JPH06254373A - Spherical fine porous cellulose particles and production thereof - Google Patents

Abstract

PURPOSE:To obtain spherical fine porous cellulose particles uniform in particle diameter and excellent in lubricity, touch, etc., by using spherical fine porous cellulose particles each having a shell layer and a porous core having specified porosity. CONSTITUTION:Fatty acid ester of cellulose such as cellulose acetate is dissolved in a solvent such as chlorinated hydrocarbon, the resulting soln. is emulsified or dispersed in an aq. medium and part of the ester is saponified to form shell layers of emulsified or dispersed particles. The solvent is then distilled out and the remaining ester is perfectly saponified to obtain the objective spherical fine porous cellulose particles each having a shell layer and a porous core having 5-50% porosity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to spherical porous cellulose fine particles useful as a chromatographic carrier and for compounding cosmetics, and a method for producing the same.

[0002]

2. Description of the Related Art Fine powders for cosmetics have good safety, low irritation to the skin, slipperiness, touch, spread, adhesion, covering properties, absorbability of sweat, etc., dispersibility and mixing properties. It is necessary to be.

Fine powders conventionally used for cosmetics are roughly classified into inorganic type and organic type. Inorganic type is talc, zinc white, mica, titanium oxide, kaolin, etc., and most of them are amorphous or needle-shaped, so they are irritating to the skin, and have adhesiveness, covering property, moldability, dispersion. In terms of sex, etc., sufficient performance was not obtained. On the other hand, organic type particles such as nylon, polyethylene, PMMA, and polystyrene are used, and they have a spherical particle shape and have improved slipperiness on skin and touch, but have problems in safety and hygroscopicity. It is inferior.

In order to solve such a problem, it has been proposed to use fine particles made of cellulose or a cellulose derivative. Cellulose has higher safety to the human body than other inorganic or organic particles. In addition to cosmetics, cellulose particles are used for a wide range of purposes such as a carrier for gel chromatography or ion exchange chromatography. When used for such applications, it is necessary that the particles have a certain shape and have a narrow particle size distribution. Especially when used as an additive for cosmetics, the average particle size is 3 to 50 μm and the maximum is 10.
Homogeneous and small particles having a size of 0 μm or less are preferable.

There are various conventional methods for obtaining cellulose fine particles. For example, as a method for obtaining viscose, viscose is dropped into a coagulation and regeneration bath of sulfuric acid and sodium sulfate, coagulated and regenerated, and regenerated granular cellulose (particle size 88 to 1
The viscose method for obtaining 168 .mu.m) is disclosed in JP-A-48-607
53, JP-A-62-265328 and JP-B-56.
-21761.

Japanese Patent Application Laid-Open No. 49-89748 discloses a pulverization method in which fibrous cellulose is hydrolyzed with an acid or an alkali and then dried and pulverized to obtain a cellulose powder. Cellulose triacetate is dissolved in methylene chloride and dropped into water in which a dispersant such as polyvinyl alcohol is dissolved while stirring, and after the droplets are dispersed, the solvent is distilled off by heating to obtain spherical particles of cellulose triacetate. An ester saponification method for obtaining cellulose particles (particle size: 30 to 500 μm) by forming and saponifying this is disclosed in JP-B-55-39565.

Further, there is a spray drying method for obtaining fine spherical particles by spray drying a solution prepared by dissolving a cellulose fatty acid ester in a mixed solvent in which three or more kinds of solvents having different boiling points by 30 ° C. or more are combined. No. 28763, or chips obtained by cutting filaments of cellulose ester are melted by heating in a melting medium such as silicone oil at 250 to 350 ° C. to form cellulose ester spherical particles, and further saponified to obtain spherical cellulose powder. The method is disclosed in JP-A-53-7759.

[0008]

[Problems of the prior art] None of the methods is suitable for obtaining porous cellulose fine particles, and when trying to obtain porous fine particles, the particles agglomerate, the shape becomes non-uniform, and the particle size varies. However, large aggregated particles are easily formed. Further, since the obtained particles are colored, fine particles having satisfactory performance could not be obtained. Therefore, the obtained cellulose fine particles were unsuitable as an additive to cosmetics.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. That is, an object of the present invention is to provide spherical cellulose fine particles having a uniform particle size and excellent in slipperiness, touch and water absorption, and a method for producing the same.

[0010]

That is, the present invention relates to spherical porous cellulose fine particles having an outer shell layer and a porous inner core, and the inner core having a porosity of 5 to 50%.

The spherical porous cellulose fine particles of the present invention are
Its inner core is porous. Therefore, for example, when added as a component of cosmetics, various other additives,
For example, an antioxidant, an ultraviolet absorber, a dye, a fragrance or the like, or a cosmetic oily component such as liquid paraffin, squalane, castor oil, olive oil or jojoba oil can be included. In addition, the sustained release effect of the encapsulated components improves the sustainability of the effects of each component. Further, it is also good in absorbing water such as sweat. On the other hand, since the outer shell has a smooth spherical shape, it has good slipperiness, low irritation to the skin, and good tactile sensation. Further, it has a good absorbency of water such as sweat.

The porosity of the inner core of the spherical cellulose fine particles of the present invention is 5 to 50%. More preferably 10-30%
Is. When the porosity is 5% or less, the effects of the present invention such as inclusion of the active ingredient cannot be obtained. Also, the porosity is 5
If it exceeds 0%, the shape cannot be kept spherical, and it becomes a bowl shape, which is not preferable.

When the spherical cellulose fine particles of the present invention are used as an additive for cosmetics, the average particle diameter is 50 μm or less, preferably 5 to 20 μm, and the maximum particle diameter is 1
It is necessary to suppress the thickness to 00 μm or less, preferably 80 μm or less. When the average particle size is 50 μm or more,
This is not preferable because the dispersibility and mixability of the cosmetic composition deteriorates.

The spherical porous cellulose fine particles of the present invention are
1) Cellulose fatty acid ester is dissolved in a solvent, 2) Solution is emulsified or dispersed in an aqueous medium, 3) Part of the ester is saponified to form an outer shell layer of emulsified dispersed particles, 4) Solvent content is It is produced by a production method including a step of distilling off, and 5) completely saponifying the remaining ester.

The cellulose fatty acid ester used in the present invention includes cellulose acetate, cellulose propionate,
Cellulose butyrate and the like can be mentioned, but cellulose acetate is preferable. In particular, a polymer of cellulose diacetate having a relatively low degree of polymerization of 140 to 180 is preferable.

As the solvent for dissolving the cellulose fatty acid ester, it is preferable to use a solvent which dissolves the cellulose fatty acid ester and has a boiling point of 100 ° C. or less, preferably 50 to 80 ° C. Particularly, it is preferable to use a chlorinated hydrocarbon or a mixed solvent of a chlorinated hydrocarbon and a lower alcohol. Examples of the chlorinated hydrocarbon used in the present invention include methylene chloride, chloroform, ethane dichloride, ethane trichloride and the like. Further, examples of the lower alcohol include methanol, ethanol, isopropyl alcohol and the like. A particularly suitable solvent is methylene chloride-ethano-
And the mixture ratio of both is 95: 5 to 80:20.

The cellulose fatty acid ester has a concentration of the cellulose ester in the solvent of 1 to 25% by weight, preferably 1
Dissolve to be 5 to 20% by weight. The viscosity of this solution is 30 to 10,000 cps, preferably 1000 to 80
It is 00 cps.

It is preferable to add a surfactant, particularly a nonionic surfactant, to the solvent for dissolving the cellulose ester. By adding a nonionic surfactant, a fine emulsion can be obtained when this solution is further emulsified and dispersed in an aqueous medium. As the nonionic surfactant suitable for the present invention, those having an alkyl group having 12 to 22 carbon atoms and a polyoxyethylene chain composed of 1 to 9 ethylene oxide groups are preferable, and specifically, a polyoxyethylene alkyl ether. , An ether type surfactant such as polyoxyethylene alkylphenyl ether, an ether ester type surfactant such as polyoxyethylene glycerin fatty acid ester, or an ester type surfactant such as polyethylene glycol fatty acid ester. Particularly preferred is an alkyl group having 12 carbon atoms.
To 18 and the polyoxyethylene alkyl ether has 1 to 9 and particularly preferably 5 to 9 ethylene oxide groups in the polyoxyethylene chain. Suitable HLB
Is 8-18, especially 10-15. The nonionic surfactant is added in an amount of 1 to 20% by weight, preferably 8 to 16% by weight, based on the cellulose fatty acid ester.

Next, the obtained solution of cellulose fatty acid ester is emulsified and dispersed in an aqueous medium. This aqueous medium preferably contains 0.1 to 10% by weight of a dispersant.

Amphoteric surfactants are particularly preferred as the dispersant. Other than amphoteric, that is, it is possible to emulsify and disperse even using an anion, a cation or a nonionic surfactant, but a pH change occurs during the subsequent partial saponification with alkali, and the state of emulsification changes, The particles are likely to aggregate. The amphoteric surfactant maintains the emulsion stability due to the pH buffering action and can obtain uniform fine particles. The amphoteric surfactant preferably used in the present invention includes carboxybetaines

[0021]

[Chemical 1]

[Wherein R ₁ : C _{12 to} C ₁₈ , R ₂ , R ₃ : C
H ₃ , n: 1 to 2] or an aminocarboxylic acid salt

[0023]

[Chemical 2]

[In the formula, R: C _{12 to} C ₂₂ and n: 1 to 2 are shown]. Particularly preferred are carboxybetaines. The amphoteric surfactant is added in an amount of 1 to 5% by weight of water in the aqueous medium.

If desired, a thickener and an antifoaming agent are added to the aqueous medium in which the cellulose fatty acid ester solution is dispersed. As the thickener, polyvinyl alcohol, gelatin, polyvinyl alcohol and the like are preferably used.
The defoaming agent is not particularly limited, and those generally used may be used. The amount of these additives added may be appropriately selected depending on the particle size of the target fine particles.

When the above-mentioned cellulose ester solution is emulsified and dispersed in an aqueous medium, the volume ratio of the cellulose ester solution and the aqueous medium is 1: 9 to 1: 1, and particularly 1: 9 to 3:
It is preferably 7. When the ratio of the aqueous medium is low, the emulsion becomes w / o type, which is not preferable. Further, when the ratio of the aqueous medium exceeds 1: 9, it becomes difficult to reduce the particle size, and the particles easily aggregate.

The emulsion dispersion is carried out by adding the cellulose fatty acid ester solution little by little to an aqueous medium kept at room temperature with stirring with a homomixer. The obtained emulsified dispersed particles are high in stability due to the action of the amphoteric surfactant even if alkali is added in the saponification to be performed later. Therefore, the size of the spherical porous cellulose fine particles of the present invention is the emulsified dispersed particles obtained here. It depends on the size of. For example, when obtaining fine particles having an average particle diameter of 50 μm or less and a maximum particle diameter of 100 μm or less, the particle diameter of the emulsified dispersed fine particles is preferably about 10 μm because it swells in the saponification step that follows. It may be appropriately selected depending on the desired particle size. The particle size can be adjusted mechanically by changing the rotation speed of the homomixer or by adjusting the HLB of the nonionic surfactant. By the method of the present invention, it is possible to produce spherical porous fine particles having a uniform and minute particle size. Further, according to the method of the present invention, it is possible to relatively easily obtain spherical fine particles having an average particle diameter of 50 μm or less and a maximum particle diameter of 100 μm or less, which has been difficult so far.

Subsequently, the obtained emulsified dispersed particles are primarily saponified with an alkali. It is preferable to use either sodium hydroxide or potassium hydroxide as the alkali. Usually, a 1N sodium hydroxide aqueous solution is used. If the alkali concentration is too high, the particles agglomerate, which is not preferable. Since an amphoteric surfactant is used as a dispersant in the present invention, stable particles can be obtained without any effect even when an alkali is added. Saponification is room temperature ~
200 rpm with a stirrer at a temperature of 40 ° C for 2-3 hours
It may be performed while gently stirring. Alkali is completely consumed by saponification. 5 of ester here
The outer shell of the cellulose fine particles is formed by saponifying 50%, more preferably 10 to 20%. If the saponification is less than 5% of the total amount of the ester, no shell is formed on the ester fine particles, which is not preferable. Since the outer shell layer insoluble in the solvent is formed by the primary saponification, even in the subsequent steps of distilling off the solvent and secondary saponification, the particles do not aggregate, and uniform fine particles can be obtained.

After the completion of the primary saponification, the solvent is heated from the emulsified dispersion to completely distill it off. The distillation is performed at a temperature of 40 ° C to 80 ° C for about 5 to 6 hours.

Next, after distilling off the solvent, an equivalent amount of alkali is further added to the aqueous dispersion of cellulose fatty acid ester to completely saponify the residual ester. For secondary saponification, 3-5 of sodium hydroxide or potassium hydroxide
An aqueous solution of N is used. Similar to the primary saponification, the saponification is performed at room temperature to 40 ° C. for 3 hours or more with gentle stirring.

In the secondary saponification, a part of the cellulose ester inside the particles oozes out into the cellulose outer shell layer previously formed. By saponifying in this state, fine particles having a smooth outer shell layer and a porous inner core of the present invention can be obtained. The porosity of the spherical porous fine particles of the present invention is 5 to
It is 50%, preferably 10 to 30%. The porosity can be controlled by changing the saponification rate during the primary saponification.

In order to promote saponification inside the particles, a phase transfer catalyst may be added to the solvent in which the cellulose fatty acid ester is dissolved. Addition of the phase transfer catalyst has the effect of promoting the saponification rate. Examples of the phase transfer catalyst include tetrabutylammonium bromide, tetraethylammonium bromide, tetrabutylammonium chloride, tetraethylammonium chloride and the like. About 5 per 1 kg of cellulose fatty acid ester
˜100 g, preferably 10-30 g of phase transfer catalyst may be added.

After the completion of the secondary saponification, the obtained particles are filtered, and the thickener, dispersant and the like are removed by a conventional method, and methanol,
The spherical porous cellulose fine particles of the present invention are obtained by washing with an alcohol solvent such as ethanol, dehydration and drying.

Has a uniform particle size according to the method of the present invention,
Spherical porous cellulose fine particles having a smooth spherical outer shell layer and a porous inner core can be obtained.

[0035]

Example 1 Production of Spherical Porous Cellulose Fine Particles An oil phase and an aqueous phase were prepared with the following compositions.

[0036]

The above oil phase and water phase were mixed with T. K. High speed stirring was performed for 20 minutes using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to disperse the oil phase in the aqueous phase. 1N of N was added to this dispersion.
2000 parts by weight of aOH was added, and part of the ester was saponified at room temperature for 2 hours with stirring at 200 rpm to form a cellulose outer shell layer. The temperature was raised to 60 ° C. while continuing stirring, and methylene chloride was removed by evaporation. After the removal, 2500 parts by weight of 5N NaOH was added and stirred at room temperature for 5 hours to completely saponify the remaining ester. After the saponification was completed, the mixture was neutralized with acetic acid.

By the above processing, the cellulose fine particles 71
5 g was obtained, and further, various steps such as filtration, MeOH washing, water washing, drying, and sieving were performed to obtain spherical porous cellulose fine particles as a final product. The particle size distribution, oil absorption, and water absorption of the obtained fine particles are as shown in Table 1.

[0039]

[Table 1]

EXAMPLE 2 Manufacture of Foundation The following ingredients

After the above components 1 to 7 were mixed with a Henschel mixer, the mixture 8 to 11, which had been heated and mixed in advance, was added to uniformly mix the oil. This was crushed, further sieved, and then punched into an inner plate to obtain a powdery type dual-use solid foundation of the example.

Comparative Example Instead of the spherical porous cellulose fine particles of Example 1, Table 2
A powdery-type dual-use solid foundation was obtained in the same manner as in Example 2 except that the spherical acrylic beads having the characteristics shown in 1 above were used.

[0043]

[Table 2]

Evaluation The foundations obtained in Example 2 and Comparative Example were evaluated for removal, stickiness, elongation, adhesion to skin, refreshing feeling and creamy feeling. The evaluation was performed in the following four stages. ⊚: Very good ∘: Slightly good Δ: Slightly bad ×: Very bad Results are shown in Table 3.

[0045]

[Table 3]

In the foundation of Comparative Example, good results were obtained with respect to peeling and spread, but insufficient results were obtained with respect to stickiness and adhesion to the skin, and incomplete results were obtained with respect to refreshing feeling and creamy feeling. It was On the other hand, the foundation containing the spherical porous cellulose fine particles of the present invention of Example 2 provided good results in all respects as compared with the comparative example.

[Procedure amendment]

[Submission date] August 24, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

The spherical porous cellulose fine particles of the present invention are: 1) Cellulose fatty acid ester dissolved in a solvent, 2) Emulsifying or dispersing the solution in an aqueous medium, 3) Part of the ester is saponified and emulsified dispersed particles To form a shell layer, and 4) distill off the solvent component, and 5) completely saponify the remaining ester.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

If desired, a thickener and an antifoaming agent are added to the aqueous medium in which the cellulose fatty acid ester solution is dispersed. Polyvinyl alcohol and gelatin are preferably used as the thickener. The defoaming agent is not particularly limited, and those generally used may be used. The amount of these additives added may be appropriately selected depending on the particle size of the target fine particles.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

The emulsion dispersion is carried out by adding the cellulose fatty acid ester solution little by little to an aqueous medium kept at room temperature with stirring with a homomixer. The obtained emulsified dispersed particles are high in stability due to the action of the amphoteric surfactant even if alkali is added in the saponification to be performed later. Therefore, the size of the spherical porous cellulose fine particles of the present invention is the emulsified dispersed particles obtained here. It depends on the size of. For example, when obtaining fine particles having an average particle diameter of 50 μm or less and a maximum particle diameter of 100 μm or less, the particle diameter of the emulsified dispersed fine particles is preferably about 10 μm because it swells in the saponification step that follows. It may be appropriately selected depending on the desired particle size. The particle size can be adjusted mechanically by changing the rotation speed of the homomixer or by adjusting the HLB of the nonionic surfactant. By the method of the present invention, it is possible to produce spherical porous fine particles having a uniform and minute particle size. Further, according to the method of the present invention, it is possible to relatively easily obtain spherical fine particles having an average particle diameter of 50 μm or less and a maximum particle diameter of 100 μm or less, which has been difficult so far.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

The above oil phase and water phase were mixed with T. K. High speed stirring was performed for 20 minutes using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to disperse the oil phase in the aqueous phase. 1N of N was added to this dispersion.
2000 parts by weight of aOH was added, and part of the ester was saponified for 2 hours at room temperature with stirring at 200 rpm to form a cellulose outer shell layer. The temperature was raised to 60 ° C. while continuing stirring, and methylene chloride was removed by evaporation. After the removal, 2500 parts by weight of 5N NaOH was added and stirred at room temperature for 5 hours to completely saponify the remaining ester. After the saponification was completed, the mixture was neutralized with acetic acid.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location B01J 13/12 C08J 3/14 CEP 9268-4F G01N 30/48 T 8310-2J // C08L 1: 00

Claims (5)

[Claims] 1. Spherical porous cellulose fine particles having an outer shell layer and a porous inner core, wherein the inner core has a porosity of 5 to 50%. 2. The average particle size is 50 μm or less and the maximum particle size is 1.
The spherical porous cellulose fine particles according to claim 1, which have a diameter of not more than 00 μm. 3. A cellulose fatty acid ester is dissolved in a solvent, 2) a solution is emulsified or dispersed in an aqueous medium, and 3) a part of the ester is saponified to form an outer shell layer of emulsified dispersed particles. The method for producing spherical porous cellulose fine particles according to claim 1, further comprising the steps of 4) distilling off a solvent component, and 5) completely saponifying the remaining ester. 4. The method according to claim 3, wherein the cellulose fatty acid ester is dissolved in a solvent containing a nonionic surfactant. 5. The method according to claim 3, wherein the cellulose fatty acid ester solution is emulsified or dispersed in an aqueous medium containing an amphoteric surfactant.