JP3347140B2 - Microcapsule containing dye, ultraviolet absorber, and antioxidant, and method for producing the microcapsule - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing microcapsules containing a pigment, an ultraviolet absorber, and an antioxidant.

(Problems to be Solved by Conventional Techniques and Inventions) In general, some dyes, especially organic dyes, blended in cosmetics have poor light resistance. In some cases, there is a problem of fading and lowering of safety of quality.

As means for solving this problem, for example,
As described in JP-A-43962 and JP-A-63-43963, there is a method in which the surface of a pigment is coated with particles such as fine particles of titanium oxide.

Further, as disclosed in Japanese Patent Application Laid-Open No. Sho 62-263112, there is a technique in which a pigment (pigment) is encapsulated in microcapsules having shellac as a wall material to improve light resistance. Since the pigment is merely encapsulated in the microcapsules, the light fastness required for cosmetics cannot be maintained.

Therefore, the incorporation of organic pigments having poor light resistance into cosmetics tends to be discouraged, and practically, cosmetics incorporating pigments having poor light resistance have hardly been developed.

The present invention has been made to solve such problems, and generally improves the light resistance of a dye having poor light resistance, particularly an organic dye, and mixes it with a cosmetic to provide light resistance (color tone stability). It is an object of the present invention to provide a cosmetic that is excellent in safety, adhesion, spreadability, and feeling of use.

(Means for Solving the Problems) The present inventors have conducted intensive studies to solve such problems, and as a result, the cause of fading of the organic dye having poor light resistance is the influence of ultraviolet irradiation and oxidation. It has been recognized that discoloration and fading are suppressed by adding a certain kind of ultraviolet absorber and antioxidant, and the present invention has been completed.

That is, the present invention solves the above problem by dissolving a dye that is soluble in an alkaline aqueous solution and has a property of being insoluble in a neutral or acidic aqueous solution and an organic solvent in an alkali metal silicate aqueous solution, An ultraviolet absorber and / or an antioxidant having the property of being soluble in an aqueous solution and being insoluble in a neutral or acidic aqueous solution and an organic solvent is added and dissolved, and the aqueous solution is mixed with the dye, the ultraviolet absorber and / or the antioxidant. A W / O emulsion is prepared by mixing an agent and an organic solvent having a solubility of 5% or less in water, and then mixing with the alkali metal silicate, pigment, ultraviolet absorber and / or antioxidant. An acidic aqueous solution capable of forming a water-insoluble precipitate by the summation reaction is mixed with the emulsion, and then, if necessary, filtered,
Washing and drying are to encapsulate the pigment, ultraviolet absorber and / or antioxidant in spherical fine particles containing silica as a main component and having an average particle diameter of 0.1 to 30 μm.

Incidentally, the ultraviolet absorber used in the preparation of microcapsules, in its structure, phenolic
It is preferable to use an ultraviolet absorber that has an OH group, is soluble in an alkaline aqueous solution, and is insoluble in a neutral or acidic aqueous solution and an organic solvent. For example, the general formula (In the formula, m Xs and n Ys represent the same or different alkyl groups, alkoxy groups, or sulfonic acid groups having 1 to 24 carbon atoms, or an alkali metal salt thereof, and m and n represent 0
Represents an integer of 1 to 3, and k + 1 represents an integer of 1 to 4).

 More specifically, the following derivatives are mentioned.

(A) 2,2'-dihydroxy-4-methoxybenzophenone (b) 2-hydroxy-4-methoxybenzophenone (c) 2-hydroxy-4-methoxybenzophenone-
5-Sulfonic acid (d) 2,2'-dihydroxy-4,4'-dimethoxybenzophenone (e) 2,2 ', 4,4'-tetrahydroxybenzophenone (f) 2,2'-dihydroxy-4,4 '-Dimethoxybenzophenone-5-sodium sulfonate (g) 2,4-dihydroxybenzophenone (h) 2-hydroxy-4-methoxybenzophenone-
Sodium 5-sulfonate Also, the following general formula (In the formula, m X and n Y each represent the same or different alkyl group having 1 to 18 carbon atoms, alkoxy group, carboxyl group, or halogen, and m and n each represent an integer of 0 to 3, k + 1 represents an integer of 1 to 4).

 More specifically, the following derivatives are mentioned.

(A) 4,4'-dihydroxydibenzoylmethane (b) 4-hydroxy-4'-methoxydibenzoylmethane (c) 2,4'-dihydroxydibenzoylmethane (d) 2,4-dihydroxy-4'- Methoxydibenzoylmethane (e) 2,4-dihydroxydibenzoylmethane (f) 4-hydroxydibenzoylmethane The antioxidant has a phenolic OH group in its structure, like an ultraviolet absorber, and is an alkaline aqueous solution. An antioxidant which is soluble in water and insoluble in neutral or acidic aqueous solutions and organic solvents is used.

For example, n-propyl gallate, isoamyl gallate, nordihydroguaiaretic acid, ethyl protocatechuate and the like can be mentioned.

Further, in the present invention, examples of the alkali metal silicate include JIS No. 1 sodium silicate, JIS No. 2 sodium silicate, JIS No. 3 sodium silicate, sodium metasilicate, and potassium silicate (K ₂ O · nSiO ₂ , n = 2 to 3.8)
Etc. are exemplified.

As the organic solvent, n-hexane, decane, octane, toluene, or the like having a solubility of 5% or less in a dye, an ultraviolet absorber, an antioxidant, and water is used.

Of course, each of these solvents can be used alone or in combination of two or more.

Furthermore, as the emulsifier, preferably, the HLB value is 3.5 to 6.
Nonionic surfactants in the range of 0 can be used.
Representative examples include sorbitan sesquioleate, sorbitan monooleate, polyoxyethylene sorbitan trioleate, and the like.

Further, the acidic aqueous solution preferably contains a polyvalent anion such as a sulfate ion or a phosphate ion.

Further, the types of the above-mentioned ultraviolet absorber, antioxidant, alkali metal silicate, organic solvent, emulsifier, acidic aqueous solution and the like are not limited to those described above.

(Action) FIG. 1 is an explanatory view showing the process of producing microparticles of the microcapsule of the present invention.

First, the dye is dissolved in an aqueous solution of an alkali metal silicate, and an ultraviolet absorber and / or an antioxidant are further added.
After dissolving and mixing the aqueous solution with the organic solvent, as shown in FIG. 1 (a), a mixed solution of the dye, the ultraviolet absorber and / or the antioxidant, and the alkali metal silicate aqueous solution is dispersed. 2, and a W / O emulsion having an organic solvent as a dispersion medium 1 is prepared. The dye 3 is dispersed in the dispersed phase 2, that is, in the droplet.

 Next, this emulsion is mixed with the above acidic aqueous solution.

At this time, the following chemical reaction occurs at the interface between the inner aqueous phase (an aqueous solution of an alkali metal silicate containing a dye, an ultraviolet absorber and / or an antioxidant) and the outer aqueous phase (an acidic aqueous solution).

(A) Si ₂ O ₅ ^2- + 2H ⁺ → 2SiO ₂ + H ₂ O (b) R−O ⁻ + H ⁺ → R-OH (where R represents a basic skeleton of an ultraviolet absorber or an antioxidant) In the reaction (b), R is, for example, 2,4-
In the case of dihydroxybenzophenone, it is as follows.

Further, in the case of 4,4'-dihydroxydibenzoylmethane, the result is as follows.

The chemical reaction at the interface in the present invention is as described in the above (a),
(B) is a coprecipitation reaction in which the two chemical reactions proceed simultaneously.

When the dye is soluble in an alkaline aqueous solution and insoluble in a neutral or acidic aqueous solution, precipitation of the dye occurs simultaneously with the above reaction.

In this interfacial precipitation reaction, the precipitation reaction of the inorganic wall material silica is predominant first, followed by the precipitation reaction of the ultraviolet absorber and the antioxidant.

Therefore, as shown in FIG. 2, the outermost shell becomes a layer rich in silica 4, and the inner side becomes a layer rich in ultraviolet absorber and / or antioxidant 5, as shown in FIG. In some parts, a layer rich in dye 3 is formed.

Therefore, the ultraviolet absorber, antioxidant and pigment are contained in the spherical fine particles mainly composed of silica,
In the case where contact dermatitis due to these is feared, it is also suppressed by this microencapsulation method.

(Example) Hereinafter, an example of the present invention will be described.

[Reference examples of microcapsules]

REFERENCE EXAMPLE 1 The microcapsules of Reference Example 1 were obtained by dispersing an Al lake of Red No. 213 (rhodamine B) of the following formula [A] in spherical fine particles containing silica as a main component, and 2,2 ′, 4, It is composed of 41.4% by weight of 4′-tetrahydroxybenzophenone and has an average particle size of 2.0 μm.

REFERENCE EXAMPLE 2 The microcapsules of Reference Example 2 were obtained by dispersing a red fine particle No. 213 Al lake of the above formula [A] and 2,2 ', 4,4'-tetra It is composed of hydroxybenzophenone each containing 11.4 wt% of n-propyl gallate of the following formula [C] of 0.3 wt%, and has an average particle size of 2.5 μm.

REFERENCE EXAMPLE 3 The microcapsules of Reference Example 3 were obtained by dissolving 8 wt% of Al lake of red No. 231 (phloxine BK) of the following formula [D] and red 202 No. BCA) 1 wt%, Formula F yellow yellow 205 (benzidine yellow-G) 1 wt%, 2,2 ′, 4,4′-tetrahydroxybenzophenone 5 wt% of the above formula [B], the following formula [G] 2,4
It comprises 5 wt% of dihydroxybenzophenone and 1 wt% of nordihydroguaiaretic acid of the following formula [H], and has an average particle diameter of 2.3 μm.

REFERENCE EXAMPLE 4 The microcapsules of Reference Example 4 were prepared by dispersing red No. 223 (tetrabromofluorescein) of the following formula [I] in spherical fine particles containing silica as a main component, and 2,2 ′, 4,4 of the above formula [B]. '-Tetrahydroxybenzophenone, each containing 11.1% by weight and 2.8% by weight of nordihydroguaiaretic acid of the above formula [H], and has an average particle diameter of 2.3 µm.

Reference Example 5 The microcapsules of Reference Example 5 were obtained by adding yellow No. 205 of the above formula (F) and 2,4-dihydroxybenzophenone of the above formula [G] to spherical fine particles containing silica as a main component, respectively.
3wt%, 1.98wt% isoamyl gallate of the following [J] formula
The average particle size is 2.0μ
m.

REFERENCE EXAMPLE 6 The microcapsules of Reference Example 6 are each composed of spherical fine particles containing silica as a main component, and the red lake No. 213 of the above formula (A) and Al, 2,2 ′, 4,4′-dihydroxybenzophenone in each of 11.
1 wt%, nordihydroguaiaretic acid of the formula [H] 2.8
wt%, and has an average particle size of 2.
6 μm.

Example 1 This example is an example of the method for producing the microcapsule of Reference Example 1 described above.

8 g of Al Red Lake No. 213 and 8 g of 2,2 ', 4,4'-tetrahydroxybenzophenone were dissolved in 300 m of a 1.5 M aqueous solution of sodium silicate No. 1, and the aqueous solution was dissolved in POE (20) sorbitan trioleate and sorbitan. The mixture is poured into 400 m of a 5% toluene solution of a mixture of sesquioleate (mixing ratio 1: 4), and emulsified with a homomixer for 3 minutes to prepare a W / O emulsion.

Next, the W / O emulsion was mixed with 1.2 M ammonium sulfate,
Pour into 1500 m of a mixed aqueous solution of 0.88 M sodium dihydrogen phosphate and 0.72 M phosphoric acid, stir for 1 hour, and leave overnight.

Then, after solid-liquid separation by centrifugation, filtration, washing with water, and drying using a vacuum pump. As a result, microcapsules having an average particle diameter of 2.0 μm and containing 11.4 wt% of each of Al Red Lake No. 213 and 2,2 ′, 4,4′-tetrahydroxybenzophenone in spherical fine particles containing silica as a main component were obtained. g was obtained.

Example 2 This example is an example of the method for producing the microcapsules of Reference Example 2 described above.

Red Lake No. 213 Al lake 8g, 2,2 ', 4,4'-tetrahydroxybenzophenone 8g, n-propyl gallate 1.88g,
Dissolve in 1.5m of 1.5M sodium silicate aqueous solution of 1.5M,
The aqueous solution is POE (20) sorbitan trioleate,
Pour the mixture of sorbitan sesquioleate (mixing ratio 1: 4) into a 5% n-hexane solution (400 m) and mix with a homomixer.
Emulsify for 1 minute to prepare a W / O emulsion.

Next, the W / O emulsion was mixed with 1.2 M ammonium sulfate,
Pour into 1500 m of a mixed aqueous solution of 0.88 M sodium dihydrogen phosphate and 0.72 M phosphoric acid, stir for 1 hour, and leave overnight.

Then, after solid-liquid separation by centrifugation, filtration, washing with water, and drying using a vacuum pump. In this way, the red fine No. 213 Al lake and 2,2 ′, 4,4′-tetrahydroxybenzophenone were respectively included in spherical fine particles mainly composed of silica at 11.4 wt%, and 0.3 wt% of n-propyl gallate was contained.
70.2g of microcapsules with an average particle size of 2.5μm
I got

Example 3 This example is an example of the method for producing the microcapsules of Reference Example 4 described above.

8 g of Red No. 223, 8 g of 2,2 ', 4,4'-tetrahydroxybenzophenone and 2.3 g of nordihydroguaiaretic acid were added to 1.5 M
5% of a mixture of POE (20) sorbitan trioleate and sorbitan sesquioleate (mixing ratio 1: 2.5)
The mixture is poured into an n-hexane solution (400 m) and emulsified with a homomixer for 2 minutes to prepare a W / O emulsion.

Next, the W / O emulsion was mixed with 1.2 M ammonium sulfate,
Pour into 1500 m of a mixed aqueous solution of 0.88 M sodium dihydrogen phosphate and 0.72 M phosphoric acid, stir for 1 hour, and leave overnight.

Thereafter, the same post-treatment as in Examples 1 and 2 described above was performed, whereby spherical red particles containing silica as a main component were added.
No. 3, 11.2 wt% of 2,2 ', 4,4'-tetrahydroxybenzophenone, 2.8 wt% of nordihydroguaiaretic acid
72.0 g of microcapsules with an average particle diameter of 2.3 μm
I got

Example 4 This example is an example of the method for producing the microcapsules of Reference Example 6 described above.

Red No. 213 Al lake 8 g, 2,2 ', 4,4'-tetrahydroxybenzophenone 8 g, nordihydroguaiaretic acid 2.8 g
Was dissolved in 300 m of an aqueous solution of sodium silicate No. 1 and the resulting solution was mixed with a mixture of POE (20) sorbitan trioleate and sorbitan sesquioleate (mixing ratio 1: 4).
The mixture is poured into a 400 m% n-hexane solution and emulsified with a homomixer for 3 minutes to prepare a W / O emulsion.

Next, the W / O type emulsion was mixed with 2.4 M ammonium sulfate,
Pour the mixture into 1500 m of a mixed aqueous solution of 1.76 M sodium dihydrogen phosphate and 1.44 M phosphoric acid, stir for 1 hour, and allow to stand overnight.

Thereafter, by performing the same post-treatment as in Examples 1 to 3, the spherical fine particles containing silica as a main component were converted into red particles.
No. 213 Al lake, 11.2 wt% of 2,2 ', 4,4'-tetrahydroxybenzophenone, and 72.0 g of microcapsules having an average particle diameter of 2.6 μm and containing 2.8 wt% of nordihydroguaiaretic acid were obtained. .

The particle diameter of the microcapsules of the present invention is not limited to the above examples, but the point is that the average particle diameter of the spherical fine particles constituting the outer wall of the microcapsules is 0.1 to 3
What is necessary is just to form it in 0 micrometers.

Comparative Example 1 1.1 g of Yellow No. 205 was wetted with 0.67 m of methanol,
A 30% aqueous carboxymethylcellulose (CMC Daicel 1110) solution (30 m) is added and stirred. To this, a 2.0 M aqueous sodium silicate No. 1 (30 m) is added and stirred overnight.

Next, the suspension was poured into 80 m of a 6% n-hexane solution of a mixture of POE (20) sorbitan trioleate and sorbitan sesquioleate (mixing ratio 1: 2.5), and emulsified with a homomixer for 30 seconds. Prepare a / O emulsion.

Next, the W / O emulsion was mixed with 1.2 M ammonium sulfate,
The mixture is poured into 300 m of a mixed aqueous solution of 0.88 M sodium dihydrogen phosphate and 0.72 M phosphoric acid, stirred for 1 hour, and left to stand overnight.

Thereafter, by performing the same post-treatment as in each of the above Examples, yellow 205
8.19 g of microcapsules having an average particle diameter of 1.8 μm containing No. 13.3 wt% were obtained.

Test Example In this test example, the light fastness of the microcapsules of each of the above Reference Examples and Comparative Example 1 was measured and compared.

Mercury lamp (light source 400W, distance 30c from light source)
m, temperature 45 ° C .; Mitsubishi color fading tester), and the fading (color difference) with time was measured, and the light resistance was evaluated from the color difference.

FIG. 3 shows a change in color tone when irradiating a mercury lamp in a dry state of an untreated red No. 213 Al lake and microcapsules manufactured by the manufacturing methods of Examples 1 and 2.

Compared with untreated dyes, microcapsules containing UV absorbers and antioxidants at the same time are more resistant to fading,
It was recognized that the light resistance was improved.

FIG. 4 shows Comparative Example 1 in which untreated yellow No. 205 and inorganic hollow spherical particles (abbreviated as MB in FIG. 4) were mixed at the same ratio as the encapsulation rate of the microcapsules, and obtained in Reference Example 5. 3 shows a change in color tone when a microcapsule is irradiated with a mercury lamp in a dry state.

It was confirmed that the microcapsules obtained in Reference Example 5 had better light fastness.

[Presentation example of cosmetics]

 Next, an example of a cosmetic formulation will be described.

The cosmetic containing the microcapsules produced by the production method of the present invention is obtained by blending the above-mentioned microcapsules with a known cosmetic base according to a conventional method, such as nail polish, lipstick, eye shadow and the like. It is applied to various cosmetics requiring light resistance.

Formulation Example 1 Formulation Example 1 is a formula example of a nail varnish as an example of a cosmetic containing the microcapsules of the present invention.

That is, the composition of the cosmetic of Formulation Example 1 is as follows.

Ingredients% by weight Microcapsules of Reference Example 1 0.15 Triethyl acetylcitrate 2.675 Acrylic resin solution 20.4 Purified camphor 3.00 Ethyl acetate 6.875 Butyl acetate 20.0 Toluene 15.0 Nitrocellulose (1/2) 13.8 Titanium acetate 2.1 Bentonite gel TGF 16.0 Makeup of Formulation Example 1 The mixture is prepared by uniformly dispersing the microcapsules produced by the production method of Example 1 in a plasticizer (triethyl acetylcitrate) and then preparing the mixture according to the above formulation.

Formulation Example 2 Formulation Example 2 is a formula example for manicure, similar to Formulation Example 1 described above.

 The composition of the cosmetic of Formulation Example 2 is as follows.

Ingredient Weight% Microcapsules of Reference Example 2 0.15 Triethyl acetylcitrate 2.675 Acrylic resin solution 20.4 Purified camphor 3.00 Ethyl acetate 6.875 Butyl acetate 20.0 Toluene 15.0 Nitrocellulose (1/2) 13.8 Titanium acetate 2.1 Bentonite gel TGF 16.0 Makeup of Formulation Example 2 The preparation was prepared by the same method as in Formulation Example 1 except that the microcapsules produced by the method of Example 2 were used.

The nail polish of the prescription example 1 and the prescription example 2 and the nail polish of the following prescription of the comparative example 2 were combined with a fluorescent lamp (70001u).
FIG. 5 shows the results of measuring the change in color tone (color difference) over time upon irradiation with x).

As a result, it was recognized that the light fastness of the nail polish was improved by blending microcapsules containing an ultraviolet absorber and an antioxidant together with a dye.

Comparative Example 2 The composition of the cosmetic of Comparative Example 2 is as follows.

Ingredients% by weight Untreated Red No. 213 Al lake 0.015 Triethyl acetylcitrate 2.485 Acrylic resin solution 20.4 Purified camphor 3.00 Ethyl acetate 6.875 Butyl acetate 20.325 Toluene 15.0 Nitrocellulose (1/2) 13.8 Titanium oxide 2.1 Bentonite gel TGF 16.0 Formulation example 3 Formulation Example 3 is a formula example of lipstick as an example of a cosmetic containing the microcapsules of the present invention.

 The composition of the cosmetic of Formulation Example 3 is as follows.

Ingredient% by weight Microcapsules of Reference Example 3 20.0 Candelilla wax 1.6 Carnauba wax 1.6 Ceresin 12.7 Resiner 5.6 Octyldodecanol 8.0 Diisostearyl malate 25.8 Tri-2-ethylhexanoic acid glycerin 19.1 Neopentyl glycol dioctanoate 5.6 Preservative, antioxidant In order to produce the cosmetic of Formulation Example 3, first, the above-mentioned microcapsules were added to a mixture of and uniformly dispersed with three rollers, and then heated and melted together with other components. Disperse evenly with a homomixer.

Then, it is manufactured by pouring into a mold, quenching, and sticking the material into a container, followed by framing.

The cosmetic of Formulation Example 3 adheres thinly and evenly to the lips, has good spreadability, and is excellent in use feeling and long-lasting makeup.

Formulation Example 4 Formulation Example 4 is a formulation example of blusher as an example of a cosmetic containing the microcapsules of the present invention.

 The composition of the cosmetic of Formulation Example 4 is as follows.

Ingredients% by weight Microcapsules of Reference Example 4 8.0 Talc Remaining amount of sericite 25.0 Kaolin 8.0 Titanium oxide 6.0 Magnesium stearate 4.0 Liquid paraffin 2.5 Octyldodecyl myristate 3.5 Preservative, antioxidant Trace amount Perfume Appropriate amount Cosmetic of Formulation Example 4 is manufactured If you do, mix the other ingredients uniformly while mixing well with a Henschel mixer, and process with a crusher,
It is manufactured by compression molding.

The cosmetic of Formulation Example 4 was excellent in adhesiveness and spreadability, and could be thinly and uniformly adhered to the skin.

In addition, a soft feeling of use was obtained, and the durability of the makeup was good.

Formulation Example 5 Formulation Example 5 is a formulation example of an eye shadow as an example of a cosmetic containing the microcapsules of the present invention.

The composition of the cosmetic of Formulation Example 5 is as follows. Ingredients% by weight Microcapsules of Reference Example 2 11.0 Microcapsules of Reference Example 5 4.0 Talc Remaining sericite 20.0 Mica 10.0 Titanium mica 5.0 Titanium oxide 3.0 Black iron oxide 0.1 Bengala 1.0 Magnesium stearate 1.0 Octyldodecyl myristate 1.5 Liquid paraffin 5.5 Preservative Agent, antioxidant trace amount fragrance appropriate amount When manufacturing cosmetics of prescription example 5, the above-mentioned ~ is mixed well with a Henschel mixer, the mixture of other components is added uniformly, and the mixture is treated with a pulverizer.
It is manufactured by compression molding.

The cosmetic of Formulation Example 5 adheres thinly and uniformly to the eyelids, has spreadability, and has an excellent feeling in use. Also, the persistence of makeup was good.

(Effects of the Invention) (a) As described above, the present invention encapsulates a pigment having poor light resistance in a microcapsule together with an ultraviolet absorber and / or an antioxidant. Is absorbed by the dye, so that the dye itself is not affected by ultraviolet rays, and the presence of the antioxidant prevents the dye from being oxidized, thereby preventing discoloration and fading of the dye.

As a result, there was obtained an effect that the light resistance of a dye, which had a problem with light resistance in the past, particularly an organic dye, can be significantly improved.

(B) Further, by being encapsulated in the microcapsules, the ultraviolet absorber and the antioxidant do not come into direct contact with the skin, and therefore, their safety is maintained.

(C) Further, since the microcapsules are spherical powders, the extensibility of the cosmetic containing the microcapsules becomes extremely good.

(D) According to the above (a) to (c), there is a merit that a cosmetic excellent in safety, spreadability, usability, and adhesion can be provided in addition to light resistance.

(E) Further, in the production method of the present invention, the dye is dissolved in an aqueous solution of an alkali metal silicate together with an ultraviolet absorber and an antioxidant, and the aqueous solution is mixed with an organic solvent to prepare a W / O-type milk. A method for producing microcapsules by mixing the emulsion with an aqueous acidic solution capable of forming a water-insoluble precipitate with the alkali metal silicate, the dye, and the like. The microcapsules can be produced by being encapsulated in spherical fine particles containing silica as a main component together with an absorbent and an antioxidant.

In particular, the following coprecipitation reaction at the interface: (a) Si ₂ O ₅ ^2- + 2H ⁺ → 2SiO ₂ + H ₂ O (b) R−O ⁻ + H ⁺ → R-OH (where R is an ultraviolet absorber, antioxidant Shows the skeleton of the agent).

In the above, the reaction of (a) proceeds faster than the reaction of (b), so that the dye is reliably encapsulated in the spherical fine particles together with the ultraviolet absorber and / or the antioxidant, and therefore, the production of microcapsules can be reliably performed. This has the effect.

[Brief description of the drawings]

FIG. 1 and FIG. 2 are explanatory views showing the process of producing microcapsules, and FIG. 1 (a) is an explanatory view at the time of preparing an emulsion,
(B) is an enlarged explanatory view of (A), and FIG. 2 is an enlarged explanatory view when a wall material is formed. 3 to 5 show graphs of measurement results of light fastness.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B01J 13/02 A61K 7/00, 7/021

Claims (1)

(57) [Claims] A dye which is soluble in an alkaline aqueous solution and has a property of being insoluble in a neutral or acidic aqueous solution and an organic solvent is dissolved in an aqueous solution of an alkali metal silicate, and is soluble in an alkaline aqueous solution and neutral. Alternatively, an ultraviolet absorber and / or an antioxidant having a property insoluble in an acidic aqueous solution and an organic solvent is added and dissolved, and the solubility of the aqueous solution with the dye, the ultraviolet absorber and / or the antioxidant, and water is 5%. The following organic solvents are mixed to form a W / O emulsion, and then a water-insoluble precipitate is formed by a neutralization reaction with the alkali metal silicate, pigment, ultraviolet absorber and / or antioxidant. A possible acidic aqueous solution is mixed with the above-mentioned emulsion, and then, if necessary, filtered, washed with water, and dried to make the pigment, the ultraviolet absorber and / or the antioxidant an average containing silica as a main component. Particle size Dyes, characterized in that the manufactured brought enclosed in spherical microparticles of 0.1 to 30 [mu] m, UV absorbers, a manufacturing method of microcapsules containing an antioxidant.