Powder cosmetic and cosmetic composition

Abstract

A powder cosmetic comprising an inorganic powder, and a polyaspartic acid alkali metal salt that coats a part or all of the surface of the aforementioned inorganic powder, the weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt being 1,000 to 150,000, and the weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt, and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali metal salt satisfying y ≤ 1.6 x 10 7 x ‑2.275 and y ≥ 1.3 x 10 5 x ‑2.232 .

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a powder cosmetic and a cosmetic composition. BACKGROUND

[0002] A powder (powdered) cosmetic is a substance that utilizes the optical properties of a powder to impart satisfactory aesthetic properties and the like. In the past, powder cosmetics that are better to use have been developed by improving the components or blending amounts of the powder and the like.

[0003] For example, Japanese Patent Application Publication No. 2006-265214 describes a powder cosmetic obtained by blending (a) a specific irregularly shaped composite powder and (b) one or two or more water-soluble components selected from among amino acids, polyamino acids, derivatives or salts thereof. It is disclosed that this results in a powder cosmetic that is excellent in terms of smooth spreadability when the cosmetic is applied, adhesion to the skin, and moisturizing sensation, and in terms of the effect of making the unevenness of the skin less noticeable. SUMMARY

[0004] PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] However, Japanese Patent Application Publication No. 2006-265214 described above is premised on the use of an irregularly shaped composite powder that is integrated by agglomeration of a plurality of substantially spherical particles and has a shape with a plurality of unevennesses on the surface. The method of confirming the effects of smooth spreadability when the cosmetic is applied, adhesion to the skin, and moisturizing sensation, and the effect of making the unevenness of the skin less noticeable in Japanese Patent Application Publication No. 2006-265214 described above is performed only by sensory evaluation by an evaluator. That is, the effects are not effects that have been confirmed using objective indices. Furthermore, in Japanese Patent Application Publication No. 2006-265214 described above, there is no description at all regarding the effects (a sense of resistance when layered, occurrence of makeup removal, and the like) when a cosmetic is layered, and it is known that sometimes the smooth spreadability of a cosmetic on the skin cannot still be sufficiently obtained.

[0006] The present disclosure was made in view of the above circumstances, and an object of one embodiment of the present disclosure is to provide a powder cosmetic that has less sense of resistance on the skin at the time of layering of the powder cosmetic and that is less likely to cause makeup removal. Furthermore, an object of another embodiment of the present disclosure is to provide a cosmetic composition that has less sense of resistance on the skin at the time of layering of the cosmetic composition and that is less likely to cause makeup removal.

[0007] MEANS FOR SOLVING THE PROBLEMS

[0008] Specific means for solving the problems include the following modes.

[0009] <1> A powder cosmetic comprising:

[0010] an inorganic powder, and

[0011] polyaspartic acid alkali metal salt that coats a part or all of the surface of the aforementioned inorganic powder;

[0012] The weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt is 1,000 to 150,000,

[0013] Furthermore, the weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt, and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali metal salt satisfy the following formula (1) and formula (2).

[0014] y ≤ 1.6 x 10 7 x -2.275 Formula (1)

[0015] y ≥ 1.3 x 10 5 x -2.232 Formula (2)

[0016] <2> The powder cosmetic according to the aforementioned <1>, wherein the weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt, and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali metal salt further satisfy the following formula (3).

[0017] y ≤ 1.0 x 10 7 x -2.275 Formula (3)

[0018] <3> The powder cosmetic according to the aforementioned <1>, wherein the weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt, and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali metal salt further satisfy the following formula (4).

[0019] y ≤ 8.0 x 10 6 x -2.275 Formula (4)

[0020] <4> The powder cosmetic according to any one of the aforementioned <1> to <3>, wherein the weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt, and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali metal salt further satisfy the following formula (5).

[0021] y ≥ 1.5 x 10 5 x -2.232 Formula (5)

[0022] <5> As mentioned above <1> ~ <4> In any one of the powder cosmetics, the weight-average molecular weight x of the aforementioned polyaspartic alkali metal salt is 8,000 to 120,000.

[0023] <6> As mentioned above <1> ~ <5> The powder cosmetic as described in any one of the above, wherein the aforementioned polyaspartic alkali metal salt is at least one selected from the group consisting of lithium polyaspartic acid, potassium polyaspartic acid, and sodium polyaspartic acid.

[0024] <7> As mentioned above <1> ~ <6> The powder cosmetic described in any one of the above-mentioned polyaspartic acid alkali metal salts contains at least sodium polyaspartic acid.

[0025] <8> As mentioned above <1> ~ <7> The powder cosmetic described in any one of the above-mentioned inorganic powders contains at least one selected from the group consisting of talc, mica, sericite, and titanium dioxide.

[0026] <9> As mentioned above <1> ~ <8> In any one of the powder cosmetics, the average particle size (D50) of the aforementioned inorganic powder is 1 μm to 100 μm.

[0027] <10> Cosmetic composition comprising the aforementioned <1> ~ <9> The powder cosmetic as described in any one of the above, and at least one selected from water and oil.

[0028] Invention Effects

[0029] According to one aspect of this disclosure, a powder cosmetic product can be provided that exhibits smooth spreadability with minimal resistance to the skin when layered and is less prone to makeup smudging. Furthermore, according to another aspect of this disclosure, a cosmetic composition can be provided that exhibits smooth spreadability with minimal resistance to the skin when layered and is less prone to makeup smudging. Attached Figure Description

[0030] [ Figure 1 This is a graph used to illustrate the method for determining the degree of destruction of the envelope and curvature.

[0031] [ Figure 2 [This is a scatter plot showing the relationship between the relative values ​​of the curve degree and the weight-average molecular weight of polyaspartic alkali metal salt [-] and the mass ratio of polyaspartic alkali metal salt [-]. Detailed Implementation

[0032] The contents of this disclosure will be described in detail below. The description of the constituent elements described below is sometimes based on representative embodiments of this disclosure, but this disclosure is not limited to such embodiments.

[0033] In the numerical ranges described in stages in the present disclosure, the upper limit value or the lower limit value described in one numerical range can be replaced with the upper limit value or the lower limit value of other numerical ranges described in stages. In addition, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range can be replaced with the value shown in the examples.

[0034] In the present disclosure, the numerical range represented by "~" means a range including the numerical values described before and after the "~" as the lower limit value and the upper limit value.

[0035] Further, in the present disclosure, the amount of each component in the composition such as the powder cosmetic or the cosmetic composition, in the case where a plurality of substances belonging to each component in the composition exist, the total amount of the respective plurality of substances existing in the composition is meant, unless otherwise specified.

[0036] In addition, in the description of the group (radical) in the present specification, the description of the substituted and unsubstituted is meant to include the case without the substituent, as well as the case with the substituent.

[0037] In addition, the term "step" in the present specification includes not only a separate step, but also a case where the step cannot be clearly distinguished from other steps, as long as the desired purpose of the step is achieved.

[0038] In addition, in the present disclosure, "mass%" is synonymous with "weight%", and "mass parts" is synonymous with "weight parts".

[0039] Further, in the present disclosure, a combination of two or more of the preferred modes is a more preferred mode.

[0040] <<Powder cosmetic>>

[0041] The powder cosmetic of the present disclosure is a powder cosmetic including an inorganic powder, and a polyaspartic acid alkali metal salt that coats a part or all of the surface of the inorganic powder, the weight average molecular weight x of the polyaspartic acid alkali metal salt is 1,000 to 150,000, and the weight average molecular weight x of the polyaspartic acid alkali metal salt and the mass ratio y of the polyaspartic acid alkali metal salt with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt satisfy the following formula (1) and formula (2).

[0042] y ≤ 1.6 x 10 7 x -2.275 Formula (1)

[0043] y ≥ 1.3 x 10 5 x -2.232 Formula (2)

[0044] With regard to the powder cosmetics disclosed herein, the powder cosmetics have a smooth spreadability with little resistance to the skin when layered, and are not prone to makeup smudging.

[0045] Although the function of the powder cosmetics mentioned in this disclosure is not clear, the following can be inferred.

[0046] In this disclosure, the evaluation of powder cosmetics during layering utilizes powder layer shear force determination. In powder layer shear force determination, loads are applied in both the vertical and horizontal directions to the powder filled in a sample cell. After the vertical stress σ and shear stress τ reach a stable state, the vertical stress σ is allowed to decay, thereby obtaining a destruction envelope representing the relationship between shear stress τ and vertical stress σ. Figure 1 The state of the powder layer when it is sheared while under load is similar to the state of the powder layer when applying powder cosmetics to skin and then further layering powder cosmetics (e.g., for touch-ups, concealing blemishes, or covering dirt) using a makeup tool with powder cosmetics attached. Therefore, in this disclosure, an objective evaluation is conducted by setting the evaluation method for the user experience when powder cosmetics are layered using an evaluation method that utilizes the powder layer shear force measurement.

[0047] It should be noted that while the effects of this application are most effective when layered with powder cosmetics, the same effect can certainly be expected even in situations where layering is not described above. That is, the effect of this application is not limited to layering the powder cosmetics described in this disclosure with other powder cosmetics described in this disclosure. Even when applying the powder cosmetics described in this disclosure to bare skin, to a base (liquid, cream, etc.) applied to bare skin, or to blush, concealer, etc. (liquid, powder, etc.) applied over the powder cosmetics described in this disclosure, the effect of this application can still be achieved (i.e., providing a smooth, spreadable powder cosmetic with low resistance to the skin and less prone to fading).

[0048] Note that, in the present disclosure, the "use feeling" of the powder cosmetic or the cosmetic composition, etc. includes a feeling that the powder cosmetic has less resistance to the skin and a smooth extensibility at the time of overlapping application of the powder cosmetic, or at the time of application of only the powder cosmetic, etc., and that it is not easy to cause makeup removal. In the present disclosure, since extensibility or makeup removal is directly mentioned, extensibility or makeup removal is sometimes also described in parallel with the use feeling. In addition, in the present disclosure, the feeling of skin compatibility, a moisturizing feeling, smoothness, etc. of the powder cosmetic or the cosmetic composition, which a user feels, is also one of the "use feeling" of the powder cosmetic or the cosmetic composition, etc. Note that, the "makeup removal" is a change in the powder layer adhered to the skin, and for example, refers to foundation creasing.

[0049] As Figure 1The curvilinearity can be obtained from the failure envelope obtained by the aforementioned powder layer shear force measurement. The curvilinearity is calculated from the formula: curvilinearity = [slope of straight line of lower portion of failure envelope] / [slope of straight line of upper portion of failure envelope]. Note that the slope of straight line of lower portion of failure envelope indicates the slope of a straight line of the failure envelope when the vertical stress σ and the shear stress τ are in a steady state, and the value of the vertical stress σ is 0% to 30% in the case where the vertical stress σ when the vertical stress σ and the shear stress τ are in a steady state is taken as 100%. The slope of straight line of upper portion of failure envelope indicates the slope of a straight line of the failure envelope when the vertical stress σ and the shear stress τ are in a steady state, and the value of the vertical stress σ is 70% to 100% in the case where the vertical stress σ when the vertical stress σ and the shear stress τ are in a steady state is taken as 100%. The aforementioned curvilinearity is related to the sliding property of the powder. The higher the value of the curvilinearity, the higher the shear adhesion stress, and the lower the sliding property of the powder, that is, the more likely it is to cause the aforementioned problems of smooth extensibility with less resistance to the skin and makeup removal during the application of the powder cosmetic. On the other hand, the lower the value of the curvilinearity, the lower the shear adhesion stress, and the higher the sliding property of the powder, that is, the less likely it is to cause the aforementioned problems during the application of the powder cosmetic. Note that the "shear stress τ" indicates the stress required to slide and shear the powder layer along a certain cross section parallel to the section in the case where a pair of forces facing in opposite directions are applied to the upper and lower layers of the section. That is, the shear stress τ is the stress required to slide the upper and lower powder layers in the section in the direction parallel to the section. The "shear adhesion stress" is the stress equal to the intercept of the straight line obtained by fitting the failure envelope to a straight line using the least squares method, and the axis of the shear stress τ. That is, the shear adhesion stress indicates the extrapolated value of the shear stress τ when the vertical stress σ of the fitting formula is 0. The shear stress τ and the shear adhesion stress can be used as indicators of the adhesion between the compressed powders.

[0050] The powder cosmetic according to the present disclosure contains inorganic powder and polyaspartic acid alkali metal salt. The polyaspartic acid alkali metal salt is present between the inorganic powder (i.e., on the surface of two particles when the particles of the inorganic powder approach each other), whereby the friction between the inorganic powders can be reduced, and the sliding property of the powder cosmetic can be improved. The meanings of the aforementioned formulae (1) and (2) satisfied by the weight average molecular weight x of the polyaspartic acid alkali metal salt and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali metal salt according to the present disclosure can be inferred as follows.

[0051] When the weight average molecular weight x of the polyaspartic acid alkali metal salt is excessively large in the powder cosmetic according to the present disclosure, the interaction between the polyaspartic acid alkali metal salts (i.e., between the molecules of the polyaspartic acid alkali metal salt) is strong, and the increase in viscosity becomes significant, which impairs the workability and the like during manufacturing. In addition, the following problems are sometimes easily caused. Note that, in this case, the value of the curve degree of the powder cosmetic becomes high.

[0052] (1a) The friction between the powder layers of the powder cosmetic is large, and the sliding property is low.

[0053] (1b) The smooth spreadability with less resistance to the skin is not obtained during the overlapping of the powder cosmetic, and the makeup removal is easily caused.

[0054] In addition, when the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt is excessively large in the powder cosmetic according to the present disclosure, the following problems are caused. Note that, in this case, the value of the curve degree of the powder cosmetic becomes high.

[0055] (2a) The amount of the polyaspartic acid alkali metal salt present between the inorganic powders is large, and thus the interaction between the polyaspartic acid alkali metal salts is strong.

[0056] (2b) The viscosity of the powder cosmetic containing the aqueous polyaspartic acid alkali metal salt solution increases significantly.

[0057] (2c) The friction between the powder layers of the powder cosmetic is large, and the sliding property is low.

[0058] (2d) The smooth spreadability with less resistance to the skin is not obtained during the overlapping of the powder cosmetic, and the makeup removal is easily caused.

[0059] According to the above, when the weight average molecular weight x of the polyaspartic acid alkali metal salt is excessively large and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt is excessively large in the powder cosmetic, the value of the curve degree of the powder cosmetic becomes higher, and the above problems are more easily caused.

[0060] On the other hand, when the weight average molecular weight x of the polyaspartic acid alkali metal salt is excessively small in the powder cosmetic according to the present disclosure, the interaction between the polyaspartic acid alkali metal salts is weak, which impairs the workability and the like during manufacturing. In addition, the following problems are sometimes easily caused. Note that, in this case, the value of the curve degree of the powder cosmetic also becomes high.

[0061] (3a) The friction between the powder layers of the powder cosmetic caused by the polyaspartic acid alkali metal salt is large, and the effect of improving the sliding property cannot be sufficiently exerted.

[0062] (3b) In the case of the powder cosmetic, the smooth extensibility with less resistance to the skin is not obtained, and the makeup removal is easily caused.

[0063] Further, in the powder cosmetic according to the present disclosure, when the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt is too small, the following problems occur. Note that in this case, the value of the curvature of the powder cosmetic also becomes high.

[0064] (4a) The amount of the polyaspartic acid alkali metal salt present between the inorganic powders is small, and thus the interaction between the polyaspartic acid alkali metal salts is weak.

[0065] (4b) The polyaspartic acid alkali metal salt is present locally in the inorganic powder, and thus the uniform flow of the powder cosmetic caused by the polyaspartic acid alkali metal salt is hindered, the friction between the powder layers is large, and the effect of improving the sliding property cannot be sufficiently exerted.

[0066] (4c) In the case of the powder cosmetic, the smooth extensibility with less resistance to the skin is not obtained, and the makeup removal is easily caused.

[0067] According to the above, in the powder cosmetic, when the weight average molecular weight x of the polyaspartic acid alkali metal salt is too small, and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt is too small, the value of the curvature of the powder cosmetic becomes even higher, and the above problems are more easily caused.

[0068] For the above reasons, in the powder cosmetic, the aforementioned formula (1) and formula (2) are required to be satisfied by the weight average molecular weight x of the polyaspartic acid alkali metal salt, and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt. Note that in the present disclosure, the aforementioned weight average molecular weight x of the polyaspartic acid alkali metal salt being too large means that the weight average molecular weight of the polyaspartic acid alkali metal salt is greater than 150,000. The aforementioned weight average molecular weight x of the polyaspartic acid alkali metal salt being too small means that the weight average molecular weight of the polyaspartic acid alkali metal salt is less than 1,000.

[0069] As described above, the coefficients in formula (1) "y ≤ 1.6 x 10 7 x -2.275 " and formula (2) "y ≥ 1.3 x 10 5 x -2.232 " that are satisfied by the aforementioned weight average molecular weight x of the polyaspartic acid alkali metal salt, and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali metal salt are values derived from experience.

[0070] Note that in the powder cosmetic according to the present disclosure, the value of the mass ratio of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt is made to be a smaller value. Therefore, although the polyaspartic acid alkali metal salt coats part or all of the surface of the particles of the inorganic powder, the amount of the coating is suppressed to be small. Therefore, in the powder cosmetic according to the present disclosure, excessive increase in viscosity due to the polyaspartic acid alkali metal salt being hydrophilic is suppressed.

[0071] Note that in the present disclosure, the mass ratio of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt is also simply referred to as the mass ratio of the polyaspartic acid alkali metal salt.

[0072] The value of the mass ratio of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt according to the present disclosure is dimensionless, and therefore does not have a unit.

[0073] Regarding the weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali metal salt, in a region surrounded by y ≤ 1.6 × 10 7 x -2.275 (Formula (1)) and y ≥ 1.3 × 10 5 x -2.232 (Formula (2)) and the weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt being in the range of 1,000 to 150,000, the powder cosmetic according to the present disclosure exerts an effect.

[0074] Note that the aforementioned range corresponds to the range shown by the four-sided polygon of the thick frame within the graph region of Figure 2 .

[0075] Regarding the weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali metal salt, in a region surrounded by y ≤ 1.0 × 10 7 x -2.275 (Formula (3)) and y ≥ 1.3 × 10 5 x -2.232 (Formula (2)) and the weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt being in the range of 1,000 to 150,000, the powder cosmetic according to the present disclosure further exerts an effect.

[0076] with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt, the mass ratio y of the polyaspartic acid alkali metal salt is in the range of y < 1.6 x 10 6 x -2.275 (1) and y > 1.3 x 10 5 x -2.232 (2) and the weight average molecular weight x of the polyaspartic acid alkali metal salt is in the range of 1,000 to 150,000, the powder cosmetic of the present disclosure further exerts effects.

[0077] with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt, the mass ratio y of the polyaspartic acid alkali metal salt is in the range of y < 1.6 x 10 7 x -2.275 (1) and y > 1.5 x 10 5 x -2.232 (5) and the weight average molecular weight x of the polyaspartic acid alkali metal salt is in the range of 1,000 to 150,000, the powder cosmetic of the present disclosure further exerts effects.

[0078] with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt, the mass ratio y of the polyaspartic acid alkali metal salt is in the range of y < 1.0 x 10 7 x -2.275 (3) and y > 1.5 x 10 5 x -2.232 (5) and the weight average molecular weight x of the polyaspartic acid alkali metal salt is in the range of 1,000 to 150,000, the powder cosmetic of the present disclosure further exerts effects.

[0079] with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt, the mass ratio y of the polyaspartic acid alkali metal salt is in the range of y < 8.0 x 10 6 x -2.275 (4) and y > 1.5 x 10 5 x -2.232 (5) and the weight average molecular weight x of the polyaspartic acid alkali metal salt is in the range of 1,000 to 150,000, the powder cosmetic of the present disclosure further exerts effects.

[0080] Note that, from the viewpoint of improving the slipperiness of the powder, and the viewpoint of the operation at the time of production and the like described later, the powder cosmetic of the present disclosure further exerts an effect in a region surrounded by the above formula, and the range of the weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt of 8,000 to 120,000.

[0081] Further, from the viewpoint of the smooth extensibility having less resistance feeling to the skin, and the viewpoint of making it difficult for the makeup to come off, the powder cosmetic of the present disclosure further exerts an effect in a region surrounded by the above formula (1), formula (3), or formula (4), and y ≤ 5.0 x 10 6 x -2.275 Further, from the viewpoint of the smooth extensibility having less resistance feeling to the skin, and the viewpoint of making it difficult for the makeup to come off, the powder cosmetic of the present disclosure further exerts an effect in a region surrounded by the above formula (1), formula (3), or formula (4), and y ≤ 5.0 x 10

[0082] Further, from the viewpoint of the smooth extensibility having less resistance feeling to the skin, and the viewpoint of making it difficult for the makeup to come off, the powder cosmetic of the present disclosure further exerts an effect in a region surrounded by the above formula (1), formula (3), or formula (4), and y ≤ 5.0 x 10 5 x -2.232 Further, from the viewpoint of the smooth extensibility having less resistance feeling to the skin, and the viewpoint of making it difficult for the makeup to come off, the powder cosmetic of the present disclosure further exerts an effect in a region surrounded by the above formula (1), formula (3), or formula (4), and y ≤ 5.0 x 10 5 x -2.232 Further, from the viewpoint of the smooth extensibility having less resistance feeling to the skin, and the viewpoint of making it difficult for the makeup to come off, the powder cosmetic of the present disclosure further exerts an effect in a region surrounded by the above formula (1), formula (3), or formula (4), and y ≤ 5.0 x 10 5 x -2.232 Further, from the viewpoint of the smooth extensibility having less resistance feeling to the skin, and the viewpoint of making it difficult for the makeup to come off, the powder cosmetic of the present disclosure further exerts an effect in a region surrounded by the above formula (1), formula (3), or formula (4), and y ≤ 5.0 x 10 5 x -2.232 Further, from the viewpoint of the smooth extensibility having less resistance feeling to the skin, and the viewpoint of making it difficult for the makeup to come off, the powder cosmetic of the present disclosure further exerts an effect in a region surrounded by the above formula (1), formula (3), or formula (4), and y ≤ 5.0 x 10 5 x -2.232 .

[0083] When the weight average molecular weight x of the aforementioned polyaspartic acid alkali metal salt, and the mass ratio y of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali metal salt are values in a region surrounded by the aforementioned ranges, the interaction between the polyaspartic acid alkali metal salts is not too strong, the friction between the powder layers is reduced, the slipperiness of the powder is improved, the operation at the time of production is favorably performed, and the effects of the present application can be further obtained. Alternatively, the interaction between the polyaspartic acid alkali metal salts is not too weak, the friction between the powder layers is reduced, the slipperiness of the powder is improved, the operation at the time of production is favorably performed, and the effects of the present application can be further obtained.

[0084] As described above, there is a preferable range of the mass ratio y of the polyaspartic acid alkali metal salt with respect to the weight average molecular weight x of the polyaspartic acid alkali metal salt. It is preferable that the larger the weight average molecular weight x of the polyaspartic acid alkali metal salt, the smaller the mass ratio y of the polyaspartic acid alkali metal salt. It is preferable that the smaller the weight average molecular weight x of the polyaspartic acid alkali metal salt, the larger the mass ratio y of the polyaspartic acid alkali metal salt. The strength of the force of the interaction between the polyaspartic acid alkali metal salts as polymers varies depending on the size of the weight average molecular weight x (or the number average molecular weight) of the polyaspartic acid alkali metal salt. Therefore, it is considered that there is a preferable range of the mass ratio y of the polyaspartic acid alkali metal salt with respect to the weight average molecular weight x (or the number average molecular weight) of the polyaspartic acid alkali metal salt.

[0085] Note that the present disclosure is not limited to the above-described inference mechanism.

[0086] (Polyaspartic acid alkali metal salt)

[0087] Polyaspartic acid alkali metal salt

[0088] The polyaspartic acid alkali metal salt is a polymer formed using the amide bond of the aspartic acid alkali metal salt, and generally has a structure including a plurality of the following structural units.

[0089] [Chemical Formula 1]

[0090]

[0091] In the formula, n is an integer of 1 or more. In the formula, M represents an alkali metal. As the alkali metal in M, lithium, sodium, potassium, rubidium, cesium, or francium is included. The amide bond in the main chain of the polyaspartic acid alkali metal salt can be an a bond or a β bond. In addition, these bonding modes can be the same or different in each structural unit. Note that, for the aforementioned amide bond, the amino group of the adjacent structural unit is bonded to the carboxyl group at the a position of the aspartic acid alkali metal salt when it is an a bond, and is bonded to the carboxyl group at the β position of the aspartic acid alkali metal salt when it is a β bond.

[0092] In addition, the stereostructure of the structural unit can be L type or D type independently of each other, for example, as a whole, can be a polymer of L type, a polymer of D type, or a racemate.

[0093] The polyaspartic acid alkali metal salt according to the present disclosure is not particularly limited in composition, as long as the powder cosmetic according to the present disclosure exhibits the effects. The polyaspartic acid alkali metal salt according to the present disclosure preferably includes at least one polyaspartic acid alkali metal salt selected from the group consisting of lithium polyaspartate, potassium polyaspartate, and sodium polyaspartate. In one embodiment of the present disclosure, by using a polyaspartic acid alkali metal salt, a powder cosmetic that has less resistance to the skin and a smooth extensibility at the time of overlying application of the powder cosmetic, and that is less likely to cause makeup removal, can be achieved. More preferably, the polyaspartic acid alkali metal salt according to the present disclosure contains at least sodium polyaspartate.

[0094] Sodium polyaspartate, which is one example of the polyaspartic acid alkali metal salt according to the present disclosure, is a polymer formed using the amide bond of sodium aspartate, and generally has a structure including a plurality of the following structural units.

[0095] [Chemical Formula 2]

[0096]

[0097] In the formula, n is an integer of 1 or more. The amide bond in the main chain of sodium polyaspartate can be an α bond or a β bond. In addition, these bonding modes can be the same or different in each structural unit. Note that, for the aforementioned amide bond, the amino group of the adjacent structural unit is bonded to the carboxyl group at the α position of sodium aspartate when it is an α bond, and is bonded to the carboxyl group at the β position of sodium aspartate when it is a β bond.

[0098] Molecular weight of polyaspartic acid alkali metal salt

[0099] Hereinafter, the molecular weight of the polyaspartic acid alkali metal salt will be described in detail from the viewpoints of the weight average molecular weight (Mw), the number average molecular weight (Mn), and the polydispersity of the molecular weight (weight average molecular weight (Mw) / number average molecular weight (Mn)).

[0100] When the weight average molecular weight of the polyaspartic acid alkali metal salt is too large, the following problems occur. Since the viscosity of the aqueous polyaspartic acid alkali metal salt solution increases significantly, it becomes stringy, and the operation becomes difficult at the time of powder mixing in the manufacturing process of the powder cosmetic. The viscosity can be suppressed by further diluting the aqueous polyaspartic acid alkali metal salt solution with water, but as a result, the amount of water added with respect to the inorganic powder increases, and thus, at the time of powder mixing, the powder absorbs moisture, and adhesion to the mixing tank and agglomeration between the powders occur, making it difficult to perform uniform powder mixing. In order to eliminate such difficulties at the time of powder mixing, it is also possible to consider concentrating the aqueous polyaspartic acid alkali metal salt solution in advance, and reducing the amount of the concentrated aqueous polyaspartic acid alkali metal salt solution added with respect to the inorganic powder. However, a new concentration process needs to be newly introduced in the manufacturing process of the powder cosmetic, and thus, the manufacturing cost increases.

[0101] On the other hand, the problem caused by the low weight average molecular weight of the polyaspartic acid alkali metal salt is as described above.

[0102] From the above viewpoint, the weight average molecular weight of the polyaspartic acid alkali metal salt according to the present disclosure is set to 1,000 to 150,000.

[0103] The weight average molecular weight of the polyaspartic acid alkali metal salt according to the present disclosure is 1,000 to 150,000. The weight average molecular weight of the polyaspartic acid alkali metal salt according to the present disclosure is not particularly limited, and from the viewpoint of improving the sliding property of the powder and the viewpoint of handling and the like at the time of production, it is preferably 8,000 to 120,000, more preferably 10,000 to 120,000, further preferably 10,000 to 100,000, particularly preferably 16,000 to 60,000, more preferably 20,000 to 35,000, and further preferably 20,000 to 27,000.

[0104] In the polyaspartic acid alkali metal salt according to the present disclosure, the number average molecular weight of the polyaspartic acid alkali metal salt is not particularly limited, and for example, it can be set to 1,000 to 60,000. Note that from the viewpoint of improving the sliding property of the powder and the viewpoint of handling and the like at the time of production, the number average molecular weight of the polyaspartic acid alkali metal salt is preferably 6,000 to 50,000, more preferably 7,000 to 48,000, further preferably 8,000 to 40,000, particularly preferably 10,000 to 36,000, more preferably 12,000 to 20,000, and further preferably 13,000 to 16,000.

[0105] The polydispersity of the molecular weight of the polyaspartic acid alkali metal salt according to the present disclosure is not particularly limited, and for example, it can be set to 1.00 to 2.60. From the viewpoint of improving the sliding property of the powder and the viewpoint of handling and the like at the time of production, the polydispersity of the molecular weight of the polyaspartic acid alkali metal salt is preferably 1.20 to 2.40, more preferably 1.30 to 1.90, further preferably 1.40 to 1.80, particularly preferably 1.50 to 1.75, and most preferably 1.50 to 1.70.

[0106] The polyaspartic acid alkali metal salt having the weight average molecular weight, the number average molecular weight, and the polydispersity of the molecular weight within the above range can be obtained, for example, by using the production method of the polyaspartic acid alkali metal salt described later.

[0107] Method for measuring the molecular weight of the polyaspartic acid alkali metal salt

[0108] Note that in the present disclosure, the weight average molecular weight and the number average molecular weight of the polyaspartic acid alkali metal salt each refer to a value determined by the following GPC measurement method using gel permeation chromatography (GPC).

[0109] Used were:

[0110] LC-Solution (manufactured by Shimadzu Corporation) as an analysis device,

[0111] RID-10A (manufactured by Shimadzu Corporation) as a detector,

[0112] DGU-20A (manufactured by Shimadzu Corporation) as a degassing device,

[0113] LC-20AD (manufactured by Shimadzu Corporation) as a pump,

[0114] SIL-20A (manufactured by Shimadzu Corporation) as an autosampler,

[0115] CTO-20A (manufactured by Shimadzu Corporation) as a liquid delivery unit,

[0116] Shodex Asahipak GF-7M HQ x 1 (manufactured by Showa Denko K.K.) as a column,

[0117] Shodex Asahipak GF-1G7B (manufactured by Showa Denko K.K.) as a guard column.

[0118] The temperature of the column oven was set to 45°C. The standard sample was pullulan (Shodex STANDARD P-82 (standard sample set reagent kit manufactured by Showa Denko K.K.)), and P-5, P-10, P-20, P-50, P-100, and P-200 thereof were used to prepare a three-order standard curve. As the mobile phase, 0.1 mol / L saline was used. The weight average molecular weight and the number average molecular weight were calculated from the main peak of the polymer in the obtained elution curve.

[0119] -Method for producing polyaspartic acid alkali metal salt-

[0120] The alkali metal salt of polyaspartic acid can be obtained, for example, as described in Japanese Patent No. 3384420, by a method including a step of heating aspartic acid to 200 to 230°C in a non-water-soluble solvent to obtain a polysuccinimide, and a step of hydrolyzing the obtained polysuccinimide in an aqueous alkali metal hydroxide solution to produce the alkali metal salt of polyaspartic acid. As the non-water-soluble solvent, a solvent that is layered when mixed with water and has a boiling point of 200°C or higher can be used. For example, saturated hydrocarbon compounds such as n-alkanes and liquid paraffin, silicone-based oils, fluorine-based oils, and the like can be given, and a solvent having a boiling point of 200°C or higher (preferably 230°C or higher) and a viscosity of 100 cP or less (preferably 20 cP or less) at 25°C can be suitably used.

[0121] The polysuccinimide as the precursor can also be obtained by heating maleamic acid at a temperature of 160 to 330°C. Alternatively, maleic anhydride can be reacted with aqueous ammonia in an aqueous solvent, and then heated to a temperature of at least 170°C to obtain the polysuccinimide. Alternatively, the alkali metal salt of polyaspartic acid can be produced by a method including a step of preparing a polyaspartic acid precursor polymer by polymerization using at least one selected from the group consisting of a reaction product of maleic anhydride and ammonia and maleamic acid as a monomer, and a step of obtaining the alkali metal salt of polyaspartic acid by treating the obtained polyaspartic acid precursor polymer with an aqueous alkali metal hydroxide solution, as described in International Publication No. 2011 / 102293.

[0122] In the production method of the sodium salt of polyaspartic acid, for example, in one example, (1) L-aspartic acid is spread in a SUS-made barrel, and left for 4 hours in an oven at 230°C under a nitrogen atmosphere at normal pressure to obtain a powder of polysuccinimide, and further, (2) distilled water is added to the obtained powder of polysuccinimide, and the temperature of the solution is controlled so as to be 45 to 55°C, and a 32 mass% aqueous sodium hydroxide solution is added dropwise in small amounts each time, and when the reactants become fluid, pH measurement is started, and the 32 mass% aqueous sodium hydroxide solution is further added dropwise while measuring the pH, and when the pH does not change in the range of pH 10 to pH 10.5, the addition is ended, and an aqueous sodium salt of polyaspartic acid solution containing the sodium salt of polyaspartic acid is obtained.

[0123] Among the alkali metal salts of polyaspartic acid, for example, in the case of polyaspartic acid sodium obtained by hydrolysis of poly(succinimide), a part of the succinimide structural units can remain unhydrolyzed in the polymer. In other words, the polyaspartic acid sodium according to the present disclosure can contain a part (e.g., 10% or less, or 5% or less, or 1% or less of the total number of structural units) of succinimide structural units, or can not contain succinimide structural units at all.

[0124] - Mass ratio of polyaspartic acid alkali metal salt -

[0125] The mass ratio of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of inorganic powder and polyaspartic acid alkali metal salt in the powder cosmetic according to the present disclosure is preferably in the range of 0.00000095 to 0.0045, more preferably in the range of 0.000035 to 0.0010. By being in the aforementioned range, the powder cosmetic has further less resistance to the skin and smooth extensibility at the time of overcoating of the powder cosmetic, and is less likely to cause makeup removal. Note that the aforementioned mass ratio of polyaspartic acid alkali metal salt with respect to the total amount of inorganic powder and polyaspartic acid alkali metal salt can be calculated from the formula [mass of polyaspartic acid alkali metal salt] / ([mass of inorganic powder]+[mass of polyaspartic acid alkali metal salt]).

[0126] More specifically, as follows. In the powder cosmetic according to the present disclosure, by mixing the polyaspartic acid alkali metal salt with the inorganic powder, a part or all of the surface of the inorganic powder is coated with the polyaspartic acid alkali metal salt. The polyaspartic acid alkali metal salt is present between the inorganic powders, whereby the friction between the inorganic powders can be reduced, and the slipperiness of the powder cosmetic can be improved.

[0127] Therefore, when the aforementioned mass ratio of polyaspartic acid alkali metal salt with respect to the total amount of inorganic powder and polyaspartic acid alkali metal salt is too large, the aforementioned problems (2a) to (2d) occur, i.e., the aforementioned problems at the time of overcoating are caused. On the other hand, when the aforementioned mass ratio of polyaspartic acid alkali metal salt with respect to the total amount of inorganic powder and polyaspartic acid alkali metal salt is too small, the aforementioned problems (4a) to (4c) occur, i.e., the aforementioned problems at the time of overcoating are caused.

[0128] From the viewpoint of the interaction between the polyaspartic acid alkali metal salt and the inorganic powder, and the friction between the powder layers, the mass ratio of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt is preferably 0.000035 to 0.0010, more preferably 0.000035 to 0.00065, further preferably 0.000055 to 0.00065, particularly preferably 0.000085 to 0.00065, more particularly preferably 0.00015 to 0.00065, and further more preferably 0.00020 to 0.00065.

[0129] (Inorganic powder)

[0130] Inorganic powder

[0131] The inorganic powder contained in the powder cosmetic according to the present disclosure is not particularly limited, and an inorganic powder that is generally used as an inorganic powder for powder cosmetics can be used. The shape of the inorganic powder can be a spherical shape, a plate shape, a needle shape, or the like, and can be porous or non-porous.

[0132] The material of the inorganic powder can be any of a general inorganic powder, a glittering powder, an organic powder, a pigment powder, or a composite powder. As examples of the inorganic powder, specifically, there can be mentioned a general inorganic powder such as titanium oxide, black titanium oxide, iron blue pigment, ultramarine, red iron oxide, yellow iron oxide, black iron oxide, zinc oxide, aluminum oxide, silicon dioxide, magnesium oxide, zirconium oxide, magnesium carbonate, calcium carbonate, chromium oxide, chromium hydroxide, carbon black, aluminum silicate, magnesium silicate, magnesium aluminum silicate, mica, synthetic mica, synthetic mica iron, sericite, talc, kaolin, silicon carbide, barium sulfate, bentonite, hectorite, or boron nitride, a glittering inorganic powder such as bismuth oxychloride, titanium oxide-coated mica, iron oxide-coated mica, iron oxide-coated mica titanium, iron oxide-titanium oxide sintered body, or aluminum powder, or a composite inorganic powder such as fine particle titanium oxide-coated mica titanium, fine particle zinc oxide-coated mica titanium, barium sulfate-coated mica titanium, titanium oxide-encapsulated silicon dioxide, or zinc oxide-encapsulated silicon dioxide. The powder cosmetic according to the present disclosure can use any one of these inorganic powders alone, or can contain two or more in any combination.

[0133] From the viewpoint of having less resistance to the skin and smooth extensibility at the time of overlapping the powder cosmetic, and less occurrence of makeup removal, the inorganic powder according to the present disclosure preferably contains at least one selected from the group consisting of talc, mica, sericite, and titanium oxide. The inorganic powder according to the present disclosure can also be, for example, a mixture of talc and titanium oxide. The inorganic powder according to the present disclosure more preferably contains at least one selected from the group consisting of talc, mica, and sericite, and further preferably contains talc.

[0134] - average particle diameter -

[0135] The particle diameter of the inorganic powder contained in the powder cosmetic according to the present disclosure is not particularly limited and can be appropriately selected in the range of ultrafine particle sizes of about 0.02 pm or less to larger sizes of about 200 pm or more, according to the purpose. Note that the average particle diameter according to the present disclosure refers to the particle diameter at which the cumulative volume becomes 50% of the total volume when the volume of each particle based on the particle diameter of each particle measured in a state in which the inorganic powder is dispersed in a solvent is cumulatively added from the small particle diameter side. That is, the average particle diameter according to the present disclosure is synonymous with the median particle diameter and is also referred to as "average particle diameter (D50)" or "volume average particle diameter D50". For the volume average particle diameter D50 of the inorganic powder contained in the powder cosmetic according to the present disclosure, reagent-grade hexane (solvent refractive index: 1.38) (manufactured by FUJIFILM Wako Pure Chemical Corporation) can be used as a dispersion solvent, which is dispersed by in-device circulation, and measurement can be performed using a Microtrac MT3300EXII (particle size distribution meter manufactured by Microtrac) at a concentration within an appropriate range of a device loading index (Loading Index) at a circulation speed of 50% (65 mL / sec when 100%).

[0136] The average particle diameter of the inorganic powder according to the present disclosure is not particularly limited and is, for example, 1 pm to 100 pm. Note that, from the viewpoint that a use feeling is not obtained when the average particle diameter of the inorganic powder is too small and the use feeling is poor when the average particle diameter is too large, the average particle diameter is preferably 3 pm to 60 pm, more preferably 4 pm to 40 pm, further preferably 5 pm to 30 pm, and particularly preferably 6 pm to 20 pm.

[0137] (Other powders)

[0138] The powder cosmetic according to the present disclosure can contain other powders than the aforementioned inorganic powder whose part or all of the surface is coated with the polyaspartic acid alkali salt, as long as the effect thereof is not impaired. As examples of the other powders, there are inorganic powders exemplified above in a state where the surface is not coated with the polyaspartic acid alkali salt, organic pigment-coated mica titanium, nylon powder, polymethyl methacrylate powder, acrylonitrile-methacrylic acid copolymer powder, vinylidene chloride-methacrylic acid copolymer powder, polyethylene powder, polystyrene powder, organic polysiloxane elastomer powder, polymethylsilsesquioxane powder, polyurethane powder, wool powder, silk powder, or crystalline cellulose powder, and the like organic powders, or pigment powders such as organic tar-based pigments or lake pigments, and the like. In addition, the powder cosmetic according to the present disclosure can contain the additional ingredients described below in the column of powder cosmetic composition to be described later, as long as the effect thereof is not impaired.

[0139] <Method for producing powder cosmetic>

[0140] The method for producing the powder cosmetic according to the present disclosure can include the following steps: a step of mixing an inorganic powder with a polyaspartic acid alkali salt to obtain a mixture containing the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali salt; a step of pulverizing the aforementioned mixture; and a step of drying the pulverized aforementioned mixture.

[0141] The powder cosmetic according to the present disclosure can be produced by the aforementioned production method. However, the method for producing the powder cosmetic according to the present disclosure is not limited to the aforementioned production method, and the powder cosmetic according to the present disclosure can be produced by other methods.

[0142] The mixing of the inorganic powder with the polyaspartic acid alkali salt can be performed at room temperature, but is not limited thereto, and can be performed at any temperature at which the aqueous solution of the polyaspartic acid alkali salt does not freeze or boil. For example, the mixing can be performed at a temperature in the range of 5°C to 95°C. At the time of mixing, an aqueous medium can be present, but can not be present. That is, the step of mixing the aforementioned inorganic powder with the polyaspartic acid alkali salt can or can not include a step of mixing the inorganic powder, the polyaspartic acid alkali salt, and the aqueous medium. The aforementioned aqueous medium can be water alone, or a mixed solvent of water and a water-miscible solvent. As examples of such water-miscible solvents, there are methanol, ethanol, propanol, and ethylene glycol, or the like alcohol, or acetone, or the like.

[0143] The mixing of inorganic powders with polyaspartic alkali metal salts can be performed using a disperser, Henschel mixer, Loedige mixer, kneader, V-mixer, roller mill, bead mill, or twin-screw mixer. The mixing time can be set from 1 minute to 1 hour, or from 2 minutes to 20 minutes. Mixing can be performed, for example, by adding the polyaspartic alkali metal salt to the inorganic powder or to a mixture containing the inorganic powder and an aqueous medium, or by adding an aqueous solution of the polyaspartic alkali metal salt. In this case, the polyaspartic alkali metal salt can be added in its entirety initially, or in portions multiple times.

[0144] The amount of polyaspartic acid alkali metal salt added can be set to 0.00000095–0.0045 or 0.000035–0.0010 relative to the total amount of inorganic powder and polyaspartic acid alkali metal salt. By setting the amount of polyaspartic acid alkali metal salt added to 0.00000095–0.0045 relative to the total amount of inorganic powder and polyaspartic acid alkali metal salt, it is possible to further obtain a powder cosmetic with smooth spreadability and low skin resistance, and which is less prone to makeup smudging. It should be noted that when mixing inorganic powder and polyaspartic acid alkali metal salt, in addition to inorganic powder and polyaspartic acid alkali metal salt, other powders mentioned above and additional ingredients listed in the powder cosmetic composition section below can also be mixed together.

[0145] The description of the types and weight-average molecular weight of polyaspartic acid alkali metal salts in the manufacturing method of powder cosmetics disclosed herein can be adapted from the above-mentioned description of the types and weight-average molecular weight of polyaspartic acid alkali metal salts in the powder cosmetics disclosed herein. Similarly, the description of the formula satisfying the weight-average molecular weight x of polyaspartic acid alkali metal salts and the mass ratio y of the aforementioned polyaspartic acid alkali metal salts relative to the total amount of the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali metal salts in the manufacturing method of powder cosmetics disclosed herein can be adapted from the above-mentioned description of the formula satisfying the weight-average molecular weight x of polyaspartic acid alkali metal salts and the mass ratio y of the aforementioned polyaspartic acid alkali metal salts relative to the total amount of the aforementioned inorganic powder and the aforementioned polyaspartic acid alkali metal salts in the powder cosmetics disclosed herein.

[0146] The mixture obtained by the aforementioned mixing, which contains the inorganic powder and the polyaspartic acid alkali metal salt, or the mixture obtained by the aforementioned mixing and further containing an aqueous medium, is subjected to a pulverization treatment. The pulverization treatment can be performed using a jaw crusher, a gyratory crusher, an impact crusher, a cone crusher, a roll crusher, a chopper, an autogenous pulverizer, a stamp mill, a stone mill type, a mortar, a polisher, a ring mill, a roller mill, an air jet pulverizer, a hammer mill, a pin mill, a rotary mill, a vibration mill, a planetary mill, an attritor, a bead mill, or an atomizer, or the like. A suitable pulverizer can be selected in a manner such that a desired particle diameter appropriate for the use of the powder cosmetic can be obtained.

[0147] The mixture after the pulverization treatment can be arbitrarily filtered as needed. By performing the filtration, the inorganic powder having a desired particle diameter can be recovered, and in the presence of the aqueous medium, drying can be facilitated by separating the inorganic powder from the aqueous medium. The pore size of the filter used in the filtration can be selected according to the desired particle diameter.

[0148] By drying the mixture in the mixture after the aforementioned pulverization treatment, or by drying the inorganic powder obtained by the aforementioned filtration arbitrarily performed, a powder cosmetic containing the inorganic powder having a part or all of the surface coated with the polyaspartic acid alkali metal salt can be obtained. The method of drying is not particularly limited. The drying can be performed by natural drying, under reduced pressure, or under heating. In the case of performing the reduced pressure, for example, the reduced pressure can be performed to an absolute pressure of about 1 kPa to about 20 kPa, and in the case of performing the heating, for example, the drying can be performed by heating to about 60°C to about 150°C.

[0149] The inorganic powder having a part or all of the surface coated with the polyaspartic acid alkali metal salt obtained by the drying can be arbitrarily mixed with the other powder described above.

[0150] <<Cosmetic Composition>>

[0151] The powder cosmetic according to the present disclosure can be used alone in the form of a powder, but can also be used in a form containing the powder cosmetic according to the present disclosure and a cosmetic composition selected from at least one of water and an oil agent. That is, the cosmetic composition according to the present disclosure can be prepared to contain the powder cosmetic according to the present disclosure and a cosmetic composition selected from at least one of water and an oil agent. Even in the case of use in such a cosmetic composition, the cosmetic composition according to the present disclosure exerts an effect of having a smooth extensibility with less resistance to the skin, and is less likely to cause makeup removal.

[0152] As examples of the oil agent, there are hydrocarbons such as paraffin wax, ceresin wax, ozokerite, microcrystalline wax, montan wax, Fischer-Tropsch wax, polyethylene wax, liquid paraffin, squalane, vaseline, polyisobutylene, or polybutene; natural waxes such as carnauba wax, beeswax, lanolin wax, or candelilla wax; esters such as glycerin tribehenate, pentaerythritol myristate, jojoba oil, isooctanoic acid cetyl ester, isopropyl myristate, glycerin trioctanoate, diglycerin triisostearate, or fatty acid dipentaerythritol ester; fatty acids such as stearic acid, behenic acid, or 12-hydroxystearic acid; higher alcohols such as cetyl alcohol, stearyl alcohol, or behenyl alcohol; oils and fats such as olive oil, castor oil, mink oil, or wood wax; lanolin derivatives such as isopropyl lanolin fatty acid ester or lanolin alcohol; amino acid derivatives such as N-lauroyl-L-glutamic acid di(cholesteryl / behenyl / octyldodecyl) ester; or fluorine-based oil agents such as perfluoropolyether, perfluorodecane, or perfluorooctane.

[0153] The cosmetic composition according to the present disclosure can contain components other than the above-mentioned powder cosmetic, water, and oil agent, as long as the effects thereof are not impaired. As examples of such additional components, there are components generally used in cosmetics, such as water-miscible solvents, surfactants, oil gelation agents, polyhydric alcohols or water-soluble components such as humectants, ultraviolet absorbers, preservatives, cosmetic components, or fragrances.

[0154] The cosmetic composition according to the present disclosure can be produced by mixing the powder cosmetic according to the present disclosure with at least one of water and an oil agent, and optionally the aforementioned other components.

[0155] The form (cosmetic product form) of the powder cosmetic according to the present disclosure and the cosmetic composition according to the present disclosure is not particularly limited, and can be appropriately selected according to the purpose. The powder cosmetic according to the present disclosure or the cosmetic composition according to the present disclosure can be, for example, a powder, a pressed powder, a two-way cake, a powder foundation, a liquid foundation, a cream foundation, a concealer, a BB cream, a CC cream, a base makeup, a primer, an eye shadow, or a blush.

[0156] As described above, according to the powder cosmetic according to the present disclosure and the cosmetic composition according to the present disclosure, a smooth extensibility with less resistance to the skin, and an effect that makeup is less likely to come off, are exerted.

[0157] Examples

[0158] Hereinafter, the present disclosure will be described more specifically by way of examples, but the present disclosure is not limited to the following examples, as long as the gist thereof is not deviated. Note that, unless otherwise specified, "parts" is based on mass. The same applies to "%".

[0159] <Example 1>

[0160] An aqueous solution of sodium polyaspartate A was prepared by the following operation. First, 320 g of L-aspartic acid (FUJIFILM Wako Pure Chemical Corporation, reagent special grade) was spread in a SUS-made bucket, and left in an oven at 230°C for 4 hours under normal pressure in a nitrogen atmosphere, whereby 233 g of a powder of polyaspartic acid was obtained. To the obtained 233 g of polyaspartic acid, 166 g of distilled water was added while controlling the temperature of the solution to be 45°C to 55°C, and 32 mass% sodium hydroxide aqueous solution was added little by little each time. When the reagents became fluid, pH measurement was started, and 32 mass% sodium hydroxide aqueous solution was further added while measuring the pH, and the addition was ended when the pH did not change in the range of pH 10 to pH 10.5. The 32 mass% sodium hydroxide aqueous solution used was 291 g. As a result, a uniform brown transparent aqueous solution of sodium polyaspartate A was obtained. Further, 128 g of distilled water was added, whereby 818 g of a 40 mass% aqueous solution of sodium polyaspartate A was obtained.

[0161] The molecular weight of sodium polyaspartate A contained in the obtained 40 mass% aqueous solution of sodium polyaspartate A was measured, and as a result, the weight average molecular weight (Mw) was 22,000, and the number average molecular weight (Mn) was 14,000. Note that the molecular weight measurement was performed using the above-described gel permeation chromatography (GPC) device and GPC measurement method.

[0162] As an inorganic powder, 1.0 kg of talc (Shoda Seiren Co., Ltd., JA-46R (for cosmetics)) was charged into a Henschel mixer (Model FM10C / I: Nippon Coke & Engineering Co., Ltd.). Further, the above-described 40 mass% aqueous solution of sodium polyaspartate A was used to add a solution obtained by diluting 10 g of distilled water in such a manner that the addition amount of sodium polyaspartate A with respect to the inorganic powder was the prescribed amount shown in Table 1 (the mass ratio of the above-described sodium polyaspartate A with respect to the total amount of the inorganic powder and sodium polyaspartate A was 0.0004). When half of the prescribed amount of the above-described 40 mass% aqueous solution of sodium polyaspartate A was added, the addition was temporarily stopped, and the Henschel mixer was used to mix for 3 minutes at 3000 rpm (revolutions / minute). The remaining half of the prescribed amount of the above-described 40 mass% aqueous solution of sodium polyaspartate A was further added, and the Henschel mixer was used to mix for 3 minutes at 3000 rpm (revolutions / minute).

[0163] The powder after mixing with a Henschel mixer was given to an ultrafine jet mill (Model K2-1, Fuji Paudal Co, Ltd.) to pulverize the solid components. The pulverization with the ultrafine jet mill was performed with a screen diameter of 2 mmφ, a screw pitch of 20 mm, and a stepped gasket. The pulverization time was set to 30 to 60 minutes. The obtained pulverized product was filtered using a filter cloth having a pore size of 2 mm, and the powder on the filter cloth was recovered.

[0164] The recovered powder was dried with an apparatus dryer. As for the drying temperature and the drying time, drying was performed at 80°C for 3 hours, and then drying was performed by leaving at 40°C overnight. As a result of the drying, an inorganic powder of which a part or all of the surface was coated with sodium polyaspartate A (hereinafter, also referred to as "mixed powder") was obtained.

[0165] <Examples 2 to 5 and Comparative Example 2>

[0166] In Examples 2 to 5 and Comparative Example 2, the mass ratio of the aforementioned sodium polyaspartate A with respect to the total amount of the inorganic powder and sodium polyaspartate A was changed as described in Table 1, and otherwise, the same operation as in Example 1 was performed to obtain a mixed powder.

[0167] <Comparative Example 1>

[0168] In Comparative Example 1, 10 g of a 40 mass% aqueous solution of sodium polyaspartate A was added to 1.0 kg of the inorganic powder, and the mass ratio of the aforementioned sodium polyaspartate A with respect to the total amount of the inorganic powder and sodium polyaspartate A was changed to 0.004, and otherwise, the same operation as in Example 1 was performed to obtain a mixed powder.

[0169] <Example 6>

[0170] In Example 6, instead of the polyaspartic acid sodium A in Example 1, polyaspartic acid sodium B obtained by the following operation was used. According to the method of Example 1 of Japanese Patent No. 3384420, L-aspartic acid 133.0 g and liquid paraffin (FUJIFILM Wako Pure Chemical Corporation, reagent grade) 200 g were added to a 1 L flask. It was allowed to react at 220°C for 4 hours, and cooled to 50°C. Further, 14% sodium hydroxide aqueous solution 286.0 g was added, and stirred for 1 hour. The reaction product was separated into a water layer and an organic layer, and the water layer was taken out. The obtained water layer was turbid due to the residual liquid paraffin. Diatomaceous earth and activated carbon were added to treat the water layer, whereby a uniform yellow transparent polyaspartic acid sodium B aqueous solution was obtained. The molecular weight measurement of the polyaspartic acid sodium B was performed by the GPC measurement method, and as a result, the weight average molecular weight (Mw) was 10,000, and the number average molecular weight (Mn) was 7,000. Using the polyaspartic acid sodium B, the same operation as Example 1 was performed except for the mass ratio of the aforementioned polyaspartic acid sodium B to the total amount of the inorganic powder and the polyaspartic acid sodium B, and a mixed powder was obtained.

[0171] <Example 7, Example 8, and Comparative Example 4>

[0172] In Example 7, Example 8, and Comparative Example 4, the mass ratio of the aforementioned polyaspartic acid sodium B to the total amount of the inorganic powder and the polyaspartic acid sodium B was changed as described in Table 1, and the same operation as Example 6 was performed except for this, and a mixed powder was obtained.

[0173] <Comparative Example 3>

[0174] In Comparative Example 3, to the inorganic powder 1.0 kg, 30 mass% polyaspartic acid sodium B aqueous solution 58.7 g was added, and the mass ratio of the aforementioned polyaspartic acid sodium B to the total amount of the inorganic powder and the polyaspartic acid sodium B was changed to 0.0176, and the same operation as Example 6 was performed except for this, and a mixed powder was obtained.

[0175] <Example 9>

[0176] In Example 9, instead of the polyaspartic acid sodium A in Example 1, polyaspartic acid sodium C obtained by the following operation was used.

[0177] That is, L-aspartic acid (FUJIFILM Wako Pure Chemical Corporation, reagent special grade) 118 g, sulfolane (FUJIFILM Wako Pure Chemical Corporation, no grade) 235 g, xylene (FUJIFILM Wako Pure Chemical Corporation, and light special grade) 83 g, and 35% hydrochloric acid (FUJIFILM Wako Pure Chemical Corporation, reagent special grade) 70 g were charged into a 3L four-necked flask, and a reaction was performed at 110°C to 115°C for 3 hours. For the water of distillation, collection and extraction were suitably performed using a Dean-Stark apparatus. Then, a reaction was performed at 118°C to 147°C for 5 hours, and at 147°C to 154°C for 5 hours. Further, at 154°C to 162°C, xylene was collected and extracted for 2 hours using a Dean-Stark apparatus. Then, acetonitrile (FUJIFILM Wako Pure Chemical Corporation, reagent special grade) 1600 g was added, and crystallization was performed and stirred at room temperature for 1 hour. Then, filtration was performed using filter paper having a pore size of 7 μm, and the white powder remaining on the filter paper was dried for 24 hours at 70°C, 5 torr using a vacuum drier, whereby white powder of polysuccinimide 81 g was obtained. To the obtained polysuccinimide 81 g, distilled water 99 g was added, while controlling the temperature of the solution to be 45°C to 55°C, and 32 mass% sodium hydroxide aqueous solution was added little by little each time. When the reaction became fluid, pH measurement was started, and 32 mass% sodium hydroxide aqueous solution was further added while measuring the pH, and the addition was ended when the pH did not change in the range of pH 10 to pH 10.5. The 32 mass% sodium hydroxide aqueous solution used was 94 g. As a result, a uniform yellow transparent aqueous solution of polysodium aspartate C was obtained. Further, distilled water 12 g was added, whereby 40 mass% aqueous solution of polysodium aspartate C 286 g was obtained. The molecular weight measurement of the obtained polysodium aspartate C was performed using a GPC measurement method, and as a result, the weight average molecular weight (Mw) was 50,000, and the number average molecular weight (Mn) was 30,000.

[0178] Polysodium aspartate C was used, and the mass ratio of the aforementioned polysodium aspartate C with respect to the total amount of the inorganic powder and the polysodium aspartate C was changed to 0.00001, and otherwise, the same operation as in Example 1 was performed, whereby a mixed powder was obtained.

[0179] <Example 10, Example 11, and Comparative Examples 5 to 7>

[0180] In Example 10, Example 11, and Comparative Examples 5 to 7, the mass ratio of the aforementioned polyaspartic acid sodium C with respect to the total amount of the inorganic powder and polyaspartic acid sodium C was changed as described in Table 1, and otherwise, the same operation as in Example 9 was performed to obtain a mixed powder.

[0181] <Example 12>

[0182] In Example 12, instead of polyaspartic acid sodium A in Example 1, polyaspartic acid sodium D obtained by the operation described below was used.

[0183] That is, L-aspartic acid (FUJIFILM Wako Pure Chemical Corporation, reagent special grade) 58 g, and sulfolane (FUJIFILM Wako Pure Chemical Corporation, no grade) 96 g and polyphosphoric acid-105 (Nippon Shokubai Co., Ltd.) 29 g were charged in a 3L four-necked flask, and a reaction was performed at 155°C to 175°C for 3 hours. With respect to the distilled water, collection and extraction were appropriately performed using a Dean-Stark device. Then, dilution was performed using N,N-dimethylformamide (FUJIFILM Wako Pure Chemical Corporation, reagent special grade) 203 g, and cooling was performed to 50°C. Further, methanol (FUJIFILM Wako Pure Chemical Corporation, reagent special grade) 348 g was added, and crystallization was performed and stirring was performed at room temperature for 1 hour. Then, filtration was performed using filter paper having a pore size of 7 μm, and white powder remaining on the filter paper was dried using a vacuum drier at 100°C, 5 torr for 24 hours, whereby poly-succinimide 43 g of white powder was obtained. To the obtained poly-succinimide 43 g, distilled water 51 g was added, while controlling the temperature of the solution to be 45°C to 55°C, and 32 mass% sodium hydroxide aqueous solution was added little by little each time. When the reagent obtained fluidity, pH measurement was started, and further 32 mass% sodium hydroxide aqueous solution was added while measuring the pH, and the addition was ended when the pH did not change in the range of pH 10 to pH 10.5. The 32 mass% sodium hydroxide aqueous solution used was 55 g. As a result, a uniform yellow transparent polyaspartic acid sodium D aqueous solution was obtained. Further, distilled water 3 g was added, whereby 152 g of a 40 mass% polyaspartic acid sodium D aqueous solution was obtained. The molecular weight measurement of the obtained polyaspartic acid sodium D was performed using a GPC measurement method, and as a result, the weight average molecular weight (Mw) was 120,000, and the number average molecular weight (Mn) was 48,000.

[0184] Polyaspartic acid sodium D was used, and the mass ratio of the aforementioned polyaspartic acid sodium D with respect to the total amount of the inorganic powder and polyaspartic acid sodium D was changed to 0.000001, and otherwise, the same operation as in Example 1 was performed to obtain a mixed powder.

[0185] <Comparative Example 8 and Comparative Example 9>

[0186] In Comparative Example 8 and Comparative Example 9, the mass ratio of the aforementioned polyaspartic acid sodium D with respect to the total amount of the inorganic powder and polyaspartic acid sodium D was changed as described in Table 1, and otherwise, the same operation as in Example 12 was performed to obtain a mixed powder.

[0187] <Example 13>

[0188] In Example 13, sericite (manufactured by Ohchem Commerce Co., Ltd., OC-100R) was used as the inorganic powder, and otherwise, the same operation as in Example 1 was performed to obtain a mixed powder.

[0189] <Comparative Example 10>

[0190] In Comparative Example 10, 40 mass% polyaspartic acid sodium A aqueous solution 10 g was added to 1.0 kg of inorganic powder, and the mass ratio of the aforementioned polyaspartic acid sodium A with respect to the total amount of the inorganic powder and polyaspartic acid sodium A was changed to 0.004, and otherwise, the same operation as in Example 13 was performed to obtain a mixed powder.

[0191] <Example 14>

[0192] In Example 14, mica (manufactured by Yamaguchi Mica Co., Ltd., Y-2300X) was used as the inorganic powder, the mass ratio of the aforementioned polyaspartic acid sodium A with respect to the total amount of the inorganic powder and polyaspartic acid sodium A was changed to 0.0001, and otherwise, the same operation as in Example 1 was performed to obtain a mixed powder.

[0193] <Measurement of Powder Layer Shear Force>

[0194] For the inorganic powder (mixed powder) in which a part or all of the surface was covered with polyaspartic acid alkali metal salt obtained in Examples 1 to 14 and Comparative Examples 1 to 10, powder layer shear force measurement was performed by the following operation to obtain a failure envelope of the powder layer.

[0195] (Measurement Method of Powder Layer Shear Force)

[0196] As a device for measuring the powder layer shear force, a powder layer shear force measuring device NS-S500 (manufactured by NanoSeeds Corporation) was used.

[0197] The method for measuring the powder layer shear force is described below.

[0198] (1) The inside of a cylindrical sample cell (upper fixed sample cell, lower movable sample cell) was filled with a powder sample, and vertical stress was slowly applied at a certain speed.

[0199] (2) After the vertical stress reached 150 N, the application of vertical stress was stopped, and the relaxation time of the powder layer was set in a constant volume state.

[0200] (3) After stress relaxation was sufficiently performed, an external force in the horizontal direction was applied to the sample cell at a certain speed.

[0201] (4) After the shear reached a steady state (i.e., a state in which the values of the vertical stress and the shear stress each became constant), the vertical stress was slowly attenuated while maintaining the external force in the horizontal direction.

[0202] (5) During the aforementioned attenuation process, the vertical stress and the shear stress were detected, and the shear stress τ (vertical axis; y-axis) corresponding to each vertical stress σ (horizontal axis; x-axis) obtained was plotted to obtain a failure envelope.

[0203] Note that the measurement conditions of the powder layer shear force are described in more detail below.

[0204] Sample amount: 20 g

[0205] Sampling frequency: 10 Hz

[0206] Device configuration identification symbol: BF22XB

[0207] Inner diameter of the upper fixed sample cell: 43 mm

[0208] Depth of the lower movable sample cell: 5 mm

[0209] Shear rate: 10 μm / sec

[0210] Shear band thickness: 0.2 mm

[0211] Compression rate: 0.2 mm / sec

[0212] Note that in (2) of the measurement method of the powder layer shear force, the vertical stress was set to 150 N, assuming the pressure applied to the skin when the powder cosmetic is applied to the skin.

[0213] The curve degree was obtained from the failure envelope obtained using each mixed powder. The curve degree was calculated from the formula: curve degree = [slope of straight line of lower portion of failure envelope] / [slope of straight line of upper portion of failure envelope]. Note that the slope of straight line of lower portion of failure envelope indicates the slope of straight line of failure envelope when the value of vertical stress σ is 0% to 30% in the case where the vertical stress σ at the time when the vertical stress σ and the shear stress τ become a steady state is taken as 100%. The slope of straight line of upper portion of failure envelope indicates the slope of straight line of failure envelope when the value of vertical stress σ is 70% to 100% in the case where the vertical stress σ at the time when the vertical stress σ and the shear stress τ become a steady state is taken as 100%.

[0214] The relative values [-] of the curve degree of each mixed powder in Examples 1 to 14 and Comparative Examples 1 to 10 are shown in Table 1, when the value of the curve degree of the inorganic powder alone is taken as 1.00. Note that in Table 1, the relative value of the curve degree, the mass ratio of polyaspartic acid alkali metal salt, and the weight average molecular weight of polyaspartic acid alkali metal salt do not have units, and therefore the units are expressed with [-].

[0215] A mixed powder having a relative value of the curve degree greater than 1.00 indicates that the slidability is decreased compared to the inorganic powder before the addition of polyaspartic acid alkali metal salt (i.e., the inorganic powder alone). A mixed powder having a relative value of the curve degree less than 1.00 indicates that the slidability is increased compared to the inorganic powder before the addition of polyaspartic acid alkali metal salt. When the relative value of the curve degree of a mixed powder is less than 1.00, it is judged that "the mixed powder has a smooth extensibility with less resistance feeling to the skin at the time of overcoating, and is not likely to cause makeup removal."

[0216] [Table 1]

[0217]

[0218] In Examples 1 to 14 and Comparative Examples 1 to 10, the relationship of the relative value of the curve degree with respect to the weight average molecular weight of polyaspartic acid alkali metal salt [-] and the mass ratio of polyaspartic acid alkali metal salt [-] is shown in Figure 2 . Note that Figure 2 in which the horizontal axis is the weight average molecular weight of polyaspartic acid alkali metal salt. The weight average molecular weight is a relative value, and therefore the unit is expressed with [-]. Figure 2In the graph, the vertical axis is the mass ratio of the polyaspartic acid alkali metal salt (i.e., the mass ratio of the aforementioned polyaspartic acid alkali metal salt with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt). The mass ratio of the polyaspartic acid alkali metal salt does not have a unit, and thus the unit is expressed with [-]. Note that the vertical axis is expressed on a logarithmic axis. Figure 2 In the graph, the black circles indicate examples, i.e., indicate that the relative value of the curve degree of the mixed powder is less than 1.00. The white circles indicate comparative examples.

[0219] From Table 1 and Figure 2 It was confirmed that the relative value of the curve degree depends on the weight average molecular weight [-] of the polyaspartic acid alkali metal salt and the mass ratio of the polyaspartic acid alkali metal salt.

[0220] According to the above, among the examples included in the region surrounded by the aforementioned formula (1) (or the aforementioned formula (3) or formula (4)) and the aforementioned formula (2) (or the aforementioned formula (5)) and the weight average molecular weight x of the polyaspartic acid alkali metal salt being in the range of 1,000 to 150,000 (or 8,000 to 120,000) with respect to the weight average molecular weight x of the polyaspartic acid alkali metal salt and the mass ratio y of the polyaspartic acid alkali metal salt with respect to the total amount of the inorganic powder and the polyaspartic acid alkali metal salt, in Examples 1 to 14, a powder cosmetic having less resistance feeling to the skin at the time of overcoating of the powder cosmetic and smooth extensibility and not easily causing makeup removal can be obtained. On the other hand, in Comparative Examples 1 to 10 not included in the region surrounded by the aforementioned range, the powder cosmetic as described above cannot be obtained.

[0221] The entire disclosure of Japanese Patent Application No. 2020-154913 filed on September 15, 2020 is incorporated herein by reference.

[0222] All of the documents, patent applications and technical standards cited in this specification are incorporated herein by reference to the same extent as if each document, patent application or technical standard were specifically and individually indicated to be incorporated by reference.

Claims

1. A powder cosmetic comprising: an inorganic powder, and a polyaspartic acid alkali metal salt that coats a part or all of the surface of the inorganic powder; the inorganic powder contains at least one selected from the group consisting of talc, mica, and sericite; a weight average molecular weight x of the polyaspartic acid alkali metal salt is 8,000 to 120,000, a mass ratio y of the polyaspartic acid alkali metal salt with respect to a total amount of the inorganic powder and the polyaspartic acid alkali metal salt is 0.000035 to 0.0010, and the weight average molecular weight x of the polyaspartic acid alkali metal salt and the mass ratio y of the polyaspartic acid alkali metal salt with respect to a total amount of the inorganic powder and the polyaspartic acid alkali metal salt satisfy the following formula (1) and formula (2): y < 1.6 x 10 7 x -2.275 Equation (1), y > 1.3 x 10 5 x -2.232 Formula (2).

2. The powder cosmetic according to claim 1, wherein the weight average molecular weight x of the polyaspartic acid alkali metal salt and the mass ratio y of the polyaspartic acid alkali metal salt with respect to a total amount of the inorganic powder and the polyaspartic acid alkali metal salt further satisfy the following formula (3): y < 1.0 x 10 7 x -2.275 Formula (3).

3. The powder cosmetic according to claim 1, wherein the weight average molecular weight x of the polyaspartic acid alkali metal salt and the mass ratio y of the polyaspartic acid alkali metal salt with respect to a total amount of the inorganic powder and the polyaspartic acid alkali metal salt further satisfy the following formula (4): y < 8.0 x 10 6 x -2.275 Formula (4).

4. The powder cosmetic according to claim 1 or claim 2, wherein the weight average molecular weight x of the polyaspartic acid alkali metal salt and the mass ratio y of the polyaspartic acid alkali metal salt with respect to a total amount of the inorganic powder and the polyaspartic acid alkali metal salt further satisfy the following formula (5): y > 1.5 x 10 5 x -2.232 Formula (5).

5. The powder cosmetic according to claim 1 or claim 2, wherein the polyaspartic acid alkali metal salt is at least one selected from the group consisting of polyaspartic acid lithium, polyaspartic acid potassium, and polyaspartic acid sodium.

6. The powder cosmetic according to claim 1 or claim 2, wherein the polyaspartic acid alkali metal salt contains at least polyaspartic acid sodium.

7. The powder cosmetic according to claim 1 or claim 2, wherein an average particle diameter D50 of the inorganic powder is 1 μm to 100 μm.

8. A cosmetic composition comprising the powder cosmetic according to claim 1 or claim 2, and at least one selected from water and an oil agent.

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