JP2003121259A - Evaluation method for washing agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To evaluate a washing effect without depending on a difference in a color of the skin, a color of a make-up cosmetic or the like, and to objectively exactly evaluate a washing agent and a washing method. SOLUTION: This method comprises a method for finding a residual rate of the cosmetic on the skin based on a ratio of inter-coordinate distances on a three-dimensional coordinate shown by an L*a*b* color specification value expressing the color of the skin by an L*a*b* color specification method, and a method for evaluating the washing effect based on the ratio of the inter- coordinate distances on the three-dimensional coordinate shown by the L*a*b* color specification value expressing the color of the skin by the L*a*b* color specification method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating the degree of cleansing of cosmetics and external preparations for skin adhering to the skin.

[0002]

2. Description of the Related Art After using cosmetics, especially makeup cosmetics, it is important to remove unnecessary components on the skin when the makeup is removed by washing the face. A variety of facial cleansers and cleansing agents, which are cosmetics for such face washing, have been developed.

By the way, there is no index for evaluating the accuracy of the cleaning with respect to the cleaning method using such a face wash and the cleaning action thereof, and it often depends on the visual evaluation. Therefore, the evaluation result is largely dependent on the sensitivity of the person who evaluates the evaluation result, which results in a subjective evaluation, which makes it difficult to make an objective evaluation.
Therefore, it has been desired to develop a cleaning method and a method for accurately evaluating the cleaning action of a facial cleansing cosmetic.

[0004]

The present invention provides a cleaning method,
It is an object of the present invention to provide a method for accurately evaluating the cleaning action of a facial cleansing cosmetic composition.

[0005]

The present inventor has found that the cleaning effect can be evaluated by showing the skin color in three-dimensional coordinates and measuring the coordinate change of the skin color.

That is, the present invention is as follows: The residual rate of the cosmetics on the skin is obtained from the ratio of the distance between the coordinates on the three-dimensional coordinates, which is the L ^* a ^* b ^* colorimetric value of the skin color as the L ^* a ^* b ^* colorimetric value Method, and 2. A method for evaluating the cleaning action by the ratio of the inter-coordinate distances on the three-dimensional coordinates, which indicates the skin color by the L ^* a ^* b ^* colorimetric method as the L ^* a ^* b ^* colorimetric method value. Regarding

According to the evaluation method of the present invention, it is possible to make an objective evaluation without being influenced by the skin color and the color of the makeup cosmetics used.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION L ^* a ^* used in the present invention
The b ^* colorimetric method is a colorimetric method commonly used in various fields to represent the color of an object, and is adopted in JIS. In the L ^* a ^* b ^* colorimetric method, the lightness is L ^* ,
Chromaticity indicating hue and saturation is represented by a ^* b ^* . a ^* b
^* Indicates the direction of color, a ^* indicates the red direction, -a ^* indicates the green direction, b ^* indicates the yellow direction, and -b ^* indicates the blue direction. The color becomes vivid as these values increase, and becomes dull as it approaches zero. This can be measured using a spectrophotometer.

In the present invention, the skin color is L ^* a ^* b ^*.
It is expressed in three-dimensional coordinates by the color specification method. Skin color L ^* a ^*
b ^* The difference in skin color can be indicated by the inter-coordinate distance in three-dimensional coordinates by the color specification method. By obtaining the ratio of the inter-coordinate distances, it is possible to objectively show the change in the skin color without being affected by the skin color or the color of makeup cosmetics used.

Specifically, before applying makeup cosmetics
And, after applying, measure the skin color, L ^*a^*b^*Colorimetric
Each value is shown. Next, use a cleaning agent to apply makeup.
Rinse away the cosmetics and then the skin's L^*a^*b^*Color
Measure each value according to the method. Makeup cosmetics
L before application^*a^*b^*The point in the three-dimensional coordinate of the value and after application
L^*a^*b^*The distance between the coordinates of the value and the point in three-dimensional coordinates (R
₁) Indicates that all makeup cosmetics remain.
Forget L before applying makeup cosmetics^*a^*b ^*Three of value
L after washing with a point in dimensional coordinates and a washing agent^*a^*b^*
The distance between the coordinates of the value and the point in three-dimensional coordinates (R_Two) Is Mei
When makeup cosmetics are washed away by cleaning agents,
Represents the state in which makeup cosmetics remain.

The inter-coordinate distance R between two points (point I and point II) in three-dimensional coordinates is calculated by the following equation 1. _{^{R = [(L * I -L}} * II) 2 + (a * I -a * II) 2 + (b * I -b * II) 2] 1/2 ...... Formula 1 In the formula, R, The distance between the coordinates of the two points I and II, L ^*
_I and L ^* _II are the lightness of point I and point II, a ^* _I and b, respectively.
^* _I , a ^* _II , and b ^* _II represent the chromaticity of point I and point II, respectively. ]

The residual rate K of the makeup cosmetics after cleaning with the cleaning agent can be expressed by the following equation (2). K = R ₂ / R ₁ × 100 (%) (Equation 2) When the residual rate K is large, it means that a large amount of makeup cosmetics remains unwashed and the cleaning action of the used cleaning agent is weak.

[0013]

[Examples] Evaluation test of facial cleansing effect by facial cleansers Facial cleansers A and B were manufactured according to the formulations shown in Table 1 below.

[0014]

[Table 1]

For the two subjects (subjects 1 and 2),
Measure the skin color of the skin before going to L ^*a^*b^*Ask for a value
It was Next, apply a lip color (red) on the skin and
Measure the skin color of^*a^*b^*The value was calculated. Furthermore
To the face wash A and B produced according to the formulation shown in Table 1.
Use to measure the skin color after washing your face and
L^*a^*b^*The value was calculated. The values are shown in Table 2 (Subject 1) and
2 and 3 (subject 2). Cleaning charge A was used for subject 1.
Residual rate of makeup cosmetics when used K_A1And the subject
Makeup cosmetics remaining when using the cleaning agent A in 2
Rate K_A2, Subject 1 when using cleaning charge B
Residual rate of makeup cosmetics K_B1And the cleaning charge B for subject 2
Makeup cosmetics residual ratio K when using_B2Is that
The results are shown in Tables 2 and 3, respectively.

[0016]

[Table 2]

[0017]

[Table 3]

L ^* in the case of using the face wash A of the subject 1
The a ^* b ^* values are shown in FIG. 1 as point I (before make-up), point II (after make-up, that is, after lip color application) and point III (after face wash with face wash A), respectively. Tables 4 and 5 show the results of the same evaluation using the eye color (blue).

[0019]

[Table 4]

[0020]

[Table 5]

In each case, the makeup remaining rate K
Value of the cleaning agent B is about 3 to 7 times that of the cleaning agent A, and the cleaning with the cleaning agent A shows an excellent cleaning effect as compared with the case of the cleaning agent B. Can be evaluated. In addition, the visual evaluation before and after the cleaning using the cleaning agents A and B and the evaluation of the actual use by the test subjects all showed that the cleaning agent A was superior. From this result, it can be seen that the cleaning effect of the cleaning agent can be comparatively evaluated without depending on the difference in skin color between subjects and the color of makeup cosmetics.

[0022]

Industrial Applicability According to the present invention, a cleaning effect can be evaluated without depending on the difference in skin color, the color of makeup cosmetics and the like, and a method for objectively and accurately evaluating the cleaning agent and cleaning method is provided. be able to.

[Brief description of drawings]

FIG. 1 is a three-dimensional coordinate showing L ^* a ^* b ^* values for evaluating the cleaning power of a lip color (red) with a cleaning material A.

Claims (2)

[Claims] 1. The skin color is L ^* by L ^* a ^* b ^* colorimetric method ^.
a ^* b ^* A method of obtaining the residual rate of the cosmetics on the skin by the ratio of the inter-coordinate distances on the three-dimensional coordinates indicated by the colorimetric value. 2. The skin color is L ^* by the L ^* a ^* b ^* colorimetric method ^.
a ^* b ^* A method of evaluating the cleaning action based on the ratio of the inter-coordinate distances on the three-dimensional coordinates indicated by the colorimetric value.