WO2010024332A1

WO2010024332A1 - Method for producing aqueous nail enamel dispersion

Info

Publication number: WO2010024332A1
Application number: PCT/JP2009/064963
Authority: WO
Inventors: 昭生佐藤; 大泉　哲朗
Original assignee: 東洋インキ製造株式会社
Priority date: 2008-08-29
Filing date: 2009-08-27
Publication date: 2010-03-04
Also published as: JP2010077122A

Abstract

Provided is an aqueous nail beauty product which has less physical effect on the nail and is more nail-friendly than an organic solvent-based nail beauty product, and achieves gloss, color development and water resistance. A method for producing an aqueous nail enamel dispersion, comprising a step (1) of forming solid chips by kneading a pigment, a water-soluble resin, and water or a volatile solvent using two rolls; and a step (2) of dispersing the solid chips in an aqueous medium, wherein the blending ratio of the pigment to the water-soluble resin in the step (1) is 60/40 (weight of pigment/weight of water-soluble resin) or more.

Description

Method for producing dispersion for aqueous nail enamel

The present invention relates to a water-based nail polish that is excellent in pigment dispersion stability, gloss, and color development, and that does not deteriorate coating properties such as water resistance.

General nail materials are roughly classified into organic solvent and water based on their purpose and characteristics. Organic solvent-based nail polish is made by adding a film forming agent such as nitrocellulose and resin such as alkyd resin, sulfonamide resin, sucrose resin, acrylic resin, and other additives such as plasticizer and coloring material to toluene. , Dissolved in an organic solvent such as ethyl acetate or butyl acetate. Such a nail polish is excellent in various physical properties as a coating film, and is useful in the ease of blending, usability and quick drying. On the other hand, since organic solvents are used, there is a problem of adverse effects on the human body. For example, the nails and skin may become rough, and as a result, the gloss of the nails may be lost, yellowing, and troubles such as two nails may occur. There are also problems such as inhalation of organic solvents. Furthermore, since an organic solvent is used, there are flammability problems, and there are many problems to be improved.

On the other hand, water-based nail polish has less physical influence on the nail than organic solvent-based nail polish and has nail-friendly properties.

As an alternative to solvent-based beauty nails, water-based beauty nails that use aqueous polymer emulsions have been proposed. However, a water-soluble resin having a high acid value is used as the resin used for the water-based nail polish. Therefore, in general, mechanical properties such as gloss and hardness are inferior. Further, when the resin is used in a larger amount than the pigment, the hot water resistance is lowered. That is, it was inadequate quality compared with the organic solvent beauty nail.

For example, Japanese Patent Publication Nos. 55-43445 and 61-1043 disclose that a pigment is added to an aqueous polymer emulsion together with a surfactant and dispersed with a disper. However, the pigment is not sufficiently dispersed, and good color development and gloss cannot be obtained. On the other hand, as an aqueous beauty nail having excellent color development and gloss and good pigment dispersion stability, JP-A-4-103516 discloses an average particle size of 0 obtained by wet-pulverizing a pigment together with an aqueous polymer emulsion. It is disclosed to contain a pigment of 5 μm or less. Japanese Patent Application Laid-Open No. 2002-114641 discloses a water-based beauty nail material excellent in pigment dispersion stability, gloss and color development by wet pulverization using a water-soluble polymer dispersant having a specific chemical structure instead of an aqueous polymer emulsion. Has been. WO 2005/032500 discloses an example of using a resin-type dispersant that does not impair mechanical properties (gloss, hardness) and light removal properties.

However, the resin-type dispersant is considerably more expensive than the water-soluble resin, and further, the resin-type dispersant is insufficient in quality as compared with the solvent type.

Japanese Patent Publication No.55-43445 Japanese Examined Patent Publication No. 61-1043 Japanese Patent Laid-Open No. 4-103516 JP 2002-114611 A WO2005 / 032500

An object of the present invention is to provide a water-based beauty nail material that achieves both gloss, color development and water resistance.

That is, the present invention includes a step (1) of kneading a pigment, a water-soluble resin, and water or a volatile solvent with two rolls to form a solid chip, and a step (2) of dispersing the solid chip in an aqueous medium. A method for producing a dispersion for an aqueous nail enamel, wherein the blending ratio of pigment to water-soluble resin (pigment weight / water-soluble resin weight) is 60/40 or more in the step (1) About.

The present invention also relates to a method for producing the above dispersion for aqueous nail enamel, comprising dispersing in an aqueous medium using an alkali compound in step (2).

The present invention also relates to a method for producing a dispersion for an aqueous nail enamel, comprising the step (3) of further dispersing the dispersion obtained in the step (2) with a media-type disperser.

The present invention also relates to a method for producing a dispersion for aqueous nail enamel, wherein the average particle size of the pigment of the dispersion for aqueous nail enamel including step (3) is 500 nm or less.

Further, the present invention is a method for producing a dispersion for an aqueous nail enamel, wherein the blending ratio (weight ratio) of the pigment and the water-soluble resin is 80/20 or less.

The disclosure of this specification relates to the subject matter included in Japanese Patent Application No. 2008-220611 (filed on Aug. 29, 2008), and is incorporated herein in its entirety by reference to this application specification. Shall.

As can be seen from the above, according to the present invention, it is possible to obtain a water-based beauty nail material which is excellent in pigment dispersion stability, gloss and color development and which does not deteriorate the film properties such as water resistance.

The method for producing a dispersion for an aqueous nail enamel according to the present invention comprises a step (1) of kneading a pigment, a water-soluble resin, and water or a volatile solvent with two rolls to form a solid chip, Including the step (2) of dispersing in an aqueous medium, and in the step (1), the blending ratio of pigment to water-soluble resin (weight of pigment / weight of water-soluble resin) is 60/40 or more.

Examples of water-soluble resins used in the present invention are roughly classified into natural polymer resins and synthetic polymer resins.

Specific examples of the natural polymer resin include proteins such as glue, gelatin, casein, and albumin, natural gums such as gum arabic, tragacanth, and xanthan gum, glucosides such as saponin, alginic acid and propylene glycol alginate, and triethanol alginate. Examples thereof include alginic acid derivatives such as amine and ammonium alginate, and cellulose derivatives such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, and ethylhydroxycellulose.

Examples of synthetic polymer resins include acrylic copolymers, styrene-acrylic acid copolymers, styrene-maleic acid copolymers, alkyd-based, epoxy-based, polyester-based, urethane-based, cellulose-based, and polyvinylpyrrolidone. Acrylic resins such as acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer, vinyl acetate-acrylic ester copolymer, acrylic acid-acrylic ester copolymer, styrene-methacrylic acid Styrene-acrylic such as copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer Copolymer resin, styrene-maleic anhydride copolymer, etc. Styrene-maleic acid copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene copolymer such as vinyl naphthalene-maleic acid copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl ethylene copolymer Examples thereof include vinyl acetate-based copolymers such as polymers, vinyl acetate-maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers, vinyl acetate-acrylic acid copolymers, and salts thereof. Among these, a copolymer of a monomer having a hydrophobic group and a monomer having a hydrophilic group, or a polymer comprising a monomer having both a hydrophobic group and a hydrophilic group in the molecular structure is preferable. In the case of a copolymer of a monomer having a hydrophobic group and a monomer having a hydrophilic group, or a polymer comprising a monomer having both a hydrophobic group and a hydrophilic group in the molecular structure, the hydrophobic group has a styrene group. More preferred.

As the water-soluble resin used in the present invention, those having a weight average molecular weight of 100,000 or less can be preferably used from the viewpoint of solubility and dispersibility. More preferably 1000 to 50000, and particularly preferably 1500 to 30000 can be used. When the water-soluble resin is hardly soluble in water, the water-solubility can be enhanced by neutralizing with a neutralizing agent such as ammonium, amine, inorganic alkali or the like. Furthermore, when the aqueous solution of the water-soluble resin is acidic, it is desirable to neutralize using a neutralizing agent. In consideration of dispersibility and water resistance, the blending ratio (weight ratio) of the pigment and the resin in the present invention is preferably 60/40 or more, preferably 80/20 or less, more preferably 65/35 to 75/25. .

The above water-soluble resins may be used alone or in combination of two or more. These copolymers and polymers can be obtained by known solution polymerization.

As the pigment, those conventionally blended in cosmetics can also be used in the present invention. Specifically, red 201, red 202, red 204, red 205, red 220, red 226, red 228, red 405, orange 203, orange 204, yellow 205, yellow Organic pigments such as No. 401 and Blue No. 404; Red No. 3, Red No. 104, Red No. 106, Red No. 227, Red No. 230, Red No. 401, Orange No. 205, Yellow No. 4, Yellow No. 5, Yellow No. 202 And known organic pigments such as Zirconium, Barium, Aluminum Lake, etc. Besides these organic pigments, titanium oxide, zinc oxide, iron oxide, iron titanate, γ-iron oxide, yellow iron oxide, ocher, black iron oxide, carbon black, manganese violet, cobalt violet, chromium oxide, hydroxide Inorganic pigments such as chromium, cobalt titanate, ultramarine, bitumen, mica titanium, bismuth oxychloride and the like can also be used. Resin powders such as acrylic resins and nylon resins can also be used.

In consideration of water resistance and dispersion stability, the water-soluble resin and pigment in the aqueous nail enamel dispersion are 0.5 to 40 in terms of solid content (that is, in the coating film obtained by curing the dispersion). %, More preferably 5% to 25%, the pigment content is 0.5 to 50%, more preferably 10% to 30%, and the remainder may be water. However,% is weight%.

The water or volatile solvent used in step (1) in the present invention is used as a binder that promotes dispersion of the pigment when kneading the two rolls. It is not desirable for this water or volatile solvent to remain until the final nail polish. As the volatile solvent, a solvent that volatilizes 100% by heat when kneading the two rolls is desirable. The boiling point of the volatile solvent is preferably about 80 to 200 ° C. As the volatile solvent, specifically, alcohols that have been conventionally blended in cosmetics are preferable, and ethanol, glycerin, propylene glycol, hexyl decanol, stearyl alcohol, hexylene glycol, behenyl alcohol, benzyl alcohol, government-specified non-modified alcohol , Government-designated denatured alcohol.

The aqueous medium in step (2) in the present invention includes water and alcohol. Further, in order to facilitate dissolution of the water-soluble resin, the solid chip may be dispersed in an aqueous medium using an alkali compound. Examples of alkali compounds used include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, various organic amine compounds such as 2-aminoethanol, 2-dimethylaminoethanol, 2-diethylaminoethanol, ammonia, sodium hydroxide Inorganic basic substances represented by the above, and various other quaternary ammonium compounds can be used. Preferably, ammonia which has little influence on the human body and has high volatility is desirable.

The amount of alkali compound added varies depending on the amount of water-soluble resin used and the acid value, but it is not desirable to add an excessive amount to cause odor. A preferable addition amount is 0.5 to 2%.

In the present invention, in the step (1), the pigment, the water-soluble resin, and water or a volatile solvent are kneaded with two rolls to obtain a solid chip. Specifically, a pigment, a resin, a solvent, or water are kneaded to prepare a single sheet, which is kneaded, that is, dispersed many times between two rolls, and then the solvent or water is heated by heat. Evaporate to a solid chip. According to the two rolls, since the dispersibility is improved with a small amount of water-soluble resin, the water resistance when the nail enamel is made is excellent.

Next, in the step (2), the obtained solid chip is dispersed in an aqueous medium. A dispersing machine may be used for dispersing, and a media type dispersing machine is preferable.

Media type dispersers include ball mills, attritors, roll mills, colloid mills, high speed disk impellers, high speed collision mills, high speed stone mills, pebble mills, sand mills and batch grinders, coball mills, basket mills, flow-type wet bead mills, ultrasonic homogenizers, etc. It can carry out using the well-known apparatus. Moreover, you may use combining them. The average particle diameter of the pigment is preferably dispersed until it becomes 500 nm or less from the viewpoint of stability and color developability. Furthermore, it is preferably 400 nm or less.

In the water-based nail polish of the present invention, components commonly used as water-based beauty nail ingredients other than the above-described components, such as oils, moisturizers, ultraviolet absorbers, chelating agents, as long as the effects of the present invention are not impaired. , PH adjusters, antifoaming agents, leveling agents, thickeners, dyes, fragrances, preservatives, resin powders such as acrylic resins and nylon resins, and the like can be appropriately blended. Among these, as thickeners, water-swellable clay minerals such as organic thickeners such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyethylene oxide, methylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, and inorganic bentonite Hydrous oxides such as boehmite, silicates such as aluminum magnesium silicate, silicic anhydride and the like can be preferably used.

Hereinafter, the present invention will be described based on examples. In the examples, “parts” and “%” respectively represent “parts by weight” and “% by weight”.

<Example 1>
[Step (1)]
The following mixture was treated 10 times with two rolls to evaporate propylene glycol to obtain solid chips.

60.0 parts of pigment (red No. 202),
Water-soluble resin A 40.0 parts,
Propylene glycol 10.0 parts Water-soluble resin A is a styrene acrylic resin having a Tg of 70 ° C. and an acid value of 195 mgKOH / g, and a weight average molecular weight of 12,000.

[Step (2)]
The obtained chip was dispersed with the following composition for 60 minutes with a high speed mixer.

Solid chips 40.0 parts Commercially purified water 47.1 parts Ammonia water (28%) 2.88 parts The above mill base is circulated and dispersed with a bead mill disperser (Dynomill KDL type), media: Hibee D16 at a filling rate of 80%, and pigment Dispersion A was obtained.

[Dispersity evaluation]
The degree of dispersion of the obtained pigment dispersion A was evaluated. The dispersion was diluted to an equipment standard concentration, and the particle size distribution D ₅₀ (μm) was measured with an ultrafine particle size distribution analyzer (manufactured by Nikkiso, UPA-EX150).

[Create test piece]
The obtained pigment dispersion A was mixed with an acrylic emulsion so that the pigment content in the coating solution was 2.0% as shown in the composition below, to obtain coating solution B.

[Method of creating coating liquid B]
Pigment dispersion A 7.50 parts Acrylic emulsion (“TOCRYL W-263” manufactured by Nippon Polymer Kogyo Co., Ltd., 32 to 38% acrylic resin content, including remaining water) 85.70 parts Commercial purified water 6.80 parts The coating liquid B was developed on a glass plate with an applicator (10 mils), allowed to stand still at room temperature for 30 minutes, and then heated and dried at 40 ° C. for 30 minutes to obtain a coating film.

[Gloss evaluation]
The gloss of the coating film was evaluated. The gloss was evaluated by measuring with a gloss meter (Gloss Meter VG2000, manufactured by Nippon Denshoku Co., Ltd.) at an angle between the measurement surface and incident of 60 ° and an angle between the measurement surface and incident light of 20 °. In Table 1, they are shown as “gloss 60 ° gloss” and “gloss 20 ° gloss”.

[Transparency evaluation]
The transparency of the coating film was evaluated. The evaluation of transparency was made visually based on the following evaluation criteria. The coloring of nail enamel has the meaning that the pigment particles become finer and closer to the primary particles, and as a result, the coloring power is improved and the color becomes stronger, and the meaning becomes transparent. Here, color development was evaluated by evaluating transparency.

○: It was transparent.

X: It was opaque.

[Water resistance evaluation]
The lower half of the obtained coated glass plate was immersed in 40 ° C. warm water and held for 1 hour. Thereafter, the “gloss difference” of the immersed part and the non-immersed part was measured.

“Gloss difference” represents the percentage reduction in gloss before and after the water resistance test for a gloss of 60 ° gloss. For example, the gloss difference of Comparative Example 1 was set to (72.3-13.2) /72.3=0.817 because the gloss 60 ° gloss before the test was 72.3 (from Table 1) and after the test was 13.2 (not shown in the table).

Also, a visual “judgment” was performed. The evaluation criteria are as follows.

◎: No damage was observed on the coating film.

○: Almost no damage was observed on the coating film.

△: Some damage to the coating film was observed, but there was no practical problem.

X: Significant damage was observed on the coating film.

As shown in Table 1, the dispersion particle size, coating film gloss, and transparency of the present invention were superior to those of the comparative examples.

<Example 2>
[Step (1)]
The following mixture was processed 10 times with two rolls to obtain solid chips.

Pigment (Red No. 202) 65.0 parts
Water-soluble resin A 35.0 parts
Propylene glycol 10.0 parts [Step (2)]
The obtained chip was dispersed with the following composition for 60 minutes with a high speed mixer.

Solid chip 40.0 parts Commercial purified water 47.1 parts Ammonia water (28%) 2.67 parts The above mill base was circulated and dispersed with a bead mill disperser (Dynomill KDL type) and media: Hibee D16 at a filling rate of 80%. The degree of dispersion was evaluated by measuring the particle size distribution.

Test piece creation, coating film evaluation, and water resistance evaluation were performed in the same manner as in Example 1. <Example 3>
[Step (1)]
The following mixture was processed 10 times with two rolls to obtain solid chips.

Pigment (Red No. 202) 70.0 parts Water-soluble resin A 30.0 parts
Propylene glycol 10.0 parts [Step (2)]
The obtained chip was dispersed with the following composition for 60 minutes with a high speed mixer.

Solid chip 40.0 parts Commercial purified water 47.1 parts Ammonia water (28%) 2.16 parts The above mill base was circulated and dispersed with a bead mill disperser (Dynomill KDL type) and media: Hibee D16 at a filling rate of 80%. The degree of dispersion was evaluated by measuring the particle size distribution.

Test piece preparation, coating film evaluation, and water resistance evaluation were performed in the same manner as in Example 1. As shown in Table 1, the dispersion particle size, coating film gloss, and transparency are superior to those of the comparative example in terms of dispersion particle size, coating film gloss, and transparency. It was. In addition, the water resistance of Example 2 and Example 3 was better than Example 1.

<Comparative Example 1>
The step (1) of Example 1 was not performed, and the mill base of the step (2) was directly prepared with the same composition and was circulated and dispersed with a bead mill disperser. Otherwise, it was the same as Example 1.

<Comparative example 2>
The step (1) of Example 2 was not performed, and the mill base of the step (2) was directly prepared with the same composition and circulated and dispersed with a bead mill disperser. Otherwise, it was the same as Example 2.

<Comparative Example 3>
[Step (1)]
The following mixture was treated 10 times with two rolls to evaporate propylene glycol to obtain solid chips.

Pigment (Red No. 202) 55.0 parts Water-soluble resin A 45.0 parts
Propylene glycol 10.0 parts Water-soluble resin A is a styrene acrylic resin having a Tg of 70 ° C. and an acid value of 195 mgKOH / g, and a weight average molecular weight of 12,000.

Solid chips 40.0 parts Commercial purified water 47.1 parts Ammonia water (28%) 2.88 parts The above mill base is circulated and dispersed with a bead mill disperser (Dynomill KDL type), media: Hibee D16 at a filling rate of 80%, and pigment Dispersion A was obtained. The degree of dispersion was evaluated by measuring the particle size distribution.

Test piece creation, coating film evaluation, and water resistance evaluation were performed in the same manner as in Example 1.

Even when the two-roll treatment was performed, the water resistance was inferior at 55/45 in which the ratio of the resin to the pigment / resin was greater than 60/40 (weight ratio).

<Example 4>
A dispersion and a coating film were prepared in the same manner as in Example 2 except that the pigment was red 226. As shown in Table 1, the dispersion particle size of the dispersion, the gloss, transparency, and water resistance of the coating were superior to the corresponding comparative examples.

<Comparative example 4>
A dispersion and a coating film were prepared in the same manner as in Comparative Example 2 except that the pigment was red 226. As shown in Table 1, the dispersion particle size of the dispersion, the gloss, transparency and water resistance of the coating film were inferior to the corresponding examples.

<Example 5>
A dispersion and a coating film were prepared in the same manner as in Example 2 except that the pigment was Yellow No. 5. As shown in Table 1, the dispersion particle size of the dispersion, the gloss, transparency, and water resistance of the coating were superior to the corresponding comparative examples.

<Comparative Example 5>
A dispersion and a coating film were prepared in the same manner as in Comparative Example 2 except that the pigment was Yellow No. 5. As shown in Table 1, the dispersion particle size of the dispersion, the gloss, transparency and water resistance of the coating film were inferior to the corresponding examples.

<Example 6>
A dispersion and a coating film were prepared in the same manner as in Example 2, except that the pigment was Blue No. 1. As shown in Table 1, the dispersion particle size of the dispersion, the gloss, transparency, and water resistance of the coating were superior to the corresponding comparative examples.

<Comparative Example 6>
A dispersion and a coating film were prepared in the same manner as in Comparative Example 2 except that the pigment was Blue No. 1. As shown in Table 1, the dispersion particle size of the dispersion, the gloss, transparency and water resistance of the coating film were inferior to the corresponding examples.

<Example 7>
The same dispersion as in Example 2 except that Blue No. 1 was used and water-soluble resin B (Tg 60 ° C., styrene acrylic resin having an acid value of 195 mg KOH / g and having a weight average molecular weight of 5000) was used as the water-soluble resin. And made a coating film. As shown in Table 1, the dispersion particle size of the dispersion, the gloss, transparency, and water resistance of the coating were superior to the corresponding comparative examples.

<Example 8>
The same dispersion as in Example 2 except that Blue No. 1 was used and water-soluble resin C (Tg 70 ° C., styrene acrylic resin having an acid value of 195 mg KOH / g and having a weight average molecular weight of 25000) was used as the water-soluble resin. And made a coating film. As shown in Table 1, the dispersion particle size of the dispersion, the gloss, transparency, and water resistance of the coating were superior to the corresponding comparative examples.

<Example 9>
Blue pigment No. 1, water-soluble resin C as water-soluble resin (Tg 70 ° C., styrene acrylic resin having an acid value of 195 mg KOH / g and having a weight average molecular weight of 25,000), dispersion composition ratio Pigment / resin = 80/20 Were the same as in Example 2 to prepare a dispersion and a coating film. As shown in Table 1, the dispersion particle size of the dispersion, the gloss, transparency, and water resistance of the coating were superior to the corresponding comparative examples.

Water-soluble resins A of Comparative Examples 1 to 6 and Examples 1 to 6: Weight average molecular weight is 12000 (acid value 195, Tg 70 ° C.)
Water-soluble resin B of Example 7: weight average molecular weight 5000 (acid value 195, Tg 60 ° C.)
Water-soluble resin C of Examples 8 and 9: Weight average molecular weight 25000 (acid value 195, Tg 80 ° C.)
As can be seen from Table 1, the aqueous nail enamel dispersions according to the present invention of Examples 1 to 9 have the performances of dispersed particle size, gloss (60 ° gloss, 20 ° gloss), coating transparency, and coating water resistance. Good evaluation was obtained. On the other hand, the coating film from the dispersion obtained without going through the solid chip forming process with two rolls was evaluated to such a degree that gloss and transparency were not at a practical level (Comparative Examples 1 to 6).

Further, as can be seen from the comparison of Examples 1, 2, and 3, even if the resin amount is reduced in the blending ratio of pigment to water-soluble resin (pigment weight / water-soluble resin weight), water resistance, dispersibility, It turns out that it is excellent in gloss.

In other words, even if the resin is reduced to improve water resistance, the dispersion and gloss of the two-roll treatment is much better than the two-roll untreated, and a slight reduction in gloss due to the resin reduction is also practical. It was a level with no problem.

According to the present invention, the pigment dispersion stability of the aqueous pigment dispersion, the gloss, color development, and transparency of the coating film were excellent, and the coating film properties such as water resistance could be improved. The aqueous pigment dispersion of the present invention can be suitably used for an aqueous beauty nail material that requires gloss, transparency, and water resistance of a coating film.

Claims

A step of kneading a pigment, a water-soluble resin, and water or a volatile solvent with two rolls to form a solid chip (1), and a step (2) of dispersing the solid chip in an aqueous medium,
The method for producing a dispersion for aqueous nail enamel, wherein in the step (1), the blending ratio of pigment to water-soluble resin (weight of pigment / weight of water-soluble resin) is 60/40 or more.
The method for producing a dispersion for an aqueous nail enamel according to claim 1, comprising dispersing in an aqueous medium using an alkali compound in step (2).
The method for producing a dispersion for an aqueous nail enamel according to claim 1 or 2, further comprising a step (3) of further dispersing the dispersion obtained in the step (2) with a media-type disperser.
The method for producing a dispersion for an aqueous nail enamel according to any one of claims 1 to 3, wherein the pigment of the dispersion for an aqueous nail enamel including step (3) has an average particle diameter of 500 nm or less.
The method for producing a dispersion for an aqueous nail enamel according to claims 1 to 4, wherein the blending ratio (weight ratio) of the pigment and the water-soluble resin is 80/20 or less.