Porous cellulose particles and cosmetic product

Abstract

To provide porous cellulose particles that have superior mechanical strength and also have superior rollability and oil absorbability after a mechanical load is imparted.SOLUTION: Porous cellulose particles contain cellulose, a cellulose derivative, or a mixture thereof as a main component, have continuous pores extending from a surface of a particle to the inside of the particle, and have a BET specific surface area of 1.7 m2 / g or more and 24.0 m2 / g or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to porous cellulose particles and cosmetics.

Background Art

[0002] Patent Document 1 proposes "porous cellulose particles formed by aggregation of type I crystalline cellulose obtained by a process without intentional chemical modification, wherein the crystalline cellulose has a type I crystal form with glucose molecules as constituent units, and the porous cellulose particles have an average particle diameter d1 of 0.5 to less than 50 μm, a specific surface area of 25 to 1000 m2 / g, and a sphericity of 0.85 or more."

[0003] Patent Document 2 proposes "cellulose particles characterized by having a volume average particle diameter of 50 μm or more and 1000 μm or less and an oil absorption amount of linseed oil of 150 mL / 100 g or more."

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem of the present invention is to provide porous cellulose particles mainly composed of cellulose, a cellulose derivative, or a mixture thereof and having continuous pores leading from the particle surface to the particle interior, which are excellent in mechanical strength and also excellent in rollability and oil absorbency after mechanical load application, as compared with the case where the BET specific surface area is less than 1.7 m 2 / g or more than 24.0 m 2 / g.

Means for Solving the Problem

[0006] The means for solving the above problems include the following aspects. <1> Porous cellulose particles mainly composed of cellulose, a cellulose derivative, or a mixture thereof, having continuous pores leading from the particle surface to the particle interior and a BET specific surface area of 1.7 m 2 / g or more and 24.0 m 2 / g or less. <2> The porous cellulose particles according to <1>, wherein the BET specific surface area is 8.0 m 2 / g or more and 20.0 m 2 / g or less. <3> The porous cellulose particles according to <1> or <2>, wherein when observing the cross-section of the porous cellulose particles, the area ratio of the continuous pores is 15% or more and 90% or less. <4> The porous cellulose particles according to <3>, wherein when observing the cross-section of the porous cellulose particles, the area ratio of the continuous pores is 25% or more and 85% or less. <5> The porous cellulose particles according to any one of <1> to <4>, wherein the cellulose derivative is cellulose acylate having a degree of substitution of 0.6 or less. <6> The porous cellulose particles according to <5>, wherein the cellulose derivative is cellulose acylate having a degree of substitution of 0.2 or less. <7> The porous cellulose particles according to any one of <1> to <6>, wherein the volume average particle diameter of the porous cellulose particles is 3 μm or more and 45 μm or less. <8> Cosmetics containing the porous cellulose particles according to any one of <1> to <7>.

Advantages of the Invention

[0007] According to the invention according to <1>, in porous cellulose particles mainly composed of cellulose, a cellulose derivative or a mixture thereof and having continuous pores leading from the particle surface to the particle interior, when the BET specific surface area is less than 1.7 m 2 / g or more than 24.0 m 2 / g, porous cellulose particles are provided that are excellent in mechanical strength and also excellent in rollability and oil absorbency after mechanical load application. According to the invention according to <2>, in porous cellulose particles mainly composed of cellulose, a cellulose derivative or a mixture thereof and having continuous pores leading from the particle surface to the particle interior, when the BET specific surface area is less than 8.0 m 2 / g or more than 20.0 m 2 / g, porous cellulose particles are provided that are excellent in mechanical strength and also excellent in rollability and oil absorbency after mechanical load application. According to the invention according to <3>, porous cellulose particles are provided that are excellent in mechanical strength and also excellent in rollability and oil absorbency after mechanical load application, as compared with the case where the area ratio of the continuous pores is less than 15% or more than 90%. According to the invention according to <4>, porous cellulose particles are provided that are excellent in mechanical strength and also excellent in rollability and oil absorbency after mechanical load application, as compared with the case where the area ratio of the continuous pores is less than 25% or more than 85%. According to the invention according to <5>, porous cellulose particles are provided that are excellent in mechanical strength and also excellent in rollability and oil absorbency after mechanical load application, as compared with the case where the cellulose derivative is a cellulose acylate with a degree of substitution exceeding 0.6. According to the invention according to <6>, porous cellulose particles are provided that are excellent in mechanical strength and also excellent in rollability and oil absorbency after mechanical load application, as compared with the case where the cellulose derivative is a cellulose acylate with a degree of substitution exceeding 0.2. According to the invention according to <7>, porous cellulose particles are provided that are excellent in mechanical strength and also excellent in rollability and oil absorbency after mechanical load application, as compared with the case where the volume average particle diameter of the cellulose particles is less than 3 μm or more than 45 μm. According to the invention according to <8>, in porous cellulose particles mainly composed of cellulose, a cellulose derivative or a mixture thereof and having continuous pores leading from the particle surface to the particle interior, when the BET specific surface area is 1.7 m 2less than / g or 24.0 m 2 Compared with the case where porous cellulose particles exceeding / g are applied, cosmetics having excellent mechanical strength, smoothness, and sebum adsorbing property after mechanical loading are provided.

Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments which are examples of the present invention will be described. These descriptions and examples are illustrative of the embodiments and do not limit the scope of the invention. In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other stepwise descriptions. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0009] Each component may contain a plurality of corresponding substances. When referring to the amount of each component in the composition, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the plurality of substances present in the composition.

[0010] <Cellulose Particles> The porous cellulose particles according to the present embodiment are mainly composed of cellulose, a cellulose derivative, or a mixture thereof. And the porous cellulose particles according to the present embodiment have continuous pores leading from the particle surface to the particle interior, and the BET specific surface area is 1.7 m 2 / g or more and 24.0 m 2 / g or less.

[0011] The porous cellulose particles according to the present embodiment become porous cellulose particles having excellent mechanical strength, rolling property, and oil-absorbing property after mechanical loading due to the above configuration. The reason is presumed as follows.

[0012] The porous cellulose mainly composed of cellulose, cellulose derivatives or a mixture thereof has a light touch, high rollability, and high oil absorbency. On the other hand, when the mechanical strength is low and it is suitable for additives in products such as cosmetics, if a mechanical load such as pressing is applied during the product manufacturing process, the particle shape is deformed, the porous structure collapses, and the rollability and oil absorbency also decrease.

[0013] In contrast, the porous cellulose particles according to the present embodiment have a porous structure with continuous pores leading from the particle surface to the particle interior, thereby enhancing the rollability and oil absorbency. In addition, by reducing the BET specific surface area of the porous cellulose particles to 1.7 m 2 / g or more and 24.0 m 2 / g or less, the volume of the continuous pores is ensured, the rollability and oil absorbency are enhanced, and the thickness of the partition walls between the continuous pores is also ensured, thereby enhancing the mechanical strength.

[0014] From the above, it is presumed that the porous cellulose particles according to the present embodiment are porous cellulose particles having excellent mechanical strength and excellent rollability and oil absorbency after mechanical load application. In particular, since the cellulose particles according to the present embodiment have excellent mechanical strength and excellent rollability and oil absorbency after mechanical load application, when applied to cosmetics, the porous structure is difficult to collapse during the manufacturing process, and cosmetics having excellent mechanical strength and excellent rollability and oil absorbency after mechanical load application can be obtained.

[0015] Hereinafter, the porous cellulose particles according to the present embodiment will be described in detail.

[0016] (Porous Structure of Porous Cellulose Particles) The porous cellulose particles according to the present embodiment have continuous pores leading from the particle surface to the particle interior. Specifically, for example, when the cross-section of the porous cellulose particles is observed, the area ratio of the continuous pores is preferably 15% or more and 90% or less, more preferably 25% or more and 85% or less, still more preferably 30% or more and 70% or less, and particularly preferably 35% or more and 70% or less. When the area ratio of the continuous pores is within the above range, a sufficient volume of continuous pores is ensured, and the rollability and oil absorbency are increased.

[0017] The confirmation of the continuous pores and the area ratio of the continuous pores are as follows. After embedding the porous cellulose particles in an epoxy resin, they are cut with a diamond knife or the like, and a sample having a surface with a cross section of the porous cellulose particles as an observation surface is prepared. The prepared sample is set in a scanning electron microscope (SEM), and an SEM image (acceleration voltage: 1.0 kV, magnification: 20,000 times) of the cross section of the cellulose particles taken by the SEM is obtained. In the obtained SEM image, the presence of continuous pores leading from the particle surface to the particle interior in the cross section of the porous cellulose particles is confirmed. First, the obtained SEM image is thresholded using image analysis software (for example, ImageJ, WinROOF) so that the voids and the epoxy resin as the background can be clearly distinguished, and binarization is performed. Next, the area ratio of all pores with respect to the entire cross section of the porous cellulose particles is determined. On the other hand, the area ratio of the independent pores closed by the septa with respect to the entire cross section of the porous cellulose particles is determined. Regarding the independent pores, if they can be directly identified, the area ratio may be calculated without binarization. Also, pores that do not appear as continuous pores in the cross-sectional observation are regarded as independent pores. Next, the area ratio of the continuous pores is calculated by the formula: area ratio of continuous pores = area ratio of all pores - area ratio of independent pores. Then, the above operation is performed 10 times, and the obtained values are arithmetically averaged.

[0018] Note that, as the cross section of the porous cellulose particles to be observed, a cross section of porous cellulose particles having a cross-sectional diameter of 85% or more of the volume average particle diameter of the porous cellulose particles is selected. Here, the cross-sectional diameter refers to the maximum length of a straight line drawn between any two points on the contour line of the cross section of the porous cellulose particles (so-called major axis).

[0019] (BET specific surface area of porous cellulose particles) The BET specific surface area of the porous cellulose particles according to this embodiment is 1.7 m2 24.0 m / g or more 2 It is 24.0 m / g or less. When the BET specific surface area is 1.7 m 2 / g or more, the cellulose particles have a porous structure instead of a solid structure, and the rollability and oil absorbency are improved. When the BET specific surface area is 24.0 m 2 / g or less, the partition walls between the continuous pores become thick, and the mechanical strength is improved. Therefore, when the porous cellulose particles are applied to products such as cosmetics, due to mechanical loads such as stirring during the production of the product, the porous cellulose particles do not deform and the porous structure does not collapse, and the rollability and oil absorbency are improved. Further, even when the porous cellulose particles are used alone, the porous cellulose particles do not deform and the porous structure does not collapse due to mechanical loads, and the rollability and oil absorbency are improved. Therefore, the BET specific surface area is in the above range. The BET specific surface area is preferably 8.0 m 2 / g or more and 20 m 2 / g or less, more preferably 10 m 2 / g or more and 16 m 2 / g or less.

[0020] The BET specific surface area of the porous cellulose particles is measured by a specific surface area measuring device "Macsorb HM model-1201 type" manufactured by Mountech Co., Ltd. Specifically, after subjecting 50 mg of the particles to a pretreatment of vacuum / 34°C / 1 day and a pretreatment of 30°C / 120 minutes, the BET specific surface area is determined by the BET multipoint method using nitrogen gas with a purity of 99.99% or more.

[0021] (Layer structure of porous cellulose particles) The porous cellulose particles according to this embodiment are preferably porous cellulose particles having no coating layer. That is, the porous cellulose particles according to this embodiment are preferably porous cellulose particles having a single-layer structure mainly composed of cellulose, a cellulose derivative, or a mixture thereof.

[0022] (Components of porous cellulose particles) The porous cellulose particles according to this embodiment contain cellulose, a cellulose derivative, or a mixture thereof as the main component. Here, containing cellulose, a cellulose derivative, or a mixture thereof as the main component means that the content of cellulose, a cellulose derivative, or a mixture thereof in the porous cellulose particles is 90% by mass or more (preferably 95% by mass or more, more preferably 98% by mass or more, and most preferably 100% by mass).

[0023] - Cellulose - The number average molecular weight of cellulose is preferably 37,000 or more, and more preferably 45,000 or more. The upper limit value of the number average molecular weight of cellulose is not particularly limited, and may be, for example, 100,000 or less.

[0024] The number average molecular weight of cellulose is measured by gel permeation chromatography (using a differential refractive index detector Optilab T-rEX / manufactured by Wyatt Technology, a multi-angle light scattering detector DAWN HELEOS II / manufactured by Wyatt Technology, and columns TSKgel α-M and α-3000, one each / manufactured by Tosoh Corporation), with dimethylacetamide (added with 0.1M lithium chloride) as the solvent.

[0025] - Cellulose derivative - Examples of the cellulose derivative include cellulose acylate, cellulose ether, hydroxyalkyl cellulose, carboxymethyl cellulose, and the like. Among these, as the cellulose derivative, cellulose acylate is preferable. Cellulose acylate is likely to have enhanced rollability, oil absorbency, and mechanical strength.

[0026] Cellulose acylate is a cellulose derivative in which at least a part of the hydroxy groups in cellulose is substituted (acylated) with an acyl group. The acyl group is -CO-R AC (R ACrepresents a hydrogen atom or a hydrocarbon group. It is a group having the structure of ().

[0027] Cellulose acetate is a cellulose derivative represented by, for example, the following general formula (CA).

[0028] [Chemical formula]

[0029] In the general formula (CA), A 1 , A 2 and A 3 each independently represents a hydrogen atom or an acyl group, and n represents an integer of 2 or more. However, at least a part of the n A 1 , the n A 2 and the n A 3 represent acyl groups. The n A 1 in the molecule may all be the same, partly the same, or different from each other. Similarly, the n A 2 and the n A 3 in the molecule may also each be all the same, partly the same, or different from each other.

[0030] The acyl group represented by A 1 , A 2 and A 3 is such that the hydrocarbon group in the acyl group may be linear, branched, or cyclic, but is preferably linear or branched, and more preferably linear.

[0031] The acyl group represented by A 1 , A 2 and A 3 is such that the hydrocarbon group in the acyl group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group, but is more preferably a saturated hydrocarbon group.

[0032] The acyl group represented by A 1 , A 2 and A 3The acyl group represented by the formula (I) is preferably an acyl group having a carbon number of 1 to 6. That is, the cellulose acylate is preferably an acyl group having a carbon number of 1 to 6.

[0033] A 1 , A 2 and A 3 The acyl group represented by may be a group in which a hydrogen atom in the acyl group is substituted with a halogen atom (for example, a fluorine atom, a bromine atom, an iodine atom), an oxygen atom, a nitrogen atom or the like, but is preferably unsubstituted.

[0034] A 1 , A 2 and A 3 The acyl group represented by is a formyl group, an acetyl group, a propionyl group, Examples of the acyl group include a butyryl group (butanoyl group), a propenoyl group, and a hexanoyl group. Among these, from the viewpoint of improving the biodegradation rate, an acyl group having from 2 to 4 carbon atoms is more preferable, and an acyl group having 2 or 3 carbon atoms is even more preferable.

[0035] Examples of the cellulose acylate include cellulose acetate (cellulose monoacetate, cellulose diacetate (DAC), cellulose triacetate), cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB).

[0036] Of the cellulose acylates, cellulose acetate is preferred from the viewpoints of improving rolling properties, oil absorbency, and mechanical strength. The cellulose acylate may be used alone or in combination of two or more kinds.

[0037] The weight average degree of polymerization of the cellulose acylate is preferably 200 or more and 1,000 or less, more preferably 500 or more and 1,000 or less, and even more preferably 600 or more and 1,000 or less.

[0038] The weight-average degree of polymerization of cellulose acylate is determined from the weight-average molecular weight (Mw) by the following procedure. First, the weight average molecular weight (Mw) of the cellulose acetate is measured in terms of polystyrene using a gel permeation chromatography apparatus (GPC apparatus: manufactured by Tosoh Corporation, HLC-8320GPC, column: TSKgel α-M) with tetrahydrofuran. Next, the degree of polymerization of the cellulose acetate is determined by dividing by the molecular weight of the constituent unit of the cellulose acetate. For example, when the substituent of the cellulose acetate is an acetyl group, the molecular weight of the constituent unit is 263 when the degree of substitution is 2.4 and 284 when the degree of substitution is 2.9.

[0039] From the viewpoints of improving rollability, oil absorbency, and mechanical strength, the degree of substitution of the cellulose acetate is preferably 0.75 or less, more preferably 0.6 or less, and even more preferably 0.2 or less.

[0040] The degree of substitution of the cellulose acetate is an index indicating the degree to which the hydroxy groups of the cellulose are substituted by acyl groups. That is, the degree of substitution is an index indicating the degree of acylation of the cellulose acetate. Specifically, the degree of substitution means the average within the molecule of the number of substitutions in which the three hydroxy groups in the D-glucopyranose unit of the cellulose acetate are substituted by acyl groups. The degree of substitution is determined from the absorbance ratio between the cellulose-derived peak (1030 cm -1 ) and the acyl group-derived peak (1738 cm -1 ) in the infrared absorption spectrum (Spotlight 400 / manufactured by PerkinElmer). Specifically, the value of the absorbance at 1738 cm -1 / the absorbance at 1030 cm -1 is taken as the degree of substitution.

[0041] The degree of substitution of the cellulose acetate can be adjusted by the amount of base (for example, sodium hydroxide, etc.) added and the reaction time when saponifying the cellulose acetate.

[0042] -Other components- The porous cellulose particles according to the present embodiment may contain other components. Examples of other components include plasticizers, flame retardants, compatibilizers, mold release agents, light stabilizers, weathering agents, colorants, pigments, modifiers, anti-dripping agents, antistatic agents, hydrolysis inhibitors, fillers, reinforcing agents (such as glass fibers, carbon fibers, talc, clay, mica, glass flakes, milled glass, glass beads, crystalline silica, alumina, silicon nitride, aluminum nitride, boron nitride, etc.), acid acceptors for preventing acetic acid release (oxides such as magnesium oxide and aluminum oxide; metal hydroxides such as magnesium hydroxide, calcium hydroxide, aluminum hydroxide, hydrotalcite, etc.; calcium carbonate; talc; etc.), reactive trap agents (such as epoxy compounds, acid anhydride compounds, carbodiimides, etc.), and the like. The content of each of the other components is preferably 0% by mass or more and 5% by mass or less based on the total amount of the porous cellulose particles. Here, "0% by mass" means not containing the other components.

[0043] -Externally added agent- In the cellulose particles according to this embodiment, inorganic particles may be added as an externally added agent. When inorganic particles are externally added, secondary aggregation between the particles is suppressed, making it easier to exhibit the original characteristics of the particles. Therefore, the rollability, oil absorbency, and mechanical strength are likely to be improved.

[0044] Examples of the externally added agent include at least one selected from the group consisting of silicon-containing compound particles and metal oxide particles.

[0045] Silicon-containing compound particles refer to particles containing silicon. The silicon-containing compound particles may be particles containing only silicon or particles containing silicon and other elements.

[0046] The silicon-containing compound particles are preferably silica particles. The silica particles are silica, that is, SiO 2Particles having the main component may be used, and they may be crystalline or amorphous. Further, the silica particles may be particles produced from a silicon compound such as water glass or alkoxysilane as a raw material, or may be particles obtained by pulverizing quartz. As the metal oxide, oxides of metals other than silicon are applicable. Examples of the metal oxide include zinc oxide, magnesium oxide, iron oxide, aluminum oxide, and the like.

[0047] From the viewpoints of improving rollability, oil absorbency, and mechanical strength, the volume average particle diameter of the external additive is preferably 1 nm or more and 100 nm or less, and more preferably 5 nm or more and 30 nm or less. The volume average particle diameter of the external additive is measured in the same manner as the volume average particle diameter of cellulose.

[0048] The addition amount of the external additive is preferably 0.1% by mass or more and 2% by mass or less with respect to the total mass of the cellulose particles (cellulose particles in a state where no external additive is added).

[0049] (Volume average particle diameter) The volume average particle diameter of the cellulose particles according to the present embodiment is preferably 1 μm or more and 100 μm or less, more preferably 3 μm or more and 45 μm or less, and still more preferably 4 μm or more and 15 μm or less. By setting the volume average particle diameter of the cellulose particles according to the present embodiment to 1 μm or more and 100 μm or less, the particle diameter becomes an appropriate size, and the rollability, oil absorbency, and mechanical strength are improved.

[0050] The volume average particle diameter of the cellulose particles is measured as follows. The particle diameter is measured by an LS particle size distribution measuring device “Beckman Coulter LS13 320 (manufactured by Beckman Coulter, Inc.)”, the cumulative distribution of the particle diameter is drawn from the small diameter side on a volume basis, and the particle diameter at which the cumulative value becomes 50% is determined as the volume average particle diameter.

[0051] <Method for producing porous cellulose particles> The method for producing cellulose particles preferably includes a step of granulating cellulose acetate particles (granulation step) and a step of saponifying cellulose acetate particles (saponification step).

[0052] - Granulation step - (1) First, add cellulose acetate to a mixed solution of a water-soluble organic solvent and a poor solvent, then heat the solution to 50°C or higher and 70°C or lower to dissolve the cellulose acetate in water-soluble organic solvent A to prepare cellulose acetate solution A. (2) Next, add cellulose acetate solution A to a calcium carbonate dispersion in which calcium carbonate is dispersed in water, and while maintaining the liquid temperature at 50°C or higher and 70°C or lower, stir to prepare cellulose acetate emulsion B. By this operation, the poor solvent is dispersed in the cellulose acetate particles in cellulose acetate emulsion B, and continuous pores are formed. (3) Next, add cellulose acetate emulsion B to a large amount of warm water at a liquid temperature of 60°C or higher and 75°C or lower, and stir overnight to prepare cellulose acetate particle dispersion C. By this operation, cellulose acetate particles precipitate while maintaining the continuous pores. (4) Next, add dilute hydrochloric acid to cellulose acetate particle dispersion C to dissolve calcium carbonate, and then filter the residue. (5) Next, disperse the filtrate in pure water to obtain cellulose acetate particle dispersion D.

[0053] - Saponification step - (6) Next, add sodium hydroxide to cellulose acetate particle dispersion D, then heat and stir cellulose acetate particle dispersion D in a weakly alkaline environment to saponify cellulose acetate particles and prepare a cellulose particle suspension. (7) Next, hydrochloric acid is added to the cellulose particle suspension to adjust the pH of the suspension to near neutrality (for example, in the range of 6.5 or more and 7 or less), and then the cellulose particles are filtered off and washed with an organic solvent. Thereafter, the filtration and pure water washing of the cellulose particles are repeated. Then, after the conductivity of the filtrate reaches 10 μs / cm or less, the filtered cellulose particles are dried.

[0054] Through the above steps, porous cellulose particles mainly composed of cellulose are obtained. In addition, when obtaining porous cellulose particles mainly composed of cellulose acetate, methods such as not performing the saponification step and obtaining cellulose acylate particles in the granulation step, or reducing the amount of sodium hydroxide in the saponification step to lower the degree of saponification can be mentioned. By reducing the amount of sodium hydroxide in the saponification step, the degree of substitution of cellulose acetate can be adjusted. When obtaining porous cellulose particles mainly composed of a cellulose derivative other than cellulose acetate, methods such as not performing the saponification step and using a cellulose derivative instead of cellulose acetate to obtain cellulose derivative particles in the granulation step can be mentioned.

[0055] Here, the water-soluble organic solvent is a solvent in which water dissolves 0.1 mass% or more and 10 mass% or less with respect to the solvent at 25°C, and examples include ethyl acetate and butyl acetate. The poor solvent is a solvent in which the cellulose derivative dissolves less than 0.1 mass% with respect to the solvent at 25°C, and examples include alcohols with a boiling point of 100°C or higher (such as heptanol). Examples of the organic solvent used for washing the cellulose particles include acetone and alcohols (such as methanol, ethanol, and propanol).

[0056] -External addition step- An external additive may be added to the obtained cellulose particles. Examples of the external addition step include a process of adding an external additive to the cellulose particles using a mixing mill, a V-type blender, a Henschel mixer, a Lodige mixer, or the like.

[0057] <Use> Examples of the use of the cellulose particles according to this embodiment include granular materials for cosmetics, rolling agents, abrasives, scrubbing agents, display spacers, bead forming materials, light diffusing particles, resin reinforcing agents, refractive index control agents, biodegradation accelerators, fertilizers, water-absorbing particles, toner particles, and anti-blocking particles.

[0058] <Cosmetics> The cosmetics according to this embodiment are cosmetics containing the cellulose particles according to this embodiment.

[0059] Examples of the cosmetics according to this embodiment include, for example, base makeup cosmetics (e.g., makeup base, concealer, foundation, face powder, etc.); makeup cosmetics (e.g., lipstick, gloss, lip liner, blush, eyeshadow, eyeliner, mascara, eyebrow, nail, nail care cosmetics, etc.); skin care cosmetics (e.g., facial cleanser, cleansing, lotion, emulsion, essence, pack, face mask, eye and lip care cosmetics, etc.); and the like. In particular, the cosmetics according to this embodiment are preferred for makeup cosmetics because of their high smoothness and sebum adsorption properties.

Examples

[0060] Examples will be described below, but the present invention is not limited to these examples. In the following description, unless otherwise specified, all "parts" and "%" are based on mass.

[0061] <Example 1> -Granulation process- 120 parts of cellulose acetate (DAC "L-50" manufactured by Daicel Corporation, cellulose diacetate, weight average degree of polymerization 570) as a raw material was added to 480 parts of a mixed solution containing ethyl acetate and heptanol as a poor solvent, with the amount of the poor solvent being 20%, and the mixture was heated and stirred at a dissolution temperature of 60°C to completely dissolve the raw material in ethyl acetate. The obtained solution was added to a dispersion containing 45 parts of calcium carbonate as a dispersant and 500 parts of pure water, and stirred for 10 minutes with a high-speed emulsifier while maintaining an emulsification temperature of 60°C. The obtained emulsion was added to warm water at 60 to 75°C in an amount 5 times that of the emulsion, and stirred overnight to obtain a dispersion in which cellulose acetate particles had precipitated. Dilute hydrochloric acid was added to the obtained dispersion to dissolve calcium carbonate. After filtering the residue of the dispersion, the filtrate was dispersed again in pure water to obtain a cellulose acetate particle dispersion (solid content concentration: 10%).

[0062] -Saponification step- 17.5 parts of a 20% aqueous sodium hydroxide solution was added to 120 parts of the obtained cellulose acetate particle dispersion, and stirred at a saponification temperature of 30°C for 6 hours. Hydrochloric acid was added to the saponified suspension to adjust the pH to 7, and the obtained cellulose particles were filtered off and washed with acetone. Thereafter, the cellulose particles were repeatedly filtered off and washed with pure water until the conductivity of the filtrate became 10 μs / cm or less, to obtain porous cellulose particles.

[0063] <Examples 2 to 18, Comparative Example 1> Cellulose particles were obtained in the same manner as in Example 1, except that the following conditions were changed according to the "particle production conditions" shown in Table 1. ·Emulsification temperature ·Amount of poor solvent of the mixed solvent of ethyl acetate and heptanol ·Amount of dispersant ·Amount of 20% aqueous sodium hydroxide solution (denoted as NaOH amount)

[0064] <Comparative Examples 2 to 3> The following commercially available cellulose particles were used as the cellulose particles of Comparative Examples 2 to 3, respectively. Comparative Example 2: Daito Kasei Kogyo Co., Ltd. "CELLULOBEADS USF-X" Comparative Example 3: JNC Corporation "Cellflow C-25"

[0065] <Evaluation> (Particle properties) For the porous cellulose particles obtained in each example, the following particle properties were measured according to the methods described above. · BET specific surface area · Area ratio of continuous pores · Degree of substitution of cellulose derivative · Volume average particle diameter of cellulose particles (denoted as "particle diameter" in the table)

[0066] (Smoothness (rollability)) Twenty panelists evaluated the "smoothness" of the porous cellulose particles of each example after pressing when applied on the skin on a 5 - point scale from 1 to 5. 5 was considered to have the strongest feeling of smoothness on the skin. The average value of the 5 - point evaluations of the 20 panelists was re - expressed as A+~D according to the evaluation criteria shown below. If the evaluation was A+~C, it was judged to be excellent in smoothness, and if it was D, it was judged to be inferior in smoothness. It was judged that A+ had the strongest smoothness and D had the weakest smoothness. Note that for the pressing of the particles, 8 g of the particles were filled into a round gold dish (diameter 5.5 cm), and the pressing was carried out at a pressing pressure of 500 kgf / cm 2 and a pressing time of 10 seconds. A+: The average value of the evaluation is 4.5 or more A: The average value of the evaluation is 4 or more and less than 4.5 B: The average value of the evaluation is 3.5 or more and less than 4 C: The average value of the evaluation is 3 or more and less than 3.5 D: The average value of the evaluation is less than 3

[0067] (Sebum adsorption (oil absorption)) The oil absorption rate of linseed oil of the porous cellulose particles of each example after pressing was measured. Specifically, it was as follows. 10 g of linseed oil and 1 g of the porous cellulose particles of each example after pressing were mixed, and centrifugation was carried out under the conditions of a rotation speed of 10,000 rpm and a time of 30 minutes. After removing the supernatant linseed oil, the weight of the particles was measured, and the oil absorption rate was calculated by the following formula. Formula: Oil absorption rate = (increase in weight after centrifugation ÷ weight of particles before centrifugation) × 100 And the adsorption property was evaluated according to the following criteria. Note that for the pressing of the particles, 8 g of the particles were filled into a round gold dish (diameter 5.5 cm), and the pressing was carried out at a pressing pressure of 500 kgf / cm 2 , and a pressing time of 10 seconds. A+: Oil absorption rate ≥ 250% A: 220% ≤ oil absorption rate < 250% B: 190% ≤ oil absorption rate < 220% C: 160% ≤ oil absorption rate < 190% D: Oil absorption rate < 160%

[0068]

Table 1

[0069] From the above results, it can be seen that the cellulose particles of this example are superior in mechanical strength compared to the cellulose particles of the comparative example, and are also superior in smoothness and sebum adsorbability even after mechanical loading. Therefore, it can also be seen that the cellulose particles of this example are superior in mechanical strength compared to the cellulose particles of the comparative example, and are also superior in rollability and oil absorbency even after mechanical loading.

[0070] This embodiment includes the following aspects. (((1))) Porous cellulose particles mainly composed of cellulose, a cellulose derivative, or a mixture thereof, having continuous pores leading from the particle surface to the particle interior, and having a BET specific surface area of 1.7 m 2 / g or more and 24.0 m 2 / g or less. (((2))) The porous cellulose particles according to (((1))), wherein the BET specific surface area is 8.0 m 2 / g or more and 20.0 m 2 / g or less. (((3))) The porous cellulose particles according to (((1))) or (((2))), wherein when the cross-section of the porous cellulose particles is observed, the area ratio of the continuous pores is 15% or more and 90% or less. (((4))) The porous cellulose particles according to ((3)), wherein when observing the cross section of the porous cellulose particles, the area ratio of the continuous pores is 25% or more and 85% or less. (((5))) The porous cellulose particles according to any one of ((1)) to ((4)), wherein the cellulose derivative is a cellulose acylate having a degree of substitution of 0.6 or less. (((6))) The porous cellulose particles according to ((5)), wherein the cellulose derivative is a cellulose acylate having a degree of substitution of 0.2 or less. (((7))) The porous cellulose particles according to any one of ((1)) to ((6)), wherein the volume average particle diameter of the porous cellulose particles is 3 μm or more and 45 μm or less. (((8))) Cosmetics containing the porous cellulose particles according to any one of ((1)) to ((7)).

[0071] The effects of the above aspects are as follows. According to the invention according to ((1)), in the porous cellulose particles mainly composed of cellulose, a cellulose derivative or a mixture thereof and having continuous pores leading from the particle surface to the particle interior, the BET specific surface area is less than 1.7 m 2 / g or more than 24.0 m 2 / g, there are provided porous cellulose particles having excellent mechanical strength and excellent rolling property and oil absorption property after mechanical load application. According to the invention according to ((2)), compared with the case where the BET specific surface area is less than 8.0 m 2 / g or more than 20.0 m 2 / g, there are provided porous cellulose particles having excellent mechanical strength and excellent rolling property and oil absorption property after mechanical load application. According to the invention according to ((3)), compared with the case where the area ratio of the continuous pores is less than 15% or more than 90%, there are provided porous cellulose particles having excellent mechanical strength and excellent rolling property and oil absorption property after mechanical load application. According to the invention according to ((4)), there are provided porous cellulose particles having excellent mechanical strength and excellent rolling and oil-absorbing properties after mechanical loading, as compared with the case where the area ratio of continuous pores is less than 25% or more than 85%. According to the invention according to ((5)), there are provided porous cellulose particles having excellent mechanical strength and excellent rolling and oil-absorbing properties after mechanical loading, as compared with the case where the cellulose derivative is cellulose acetate having a degree of substitution exceeding 0.6. According to the invention according to ((6)), there are provided porous cellulose particles having excellent mechanical strength and excellent rolling and oil-absorbing properties after mechanical loading, as compared with the case where the cellulose derivative is cellulose acetate having a degree of substitution exceeding 0.2. According to the invention according to ((7)), there are provided porous cellulose particles having excellent mechanical strength and excellent rolling and oil-absorbing properties after mechanical loading, as compared with the case where the volume average particle diameter of the cellulose particles is less than 3 μm or more than 45 μm. According to the invention according to ((8)), in porous cellulose particles containing cellulose, a cellulose derivative or a mixture thereof as a main component and having continuous pores leading from the particle surface to the particle interior, when applying porous cellulose particles having a BET specific surface area of less than 1.7 m 2 / g or more than 24.0 m 2 / g, there are provided cosmetics having excellent mechanical strength and excellent smoothness and sebum adsorbing properties after mechanical loading.

Claims

1. The main component is cellulose, a cellulose derivative or a mixture thereof, The particles have continuous pores that connect the particle surface to the inside of the particle, and the BET specific surface area is 1.7 m ２ / g or more 24.0m ２ / g or less.

2. The BET specific surface area is 8.0 m ２ / g or more 20.0m ２ The porous cellulose particles according to claim 1, wherein the molecular weight of the porous cellulose particles is 1 / g or less.

3. 2. The porous cellulose particle according to claim 1, wherein when a cross-section of the porous cellulose particle is observed, the area ratio of the continuous pores is 15% or more and 90% or less.

4. 4. The porous cellulose particle according to claim 3, wherein when a cross-section of the porous cellulose particle is observed, the area ratio of the continuous pores is 25% or more and 85% or less.

5. 2. The porous cellulose particles according to claim 1, wherein the cellulose derivative is a cellulose acylate having a degree of substitution of 0.6 or less.

6. 6. The porous cellulose particles according to claim 5, wherein the cellulose derivative is a cellulose acylate having a degree of substitution of 0.2 or less.

7. The porous cellulose particles according to claim 1, wherein the volume average particle diameter of the porous cellulose particles is 3 μm or more and 45 μm or less.

8. A cosmetic comprising the porous cellulose particles according to any one of claims 1 to 7.