated pulp. Next, the obtained phosphorylated pulp was subjected to a washing treatment. The washing treatment was carried out by repeatedly pouring 10 L of ion-exchanged water over 100 g (oven-dry mass) of phosphorylated pulp to obtain a pulp dispersion, stirring the mixture to uniformly disperse the pulp, and then filtering and dewatering it. The washing process was terminated when the electrical conductivity of the filtrate was 100 μS / cm or less. Next, the washed phosphorylated pulp was subjected to alkaline treatment as follows. First, the washed phosphorylated pulp was diluted with 10 L of deionized water, and then a 1N sodium hydroxide aqueous solution was gradually added while stirring to obtain a phosphorylated pulp slurry with a pH of 12 to 13. Next, the phosphorylated pulp slurry was dehydrated to obtain alkali-treated phosphorylated pulp. Next, the alkali-treated phosphorylated pulp was subjected to the washing process described above. Deionized water was added to the obtained phosphorylated pulp to prepare a slurry with a solid content concentration of 2% by mass, and this slurry was treated three times in an ultra-high pressure homogenizer (20°C, 150 MPa) to obtain a dispersion of phosphate-esterified cellulose nanofibers. The obtained cellulose nanofibers had an average fiber diameter of 4 nm, an average fiber length of 620 nm, and a phosphate group substitution degree of 1.45 mmol / g. The transparency was 86% (solid content 1.0%). Furthermore, the CNF dispersion had a B-type viscosity of 3100 mPa·s at 60 rpm when the solid content concentration was 1 wt%.

[0079] <Production of Phosphite-Esterified Cellulose Microfibers> Reagent A was prepared by mixing 13 g of sodium hydrogen phosphite pentahydrate, 10.8 g of urea, and 76.2 g of water. 100 g of the prepared reagent A was mixed with 10 g of raw material pulp (bleached, unbeaten kraft pulp NBKP, derived from coniferous trees, manufactured by Nippon Paper Industries Co., Ltd.) by dry weight, and dried at 105°C. The dried pulp was reacted at 130°C for 2 hours, and washed with water and filtered twice to obtain cellulose fibers (phosphite-modified pulp) into which an ester of phosphorus containing cations from inorganic substances was introduced. The obtained phosphorite-modified pulp was diluted with distilled water to a solid content of 10% by mass to obtain a phosphorite-modified pulp slurry (dispersion). The phosphorite-modified pulp slurry was pre-beaten at 9200 rpm using a PFI mill. The pre-beaten phosphite-modified pulp slurry was adjusted to a solid content concentration of 1%, and subjected to two defibration treatments using a high-pressure homogenizer to obtain an aqueous dispersion of 1.0% by mass phosphite-esterified cellulose nanofibers. The obtained cellulose nanofibers had an average fiber diameter of 4 nm, an average fiber length of 650 nm, a degree of phosphite group substitution of 1.51 mmol / g, a transparency of 84%, and a B-type viscosity of 3540 mPa·s at 60 rpm when the solid content concentration was 1 wt%.

[0080] <Production of Mechanically Defibrillated (Unmodified) Cellulose Microfibers> Bleached thermomechanical pulp (BCTMP) was adjusted to 2.0% (w / v) with water, and after reducing the water content to 100 mL or less using a Niagara beater, it was processed three times with a grinder (mascolloider) to obtain a dispersion of mechanically treated microfibril cellulose (MFC). The average fiber diameter was 21 μm, and the average fiber length was 211 μm. The transparency was 25.4% (solid content 0.01%). When the solid content was 1.0%, it was too low to be measured. Furthermore, the B-type viscosity of this MFC dispersion at 60 rpm was 140 mPa·s when it was 1 wt%, and the B-type viscosity at 6 rpm was 540 mPa·s.

[0081] Examples 1 and 2 <Primer Preparation> Primers were prepared using the following formulations.

[0082] [Primer A] The formulation of Primer A is as follows (solid content concentration 1.49%, CNF solid concentration relative to solid 0.83%, CNF addition rate relative to solid 55.55%).

[0083]

[0084] -Footnote to Table 1- *A 15% aqueous solution of polyvinyl alcohol was prepared by dissolving Gosenol® EG-05C (manufactured by Mitsubishi Chemical Corporation: powder) in water.

[0085] -Manufacturing Method- Under ambient temperature conditions (room temperature: approximately 17-27°C), the raw materials shown in Table 1 were placed in a stainless steel mixer (Henschel type stirring blades, with temperature controller) and stirred. The stirring speed was increased to approximately 600-700 rpm, and the speed was adjusted as needed for 5-7 minutes of stirring. After that, the mixture was degassed using a rotary-rotating mixer and then filled into containers while filtering through a 15-mesh filter. The pH of the obtained primer A was in the range of 3.5-11. Polyvinyl alcohol ("Gosenol® EG-05C" (powder), manufactured by Mitsubishi Chemical Corporation) was dissolved in water beforehand to make a 15% aqueous solution. The mixture was stored refrigerated (approximately 4°C) until use.

[0086] [Primer B] The formulation of Primer B is as follows (solid content concentration 3.88%, CNF solid concentration relative to solid 0.97%, CNF addition rate relative to solid 25%).

[0087]

[0088] - Footnote to Table 2 - *Purified glycerin: Heat to 73°C before use

[0089] -Manufacturing Method- Under ambient temperature conditions (room temperature: approximately 17-27°C), the raw materials shown in Table 2 were placed in a stainless steel mixer (Henschel type stirring blades, with temperature controller) and stirred. The stirring speed was increased to approximately 600-700 rpm, and the speed was adjusted as needed for 5-7 minutes of stirring. After that, the temperature controller (hot water jacket) was heated to 73°C or higher (gelatin melting temperature). Subsequently, the mixture was degassed using a rotary-rotating mixer and then filled into containers while filtering through a 15-mesh filter. The pH of the obtained primer B was in the range of 3.5-11. It was stored refrigerated (approximately 4°C) until use.

[0090] -Evaluation of each primer- [Evaluation of primer properties] ・B6 viscosity: Measured using a B-type viscometer (No. 4 rotor) at a rotation speed of 6 rpm. ・Color, appearance, odor: Evaluated by the experimenter by visual inspection and odor check. ・Dispersibility: Measured using a twin-groove grindometer. ・Measurement of 3D surface roughness Sa: In accordance with ISO 25178, the 3D average height (Sa) was calculated based on the reference surface at each point in the measurement surface area (559 μm × 558 μm) using a white light interference microscope (Ryoka Systems Co., Ltd., VertScan 3.0) with a 10x objective lens. The coating film samples used for measurement were prepared by hand-applying each composition onto a glass plate with a No. 40 bar, placing the glass plate in a constant temperature tester at a set temperature of 100°C for 2 minutes, and allowing it to dry almost completely to form a coating film. The average value of Sa measured at 10 locations on the hand-applied coating film was used for calculation.

[0091] [Evaluation of Applicability, Adhesion, and Peelability] The nail surface, including the little fingernail, of each of the 24 subjects (nail technicians, female, aged 20-40) was wiped clean and lightly sanded. Then, an appropriate amount (average of about 0.1g per nail) of Type A formula and Type B formula (containing and not containing CNF, respectively) was applied to cover the entire surface. After that, a hairdryer or infrared heater was applied for 15-60 seconds to dry the nails almost completely, and then base gel ("Base Gel for Salon" manufactured by Dorcus Co., Ltd.), color gel ("Skin #305" manufactured by Rinogel Co., Ltd.), clear gel ("Clear Gel EX" manufactured by Paragel Co., Ltd.), and top coat gel ("Hygloss Top Coat RN" manufactured by Calgel Co., Ltd.) were applied in order to complete the gel nail according to the standard procedure.

[0092] - Application evaluation: The ease of application during the procedure was evaluated. - Adhesion evaluation: After the procedure, patients continued their daily lives and the presence or absence of peeling was checked after 3 weeks. - Peelability evaluation: After application, ultrasonic irradiation was performed for approximately 30 seconds (15-40 seconds) (using an ultrasonic cleaner (LifeBasis CDS100 42,000Hz, eyeglass cleaner with 5-stage timer) at 40,000Hz, or an electric toothbrush (Omron Braun electric toothbrush (Electric toothbrush HT-B222-W White, battery-operated, vibration frequency 18,000 times / min) at 6,000Hz, 20,000±3,000Hz) to check whether it peeled off cleanly.

[0093] [Results] For both Type A and Type B formulations, the B6 viscosity was 40,000 mPa·s or less, the appearance was transparent with no colored foreign matter, there was no odor, and the dispersibility was 5 μm or less.

[0094] Regarding applicability, in the Type B formulation (Example 2), some of the gelatin sometimes formed a crystalline gel and precipitated at room temperature. On the other hand, this phenomenon did not occur in the Type A formulation (Example 1), and there were no problems during application, so the Type A formulation was slightly better. In addition, the adhesive strength of both Type A and B formulations was good, as they did not peel off even after three weeks of real-life use. Furthermore, the peelability of both Type A and B formulations was also good, as they could be easily peeled off with ultrasound, in contrast to the CNF-free formulation which could not be peeled off. The three-dimensional surface roughness (Sa) of the coating film was 130 nm or less for all formulations. In terms of safety, it was clear from the raw material composition that raw materials approved for safety in cosmetic applications were used within the specified dosage range, and both formulations were evaluated as having no problems.

[0095] Primer compositions were prepared by mixing the raw material components according to the compositions shown in the tables for Examples 3 to 10 and Comparative Examples 1 to 6, and adjusting the solid content and pH with a diluent solvent as necessary. The following evaluations were performed on each of the obtained primer compositions.

[0096] - Evaluation of primer properties B6 viscosity: Same as the measurement method in Examples 1 and 2. B60 viscosity: Measured with a B-type viscometer (generally a No. 5 rotor) at a rotation speed of 60 rpm. Transparency: Transmittance of 660 nm light was measured using a spectrophotometer (JUKI Electronics Industries, Ltd., spectrophotometer / colorimeter).

[0097] - Evaluation of Primer Composition Parameters Gel nails were completed using the same procedure as in Examples 1 and 2, and the following parameters were measured on the surface of the coating film. 3D surface roughness Sa, 3D maximum height Peak: In accordance with ISO 25178, a white-light interference microscope (VertScan 3.0, manufactured by Ryoka Systems Co., Ltd.) was used with a 10x objective lens, and the 3D average height (Sa) and 3D maximum surface height (Peak) were calculated as the average value of 10 points based on the reference surface at each point in the measurement surface area (559 μm × 558 μm).

[0098] - Adhesion Evaluation: After completing gel nails using the same procedure as in Examples 1 and 2, the adhesion was evaluated based on the following criteria before ultrasonic treatment. A rating of ○ indicates that it is considered practical. ○: Cannot be peeled off by hooking it with a cuticle pusher. ×: Can be peeled off by hooking it with a cuticle pusher.

[0099] - Evaluation of Peelability After completing the gel nails using the same procedure as in Examples 1 and 2, the peelability was evaluated based on the following criteria. Note that a rating of A, B, or C indicates that it is practical. A: The nails with the gel nails applied were immersed in water, and after ultrasonic irradiation treatment as in Examples 1 and 2, they could be peeled off by hooking them with a pusher. B: Three sets of ultrasonic irradiation treatment and peeling treatment with a pusher as in Examples 1 and 2 were performed, and the gel could be peeled off. C: Five sets of ultrasonic irradiation treatment and peeling treatment with a pusher as in Examples 1 and 2 were performed, and the gel could be peeled off. D: Ten sets of ultrasonic irradiation treatment and peeling treatment with a pusher as in Examples 1 and 2 were performed, but the gel could not be peeled off.

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108] [Footnotes to the table] EG-05C: Polyvinyl alcohol ("Gosenol® EG-05C") Values ​​in parentheses: Viscosity measured using a Type B viscometer (Rotor No. 6) (The viscosity was too high to measure with Rotor No. 5)

[0109] In Comparative Example 1, which did not contain CNF, and Comparative Example 2, which had low B-type viscosity, the liquid tended to drip during application, resulting in reduced uniformity and an × rating for adhesion (easily peeled off). In Comparative Examples 3 to 6, which had high 3D surface roughness (Sa), the peelability was rated D. It is thought that the high surface roughness of the coating film made it easy for pinholes to occur in the coating film, making it difficult to peel off by ultrasonic irradiation. In contrast, Examples 3 to 10, which contained CNF, had a B-type viscosity of 2300 mPa·s or less, and a 3D surface roughness (Sa) of 130 nm or less, did not exhibit the problems seen in the comparative examples, showed good adhesion, and exhibited peelability within a range that was not problematic in practical use.

[0110] These results demonstrate that the artificial nail composition of the present invention can exhibit good peelability, applicability, and adhesion.

Claims

1. An artificial nail composition containing cellulose microfibers and satisfying the following conditions: Condition A: The B-type viscosity (6 rpm) of the artificial nail composition is 2,300 mPa·s or more and 100,000 mPa·s or less. Condition B: The three-dimensional surface roughness (Sa) of the coating film of the artificial nail composition is 130 nm or less.

2. The composition according to claim 1, wherein the cellulose microfibers include chemically modified cellulose microfibers.

3. The composition according to claim 1, wherein the cellulose microfibers include anionically modified cellulose microfibers.

4. The composition according to claim 1, wherein the cellulose microfibers include oxidized cellulose microfibers.

5. The composition according to any one of claims 1 to 4, further comprising an adhesive component.

6. The composition according to claim 5, wherein the adhesive component is a water-based polymer.

7. The composition according to claim 6, wherein the aqueous polymer is polyvinyl alcohol or gelatin.

8. The composition according to any one of claims 1 to 4, which is for use with gel nails.

9. The composition according to any one of claims 1 to 4, for use as a primer between an artificial nail and a natural nail.

10. An artificial nail comprising a hardened layer of the composition according to any one of claims 1 to 4.

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