Porous cellulose particles, and cosmetic containing porous cellulose particles

Abstract

Disclosed are: porous cellulose particles which contain cellulose, a cellulose derivative or a mixture thereof as a main component, have continuous pores extending from the surface of the particles to the inside of the particles, and have a BET specific surface area of 1.7-24.0 m2 / g (inclusive); and a cosmetic containing the porous cellulose particles.

Description

Technical Field

[0001] The present invention relates to a porous cellulose particle and a cosmetic containing the porous cellulose particle. Background Art

[0002] In Japanese Patent Publication No. 7269239, there is proposed "a porous cellulose particle formed by aggregating type I crystalline cellulose obtained by a process without intentional chemical modification, characterized in that the crystalline cellulose is of type I crystal form having glucose molecules as structural units, and for the porous cellulose particle, the average particle diameter d1 is 0.5 to less than 50 μm, the specific surface area is 25 to 1000 m 2 / g, and the sphericity is 0.85 or more."

[0003] In International Publication No. 2018 / 147213, there is proposed "a cellulose particle characterized in that the volume average particle diameter is 50 μm or more and 1000 μm or less, and the linseed oil absorption amount is 150 mL / 100 g or more." Summary of the Invention

[0004] An object of the present invention is to provide a porous cellulose particle 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 excellent mechanical strength, rolling property, and oil absorption property 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.

[0005] According to a first aspect of the present invention, there is provided a porous cellulose particle 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.

[0006] According to a second aspect of the present invention, in the porous cellulose particle according to the first aspect, the BET specific surface area is 8.0 m 2 / g or more and 20.0 m 2 / g or less.

[0007] According to a third aspect of the present invention, in the porous cellulose particle according to the first or second aspect, when observing a cross section of the porous cellulose particle, the area ratio of the continuous pores is 15% or more and 90% or less.

[0008] According to the fourth aspect of the present invention, in the porous cellulose particles involved in the third aspect, 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.

[0009] According to the fifth aspect of the present invention, in the porous cellulose particles involved in any one of the first to fourth aspects, the cellulose derivative is an acylated cellulose with a degree of substitution of 0.6 or less.

[0010] According to the sixth aspect of the present invention, in the porous cellulose particles involved in the fifth aspect, the cellulose derivative is an acylated cellulose with a degree of substitution of 0.2 or less.

[0011] According to the seventh aspect of the present invention, in the porous cellulose particles involved in any one of the first to sixth aspects, the volume average particle diameter of the porous cellulose particles is 3 μm or more and 45 μm or less.

[0012] According to the eighth aspect of the present invention, there is provided a cosmetic containing the porous cellulose particles involved in any one of the first to seventh aspects.

[0013] (Effect)

[0014] According to the first aspect, there is provided a porous cellulose particle, which has cellulose, a cellulose derivative or a mixture thereof as a main component, has continuous pores leading from the particle surface to the particle interior, and has excellent mechanical strength compared with the case where the BET specific surface area is less than 1.7 m 2 / g or exceeds 24.0 m 2 / g, and also has excellent rollability and oil absorbency after applying a mechanical load.

[0015] According to the second aspect, there is provided a porous cellulose particle, which has excellent mechanical strength compared with the case where the BET specific surface area is less than 8.0 m 2 / g or exceeds 20.0 m 2 / g, and also has excellent rollability and oil absorbency after applying a mechanical load.

[0016] According to the third aspect, there is provided a porous cellulose particle, which has excellent mechanical strength compared with the case where the area ratio of the continuous pores is less than 15% or exceeds 90%, and also has excellent rollability and oil absorbency after applying a mechanical load.

[0017] According to the fourth aspect, there is provided a porous cellulose particle, which has excellent mechanical strength compared with the case where the area ratio of the continuous pores is less than 25% or exceeds 85%, and also has excellent rollability and oil absorbency after applying a mechanical load.

[0018] According to the fifth aspect, there is provided a porous cellulose particle which has excellent mechanical strength and excellent rollability and oil absorbency after application of a mechanical load as compared with the case where the cellulose derivative is an acylated cellulose having a degree of substitution of more than 0.6.

[0019] According to the sixth aspect, there is provided a porous cellulose particle which has excellent mechanical strength and excellent rollability and oil absorbency after application of a mechanical load as compared with the case where the cellulose derivative is an acylated cellulose having a degree of substitution of more than 0.2.

[0020] According to the seventh aspect, there is provided a porous cellulose particle which has excellent mechanical strength and excellent rollability and oil absorbency after application of a mechanical load as compared with the case where the volume average particle diameter of the cellulose particle is less than 3 μm or more than 45 μm.

[0021] According to the eighth aspect, there is provided a cosmetic which uses a porous cellulose particle. The porous cellulose particle has a main component of cellulose, a cellulose derivative, or a mixture thereof, and has continuous pores extending from the particle surface to the particle interior. The cosmetic has excellent mechanical strength and excellent smoothness and sebum adsorbency after application of a mechanical load as compared with the following case: in the porous cellulose particle used, the BET specific surface area is less than 1.7 m 2 / g or more than 24.0 m 2 / g. Detailed Description of the Invention

[0022] Hereinafter, an embodiment as an example of the present invention will be described. These descriptions and examples are for illustrating the embodiment and do not limit the scope of the invention.

[0023] Within 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 another numerically described range. Further, within 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.

[0024] Each component may also contain a plurality of corresponding substances.

[0025] When referring to the amounts of the respective components 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.

[0026] <Cellulose Particle>

[0027] The porous cellulose particle of the present embodiment has a main component of cellulose, a cellulose derivative, or a mixture thereof.

[0028] Moreover, the porous cellulose particles of the present embodiment have continuous pores that penetrate 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.

[0029] Due to the above structure, the porous cellulose particles of the present embodiment are porous cellulose particles with excellent mechanical strength, and also excellent rolling properties and oil absorption properties after being subjected to mechanical loads. The reasons are speculated as follows.

[0030] Porous cellulose mainly composed of cellulose, cellulose derivatives, or a mixture thereof has a light touch and high rolling properties, and also high oil absorption properties.

[0031] On the other hand, its mechanical strength is low. For example, when applied as an additive to products such as cosmetics, when mechanical loads such as stamping are applied during the manufacturing process of the product, the particle shape deforms, the porous structure collapses, and the rolling properties and oil absorption properties also decrease.

[0032] In contrast, the porous cellulose particles of the present embodiment have improved rolling properties and oil absorption properties by adopting a porous structure with continuous pores that penetrate from the particle surface to the particle interior. In addition to this, by setting 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 rolling properties and oil absorption properties are improved, and the thickness of the partition walls between the continuous pores is also ensured, thereby improving the mechanical strength.

[0033] As described above, it is speculated that the porous cellulose particles of the present embodiment are porous cellulose particles with excellent mechanical strength, and also excellent rolling properties and oil absorption properties after being subjected to mechanical loads.

[0034] In particular, since the cellulose particles of the present embodiment have the characteristics of excellent mechanical strength, and also excellent rolling properties and oil absorption properties after being subjected to mechanical loads, when applied to cosmetics, the porous structure is not easily collapsed during the manufacturing process, and cosmetics with excellent mechanical strength, and also excellent rolling properties and oil absorption properties after being subjected to mechanical loads can be obtained.

[0035] Hereinafter, the details of the porous cellulose particles of the present embodiment will be described.

[0036] (Porous Structure of Porous Cellulose Particles)

[0037] The porous cellulose particles of the present embodiment have continuous pores that penetrate from the particle surface to the particle interior.

[0038] Specifically, for example, when observing the cross-section of the porous cellulose particles, 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.

[0039] 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 absorption are improved.

[0040] The confirmation of the continuous pores and the area ratio of the continuous pores are as follows.

[0041] After embedding the porous cellulose particles in epoxy resin, they are cut with a diamond knife or the like to prepare a specimen having a cross-sectional surface of the porous cellulose particles as the observation surface.

[0042] The prepared specimen is placed under a scanning electron microscope (SEM) to obtain an SEM image of the cross-section of the cellulose particles taken by the SEM (acceleration voltage: 1.0 kV, magnification: 20,000 times).

[0043] On 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.

[0044] First, using image analysis software (such as ImageJ, WinROOF), a threshold value is set for the obtained SEM image in such a way that voids and the epoxy resin as the background can be clearly distinguished, and binarization is performed. Then, the area ratio of the total pores to the entire cross-section of the porous cellulose particles is obtained. On the other hand, the area ratio of the independent pores enclosed by the partition walls to the entire cross-section of the porous cellulose particles is obtained. Regarding the independent pores, as long as they can be directly identified, the area ratio can be calculated without performing binarization. In addition, pores that do not appear to be continuous pores in the cross-section observation are regarded as independent pores.

[0045] Next, for the area ratio of the continuous pores, the area ratio of the continuous pores is calculated by the formula: area ratio of the continuous pores = area ratio of the total pores - area ratio of the independent pores.

[0046] Moreover, the above operation is performed 10 times, and the obtained values are arithmetically averaged.

[0047] In addition, for the cross-section of the porous cellulose particles to be observed, a cross-section of the porous cellulose particles with 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 (the so-called major axis).

[0048] (BET specific surface area of the porous cellulose particles)

[0049] The BET specific surface area of the porous cellulose particles of the present embodiment is 1.7 m 2 / g or more and 24.0 m 2 / g or less.

[0050] When the BET specific surface area is 1.7 m 2 / g or more, the cellulose particles are not of a solid structure but become a porous structure, and the rollability and oil absorption are improved.

[0051] When the BET specific surface area is 24.0 m 2 / g or less, the partition walls between the continuous pores become thicker and the mechanical strength is improved. Therefore, when the porous cellulose particles are applied to products such as cosmetics, the porous cellulose particles will not be deformed due to mechanical loads such as stirring during the manufacture of the products, the porous structure will not collapse, and the rollability and oil absorption are improved. In addition, even when the porous cellulose particles are used alone, the porous cellulose particles will not be deformed due to mechanical loads, the porous structure will not collapse, and the rollability and oil absorption are improved.

[0052] Therefore, the BET specific surface area is set within 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.

[0053] The BET specific surface area of the porous cellulose particles is measured by a "Macsorb HM model-1201 type" specific surface area measuring device manufactured by Mountech Co., Ltd.

[0054] Specifically, after subjecting 50 mg of the particles to pretreatment at vacuum / 34 °C / 1 day and pretreatment at 30 °C / 120 minutes, the BET specific surface area is obtained by the BET multipoint method using nitrogen with a purity of 99.99% or more.

[0055] (Layer structure of porous cellulose particles)

[0056] The porous cellulose particles of the present embodiment are preferably porous cellulose particles without a coating layer. That is, the porous cellulose particles of the present embodiment are preferably porous cellulose particles having a single-layer structure mainly composed of cellulose, a cellulose derivative, or a mixture thereof.

[0057] (Composition of porous cellulose particles)

[0058] The porous cellulose particles of the present embodiment are mainly composed of cellulose, a cellulose derivative, or a mixture thereof.

[0059] Here, the main component being cellulose, a cellulose derivative, or a mixture thereof means that the content of cellulose, a cellulose derivative, or a mixture thereof relative to 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%).

[0060] - Cellulose -

[0061] The number-average molecular weight of cellulose is preferably 37,000 or more, more preferably 45,000 or more.

[0062] The upper limit value of the number-average molecular weight of cellulose is not particularly limited, and can be, for example, 100,000 or less.

[0063] The number-average molecular weight of cellulose is measured by gel permeation chromatography (differential refractive index meter Optilab T-rEX / Wyatt Technology Corporation, multi-angle light scattering detector DAWN HELEOS II / Wyatt Technology Corporation, columns TSKgel α-M and α-3000, one each / Tosoh Corporation), using dimethylacetamide (added with 0.1 M lithium chloride) as the solvent.

[0064] - Cellulose derivative -

[0065] Examples of the cellulose derivative include acylated cellulose, cellulose ether, hydroxyalkyl cellulose, carboxymethyl cellulose, and the like.

[0066] Among them, as the cellulose derivative, acylated cellulose is preferred. The rollability, oil absorbency, and mechanical strength of acylated cellulose are easily improved.

[0067] Acylated cellulose is a cellulose derivative in which at least a part of the hydroxyl groups in cellulose are substituted with acyl groups (acylated). An acyl group means a group having a structure of -CO-R AC (R AC represents a hydrogen atom or a hydrocarbon group.)

[0068] Acylated cellulose is, for example, a cellulose derivative represented by the following general formula (CA).

[0069]

[0070] In the general formula (CA), A 1 , A 2 and A 3 each independently represent a hydrogen atom or an acyl group, and n represents an integer of 2 or more. Among them, n A 1 , n A 2 and n A 3At least a part of them represents an acyl group. There are n number of A's in the molecule. 1 They can all be the same, or some of them can be the same, or they can be different from each other. Similarly, there are n number of A's in the molecule. 2 And there are n number of A's 3 respectively can all be the same, or some of them can be the same, or they can be different from each other.

[0071] Regarding A 1 、A 2 and A 3 For the acyl group represented, the hydrocarbon group in the acyl group can be any of linear, branched, and cyclic, but is preferably linear or branched, and more preferably linear.

[0072] Regarding A 1 、A 2 and A 3 For the acyl group represented, the hydrocarbon group in the acyl group can be a saturated hydrocarbon group or an unsaturated hydrocarbon group, but is more preferably a saturated hydrocarbon group.

[0073] A 1 、A 2 and A 3 The acyl group represented is preferably an acyl group having 1 or more and 6 or less carbon atoms. That is, as the acylated cellulose, acylated cellulose having 1 or more and 6 or less carbon atoms in the acyl group is preferred.

[0074] A 1 、A 2 and A 3 The acyl group represented can be a group in which a hydrogen atom in the acyl group is substituted by a halogen atom (such as a fluorine atom, a bromine atom, an iodine atom), an oxygen atom, a nitrogen atom, etc., but non-substituted is preferred.

[0075] As A 1 、A 2 and A 3 Examples of the acyl group represented include formyl group, acetyl group, propionyl group, butanoyl group, acryloyl group, hexanoyl group, etc. Among them, as the acyl group, from the viewpoint of improving the biodegradation rate, an acyl group having 2 or more and 4 or less carbon atoms is more preferred, and an acyl group having 2 or 3 carbon atoms is further preferred.

[0076] Examples of the acylated cellulose include cellulose acetate (monoacetate cellulose, diacetate cellulose (DAC), triacetate cellulose), cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB), etc.

[0077] From the viewpoints of improving rollability, oil absorption, and mechanical strength, the acylated cellulose is preferably cellulose acetate.

[0078] One type of acyl cellulose may be used alone, or two or more types may be used in combination.

[0079] The weight-average degree of polymerization of the acyl cellulose is preferably 200 or more and 1000 or less, more preferably 500 or more and 1000 or less, and still more preferably 600 or more and 1000 or less.

[0080] The weight-average degree of polymerization of the acyl cellulose is determined from the weight-average molecular weight (Mw) according to the following steps.

[0081] First, using tetrahydrofuran, the weight-average molecular weight (Mw) of the acyl cellulose is measured in terms of polystyrene using a gel permeation chromatography apparatus (GPC apparatus: manufactured by Tosoh Corporation, HLC-8320GPC, column: TSKgel α-M).

[0082] Next, divide by the molecular weight of the structural unit of the acyl cellulose to obtain the degree of polymerization of the acyl cellulose. For example, when the substituent of the acyl cellulose is an acetyl group, the molecular weight of the structural unit is 263 at a degree of substitution of 2.4, and 284 at a degree of substitution of 2.9.

[0083] From the viewpoints of improving rollability, oil absorbency, and mechanical strength, the degree of substitution of the acyl cellulose is preferably 0.75 or less, more preferably 0.6 or less, and still more preferably 0.2 or less.

[0084] The degree of substitution of the acyl cellulose is an index indicating the degree to which the hydroxyl groups possessed by the cellulose are substituted by acyl groups. That is, the degree of substitution becomes an index indicating the degree of acylation of the acyl cellulose. Specifically, the degree of substitution is the intramolecular average of the number of substitutions in which 3 hydroxyl groups present in the D-glucopyranose unit of the acyl cellulose are substituted by acyl groups. The degree of substitution is determined by infrared absorption spectroscopy (Spotlight 400 / PerkinElmer) from the absorbance ratio of the peak derived from the acyl group (1738 cm -1 ) and the peak derived from cellulose (1030 cm -1 ).

[0085] Specifically, the value of the absorbance at 1738 cm -1 / the absorbance at 1030 cm -1 is defined as the degree of substitution.

[0086] The degree of substitution of the acyl cellulose can be adjusted by the amount of base (e.g., sodium hydroxide, etc.) added and the reaction time during saponification of the acyl cellulose.

[0087] - Other components -

[0088] Other components may also be contained in the porous cellulose particles of the present embodiment.

[0089] As other components, for example, plasticizers, flame retardants, compatibilizers, mold release agents, light-resistant agents, weather-resistant agents, colorants, pigments, modifiers, anti-dripping agents, antistatic agents, hydrolysis-proof agents, fillers, reinforcing agents (such as glass fibers, carbon fibers, talc, clay, mica, glass flakes, ground glass, glass beads, crystalline silica, alumina, silicon nitride, aluminum nitride, boron nitride, etc.), acid acceptors for preventing the release of acetic acid (oxides such as magnesium oxide and alumina; metal hydroxides such as magnesium hydroxide, calcium hydroxide, aluminum hydroxide, and hydrotalcite; calcium carbonate; talc, etc.), reactive scavengers (such as epoxy compounds, acid anhydride compounds, carbodiimides, etc.) and the like can be mentioned.

[0090] With respect to the total amount of the porous cellulose particles, the content of each of the other components is preferably 0% by mass or more and 5% by mass or less. Herein, "0% by mass" means that the other components are not contained.

[0091] -External additives-

[0092] The cellulose particles of the present embodiment may also be added with inorganic particles as external additives. When inorganic particles are externally added, secondary aggregation of the particles is suppressed, and thus the inherent properties of the particles are easily exhibited. Therefore, the rollability, oil absorption, and mechanical strength are easily improved.

[0093] As the external additive, for example, at least one selected from the group consisting of silicon-containing compound particles and metal oxide particles can be mentioned.

[0094] The silicon-containing compound particles mean particles containing silicon.

[0095] As the silicon-containing compound particles, they may be particles containing only silicon, or particles containing silicon and other elements.

[0096] As the silicon-containing compound particles, silicon dioxide particles are preferably used. The silicon dioxide particles may be particles mainly composed of silicon dioxide, i.e., SiO 2 as the main component, and may be crystalline or amorphous. In addition, the silicon dioxide particles may be particles manufactured from silicon compounds such as water glass and alkoxysilanes, or particles obtained by pulverizing quartz.

[0097] As the metal oxide, oxides of metals other than silicon can be applied.

[0098] As the metal oxide, for example, zinc oxide, magnesium oxide, iron oxide, alumina, etc. can be mentioned.

[0099] From the viewpoint of improving the rollability, oil absorption, and mechanical strength, the volume average particle diameter of the external additive is preferably 1 nm or more and 100 nm or less, more preferably 5 nm or more and 30 nm or less.

[0100] The volume average particle diameter of the external additive is measured by the same method as the volume average particle diameter of cellulose.

[0101] The amount of the external additive added externally is preferably 0.1% by mass or more and 2% by mass or less based on the total mass of the cellulose particles (cellulose particles in a state where no external additive is added externally).

[0102] (Volume average particle diameter)

[0103] The volume average particle diameter of the cellulose particles of 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 further preferably 4 μm or more and 15 μm or less.

[0104] By setting the volume average particle diameter of the cellulose particles of the present embodiment to 1 μm or more and 100 μm or less, the particle diameter becomes an appropriate size, and the rollability, oil absorption, and mechanical strength are improved.

[0105] The volume average particle diameter of the cellulose particles is measured as follows.

[0106] The particle diameter is measured using an LS particle size distribution measuring device “Beckman Coulter LS13 320 (manufactured by Beckman Coulter, Inc.)”, and the cumulative distribution of the particle diameter is plotted from the small diameter side based on volume, and the particle diameter at 50% cumulative is obtained as the volume average particle diameter.

[0107] <Method for manufacturing porous cellulose particles>

[0108] The method for manufacturing cellulose particles preferably includes a step of manufacturing acylated cellulose particles (granulation step) and a step of saponifying the acylated cellulose particles (saponification step).

[0109] - Granulation step -

[0110] (1) First, after adding acylated cellulose to a mixed liquid of a water-soluble organic solvent A and a poor solvent, the liquid is heated to 50°C or more and 70°C or less, and the acylated cellulose is dissolved in the water-soluble organic solvent A to prepare an acylated cellulose solution A.

[0111] (2) Next, the acylated cellulose solution A is added to a calcium carbonate dispersion liquid in which calcium carbonate is dispersed in water, and while maintaining the liquid temperature at 50°C or more and 70°C or less, stirring is carried out to prepare an acylated cellulose emulsion B. By this operation, a poor solvent is dispersed in the acylated cellulose particles in the acylated cellulose emulsion B to form communicating pores.

[0112] (3) Next, add the acylated cellulose emulsion B to a large amount of warm water at a liquid temperature above 60°C and below 75°C, and stir overnight to prepare an acylated cellulose particle dispersion C. Through this operation, acylated cellulose particles precipitate while maintaining the state of the communication pores.

[0113] (4) Next, add dilute hydrochloric acid to the acylated cellulose particle dispersion C, dissolve the calcium carbonate, and then filter the residue.

[0114] (5) Next, disperse the filtrate in pure water to obtain an acylated cellulose particle dispersion D.

[0115] - Saponification process -

[0116] (6) Next, add sodium hydroxide to the acylated cellulose particle dispersion D, then heat and stir the acylated cellulose particle dispersion D in a weak alkaline environment to saponify the acylated cellulose particles and prepare a cellulose particle suspension.

[0117] (7) Next, add hydrochloric acid to the cellulose particle suspension to make the pH of the suspension near neutral (for example, in the range of 6.5 or more and 7 or less), and then perform filtration and organic solvent cleaning of the cellulose particles. After that, further repeat the filtration and pure water cleaning of the cellulose particles. Moreover, after the conductivity of the filtrate reaches 10 μs / cm or less, dry the filtered cellulose particles.

[0118] Through the above processes, porous cellulose particles mainly composed of cellulose are obtained.

[0119] In addition, in the case of obtaining porous cellulose particles mainly composed of cellulose acetate, methods such as obtaining acylated cellulose particles in the granulation process without performing the saponification process, and reducing the amount of sodium hydroxide and the degree of saponification in the saponification process can be cited. By reducing the amount of sodium hydroxide in the saponification process, the degree of substitution of cellulose acetate can be adjusted.

[0120] In the case of obtaining porous cellulose particles mainly composed of a cellulose derivative other than cellulose acetate, methods such as obtaining cellulose derivative particles in the granulation process by using a cellulose derivative to replace cellulose acetate without performing the saponification process can be cited.

[0121] Here, the water-soluble organic solvent is a solvent in which water dissolves 0.1% by mass or more and 10% by mass or less of the solvent at 25°C. For example, ethyl acetate, butyl acetate, etc. can be cited.

[0122] The poor solvent is a solvent in which the cellulose derivative dissolves less than 0.1% by mass of the solvent at 25°C. For example, alcohols with a boiling point of 100°C or higher (such as heptanol) can be cited.

[0123] Examples of the organic solvents used in the cleaning of cellulose particles include acetone and alcohols (such as methanol, ethanol, and propanol).

[0124] -External addition process-

[0125] External additives can also be added to the obtained cellulose particles.

[0126] As the external addition process, for example, there can be mentioned a process of adding external additives to cellulose particles using a mixing mill, a V-type blender, a Henschel mixer, a Lodige mixer, etc.

[0127] <Usage>

[0128] Examples of the uses of the cellulose particles of the present embodiment include cosmetics, rolling agents, abrasives, scouring agents, display spacers, bead molding materials, light diffusing particles, resin reinforcing agents, refractive index control agents, biodegradation promoters, fertilizers, water-absorbing particles, toner particles, and anti-caking particle granules.

[0129] <Cosmetics>

[0130] The cosmetics of the present embodiment are cosmetics containing the cellulose particles of the present embodiment.

[0131] Examples of the cosmetics of the present embodiment include: base makeup cosmetics (such as primers, concealers, foundation creams, powder puffs, etc.); beauty cosmetics (such as lipsticks, lip glosses, lip liners, blushes, eyeshadows, eyeliners, mascaras, eyebrow pencils, nail polishes, nail care cosmetics, etc.); skin care cosmetics (such as facial cleansers, makeup removers, lotions, emulsions, beauty serums, packs, face masks, eye and lip care cosmetics, etc.).

[0132] In particular, the cosmetics of the present embodiment are preferably beauty cosmetics because of their high smoothness and sebum adsorption.

[0133] [Examples]

[0134] Hereinafter, examples will be described. The present invention is not limited by any of these examples. In addition, in the following description, unless otherwise specified, "parts" and "%" are all based on mass.

[0135] <Example 1>

[0136] -Granulation process-

[0137] 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%, 120 parts of acetylated cellulose (DAC “L-50” manufactured by Daicel Corporation, diacetate cellulose, weight-average degree of polymerization 570) as a raw material was added, and heating and stirring were carried out at a dissolution temperature of 60 °C. Thus, the raw material was completely dissolved in ethyl acetate.

[0138] The obtained solution was added to a dispersion liquid containing 45 parts of calcium carbonate as a dispersant and 500 parts of pure water, and stirring was carried out with a high-speed emulsifier for 10 minutes while maintaining the emulsification temperature at 60 °C.

[0139] The obtained emulsion was added to warm water at 60 to 75 °C in an amount 5 times that of the emulsion, and stirring was carried out overnight to obtain a dispersion liquid in which acetylated cellulose particles had precipitated.

[0140] Dilute hydrochloric acid was added to the obtained dispersion liquid to dissolve calcium carbonate. After filtering the residue of the dispersion liquid, the filtrate was dispersed again in pure water to obtain a dispersion liquid of acetylated cellulose particles (solid content concentration 10%).

[0141] -Saponification step-

[0142] To 120 parts of the obtained dispersion liquid of acetylated cellulose particles, 17.5 parts of a 20% aqueous sodium hydroxide solution was added, and stirring was carried out at a saponification temperature of 30 °C for 6 hours. After adding hydrochloric acid to the saponified suspension and adjusting the pH to 7, the obtained cellulose particles were filtered out and washed with acetone. Then, the filtration of the cellulose particles and the washing with pure water were repeated until the conductivity of the filtrate became 10 μs / cm or less to obtain porous cellulose particles.

[0143] <Examples 2 to 18, Comparative Example 1>

[0144] Except for changing the following conditions according to the “particle manufacturing conditions” shown in Table 1, the operation was carried out in the same manner as in Example 1 to obtain cellulose particles.

[0145] ·Emulsification temperature

[0146] ·Amount of the poor solvent in the mixed solvent of ethyl acetate and heptanol

[0147] ·Amount of the dispersant

[0148] ·Amount of the 20% aqueous sodium hydroxide solution (marked as NaOH amount)

[0149] <Comparative Examples 2 to 3>

[0150] The following commercially available cellulose particles were respectively used as the cellulose particles of Comparative Examples 2 to 3.

[0151] Comparative Example 2: "CELLULOBEADS USF-X" by Daito Kasei Kogyo Co., Ltd.

[0152] Comparative Example 3: "Celluflow C-25" by JNC Corporation

[0153] <Evaluation>

[0154] (Particle properties)

[0155] For the porous cellulose particles obtained in each example, the following particle properties were measured according to the method described above.

[0156] · BET specific surface area

[0157] · Area ratio of continuous pores

[0158] · Degree of substitution of cellulose derivative

[0159] · Volume average particle diameter of cellulose particles (marked as "particle diameter" in the table)

[0160] (Smoothness (rollability))

[0161] Twenty panelists evaluated the "smoothness" when the porous cellulose particles of each example after stamping were applied to the skin on a scale of 1 to 5. A score of 5 was set as the strongest smoothness felt on the skin. According to the evaluation criteria shown below, the average value of the five-level evaluations of the 20 panelists was re-labeled with A+ to D. It was judged that if the evaluation was A+ to C, the smoothness was excellent, and if it was D, the smoothness was poor. It was judged that A+ was the strongest smoothness and D was the weakest smoothness.

[0162] In addition, the stamping of the particles was carried out as follows: 8 g of particles were filled in a circular metal disc (diameter 5.5 cm), the stamping pressure was 500 kgf / cm 2 , and the stamping time was 10 seconds.

[0163] A+: The average value of the evaluation is 4.5 or more

[0164] A: The average value of the evaluation is 4 or more and less than 4.5

[0165] B: The average value of the evaluation is 3.5 or more and less than 4

[0166] C: The average value of the evaluation is 3 or more and less than 3.5

[0167] D: The average value of the evaluation is less than 3

[0168] (Sebum adsorption (oil absorption))

[0169] The oil absorption rate of linseed oil of the porous cellulose particles of each example after stamping was measured. Specifically as follows.

[0170] Mix 10 g of linseed oil with 1 g of the porous cellulose particles of each example after stamping, and perform centrifugation at a rotational speed of 10,000 rpm for 30 minutes. Measure the weight of the particles after removing the supernatant linseed oil, and calculate the oil absorption rate using the following formula.

[0171] Formula: Oil absorption rate = (Increase in weight after centrifugation ÷ Weight of particles before centrifugation) × 100

[0172] Then, evaluate the adsorption property based on the following criteria.

[0173] In addition, the stamping of the particles is carried out as follows: Fill 8 g of particles in a circular metal disk (diameter 5.5 cm), and the stamping pressure is 500 kgf / cm 2 , and the stamping time is 10 seconds.

[0174] A+: 250% ≤ Oil absorption rate

[0175] A: 220% ≤ Oil absorption rate < 250%

[0176] B: 190% ≤ Oil absorption rate < 220%

[0177] C: 160% ≤ Oil absorption rate < 190%

[0178] D: Oil absorption rate < 160%

[0179] [Table 1]

[0180]

[0181] From the above results, it can be seen that the cellulose particles of this example are excellent in mechanical strength compared with the cellulose particles of the comparative example, and also excellent in smoothness and sebum adsorption property after applying mechanical load.

[0182] Therefore, it can also be known that the cellulose particles of this example are excellent in mechanical strength compared with the cellulose particles of the comparative example, and also excellent in rolling property and oil absorption property after applying mechanical load.

[0183] (Supplementary Note) (((1)))

[0185] A kind of porous cellulose particle, which has cellulose, cellulose derivative or their mixture as the main component,

[0186] has 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. (((2)))

[0188] 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)))

[0190] 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)))

[0192] 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)))

[0194] The porous cellulose particles according to any one of ((1)) to ((4)), wherein the cellulose derivative is acylated cellulose with a degree of substitution of 0.6 or less. (((6)))

[0196] The porous cellulose particles according to ((5)), wherein the cellulose derivative is acylated cellulose with a degree of substitution of 0.2 or less. (((7)))

[0198] 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)))

[0200] A cosmetic containing the porous cellulose particles according to any one of ((1)) to ((7)).

[0201] According to ((1)), there is provided a porous cellulose particle which has cellulose, a cellulose derivative or a mixture thereof as a main component, has continuous pores leading from the particle surface to the particle interior, and has excellent mechanical strength compared with the case where the BET specific surface area is less than 1.7 m 2 / g or exceeds 24.0 m 2 / g, and also has excellent rollability and oil absorbency after applying a mechanical load.

[0202] According to ((2)), there is provided a porous cellulose particle which, compared with a BET specific surface area of less than 8.0 m 2 / g or exceeding 20.0 m 2Compared with the case of / g, it has excellent mechanical strength, and also excellent rollability and oil absorption after applying mechanical load.

[0203] According to (((3))), there is provided a porous cellulose particle which has excellent mechanical strength, and also excellent rollability and oil absorption after applying mechanical load, as compared with the case where the area ratio of continuous pores is less than 15% or more than 90%.

[0204] According to (((4))), there is provided a porous cellulose particle which has excellent mechanical strength, and also excellent rollability and oil absorption after applying mechanical load, as compared with the case where the area ratio of continuous pores is less than 25% or more than 85%.

[0205] According to (((5))), there is provided a porous cellulose particle which has excellent mechanical strength, and also excellent rollability and oil absorption after applying mechanical load, as compared with the case where the cellulose derivative is an acylated cellulose having a degree of substitution exceeding 0.6.

[0206] According to (((6))), there is provided a porous cellulose particle which has excellent mechanical strength, and also excellent rollability and oil absorption after applying mechanical load, as compared with the case where the cellulose derivative is an acylated cellulose having a degree of substitution exceeding 0.2.

[0207] According to (((7))), there is provided a porous cellulose particle which has excellent mechanical strength, and also excellent rollability and oil absorption after applying mechanical load, as compared with the case where the volume average particle diameter of the cellulose particle is less than 3 μm or more than 45 μm.

[0208] According to (((8))), there is provided a cosmetic which uses a porous cellulose particle. The porous cellulose particle has continuous pores leading from the particle surface to the particle interior and has cellulose, a cellulose derivative, or a mixture thereof as a main component. The cosmetic has excellent mechanical strength, and also excellent smoothness and sebum adsorbability after applying mechanical load, as compared with the following cases: in the porous cellulose particle used, the BET specific surface area is less than 1.7 m 2 / g or more than 24.0 m 2 / g.

Claims

1. A porous cellulose particle, characterized in that: With cellulose, cellulose derivatives or mixtures thereof as main components, It has continuous pores from the particle surface to the interior of the particle, and the BET specific surface area is 1.7 m 2 / g or more and 24.0m 2 / g or less.

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

3. The porous cellulose particles according to claim 1 or 2, wherein When a 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 claim 3, wherein When a cross-section of the porous cellulose particles is observed, 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 claims 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 claim 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 claims 1 to 6, wherein The porous cellulose particles have a volume average particle size of 3 μm or more and 45 μm or less.

8. A cosmetic, characterized in that: Contains the porous cellulose particles according to any one of claims 1 to 7.

Images