Gel composition for cosmetics

Abstract

To provide a cosmetic gel composition having high transparency suitable for a cosmetic used for the face or the like.SOLUTION: There is provided a cosmetic gel composition which comprises nonionic cellulose nanofibers having an average fiber diameter of 2 to 30 nm, a diole and water. The content rate of the cellulose nanofibers is 0.1 to 5 mass%, the content the of the diole is 1 to 20 mass%, the mass ratio (A:B) between the content (A) of the cellulose nanofibers and the content (B) of the diole is 1:2 to 1:40 and the diole is at least one selected from the group consisting of 1,3-butylene glycol, pentylene glycol, propylene glycol and dipropylene glycol.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a gel-like composition for cosmetics containing cellulose nanofibers.

Background Art

[0002] As cosmetics, a gel-like composition containing a polyhydric alcohol is used for the purpose of improving moisture retention. As a gelling agent for such a composition, a new material called cellulose nanofibers (hereinafter sometimes abbreviated as "CNF") obtained by subdividing fibers constituting a plant-derived cellulose material has attracted attention.

[0003] For example, there was a topical skin preparation containing CNF (see, for example, Patent Document 1). Patent Document 1 describes that since CNF is not sticky, a good feeling in use can be obtained when applied to the skin.

[0004] In addition, there was a biocompatible material using CNF (see, for example, Patent Document 2). As cosmetics, those having a transparent appearance are preferred by consumers. However, if the fiber diameter of CNF is large or CNFs aggregate with each other, light scattering by CNF increases and the transparency of the gel-like composition decreases. Therefore, Patent Document 2 describes that in order to obtain a transparent aqueous dispersion, the fiber diameter of CNF should be 100 nm or less.

[0005] By the way, in order to produce CNF, it is necessary to finely defibrate the cellulose material as a raw material. Even if an attempt is made to defibrate the cellulose material as it is, since it is a material in which fibers are firmly bonded by hydrogen bonds, a great deal of energy is required for defibrillation, and it is difficult to obtain CNF of an appropriate size.

[0006] Therefore, in Patent Documents 1 and 2, by introducing a carboxyl group or a carboxymethyl group into cellulose, the fibers of cellulose are electrically repelled to facilitate defibrillation, and nanofibers having an anionic functional group are obtained.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] Although CNF having an anionic functional group is easy to be refined to improve transparency, since it is obtained by modifying cellulose to impart ionic properties, it is likely to change color over time when used as a cosmetic, and there is a risk that its physical properties may change when coexisting with various additives.

[0009] However, since it is difficult to remove the functional group from oxidized cellulose or carboxymethyl cellulose to return to non-ionic cellulose, the external preparation for skin of Patent Document 1 and the biocompatible material of Patent Document 2 contain CNF having an anionic functional group and are not suitable as cosmetics.

[0010] The present invention has been made in view of the above problems, and an object thereof is to provide a highly transparent cosmetic gel composition suitable for cosmetics used on the face and the like.

Means for Solving the Problems

[0011] The characteristic of the constitution of the cosmetic gel composition according to the present invention for solving the above problems is that it contains non-ionic cellulose nanofibers having an average fiber diameter of 2 to 30 nm, a diol, and water.

[0012] According to the gel composition for cosmetics of this configuration, by containing nonionic cellulose nanofibers with an average fiber diameter of 2 to 30 nm, a diol, and water, it becomes a gel composition for cosmetics that is not sticky or slimy and has good usability. Further, according to the gel composition for cosmetics of this configuration, since the cellulose nanofibers with an average fiber diameter of 2 to 30 nm are uniformly dispersed in the composition, light scattering is suppressed and high light transmittance is obtained, and the transparency required when used on the face or the like can be improved. Furthermore, since the nonionic cellulose nanofibers are chemically stable, the gel composition for cosmetics of this configuration has little discoloration over time and does not react with various additives even when coexisting with them, making it a suitable cosmetic for use on the face or the like.

[0013] In the gel composition for cosmetics according to the present invention, the content of the cellulose nanofibers is 0.1 to 5% by mass, the content of the diol is 1 to 20% by mass, and the mass ratio (A:B) of the content (A) of the cellulose nanofibers to the content (B) of the diol is preferably 1:2 to 1:40.

[0014] According to the gel composition for cosmetics of this configuration, when the content of the cellulose nanofibers is 0.1 to 5% by mass, the content of the diol is 1 to 20% by mass, and the above mass ratio (A:B) is 1:2 to 1:40, aggregation of the cellulose nanofibers is suppressed and the viscosity of the gel composition can be stabilized.

[0015] In the gel composition for cosmetics according to the present invention, the diol is preferably at least one selected from the group consisting of 1,3-butylene glycol, pentylene glycol, propylene glycol, and dipropylene glycol.

[0016] According to the gel-like composition for cosmetics of this configuration, since the diol is at least one selected from the group consisting of 1,3-butylene glycol, pentylene glycol, propylene glycol, and dipropylene glycol, the wettability is improved and the viscosity is moderately increased, resulting in a gel-like composition for cosmetics that is excellent in handleability during application to the skin and has a good skin feel.

[0017] In the gel-like composition for cosmetics according to the present invention, The transmittance of light with a wavelength of 700 nm is preferably 75% or more at an optical path length of 10 mm.

[0018] According to the gel-like composition for cosmetics of this configuration, due to the high light transmittance, the transparency required when used on the face or the like can be further improved.

[0019] In the gel-like composition for cosmetics according to the present invention, It is preferably prepared so that the viscosity is 10% or more greater than that of a cellulose nanofiber aqueous dispersion containing the same amount of cellulose nanofibers.

[0020] According to the gel-like composition for cosmetics of this configuration, since the viscosity is 10% or more greater than that of a cellulose nanofiber aqueous dispersion containing the same amount of cellulose nanofibers, the viscosity is moderately increased compared to the cellulose nanofiber aqueous dispersion, resulting in a product that is easy to use while maintaining a good skin feel.

Mode for Carrying Out the Invention

[0021] Hereinafter, the gel-like composition for cosmetics of the present invention will be described in detail. However, the present invention is not intended to be limited to the embodiments and examples described below.

[0022] 〔Gel-like composition for cosmetics〕 The gel-like composition for cosmetics of the present invention can be used as a cosmetic for use on the face or the like, or as a raw material for cosmetics, and contains CNF, diol, and water. Hereinafter, CNF, which is the main component of the gel-like composition for cosmetics of the present invention, and diol will be described. Regarding water, although a particularly detailed description is omitted, water with few impurities such as purified water and ion-exchanged water can be used.

[0023] <cnf> CNF is the main material that serves as a gelling agent in the gel-like composition for cosmetics of the present invention. As the CNF, a non-ionic one with an average fiber diameter of 2 to 30 nm is used. Since the fiber diameter of microfibrils, which are the constituent units of natural cellulose, is 2 to 3 nm in higher plants, in order to make the average fiber diameter of CNF less than 2 nm, it is necessary to apply a great deal of energy to make it finer, resulting in a high manufacturing cost. On the other hand, if the average fiber diameter of CNF is made larger than 30 nm, light scattering may increase when it is made into a gel-like composition, and the transparency may decrease. If the transparency of the gel-like composition decreases, there is a risk of white floating or the like occurring when it is applied to cosmetics used on the face or the like. The crystal form of cellulose may be either type I or type II, but if it is type I, it is stable in solvents such as water, and when blended into cosmetics or the like, it can impart better shape retention. The non-ionic CNF can be produced by suspending natural cellulose in water and making it finer by physical means. Also, rather than defibrating the cellulose material as it is, it is easier to make it into a nanofiber state by introducing ionic functional groups through chemical modification, which causes electrostatic repulsion between the fibers. Therefore, after once performing chemical modification, it is preferable to desorb and regenerate the introduced functional groups. Examples of such chemically modified cellulose include xanthated cellulose obtained by adding carbon disulfide to alkali-treated cellulose to introduce a xanthate group (-OCSS - M + ).

[0024] Zanthated cellulose can be easily regenerated by removing the zanthate group through regeneration processes such as acid treatment or heat treatment to return to a hydroxyl group. By undergoing processes such as regeneration as zanthated cellulose, impurities in CNF can be reduced. In the gel-like composition for cosmetics of the present invention, it is desirable that all of the zanthate groups introduced by chemical modification in the CNF are returned to hydroxyl groups, but as long as there is no problem in the production and use of the composition, some zanthate groups may remain. The content of the zanthate group in zanthated cellulose is evaluated by the average degree of zanthate substitution, which is the average number of hydroxyl groups substituted by zanthate groups per glucose unit of cellulose. In the gel-like composition for cosmetics of the present invention, the CNF preferably has an average degree of zanthate substitution of 0.01 or less, more preferably 0.005 or less. If the average degree of zanthate substitution is 0.01 or less, it exhibits the same reactivity as the unmodified one and can be suitably used in cosmetics used on the face and the like as non-ionic CNF.

[0025] The content of CNF in the gel-like composition for cosmetics is preferably 0.1 to 5% by mass. If the content of CNF is within the above range, the viscosity stability of the gel-like composition will be excellent. If the content of CNF is less than 0.1% by mass, there is a risk that sufficient viscosity cannot be obtained or that variations in viscosity may occur. If the content of CNF exceeds 5% by mass, the composition will not become gel-like but paste-like, and there is a risk that free water not hydrogen-bonded to CNF will escape when external pressure is applied during storage.

[0026] <diol> A diol is a type of alcohol having a structure in which hydroxyl groups are bonded to two carbon atoms one by one. In the gel-like composition for cosmetics of the present invention, the diol maintains a uniform dispersion state of CNF in the gel-like composition, and is also blended as a component that increases the viscosity in order to improve the handleability during application to the skin when the gel-like composition is used as a cosmetic or a raw material for cosmetics. Examples of such diols include 1,3-butylene glycol, pentylene glycol, propylene glycol, and dipropylene glycol. In particular, from the viewpoint of the thickening property of the gel-like composition for cosmetics, although details will be described in the examples below, 1,3-butylene glycol and pentylene glycol are preferred.

[0027] The content of the diol in the gel-like composition for cosmetics is preferably 1 to 20% by mass. Further, the mass ratio (A:B) of the content (A) of CNF and the content (B) of the diol in the gel-like composition for cosmetics is preferably in the range of 1:2 to 1:40 by mass ratio. If the content of the diol and the mass ratio (A:B) are within the above ranges, the dispersibility of CNF in the gel-like composition for cosmetics will be excellent. If the content of the diol and the mass ratio (A:B) are out of the above ranges, there is a possibility that CNF will easily aggregate in the gel-like composition for cosmetics or the transparency of the gel-like composition will decrease.

[0028] 〔Light transmittance〕 The gel-like composition for cosmetics is desirably highly light transmissive. When the optical path length of the gel-like composition of the present invention is 10 mm, the transmittance of light with a wavelength of 700 nm is preferably 75% or more. If the transmittance of light with a wavelength of 700 nm is 75% or more, the transparency required when used on the face or the like can be improved due to the high light transmittance. The light transmittance can be measured using an ultraviolet-visible spectrophotometer (V-730, manufactured by JASCO Corporation) by filling the gel-like composition in a measurement cell with an optical path length of 10 mm.

[0029] 〔Viscosity〕 When using the gel-like composition for cosmetics as a cosmetic or a raw material for cosmetics, it is desirable to increase the viscosity in order to improve the handleability during application to the skin. The gel-like composition for cosmetics of the present invention is preferably prepared so that the viscosity is 10% or more greater than that of the CNF aqueous dispersion containing the same amount of CNF. Specifically, when the viscosity in the gel-like composition for cosmetics of the present invention is V1 and the viscosity in the aqueous dispersion of CNF prepared so that the CNF content is the same as that of the gel-like composition for cosmetics is V2, the following formula (1): Viscosity ratio = 100 × (V1 - V2) / V2 ···(1) The viscosity ratio calculated by is preferably 10% or more. If the viscosity ratio is 10% or more, the viscosity becomes moderately higher compared to the aqueous dispersion of CNF, so that it is easy to use while maintaining good skin compatibility. As the viscosity of the gel-like composition for cosmetics and the aqueous dispersion, the value measured at 30 rpm using the M3 rotor of a B-type viscometer (TVB-10H, manufactured by Toki Sangyo Co., Ltd.) at a temperature of 25°C is used.

[0030] [Production of CNF] The CNF derived from xanthated cellulose suitable for use in the gel-like composition for cosmetics of the present invention can be produced by sequentially performing the following steps (I) to (V).

[0031] (I) Alkaline treatment of cellulose material Examples of the cellulose material include wood pulp such as kraft pulp and sulfite pulp, biomass-derived materials such as wood flour and rice straw, paper-derived materials such as waste paper, filter paper, and paper powder, powdered cellulose, and cellulose processed products that retain crystallinity such as micrometer-sized microcrystalline cellulose. However, it is not limited to these examples. Among these cellulose materials, it is preferable to use wood pulp because it is easily available and inexpensive.

[0032] In the alkali treatment of the cellulose material, the cellulose material is treated with an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide to obtain alkali cellulose. The concentration of the aqueous solution of the alkali metal hydroxide is preferably 4% by mass or more. When the concentration of the aqueous solution of the alkali metal hydroxide is less than 4% by mass, the mercerization of cellulose does not proceed sufficiently, and the amount of by-products generated during the subsequent xanthation becomes non-negligible, resulting in a decrease in yield.

[0033] (II) Xanthation treatment In the xanthation treatment, by reacting alkali cellulose with carbon disulfide (CS2), the (-O - M + ) group is converted to the (-OCSS - M + ) group to obtain xanthated cellulose. The average degree of xanthate substitution of the xanthated cellulose can be determined using the Bredee method. The procedure of the Bredee method is to weigh 1.5 g of the xanthated cellulose as a solid content and add 40 mL of a saturated ammonium chloride solution (5 °C). After thoroughly mixing with a glass rod, it is filtered and washed thoroughly with the saturated ammonium chloride solution. Then, 50 mL of a 0.5 mol / L sodium hydroxide solution (5 °C) is added and stirred, and then neutralized with 1.5 mol / L acetic acid. Then, 250 mL of ion-exchanged water is added and stirred well, and 10 mL of 1.5 mol / L acetic acid and 10 mL of a 0.05 mol / L iodine solution are added. This solution is titrated with a 0.05 mol / L sodium thiosulfate solution using a 1% by mass aqueous starch solution as an indicator. Using the titration amount of sodium thiosulfate and the cellulose amount (g) of the sample in the above procedure, the following formula (2): Average degree of xanthate substitution = (0.05 × 10 × 2 - 0.05 × titration amount of sodium thiosulfate (mL)) / {1000 × (cellulose amount in sample (g) / 162.1)} ···(2) Calculate the average degree of xanthate substitution. The cellulose content in the xanthated cellulose is measured as follows. First, disperse the xanthated cellulose in water, add hydrochloric acid, and perform a regeneration treatment. Next, filter the cellulose after the regeneration treatment, wash it thoroughly, dry it to a constant weight, measure the mass of only the cellulose, and calculate the cellulose content in the xanthated cellulose.

[0034] When producing CNF for use in the gel-like composition for cosmetics of the present invention, in the xanthation treatment, it is preferable that the average degree of xanthate substitution is 0.1 or more and 0.4 or less. If the average degree of xanthate substitution is less than 0.1, there is a possibility that the fibrillation treatment to be performed later cannot be sufficiently carried out. If the average degree of xanthate substitution exceeds 0.4, the hydrophilicity becomes too high, and there is a possibility of dissolution during the fibrillation treatment.

[0035] (III) Fibrillation treatment The fibrillation treatment is preferably carried out after dispersing the xanthated cellulose in water. As a method for the fibrillation treatment, a general method can be used. For example, methods of fibrillating using a rotary homogenizer, a bead mill, an ultrasonic disperser, a high-pressure homogenizer, a disk refiner, etc. can be mentioned.

[0036] The cellulose material requires a great deal of energy to be fibrillated as it is, but in the case of xanthated cellulose, the dispersibility is improved by the electrostatic repulsion between the fibers due to the xanthate group, so the energy required for fibrillation is extremely small, and it can be fibrillated under relatively mild conditions.

[0037] (IV) Regeneration treatment By subjecting the xanthated CNF to a regeneration treatment, regenerated CNF can be obtained. In this regeneration treatment, the xanthate group (-OCSS - M + ) is eliminated and changed to a hydroxyl group (-OH) to regenerate the xanthated cellulose into cellulose.

[0038] As regeneration treatment methods, methods of treating with an acid can be mentioned. By using an acid, a reaction can be made to proceed in which the xanthate group is easily detached and changed to a hydroxyl group. Examples of the acid used here include mineral acids and organic acids, and in particular, mineral acids such as hydrochloric acid, sulfuric acid, and nitric acid are preferable.

[0039] As another regeneration treatment method, by heating the xanthated CNF, carbon disulfide can also be dissociated from the molecules of the xanthated CNF and regenerated into cellulose to obtain CNF.

[0040] (V) Redispersion treatment After the regeneration treatment, the CNF has a xanthate group detached compared to the xanthated CNF before regeneration, and thus a part of it is in an aggregated state due to hydrogen bonding and entanglement between the fibers. Therefore, by performing a dispersion treatment again on the aqueous dispersion of the CNF after the regeneration treatment, a CNF dispersion is obtained. Hereinafter, this dispersion treatment performed after the regeneration treatment is referred to as "redispersion treatment". As the redispersion treatment, general apparatuses and methods used for dispersion treatment such as a rotary homogenizer, a high-pressure homogenizer, and an ultrasonic disperser can be used.

[0041] As described above, by sequentially performing the steps of (I) to (V), the average fiber diameter of the CNF derived from the xanthated cellulose obtained can be adjusted to 2 nm or more and 30 nm or less. The average fiber diameter of the CNF is measured by the following procedure. Ion-exchanged water is added to the obtained CNF to obtain an aqueous dispersion with a solid content concentration of 0.1 mass%, and centrifugation (12,000 G, 10 minutes) is performed using a centrifuge (manufactured by Beckman Coulter, Avanti J-251) to sediment undispersed substances. The supernatant is further diluted with ion-exchanged water, then coated on a support film, stained with uranyl acetate, and dried on the support film to obtain a dried specimen. Using a transmission electron microscope (TEM: manufactured by JEOL Ltd., JEM-1400), observation is performed at an acceleration voltage of 120 kV, 50 nanofibers are selected from an image at 50,000 times magnification, the fiber diameter of each is measured, and the average value is obtained and taken as the average fiber diameter.

Example

[0042] [Production Example 1 of Nonionic CNF] Softwood bleached kraft pulp (NBKP) was weighed so that the pulp solids became 100 g, 2500 g of an 8.5 mass% aqueous sodium hydroxide solution was added, and the mixture was stirred at room temperature for 3 hours for alkali treatment. After this alkali treatment, the pulp was separated into solid and liquid to obtain a dehydrated product of alkali cellulose.

[0043] The dehydrated product of alkali cellulose prepared above was weighed so that the pulp solids became 100 g, 35 g of carbon disulfide (35 mass% based on the pulp solids) was added, and the sulfidation reaction was allowed to proceed for xanthation treatment to obtain xanthated cellulose.

[0044] The above xanthated cellulose was weighed so that the pulp solids became 10 g, ion-exchanged water was added and dispersed, and solid-liquid separation was performed followed by thorough washing with ion-exchanged water. All of the washed xanthated cellulose was recovered, and ion-exchanged water was added to make 2 kg of an aqueous suspension with a cellulose concentration of 0.5 mass%. This aqueous suspension was passed through a high-pressure homogenizer three times at a pressure of 80 MPa for fibrillation treatment to obtain xanthated CNF. The average degree of xanthate substitution of the obtained xanthated CNF was 0.263, the fiber diameter was in the range of 3.0 nm to 7.4 nm, and the average fiber diameter was 6.1 nm.

[0045] To 1.5 kg of the aqueous suspension of xanthated CNF (cellulose concentration 0.5 mass%) obtained by the above procedure, 33 mL of 1 mol / L sulfuric acid was added for regeneration treatment. After the treatment was completed, it was neutralized to pH 7 with 1 mol / L sodium hydroxide solution to obtain an aqueous suspension of regenerated CNF. When the average degree of xanthate substitution was measured, it was less than 0.001, which is the lower limit of measurement, so it was confirmed that the xanthate groups had almost completely detached and returned to hydroxyl groups by the acid treatment.

[0046] The water suspension of the regenerated CNF obtained above was thoroughly washed by adding ion-exchanged water while being centrifuged and dehydrated by a centrifugal dehydrator. All the regenerated CNF after washing was collected, and ion-exchanged water was added to make 1 kg of an aqueous dispersion with a solid content concentration of 1.0 mass% of CNF. The dispersion was redispersed at a pressure of 80 MPa using a high-pressure homogenizer to obtain non-ionic CNF as a manufacturing example. After the redispersion process, the average fiber diameter of the redispersed regenerated CNF was calculated to be 3.0 to 7.4 nm, and the average fiber diameter was 6.0 nm.

[0047] [Production Example 2 of Nonionic CNF] The redispersion of the regenerated CNF (average fiber diameter 6.0 nm) obtained in Production Example 1 above was diluted to a solid content concentration of 0.5% by mass, centrifuged (75,000 G, 10 minutes) using a centrifuge (Avanti J-251, manufactured by Beckman Coulter), the centrifugal supernatant was collected, and concentrated to a solid content concentration of 1.0% by mass using an evaporator. The average fiber diameter of the regenerated CNF in the centrifugal supernatant was calculated to be 2.0 to 3.1 nm, and the average fiber diameter was 2.6 nm.

[0048] [Production Example 3 of Nonionic CNF] In the same manner as above, except that the aqueous suspension of xanthated cellulose of Production Example 1 was passed through the high-pressure homogenizer twice for defibration treatment, a xanthated CNF having an average degree of xanthate substitution of 0.264, a fiber diameter of 2.0 to 51.4 nm, and an average fiber diameter of 28.1 nm was obtained.

[0049] This xanthated CNF was treated in the same manner as in Production Example 1 to obtain a redispersion of nonionic CNF having a fiber diameter of 2.0 to 50.7 nm and an average fiber diameter of 28.0 nm.

[0050] <Preparation and Evaluation of Cosmetic Gel Compositions> A cosmetic gel composition of the present invention (Example 1) was prepared, and the viscosity was measured and the feeling of use was evaluated. For comparison, cosmetic gel compositions outside the scope of the present invention (Comparative Examples 1 and 2) were prepared, and the same measurements and evaluations were performed.

[0051] [Example 1] Ion-exchanged water and 1,3-butylene glycol (BG) as a diol were added to the aqueous dispersion of CNF (average fiber diameter: 6.0 nm) of Production Example 1, and after adjusting so that the content rate of CNF was 0.5 mass% and the content rate of 1,3-butylene glycol was 5 mass% at the final concentration, it was stirred at 3,000 rpm for 5 minutes using a homomixer (Homomixer MARKII2.5 type, manufactured by Primix Corporation). This was degassed to obtain a gel-like composition for cosmetics. In the gel-like composition for cosmetics of Example 1, the mass ratio (A:B) of the content (A) of CNF and the content (B) of the diol is 1:10.

[0052] [Comparative Example 1] Xanthan gum (KELTROL CG-T, manufactured by Sankyo Co., Ltd.) was used instead of CNF. Otherwise, a gel-like composition for cosmetics was obtained in the same manner as in Example 1.

[0053] [Comparative Example 2] An aqueous dispersion of CNF of the same lot as that of Example 1 was diluted with ion-exchanged water, and adjusted so that the final concentration (solid content) of CNF was 0.5 mass%. Otherwise, a gel-like composition for cosmetics was obtained in the same manner as in Example 1.

[0054] [Viscosity] Using the M3 rotor of a B-type viscometer (TVB-10H, manufactured by Toki Sangyo Co., Ltd.), the viscosity of the gel-like composition for cosmetics was measured at 30 rpm.

[0055] [Feeling in Use] Five monitors applied the gel-like composition for cosmetics to their upper arms, and evaluated the feeling after application according to the following criteria. When the average of the evaluations by the five monitors was 5, the feeling in use was rated as "○", when it was 3 or more and less than 5, the feeling in use was rated as "△", and when it was less than 3, the feeling in use was rated as "×". 5: No stickiness or greasiness. 4: Slightly feeling stickiness and greasiness. 3: A little stickiness and greasiness. 2: There is stickiness and greasiness. 1: Considerable stickiness and greasiness.

[0056] The manufacturing conditions, viscosity, and feel in use of the gel-like cosmetic compositions of Example 1 and Comparative Examples 1 and 2 are shown in Table 1.

[0057]

Table 1

[0058] The gel-like cosmetic composition of Example 1 had a higher viscosity and was easier to handle when applied to the skin, compared with the gel-like cosmetic composition of Comparative Example 1 using xanthan gum as the water-soluble polymer and the gel-like cosmetic composition of Comparative Example 2 not containing diol.

[0059] The gel-like cosmetic composition of Example 1 was excellent in feel in use, having neither stickiness peculiar to water-soluble polymers nor slipperiness caused by diol. On the other hand, in the gel-like cosmetic composition of Comparative Example 1 using xanthan gum as the water-soluble polymer, although the contents of the water-soluble polymer and diol were the same as those in the gel-like cosmetic composition of Example 1, it had stickiness peculiar to water-soluble polymers and slipperiness caused by diol, and was inferior in feel in use.

[0060] 〔Example 2〕 Ion-exchanged water and 1,3-butylene glycol (BG) as diol were added to the aqueous dispersion of CNF (average fiber diameter: 6.0 nm) of Production Example 1, and adjusted so that the content rate of CNF was 0.5% by mass and the content rate of 1,3-butylene glycol was 1% by mass (mass ratio (A:B) of the content of CNF to the content of diol was 1:2), 5% by mass (mass ratio (A:B) was 1:10), 10% by mass (mass ratio (A:B) was 1:20), 20% by mass (mass ratio (A:B) was 1:40), 30% by mass (mass ratio (A:B) was 1:60). After that, each was stirred at 3,000 rpm for 5 minutes using a homomixer (Homomixer MARKII2.5 type, manufactured by Primix Corporation). This was degassed to obtain a gel-like cosmetic composition.

[0061] 〔Example 3〕 To the aqueous dispersion of CNF (average fiber diameter: 2.6 nm) of Production Example 2, ion-exchanged water and 1,3-butylene glycol (BG) as a diol were added, and after adjusting so that the content rate of CNF was 0.5 mass% and the content rate of 1,3-butylene glycol was 10 mass% (mass ratio (A:B) was 1:20) at the final concentration, it was stirred at 3,000 rpm for 5 minutes using a homomixer (Homomixer MARKII 2.5 type, manufactured by Primix Corporation). This was degassed to obtain a gel-like composition for cosmetics.

[0062] [Example 4] To the aqueous dispersion of CNF (average fiber diameter: 28.0 nm) of Production Example 3, ion-exchanged water and 1,3-butylene glycol (BG) as a diol were added, and after adjusting so that the content rate of CNF was 0.5 mass% and the content rate of 1,3-butylene glycol was 10 mass% (mass ratio (A:B) was 1:20) at the final concentration, it was stirred at 3,000 rpm for 5 minutes using a homomixer (Homomixer MARKII 2.5 type, manufactured by Primix Corporation). This was degassed to obtain a gel-like composition for cosmetics.

[0063] [Example 5] To the aqueous dispersion of CNF (average fiber diameter: 6.0 nm) of Production Example 1, ion-exchanged water and pentylene glycol (PeG) as a diol were added, and after adjusting so that the content rate of CNF was 0.5 mass% and the content rate of pentylene glycol was 10 mass% (mass ratio (A:B) was 1:20) at the final concentration, it was stirred at 3,000 rpm for 5 minutes using a homomixer (Homomixer MARKII 2.5 type, manufactured by Primix Corporation). This was degassed to obtain a gel-like composition for cosmetics.

[0064] [Example 6] To the aqueous dispersion of CNF (average fiber diameter: 6.0 nm) of Production Example 1, ion-exchanged water and propylene glycol (PG) as a diol were added, and after adjusting so that the content rate of CNF was 0.5 mass% and the content rate of propylene glycol was 10 mass% (mass ratio (A:B) was 1:20) at the final concentration, it was stirred at 3,000 rpm for 5 minutes using a homomixer (Homomixer MARKII 2.5 type, manufactured by Primix Corporation). This was degassed to obtain a gel-like composition for cosmetics.

[0065] [Comparative Example 3] Instead of the CNF of the production example, mechanically defibrated CNF (manufactured by Sugino Machine Limited: BiNFi-sWMa-10002, fiber diameter 24.1 to 53.2 nm, average fiber diameter 31 nm) was used. Otherwise, a gel-like composition for cosmetics was obtained in the same manner as in Example 2.

[0066] [Comparative Example 4] Instead of the pentylene glycol of Example 5, glycerin (GLY) was used. Otherwise, a gel-like composition for cosmetics was obtained in the same manner as in Example 5.

[0067] [Example 7] Instead of the pentylene glycol of Example 5, a 1:1 mixture of 1,3-butylene glycol (BG) and glycerin (GLY) was used. Otherwise, a gel-like composition for cosmetics was obtained in the same manner as in Example 5.

[0068] [Light transmittance] The light transmittance [700 nm transmittance (T%)] of the gel-like composition for cosmetics (Examples 2 to 7) of the present invention was measured using an ultraviolet-visible spectrophotometer (V-730, manufactured by JASCO Corporation) with an optical path length of 10 mm for the light transmittance of light at a wavelength of 700 nm. Also, the light transmittance of the gel-like composition for cosmetics (Comparative Examples 3 and 4) outside the scope of the present invention was measured in the same manner.

[0069] The light transmittances of the gel-like compositions for cosmetics of Examples 2 to 7, Comparative Examples 3 and 4 are shown in Table 2. In Table 2, the light transmittance when the content rate of the polyhydric alcohol is 0 mass% is also shown.

[0070]

Table 2

[0071] As shown in Table 2, the cosmetic gel compositions of Examples 2 to 4 containing 1,3-butylene glycol which is a diol, the cosmetic gel composition of Example 5 containing pentylene glycol which is a diol, and the cosmetic gel composition of Example 6 containing propylene glycol which is a diol are compared with the comparative example using mechanically defibrated CNF (average fiber diameter 31 nm). 3 Compared with the comparative example, they had a high transmittance for visible light with a wavelength of 700 nm. In particular, in the cosmetic gel composition of Example 2, when the content of the diol was in the range of 1 to 20% by mass and the mass ratio (A:B) of the content (A) of CNF to the content (B) of the diol was in the range of 1:2 to 1:40, the higher the content of the diol, the more the transmittance of visible light at 700 nm tended to increase.

[0072] From the above, in the cosmetic gel composition of the present invention, when 1,3-butylene glycol, pentylene glycol, or propylene glycol is used as the diol and its content is adjusted to 1 to 20% by mass, it is considered that the light transmittance is particularly improved.

[0073] <Viscosity ratio> Regarding the cosmetic gel compositions of Examples 2 to 7 described above, using an M3 rotor of a B-type viscometer (TVB-10H, manufactured by Toki Sangyo Co., Ltd.), the viscosity of the cosmetic gel composition at 25 °C at 30 rpm was measured, and the increase rate with respect to the viscosity with an addition amount of 0% by mass when the content of the diol was 10% by mass, that is, the viscosity ratio, was calculated by the above formula (1). Further, for comparison, in addition to the above Comparative Example 4, cosmetic gel compositions (Comparative Examples 5 and 6) outside the scope of the present invention were prepared, the viscosity was measured in the same manner, and the viscosity ratio was calculated.

[0074] 〔Comparative Example 5〕 Instead of CNF, xanthan gum (KELTROL CG-T, manufactured by Sankyo Co., Ltd.) was used. Ion-exchanged water and 1,3-butylene glycol (BG) as a diol were added to the xanthan gum, and after adjusting so that the content rate of xanthan gum was 0.5% by mass, the content rate of 1,3-butylene glycol was 5% by mass (mass ratio (A:B) was 1:10), and 10% by mass (mass ratio (A:B) was 1:20) at the final concentration, each was stirred at 3,000 rpm for 5 minutes using a homomixer (Homomixer MARKII 2.5 type, manufactured by Primix Corporation). This was degassed to obtain a gel-like composition for cosmetics.

[0075] 〔Comparative Example 6〕 Ion-exchanged water and ethanol (EtOH) which is a monohydric alcohol were added to the aqueous dispersion of CNF (average fiber diameter 6.0 nm) of Production Example 1, and after adjusting so that the content rate of CNF was 0.5% by mass and the content rate of ethanol was 10% by mass (mass ratio (A:B) was 1:20) at the final concentration, it was stirred at 3,000 rpm for 5 minutes using a homomixer (Homomixer MARKII 2.5 type, manufactured by Primix Corporation). This was degassed to obtain a gel-like composition for cosmetics.

[0076] Table 3 shows the viscosities of the gel-like compositions for cosmetics of Examples 2 to 7 and Comparative Examples 4 to 6. In addition, Table 3 also shows the viscosity when the content rate of the diol is 0% by mass.

[0077]

Table 3

[0078] As shown in Table 3, the gelled cosmetic compositions of Examples 2 to 4 containing 1,3-butylene glycol which is a diol, the gelled cosmetic composition of Example 5 containing pentylene glycol which is a diol, and the gelled cosmetic composition of Example 6 containing propylene glycol which is a diol had increased viscosities compared to the case where no diol was added (addition amount 0% by mass). The viscosity ratios when the content of the diol was adjusted to 10% by mass were 12.9% in Example 2 using 1,3-butylene glycol as the diol, 13.1% in Example 3, 13.3% in Example 4, 11.2% in Example 5 using pentylene glycol as the diol, and 10.2% in Example 6 using propylene glycol as the diol.

[0079] On the other hand, the viscosity ratio of the gelled cosmetic composition of Comparative Example 4 containing glycerin which is a polyhydric alcohol instead of the diol was -7.7%, the viscosity ratio of the gelled cosmetic composition of Comparative Example 5 not containing CNF was 3.0%, the viscosity ratio of the gelled cosmetic composition of Comparative Example 6 containing ethanol which is a monohydric alcohol was -3.0%, and the viscosity ratio of the gelled cosmetic composition of Example 7 containing glycerin which is a polyhydric alcohol in addition to the diol was -9.5%. For the CNF aqueous dispersion containing the same amount of CNF, none of them had a sufficiently high viscosity.

[0080] From the above, in the gelled cosmetic composition of the present invention, from the viewpoint of increasing the viscosity for improving the handleability during application to the skin, it is considered preferable to use 1,3-butylene glycol, pentylene glycol, and propylene glycol as the diol, and in particular, it is considered more preferable not to contain polyhydric alcohols such as glycerin in addition to these diols.

Industrial Applicability

[0081] The gelled cosmetic composition of the present invention can be used as a raw material for cosmetics used on the face and the like.< / cnf>

Claims

1. A nonionic cellulose nanofiber having an average fiber diameter of 2 to 30 nm, a diol, and water, wherein the content of the cellulose nanofiber is 0.1 to 5% by mass, the content of the diol is 1 to 20% by mass, and a mass ratio (A:B) of the content (A) of the cellulose nanofiber to the content (B) of the diol is 1:2 to 1:40, a gel-like composition for cosmetics.

2. The gel-like composition for cosmetics according to claim 1, wherein the diol is at least one selected from the group consisting of 1,3-butylene glycol, pentylene glycol, propylene glycol, and dipropylene glycol.

3. The gel-like composition for cosmetics according to claim 1 or 2, wherein the transmittance of light with a wavelength of 700 nm is 75% or more with an optical path length of 10 mm.

4. The gel-like composition for cosmetics according to any one of claims 1 to 3, which is prepared so that the viscosity is 10% or more higher than that of a cellulose nanofiber aqueous dispersion containing the same amount of cellulose nanofibers.

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