Method for manufacturing processed powders for cosmetics

Abstract

This invention provides a manufacturing method that can efficiently provide cosmetic powders utilizing the properties of silk fibroin. [Solution] A method for producing a processed powder for cosmetics, comprising mixing a powder for cosmetics with a processing aqueous dispersion containing silk fibroin nanofibers, drying the resulting mixture, wherein the silk fibroin nanofibers are such that the viscosity of a reference aqueous dispersion containing 5% by mass of the nanofibers is 8,000 to 18,000 mPa·s when measured at 30°C using a BM II type viscometer with an M4 rotor at a rotation speed of 12 rpm.

Description

Technical Field

[0001] The present invention relates to a method for producing a treated powder for cosmetics, the obtained treated powder for cosmetics, and a powder cosmetic containing the same.

Background Art

[0002] Fibroin, which is the main component of silk cocoons, has been studied for application in various fields including cosmetics, focusing on its biocompatibility and the like.

[0003] For example, a manufacturing method has been reported in which a pigment is mixed and dispersed in a fibroin solution obtained by dissolving a refined silk raw material in an aqueous solution of copper-ethylenediamine or the like, and then a coagulating salt is added and mixed to cause fibroin to coagulate and precipitate, thereby coating the particle surface of the pigment with regenerated fibroin (Patent Document 1).

[0004] In recent years, it has also been reported that a fibroin nanofiber film obtained by mechanical fibrillation exhibits superior physical properties compared to a regenerated fibroin film without undergoing a process of dissolving and regenerating fibroin (Non-Patent Document 1).

[0005] As a specific method of mechanical fibrillation, it has been reported that fibroin can be defibrated and pulverized to a nanofiber width level by pulverizing fibroin using a pair of opposing disks (Patent Document 2).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0007]

Non-Patent Document 1

[0008] Given the technological situation described above, there is a need for a manufacturing method that can efficiently provide cosmetic powders utilizing the properties of fibroin. [Means for solving the problem]

[0009] The inventors of the present invention have discovered that cosmetic powders with excellent properties such as adhesion to the skin can be efficiently produced by treating cosmetic powders with an aqueous dispersion containing silk fibroin nanofibers (also simply referred to as "silk nanofibers" in this invention) having predetermined physical properties, and have completed the present invention.

[0010] The present invention is understood through the following configuration. [1] This involves mixing cosmetic powder with an aqueous dispersion for processing containing silk nanofibers, drying the resulting mixture, and grinding it. Silk nanofibers are such that a reference aqueous dispersion containing 5% by mass of these nanofibers has a viscosity of 8,000 to 18,000 mPa·s when measured with a BM II type viscometer using an M4 rotor at a rotation speed of 12 rpm and 30°C. A method for manufacturing processed powders for cosmetic use.

[0011] [2] The manufacturing method according to [1], wherein the processing aqueous dispersion contains 0.5 to 5% by mass of silk nanofibers.

[0012] [3] The manufacturing method according to [1] or [2], wherein the processing water dispersion is a non-Newtonian fluid.

[0013] [4] The manufacturing method according to any one of [1] to [3], wherein the aqueous dispersion for processing contains 90% by mass or more of water as a dispersion medium.

[0014] [5] A method for manufacturing according to any one of [1] to [4], wherein the cosmetic powder is an extender pigment selected from talc, sericite, synthetic fluorophlogopite, or mica, or a pearl agent selected from titanium mica, glass, titanium dioxide, or colored pearl, or a combination thereof.

[0015] [6] The manufacturing method according to any one of [1] to [5], wherein the ratio of the mass of silk nanofibers to the total mass of silk nanofibers and cosmetic powder [silk nanofibers / (silk nanofibers + cosmetic powder)] is 0.001 to 0.004.

[0016] A processed powder for cosmetics obtained by the manufacturing method described in any one of [7][1] to [6].

[0017] A powder cosmetic comprising the processed powder for cosmetics described in [8] and [7]. [Effects of the Invention]

[0018] According to the manufacturing method of the present invention, silk nanofibers can be compounded into cosmetic powder through a simple preparation process, and a cosmetic processed powder exhibiting excellent performance in terms of skin adhesion, stability on the skin, and usability can be efficiently provided. [Brief explanation of the drawing]

[0019] [Figure 1] This is a photograph, in lieu of a drawing, showing the treated powder of Example 1, obtained according to the manufacturing method of the present invention, as observed under an optical microscope. Silk nanofibers are intertwined and compounded around the powder (talc). [Figure 2]This is a photograph replacing a drawing that shows the state of the processed powder of Comparative Example 1 obtained according to the manufacturing method of the comparison target, observed with an optical microscope. The powder (talc) and silk powder are not compounded.

Mode for Carrying Out the Invention

[0020] Hereinafter, the present invention will be described in detail.

[0021] The manufacturing method of the present invention is a method for manufacturing a processed powder for cosmetics, which at least includes a step of mixing a cosmetic powder into a processing aqueous dispersion containing silk nanofibers, and a step of drying and pulverizing the obtained mixture.

[0022] The content of silk nanofibers in the processing aqueous dispersion is set from the viewpoint of efficiently attaching a sufficient amount of silk nanofibers to the surface of the cosmetic powder and easily ensuring a state (uniformity of adhesion) with less bias in adhesion. As such a content, it is preferably 0.5 to 5% by mass, more preferably 1 to 4% by mass.

[0023] The processing aqueous dispersion containing silk nanofibers typically exhibits physical properties as a non-Newtonian fluid, and more typically corresponds to a pseudoplastic fluid that becomes easier to flow as the flow becomes stronger.

[0024] The dispersion medium of the processing aqueous dispersion containing silk nanofibers is prepared such that at least most of it is water. Specifically, the water content based on the total amount of the dispersion medium is preferably 90% by mass or more, more preferably 95% by mass or more, still more preferably 98% by mass or more, and even more preferably consisting essentially of only water. As a dispersion medium other than water, for example, ethanol may be used.

[0025] The powders to be processed are not particularly limited as long as they are powders that can be used for cosmetic purposes. Examples of preferred powders include: extender pigments selected from talc, sericite, synthetic fluorophlogopite, or mica; pearlescent agents selected from titanium mica, glass, titanium dioxide, or colored pearl; or combinations thereof.

[0026] The mass ratio of silk nanofibers supplied as a processing aqueous dispersion to the cosmetic powder to be processed is set from the viewpoint of fully exhibiting the effects of the present invention. The ratio of the mass of silk nanofibers to the total mass of silk nanofibers and cosmetic powder [silk nanofibers / (silk nanofibers + cosmetic powder)] is typically 0.0005 to 0.0045, preferably 0.001 to 0.004, more preferably 0.0015 to 0.0035, and even more preferably 0.002 to 0.003.

[0027] In carrying out the manufacturing method of the present invention, no special equipment is required to mix the processing water dispersion and the cosmetic powder; a general-purpose mixing device can be used. The operating conditions of the mixing device are set to be necessary and sufficient for uniformly mixing the silk nanofiber and the cosmetic powder.

[0028] A Henschel mixer can preferably be used as the mixing device. Because a Henschel mixer allows for high-speed mixing, mixing can be completed in a relatively short time. For example, when processing cosmetic powder with silk nanofibers, depending on the amount of powder to be processed, it is preferable to repeat the mixing process several times, for example, 2 to 4 times, for about 2 to 4 minutes each time.

[0029] The mixture obtained in the mixing step is then dried to volatilize the dispersion medium of the processing water dispersion. During this drying process, the silk nanofibers are expected to adhere stably to the cosmetic powder. The drying conditions are set to efficiently volatilize the dispersion medium while avoiding excessive heating of the cosmetic powder. Specifically, it is preferable to dry the mixture at a temperature of approximately 60°C to 90°C for approximately 3 to 10 hours.

[0030] Next, the dried material can be pulverized to obtain the desired cosmetic-grade processed powder. No special equipment is required for pulverization; a general-purpose pulverizer can be used. The degree of pulverization is set according to the specifications required for the cosmetic-grade processed powder. Generally, it is considered sufficient to pulverize until a particle size and distribution similar to that of the raw cosmetic powder can be reproduced. An atomizer can preferably be used as the pulverizer. The pulverization time is set according to the desired degree of pulverization.

[0031] The silk nanofibers used in this invention are selected such that the viscosity of a reference aqueous dispersion containing 5% by mass of the silk nanofibers falls within a predetermined range. Viscosity is measured using a BM II viscometer with an M4 rotor at a rotation speed of 12 rpm and 30°C. The viscosity range is 8,000 to 18,000 mPa·s, preferably 10,000 to 16,000 mPa·s, and more preferably 12,000 to 14,000 mPa·s.

[0032] The cosmetic-grade processed powder obtained by the manufacturing method of the present invention can be suitably used as a raw material for cosmetics due to its excellent performance. Powder cosmetics containing the cosmetic-grade processed powder are typically makeup cosmetics, and specific examples include loose powder, pressed powder, powder foundation, blush, and eyeshadow. [Examples]

[0033] The following are specific examples of embodiments of the present invention.

[0034] In the following tests, JA-46R (manufactured by Asada Flour Milling Co., Ltd.) was used as talc, Silk Nanofiber N-Fibron NL (manufactured by Nagasuna Mayu Co., Ltd.) as silk nanofiber, and Silk Powder (manufactured by Shizen Cosmetics Research Institute Co., Ltd.) as silk powder.

[0035] (Example 1) A dispersion (silk nanofiber concentration 2.5%) was prepared by dispersing 2.5 g of silk nanofiber in 97.5 g of purified water. 997.5 g of talc and 100 g of the above dispersion were placed in a Henschel mixer and mixed at high speed (3600 rpm) for 2 minutes three times to obtain a homogeneous wet mixture. This was dried at 80°C for 6 hours, and the dried material was pulverized in an atomizer to obtain powder 1A.

[0036] (Comparative Example 1) 997.5g of talc and 2.5g of silk powder were placed in a Henschel mixer and mixed at high speed for 2 minutes three times to obtain a homogeneous dry mixture. This was then pulverized in an atomizer to obtain powder 1R.

[0037] The obtained powders were observed using an optical microscope. Figure 1 shows a micrograph of powder 1A, and Figure 2 shows a micrograph of powder 1B. In powder 1A, a mixture of talc and silk nanofibers, the silk nanofibers are intertwined and compounded around the talc (Figure 1), whereas in powder 1R, a mixture of talc and silk powder, such compounding does not occur (in Figure 2, the silk powder is shown as rod-shaped). Note that in Figure 2, a region with a relatively sparse amount of talc was photographed to clearly show the separation of talc and silk powder.

[0038] Next, five trained panelists evaluated the performance of powder 1A, powder 1R, and reference powder (talc only) as cosmetic powders based on the following criteria. For each criterion, the average score among the panelists was calculated and rounded to the nearest integer to obtain the evaluation result. The results are shown in Table 1.

[0039] (Adhesion) The following criteria were used to score how well the cosmetic powder adhered to the skin. 5. It applies very well to the skin. 4. It applies well to the skin. 3. It adheres to the skin to a moderate degree. 2. It doesn't adhere to the skin very well. 1. Does not adhere well to the skin.

[0040] (stability) The resistance to removal from the skin after applying the cosmetic powder was scored according to the following criteria. 5. It is very resistant to coming off the skin, and the makeup lasts a very long time. 4. It is very resistant to coming off the skin and provides good makeup longevity. 3. It is slightly resistant to coming off the skin, and the makeup has moderate staying power. 2. It tends to rub off the skin somewhat easily, and the makeup doesn't last very long. 1. It easily comes off the skin and the makeup doesn't last long.

[0041] (Dry feeling) The dryness of the skin when wearing cosmetic powder was scored according to the following criteria. 5. No feeling of dryness 4. Less dryness 3. The dryness is moderate. 2. Slightly dry feeling. 1. Very dry feeling

[0042] (Feel (powdery)) We scored the products based on the following criteria to determine whether or not there was any powder scattering when applying the cosmetic powder. 5. No powder fallout, very pleasant to use. 4. Less powder fallout, good usability. 3. There is some powder fallout, and the user experience is moderate. 2. There is a bit too much powder fallout, making the user experience somewhat poor. 1. There is a lot of powder scattering, making it unpleasant to use.

[0043] (Feel of use (thick application)) The following criteria were used to score the cosmetic powders based on their transparency on the skin. 5. It has excellent transparency and a very pleasant feel to use. 4. It has a very clear appearance and feels good to use. 3. It has a slight transparency and a moderate feel. 2. It lacks transparency and has a somewhat poor feel. 1. It lacks transparency and has a poor feel when used.

[0044] [Table 1] The powder of Example 1 showed significantly improved adhesion to the skin compared to the powder of Comparative Example 1 and the reference powder, and also yielded excellent results in terms of stability and usability (powderyness).

[0045] (Examples 2-6) Similar to Example 1, a dispersion with a silk nanofiber concentration of 2.5% was prepared. 997.5g of glass pearls (Ronastar® Noble Sparks (Merck)) and different amounts of the above dispersion were placed in a Henschel mixer and mixed at low speed (1800 rpm) for 2 minutes three times to obtain a homogeneous wet mixture. The amounts of dispersion used were 20g (Example 2), 60g (Example 3), 100g (Example 4), 140g (Example 5), and 180g (Example 6). Each wet mixture was dried at 80°C for 6 hours, and the dried material was pulverized in an atomizer to obtain powders 2A to 6A. For convenience, the untreated glass pearls were referred to as powder 4N.

[0046] Adhesion, stability, feel (powdery), and feel (thick application) were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0047] [Table 2] The evaluation results showed that increasing the amount of silk nanofibers added tended to improve adhesion to the skin, while decreasing the amount of silk nanofibers added tended to improve the user experience (thickness of application). This suggests the need to set the amount of additive while considering the balance between these two factors.

[0048] (Example 7) Similar to Example 1, a dispersion with a silk nanofiber concentration of 2.5% was prepared. 997.5g of pearl agent 1 (Timiron® Snowflack MP-99 (Merck)) and 100g of the above dispersion were placed in a Henschel mixer and mixed at low speed for 2 minutes three times to obtain a homogeneous wet mixture. This was dried at 80°C for 6 hours, and the dried material was pulverized in an atomizer to obtain powder 7A. For convenience, the untreated pearl agent 1 is referred to as powder 7N. Powder 7A was used together with powder 4A in the following Production Example 1, and powder 7N was used together with powder 4N in the following Comparative Production Example 1.

[0049] (Manufacturing example 1, comparative manufacturing example 1) Loose powder was obtained by adding the raw materials, which were in the composition ratios shown in Table 3, to a Henschel mixer and stirring for 5 minutes. The raw materials other than powders 4A, 4N, 7A, and 7N were those listed in the margin.

[0050] [Table 3] Synthetic fluorphlogopite: PDM-10S (manufactured by Topy Industries Co., Ltd.) Nylon-12: Nylon Powder Orgasol® 2002 (manufactured by Arkema) Carnauba powder: Carnauba powder N (refined) (manufactured by Ceralica NODA Co., Ltd.) Sterilizing agent: Isopropylmethylphenol Talc: Talc JA-46R (manufactured by Asada Flour Milling Co., Ltd.) Pearl agent 2: Flamenco® Superpearl (manufactured by BASF) Coloring agent 1: TAROX Synthetic Iron Oxide R-516HP (manufactured by Titanium Industry Co., Ltd.) Coloring agent 2: TAROX Synthetic Iron Oxide LL-100HP (manufactured by Titanium Industry Co., Ltd.) Coloring agent 3: TAROX Synthetic Iron Oxide BL-100HP (manufactured by Titanium Industry Co., Ltd.)

[0051] The obtained loose powder was evaluated in the same manner as in Example 1, etc. The results are shown in Table 4.

[0052] [Table 4] The evaluation results showed that loose powder containing silk nanofiber-treated powder performed better than loose powder with the same composition except that the powder was not treated with silk nanofibers in terms of adhesion, stability, dryness, and usability (powderyness).

Claims

1. The process involves mixing cosmetic powder with an aqueous dispersion containing silk nanofibers, drying the resulting mixture, and grinding it. Silk nanofibers are defined as having a viscosity of 8,000 to 18,000 mPa·s when measured using a BM II viscometer with an M4 rotor at a rotation speed of 12 rpm and 30°C, when a reference aqueous dispersion containing 5% by mass of these nanofibers is used. A method for manufacturing processed powders for cosmetic use.

2. The manufacturing method according to claim 1, wherein the processing aqueous dispersion contains 0.5 to 5% by mass of silk nanofibers.

3. The manufacturing method according to claim 1, wherein the processing water dispersion is a non-Newtonian fluid.

4. The manufacturing method according to claim 1, wherein the processing water dispersion contains 90% by mass or more of water as a dispersion medium.

5. The manufacturing method according to claim 1, wherein the cosmetic powder is an extender pigment selected from talc, sericite, synthetic fluorophlogopite, or mica, or a pearl agent selected from titanium mica, glass, titanium dioxide, or colored pearl, or a combination thereof.

6. The manufacturing method according to claim 1, wherein the ratio of the mass of silk nanofibers to the total mass of the silk nanofibers and cosmetic powder [silk nanofibers / (silk nanofibers + cosmetic powder)] is 0.001 to 0.

004.

7. A processed powder for cosmetics obtained by the manufacturing method described in claim 1.

8. A powder cosmetic comprising the processed powder for cosmetics described in claim 7.

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