JP6026203B2 - Method and apparatus for evaluating UV protection cosmetics - Google Patents

Description

  The present invention relates to an evaluation method and an evaluation apparatus for ultraviolet protective cosmetics.

  Sunlight reaching the surface of the earth contains 280-400 nm ultraviolet light. These ultraviolet rays are roughly classified into ultraviolet B waves (UVB) of 280 to 320 nm and ultraviolet A waves (UVA) of 320 to 400 nm. Each has an adverse effect on the skin due to excessive exposure. UVB causes erythema and spots, and UVA causes skin darkening and wrinkles.

  In order to protect the skin from such adverse effects of ultraviolet rays, various ultraviolet protective agents have been developed, and ultraviolet protective cosmetics containing these have been developed and sold. SPF (Sun Protection Factor) values and PFA (Protection Factor of UVA) values are used as indices indicating the ultraviolet protection effect of UV protective cosmetics. SPF is mainly used as an index indicating a protective effect against UVB, and PFA is mainly used as an index indicating a protective effect against UVA. These values are calculated by the following procedure. The minimum amount of ultraviolet rays required to cause erythema (minimum erythema amount) or blackening that lasts for several hours is observed in places where human skin is irradiated with ultraviolet rays and UV protective cosmetics are applied and where it is not. Therefore, the minimum amount of ultraviolet rays (minimum continuous immediate blackening amount) necessary for the calculation is calculated. The value obtained by dividing the minimum erythema amount at a place where the UV protective cosmetic is not applied by the minimum erythema amount at the place where the UV protective cosmetic is applied is defined as an SPF value. A value obtained by dividing the minimum sustained immediate blackening amount at a place where the UV protective cosmetic is not applied by the minimum sustained immediate blackening amount at the place where the UV protective cosmetic is applied is defined as a PFA value.

  While SPF and PFA are useful in that they can objectively evaluate the UV protection effect of UV protection cosmetics, the above-described method requires a large number of subjects, and there is a problem that it is expensive and time consuming. In addition, since human skin is irradiated with ultraviolet rays, an evaluation method that does not use humans is desired from an ethical viewpoint. Therefore, a method is known in which an ultraviolet protective cosmetic is applied on a substrate simulating human skin, and an in vitro SPF value is calculated as a predicted SPF value from the ultraviolet transmittance of the substrate. Specifically, a transmission spectrum in the ultraviolet region of the ultraviolet protective cosmetic coating film is obtained, and a value is calculated based on the following equation.

  Since this method is easy to measure, it is very useful for evaluating the UV protection effect of UV protection cosmetics in the development stage and determining the amount of UV protection agent blended.

  The UV transmittance of the UV protective cosmetic coating film obtained by the above-described method is not only the UV protective agent composition blended in the product itself, but also the uniformity of the coating film thickness (film thickness distribution in the plane direction) and the coating It is known that the value varies greatly depending on factors such as the uniformity of the distribution of UV protection agents in the film (for example, Non-Patent Documents 1 and 2). Actually, in order to measure the in vitro SPF value, a technique of applying a uniform thickness on the substrate is required, but even when the same amount of UV protective cosmetic is applied with a uniform thickness, the in vitro SPF is applied. The value fluctuates. For this reason, it is important to further control the variation factors.

J. O'Neill, Journal of Pharmaceutical Sciences, vol. 73, No. 7, p. 888-891, 1984 B. Herzog, Journal of Cosmetic Science, vol. 53, p. 11-26, 2002

  Even if the film thickness of the UV protection cosmetic is uniform, the UV protection effect changes greatly. Therefore, the present invention relates to the identification of factors other than the film thickness that influence the UV protection effect, the analysis method of the factors, and further the provision of an in vivo performance evaluation method for UV protection agents based on the analysis of the factors.

  The present inventors have found that the uniformity of the ultraviolet absorption performance in the plane direction of the UV protective cosmetic coating film greatly affects the performance of the UV protective cosmetic, and the uniformity of the UV protective performance is on the substrate. It has been found that it can be expressed by the distribution of ultraviolet transmittance in the planar direction of the applied ultraviolet protective cosmetic coating film. Furthermore, the present inventors have found that the integrated value of the UV transmittance distribution has a high correlation with UV protection performance.

  That is, the present invention measures an ultraviolet transmittance distribution in the planar direction of an ultraviolet protective cosmetic coating film applied on a substrate, and evaluates the uniformity of the coated film based on the distribution. The uniformity evaluation method is provided.

  The present invention also provides a method for evaluating the UV protection performance of UV protection cosmetics based on the above evaluation method.

  Furthermore, the present invention provides a screening method for UV protective cosmetics using the above evaluation method.

  According to the method of the present invention, it becomes possible to measure the uniformity of the UV protection performance in the planar direction of the UV protection cosmetic coating film applied on the substrate. Therefore, from the distribution of the UV protection performance, The UV protection performance can be accurately evaluated. Furthermore, it is effective for screening of UV protection cosmetics.

It is a figure which shows the outline | summary of the evaluation apparatus of this invention. It is a figure which shows the change of an ultraviolet transmitted light intensity distribution before application | coating of an ultraviolet protective cosmetic, and after application | coating. It is a figure which shows the histogram of the ultraviolet-ray transmittance of a ultraviolet protective cosmetics coating film. It is a figure which shows the graph which plotted the product of the ultraviolet-ray transmittance and the vertical axis | shaft on the horizontal axis based on the data shown in FIG. 3, and the vertical axis | shaft. It is a figure which shows distribution of the ultraviolet-ray transmitted light intensity after application | coating of the ultraviolet protective cosmetics in each resolution. It is a figure which shows the histogram of the ultraviolet-ray transmittance of the ultraviolet protective cosmetics coating film in each resolution. It is a figure which shows the histogram of the ultraviolet-ray transmittance of a W / O type emulsified cosmetic coating film. It is a figure which shows the histogram of the ultraviolet-ray transmittance of an O / W type emulsified cosmetic coating film. FIG. 8 is a graph showing a plot of ultraviolet transmittance on the horizontal axis and the product of ultraviolet transmittance and existence ratio on the vertical axis based on the data shown in FIG. 7. FIG. 9 is a graph showing a plot of ultraviolet transmittance on the horizontal axis and the product of ultraviolet transmittance and existence ratio on the vertical axis based on the data shown in FIG. 8. It is a figure which shows the relationship between the integral value of the plot of the graph shown in FIG.9 and FIG.10, and an in vitro SPF value. It is a figure which shows distribution of the ultraviolet transmitted light intensity | strength after application | coating of a ultraviolet protective cosmetic. It is a figure which shows the graph which plotted the product of the ultraviolet-ray transmittance and the existence ratio on the vertical axis | shaft about the coating film of the ultraviolet protective cosmetics shown in FIG.

  In the evaluation method of the present invention, the distribution of the ultraviolet transmitted light intensity of the UV protective cosmetic coating film is measured. The wavelength of ultraviolet rays used for evaluation is preferably 280 nm or more and 400 nm or less, and more preferably 280 nm or more and 320 nm or less when carried out in combination with the evaluation of in vitro SPF. The wavelength of ultraviolet rays used for evaluation may be a single wavelength or a plurality of wavelengths. The wavelength may be set by setting an arbitrary wavelength using a bandpass filter, a spectroscope, or the like. As the ultraviolet light source, an ultraviolet light source such as a mercury lamp, sunlight, a solar simulator (pseudo solar light source), or the like may be used.

  In order to ensure that there is no difference in the accuracy of transmittance measurement at each location on the substrate, it is desirable to irradiate the substrate with ultraviolet rays uniformly. For example, if necessary, a light diffusing plate is introduced between the substrate and the ultraviolet light source, or an integrating sphere, an optical fiber bundle, a light guide, etc. are provided so that the substrate can be illuminated uniformly. It ’s fine. In addition, by using such uniform diffuse illumination, the contribution of the light scattering agent in the preparation can be approximately handled with transmitted light.

  Although there is no restriction | limiting in particular in the board | substrate used for evaluation, The thing with the high transmittance | permeability of 280-400 nm ultraviolet rays is preferable. Examples thereof include a quartz plate and a substrate made of polymethyl methacrylate (PMMA), which are materials having high ultraviolet transmittance. Moreover, in order to match the surface shape with the skin, a substrate to which various tapes are attached can be used. Further, a thinly excised skin may be used. Although there is no restriction | limiting in particular in the thickness of excised skin, 0.5-5 mm is desirable from the ease of handling or ultraviolet-ray permeability. The tape is not particularly limited as long as it has a high transmittance of 280 to 400 nm, but for example, a transpore tape (registered trademark, manufactured by 3M), which is a medical tape, is preferable.

  The sample holder for holding the substrate is not particularly limited as long as it can hold the substrate so that it does not move when applying the UV protective cosmetic, but the sample holder is installed between the substrate and the light source. In this case, the material is preferably a material having a high ultraviolet transmittance.

  The region for evaluating the distribution of the ultraviolet transmittance is not particularly limited, but is preferably 0.1 mm square from the viewpoint of successfully evaluating the distribution of the UV protective agent in the cosmetic and the uneven coating on the substrate. More preferably, it is 0.5 mm square or more, more preferably 1 mm square or more, preferably 5 cm square or less, more preferably 3 cm square or less. This region may be set by using an objective lens having a different magnification or a camera sensor having a different size.

  For the objective lens for setting the region for evaluating the distribution of the ultraviolet transmittance, it is preferable to use a material having a high ultraviolet transmittance such as quartz. A reflecting mirror such as a Cassegrain mirror may be used instead of the lens. There is no restriction | limiting in particular in magnification, What is necessary is just to select the objective lens of the magnification which can ensure the above-mentioned required visual field. When performing this evaluation, an operation to apply UV protective cosmetics to the substrate is included, so a lens with a long working distance (2 cm or more) is selected or a mechanism that can move the lens so as not to hinder the application operation. You may have. When a mechanism for moving the lens is provided, it is necessary to select a mechanism with high position reproducibility (5 μm or less). For example, an electric revolver can be used.

  Fluorescence may be generated from the substrate itself or other components by ultraviolet irradiation. In this case, it is necessary to remove these fluorescences. A band pass filter or a spectroscope may be installed between the substrate and the detector so that the same wavelength as the irradiated ultraviolet light can be introduced into the detector.

  The detector that detects the distribution of the intensity of transmitted ultraviolet light is preferably a camera having a high light receiving sensitivity in the ultraviolet region of 280 nm to 400 nm. For example, a back-illuminated CCD (charge-coupled device) detector can be used. The distribution in the planar direction of the ultraviolet transmitted light intensity acquired by this camera may be acquired as a single image at an arbitrary time or may be acquired over time as a continuous image. As the exposure time for detecting the distribution of transmitted light intensity, an arbitrary exposure time can be set according to the intensity of transmitted light to be obtained. If necessary, the number of times of image acquisition may be increased, but the imaging conditions (exposure time, number of times of integration, etc.) before and after application of UV protective cosmetics need to be unified.

  In the detector, the ultraviolet transmitted light intensity is obtained as the ultraviolet detection intensity at each pixel. The rate of change of the UV intensity detected at each pixel before and after application of UV protective cosmetic (the intensity after application divided by the intensity before application) is calculated as the UV transmittance. By performing this operation on each pixel in the measurement region, it is possible to acquire the distribution of the ultraviolet transmittance in the plane direction. Based on the obtained ultraviolet transmittance distribution information, for example, a histogram of ultraviolet transmittance can be created. The ultraviolet transmittance of the UV protective cosmetic coating film over the entire area to be observed can be obtained by averaging the ultraviolet transmittance obtained in each pixel. From these pieces of information, it is possible to simultaneously obtain the UV transmittance distribution and the UV transmittance of the entire visual field.

The distribution of the UV transmittance represents the uniformity of the UV protection performance in the plane direction of the UV protective cosmetic coating film, and the position where the UV transmittance is high is more frequent than the average UV transmittance. If found, the uniformity is judged to be low.
Also, a graph is created in which the horizontal axis represents the ultraviolet transmittance, and the vertical axis represents the product of the ultraviolet transmittance and the existence ratio (the number of pixels divided by the total number of pixels). The integrated value of each plot in this graph (visually, the area under the curve) corresponds to the transmittance. That is, if the UV transmittance of the UV protective cosmetic coating film is high, the integrated value increases, and if the UV transmittance is low, the integrated value decreases. The integral value may be calculated as the sum of products of ultraviolet transmittance and existence ratio in each plot.

  Furthermore, when evaluating the distribution of the coating film, it is also possible to perform analysis by converting the ultraviolet transmittance obtained in each pixel into ultraviolet absorbance. Conversion from transmittance to absorbance is performed using the following equation.

  By this operation, the distribution of ultraviolet absorbance in the planar direction can be acquired, and a histogram of ultraviolet absorbance can be created. The ultraviolet absorbance is expressed by the following formula.

  In other words, if there is information on the extinction coefficient and concentration at the separately measured evaluation wavelength, the UV absorbance is divided by the extinction coefficient and concentration when the dispersibility of the UV protective agent in the coating film is approximated to be constant. The optical path length, that is, the film thickness of the ultraviolet protective cosmetic coating film can be acquired. By performing this operation for each pixel, it is possible to quantitatively obtain the distribution in the planar direction of the film thickness of the UV protective cosmetic coating film, and create a histogram of the film thickness of the UV protective cosmetic coating film. It is possible. The spread of the film thickness distribution can be evaluated from the standard deviation and half-value width of the histogram obtained here. A general-purpose personal computer or the like can be used for these calculations.

  The preferred resolution is preferably 10 pixels / mm or more, more preferably 50 pixels / mm or more, more preferably 150 pixels / mm or more, and preferably 5000 pixels / mm or less.

There are no particular restrictions on the type of UV protective cosmetic used in this evaluation. In the case of UV protective cosmetics having a high UV protection effect, the intensity of UV light that passes through the coating film will be low, so it is only necessary to adopt a more sensitive camera and change the imaging conditions such as exposure time.
There is no restriction | limiting in particular also about the application quantity and the application method of UV protection cosmetics. It can also be used to evaluate the difference in coating film distribution due to the difference in coating amount and coating method. Regarding the application amount, the sample application amount used for SPF evaluation on human skin, the sample application amount used for evaluation of in vitro SPF, or the actual use amount when applying UV protective cosmetics to human skin is desirable. . Specifically, the coating amount is preferably 0.1 mg / cm ² or more, more preferably 0.5 mg / cm ² or more, preferably 10 mg / cm ² or less, more preferably 5.0 mg / cm ² or less. desirable.
It is desirable to apply UV protective cosmetics in small spots uniformly throughout the entire substrate so that it can be applied to a uniform thickness. If so, it is not limited to this method.

  By the evaluation method of the present invention, it is possible to accurately evaluate the uniformity of the ultraviolet protection ability in the plane direction of the coating film of the ultraviolet protective cosmetic on the substrate. Therefore, the method of the present invention can be applied to research and development of UV protective cosmetics using the uniformity of the coating film as an index, performance evaluation of UV protective cosmetics, screening, formulation development, SPF, and evaluation of techniques of in vitro SPF evaluators, etc. It is preferable to use for this purpose.

With respect to the above-described embodiment, the following aspects are further disclosed in the present invention.
<1> Uniformity of an ultraviolet protective cosmetic coating film that measures the distribution of ultraviolet transmittance in the planar direction of the ultraviolet protective cosmetic coating film applied on the substrate and evaluates the uniformity of the coating film based on the distribution. Sex assessment method.
<2> The evaluation method according to <1>, including the following steps 1) to 3).
1) Measure the distribution of UV transmitted light intensity in the plane direction of the substrate to which UV protective cosmetics are not applied.
2) An ultraviolet protective cosmetic is applied to the substrate, and an ultraviolet transmitted light intensity distribution in the planar direction of the substrate after application is measured.
3) The transmitted light intensity at a specific position in the distribution of UV transmitted light intensity after application of UV protective cosmetic is divided by the transmitted light intensity at the same position in the distribution of UV transmitted light intensity before application of UV protective cosmetic. . By performing this operation on all the measurement areas on the substrate, the distribution of the ultraviolet transmittance of the ultraviolet protective cosmetic coating film is calculated.
<3> The evaluation method according to <1> or <2>, further including a step of calculating the ultraviolet transmittance of the entire coating film from the distribution of the ultraviolet transmittance of the obtained ultraviolet protective cosmetic coating film.
<4> The evaluation method according to any one of <1> to <3>, wherein the substrate is inserted between an ultraviolet light source and a camera having sensitivity in an ultraviolet region.
<5> The evaluation according to any one of <1> to <4>, further comprising a diffusion illumination unit that uniformizes light, such as a diffusion plate, an integrating sphere, or an optical fiber bundle, between the substrate and the ultraviolet light source. Method.
<6> The evaluation method according to any one of <1> to <5>, wherein a PMMA substrate, a quartz plate, a medical tape, or a cut skin is used as the substrate.
<7> The evaluation method according to any one of <1> to <6>, wherein the distribution is measured at a resolution of 10 pixels / mm or more and 5000 pixels / mm or less.
<8> A method for evaluating the ultraviolet protection performance of an ultraviolet protective cosmetic based on the evaluation method according to any one of <1> to <7>.
<9> A screening method for ultraviolet protective cosmetics using the evaluation method according to any one of <1> to <8>.
<10> The method according to any one of <1> to <9>, wherein the coating amount is 0.1 mg / cm ² or more and 10 mg / cm ² or less.
<11> The method according to any one of <1> to <10>, wherein the measurement area is 0.1 mm square or more and 5 cm square or less.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to this. Unless otherwise specified, “%” means “mass%”.

[Example 1 Difference in distribution of UV protective cosmetic coating film due to difference in drug system]
Using the evaluation method of the present invention, the difference in the distribution of the UV protective cosmetic coating film due to the difference in the agent system was evaluated. As evaluation samples, W / O type emulsified cosmetics and O / W type emulsified cosmetics were used. The composition of each sample is as shown in Table 1 (W / O emulsified cosmetic) and Table 2 (O / W emulsified cosmetic) below. Both were prepared to contain 8.0% ethyl hexyl methoxycinnamate (Ubinal MC80, manufactured by BASF) and 2.0% hexyl diethylaminohydroxybenzoyl benzoate (Ubinal Apples, manufactured by BASF) as UV protection agents. The outline of the evaluation apparatus is as shown in FIG. Application of the evaluation sample to the substrate was performed by preliminarily placing the UV protective cosmetic material in a small spot uniformly on the entire substrate and spreading it over the entire substrate. The measurement conditions are as follows.

<Measurement conditions>
Light source: Super high pressure type 130W mercury lamp INTENSILIGHT C-HGFI (manufactured by Nikon). The sample was uniformly irradiated with 380 nm using a bandpass filter FB380-10 (manufactured by thorlabs) and opal light diffusion glass (manufactured by Edmund Optics).
Evaluation substrate: A quartz plate with transpore tape (registered trademark, manufactured by 3M) attached.
Sample application amount: 2.0 mg / cm ²
Objective lens: INFINIPROBE UV microscope lens, right angle (manufactured by INFINITY)
Camera: XC-EU50 (manufactured by SONY)

Personal computer detects light detected by the camera via a camera adapter kit (DC-700, manufactured by Sony Corporation) and a USB (Universal Serial Bus) connection video capture (GV-USB2, manufactured by IO Data Corporation). And acquired as a tiff format image. Images were acquired before and 15 minutes after application of the UV protective cosmetic. The resolution under this condition is 170 pixels / mm. The measurement area was a 4 mm × 3 mm area in the coating area.
The in vitro SPF measurement (Labsphere UV-1000S UV TRANSMITTAN ANALYZER, manufactured by Labsphere) was performed on the coating film of the UV protective cosmetic used in the measurement.

FIG. 2 shows the distribution of the intensity of transmitted ultraviolet light before and after application of each ultraviolet protective cosmetic. The intensity of ultraviolet transmitted light was reduced as a whole by coating, but the degree of the intensity reduction varied greatly depending on the location. In addition, the distribution behavior of UV light intensity varies depending on the agent system.
The UV transmittance is calculated from the change in the UV transmitted light intensity before and after the UV protective cosmetic application, and the histogram is shown in FIG. In this specification, for the sake of easy viewing, the histogram is displayed as a line graph for convenience. The measured value of in vitro SPF is shown in parentheses in FIG. From this, the coating film of the O / W type emulsified cosmetic with a relatively low in vitro SPF value has a higher ultraviolet transmittance than the coated film of the W / O type emulsified cosmetic (0.7 to 0.00). 95) It was found that the area was widened. In contrast, the W / O emulsified cosmetic coating film was wider in the region where the ultraviolet transmittance was low (0.05 to 0.3).

  FIG. 4 is a graph in which the horizontal axis represents the ultraviolet transmittance, and the vertical axis represents the product of the ultraviolet transmittance and the existence ratio (the number of pixels divided by the total number of pixels). The integrated value of each plot in this graph (visually, the area under the curve) corresponds to the average transmittance in the entire observation region. That is, if the UV transmittance of the UV protective cosmetic coating film is high, the integrated value increases, and if the UV transmittance is low, the integrated value decreases. In FIG. 4, the coating film of the W / O type emulsified cosmetic having a relatively low ultraviolet transmittance and a high in vitro SPF value has a smaller integrated value than the coating film of the O / W type emulsified cosmetic. I found out that If the integrated values here are about the same, it can be seen that the ultraviolet transmittance of the coating film is also about the same. However, it can be seen that if the shape of the graph is different even if the integrated values are the same, the ultraviolet transmittance distribution and the coating uniformity of the coating film itself are different. For example, if the peak top position is on the high UV transmittance side, the coating film is relatively non-uniform, and if the peak top position is on the low UV transmittance side, the coating film is relatively uniform. It is also possible to evaluate. Thus, in this system, it is possible to simultaneously evaluate the UV transmittance and uniformity of the UV protective cosmetic coating film.

[Example 2 Difference in distribution evaluation result of UV-protective cosmetic coating film due to difference in resolution]
Using the evaluation method of the present invention, the difference in the distribution evaluation result of the UV protective cosmetic coating film due to the difference in resolution was evaluated. An O / W emulsified cosmetic was used as an evaluation sample. The composition of the sample is as shown in Table 2 described above. As UV protection agents, 8.0% of ethylhexyl methoxycinnamate (Ubinal MC80, manufactured by BASF) and 2.0% of hexyl diethylaminohydroxybenzoylbenzoate (Ubinal Apples, manufactured by BASF) were prepared. Application of the evaluation sample to the substrate was performed by preliminarily placing the UV protective cosmetic material in a small spot uniformly on the entire substrate and spreading it over the entire substrate. The measurement conditions are as follows.
<Measurement conditions>
Light source: Super high pressure type 130W mercury lamp INTENSILIGHT C-HGFI (manufactured by Nikon). The sample was uniformly irradiated with 380 nm using a bandpass filter FB380-10 (manufactured by thorlabs) and opal light diffusion glass (manufactured by Edmund Optics).
Evaluation substrate: A quartz plate with transpore tape (registered trademark, manufactured by 3M) attached.
Sample application amount: 2.0 mg / cm ²
Objective lens: INFINIPROBE UV microscope lens, right angle (manufactured by INFINITY)
Camera: XC-EU50 (manufactured by SONY)

  Personal computer detects light detected by the camera via a camera adapter kit (DC-700, manufactured by Sony Corporation) and a USB (Universal Serial Bus) connection video capture (GV-USB2, manufactured by IO Data Corporation). And acquired as a tiff format image. Images were acquired before and 15 minutes after application of the UV protective cosmetic. The resolution of the acquired image was set to 170 pixels / mm, 50 pixels / mm, 10 pixels / mm, and 5 pixels / mm. The measurement area was a 4 mm × 3 mm area in the coating area.

  FIG. 5 shows the distribution of the UV transmitted light intensity after application of the UV protective cosmetic at each resolution. The distribution evaluation result of UV transmitted light intensity was different depending on the resolution. The UV transmittance is calculated from the change in UV transmitted light intensity before and after the UV protective cosmetic application, and the histogram is shown in FIG. At 10 pixels / mm, the shape of the histogram was almost the same as that of the higher resolution, and at 50 pixels / mm or higher, the shape of the histogram did not change greatly even when the resolution was further increased. Thus, in the distribution evaluation performed using this system, 10 pixels / mm or more is necessary, and a resolution of 50 pixels / mm or more was more suitable.

[Example 3 Difference in UV-coating cosmetic coating film depending on application]
Using the evaluation method of the present invention, the difference in the distribution of the UV protective cosmetic coating film due to the difference in coating was evaluated. As evaluation samples, W / O type emulsified cosmetics and O / W type emulsified cosmetics were used. The composition of each sample is as shown in Table 1 (W / O emulsion cosmetic) and Table 2 (O / W emulsion cosmetic). Both were prepared to contain 8.0% ethyl hexyl methoxycinnamate (Ubinal MC80, manufactured by BASF) and 2.0% hexyl diethylaminohydroxybenzoyl benzoate (Ubinal Apples, manufactured by BASF) as UV protection agents. Application of the evaluation sample to the substrate was performed by preliminarily placing the UV protective cosmetic material in a small spot uniformly on the entire substrate and spreading it over the entire substrate. The measurement conditions are as follows.
<Measurement conditions>
Light source: Super high pressure type 130W mercury lamp INTENSILIGHT C-HGFI (manufactured by Nikon). The sample was uniformly irradiated with 380 nm using a bandpass filter FB380-10 (manufactured by thorlabs) and opal light diffusion glass (manufactured by Edmund Optics).
Evaluation substrate: A quartz plate with transpore tape (registered trademark, manufactured by 3M) attached.
Sample application amount: 2.0 mg / cm ²
Objective lens: INFINIPROBE UV microscope lens, right angle (manufactured by INFINITY)
Camera: XC-EU50 (manufactured by SONY)

Personal computer detects light detected by the camera via a camera adapter kit (DC-700, manufactured by Sony Corporation) and a USB (Universal Serial Bus) connection video capture (GV-USB2, manufactured by IO Data Corporation). And acquired as a tiff format image. Images were acquired before and 15 minutes after application of the UV protective cosmetic. The resolution under this condition is 170 pixels / mm. The measurement area was a 4 mm × 3 mm area in the coating area. Each of the W / O type emulsified cosmetic and the O / W type emulsified cosmetic was applied to the substrate 5 times and measured.
The in vitro SPF measurement (Labsphere UV-1000S UV TRANSMITTAN ANALYZER, manufactured by Labsphere) was performed on the coating film of the UV protective cosmetic used in the measurement.

  The UV transmittance is calculated from the change in UV transmitted light intensity before and after the UV protective cosmetic application, and the histograms are shown in FIG. 7 (W / O emulsified cosmetic) and FIG. 8 (O / W emulsified cosmetic). . In the legends of FIGS. 7 and 8, the measured values of in vitro SPF are described. From FIG. 7, in the W / O type emulsified cosmetic, the in vitro SPF value was 10.3 to 22.3. Among these, the coating film having a relatively low in vitro SPF value has a small abundance ratio of a region having a low ultraviolet transmittance (0 to 0.2). From FIG. 8, in the O / W type emulsified cosmetic, the in vitro SPF value was 6.6 to 8.7. In the O / W type emulsified cosmetic, the fluctuation of the in vitro SPF value was smaller than that of the W / O type emulsified cosmetic. The shape of the histogram shown in FIG. 8 was not significantly different, but for the coating film having the highest in vitro SPF value of 8.7, the mode value of the histogram was smaller than the others.

  FIG. 9 (W / O type emulsified cosmetic) and FIG. 10 (O / W type emulsified cosmetic) show graphs in which the horizontal axis represents the ultraviolet transmittance and the vertical axis represents the product of the ultraviolet transmittance and the existing ratio. The integrated value of each plot in this graph (visually, the area under the curve) corresponds to the transmittance. That is, if the UV transmittance of the UV protective cosmetic coating film is high, the integrated value increases, and if the UV transmittance is low, the integrated value decreases. From FIG. 9 and FIG. 10, the relationship between the reciprocal of the calculated integral value and the in vitro SPF value is shown in FIG. From FIG. 11, a high correlation was found between the reciprocal of the integral value and the in vitro SPF value. Thus, in this system, it is possible to evaluate the uniformity and the UV protection effect for each UV protection cosmetic coating film.

[Example 4 Difference in distribution of UV protective cosmetic coating film due to difference in UV protective agent composition]
Using the evaluation method of the present invention, the difference in the distribution of the UV protective cosmetic coating film due to the difference in the UV protective agent composition was evaluated. As evaluation samples, O / W type emulsified cosmetics having the compositions shown in Table 2 (Sample (A)) and Table 3 (Sample (B)) described above were used. The evaluation sample contains 8.0% ethylhexyl methoxycinnamate (Ubinal MC80, manufactured by BASF) and 2.0% diethylaminohydroxybenzoyl hexyl benzoate (Ubinal Plus, manufactured by BASF) as UV protection agents. 1. As a UV protection agent, 4.0% of ethyl hexyl methoxycinnamate (Ubinal MC80, manufactured by BASF) and diethylaminohydroxybenzoyl hexyl benzoate (Ubinal Plus, manufactured by BASF) were used as UV protection agents. Sample (B) prepared to contain 0% was used. Application of the evaluation sample to the substrate was performed by preliminarily placing the UV protective cosmetic material in a small spot uniformly on the entire substrate and spreading it over the entire substrate. The measurement conditions are as follows.
<Measurement conditions>
Light source: Super high pressure type 130W mercury lamp INTENSILIGHT C-HGFI (manufactured by Nikon). The sample was uniformly irradiated with 380 nm using a bandpass filter FB380-10 (manufactured by thorlabs) and opal light diffusion glass (manufactured by Edmund Optics).
Evaluation board: Polymethyl methacrylate (PMMA) board (HELIOPLATE HD6)
Sample application amount: 1.3 mg / cm ²
Objective lens: INFINIPROBE UV microscope lens, right angle (manufactured by INFINITY)
Camera: XC-EU50 (manufactured by SONY)

  Personal computer detects light detected by the camera via a camera adapter kit (DC-700, manufactured by Sony Corporation) and a USB (Universal Serial Bus) connection video capture (GV-USB2, manufactured by IO Data Corporation). And acquired as a tiff format image. Images were acquired before and 15 minutes after application of the UV protective cosmetic. The resolution under this condition is 170 pixels / mm. The measurement area was a 4 mm × 3 mm area in the coating area.

  FIG. 12 shows the distribution of ultraviolet transmitted light intensity after application of each ultraviolet protective cosmetic. The behavior of the distribution of UV transmitted light intensity was different depending on the blending amount of UV protective agent. FIG. 13 is a graph in which the ultraviolet transmittance is calculated from the change in the ultraviolet transmitted light intensity before and after application of the ultraviolet protective cosmetic, and the product of the ultraviolet transmittance and the existing ratio is plotted on the vertical axis. The integrated value of each plot in this graph (visually, the area under the curve) corresponds to the transmittance. That is, if the UV transmittance of the UV protective cosmetic coating film is high, the integrated value increases, and if the UV transmittance is low, the integrated value decreases. From FIG. 13, the integrated value was smaller in the sample (A) with a larger amount of UV protection agent than in the sample (B). As described above, it is possible to evaluate the decrease in the ultraviolet transmittance due to the increase in the blending amount of the ultraviolet protective agent. In addition, the peak top in FIG. 13 was shifted to the low ultraviolet transmittance side in the sample (A) having a larger amount of the ultraviolet protective agent than in the sample (B). This is considered to indicate that the region of high transmittance (0.85 to 1.0) is narrowed by increasing the blending amount of the ultraviolet protective agent. Thus, in this system, it is possible to evaluate the uniformity when the blending amount of the UV protection agent is changed.

  As described above, according to the method of the present invention, the ultraviolet transmittance distribution of the coating film of the ultraviolet protective cosmetic on the substrate can be accurately evaluated, and the uniformity of the coating film can be evaluated.

Claims (8)

A histogram of ultraviolet transmittance in the planar direction of the UV protective cosmetic coating film applied on the substrate is measured with a resolution of 10 pixels / mm or more and 5000 pixels / mm or less , and the uniformity of the coating film is determined based on the histogram. Uniformity evaluation method of UV protective cosmetic coating film to be evaluated. The evaluation method according to claim 1, comprising the following steps 1) to 4 ).
1) The distribution of the ultraviolet transmitted light intensity in the plane direction of the substrate to which the UV protective cosmetic is not applied is measured with a resolution of 10 pixels / mm or more and 5000 pixels / mm or less .
2) An ultraviolet protective cosmetic is applied to the substrate, and the distribution of ultraviolet transmitted light intensity in the planar direction of the substrate after application is measured with the resolution .
3) The transmitted light intensity at a specific position in the distribution of UV transmitted light intensity after application of UV protective cosmetic is divided by the transmitted light intensity at the same position in the distribution of UV transmitted light intensity before application of UV protective cosmetic. . By performing this operation on all the measurement areas on the substrate, the distribution of the ultraviolet transmittance of the ultraviolet protective cosmetic coating film is calculated.
4) Create a histogram based on the distribution. The evaluation method according to claim 1, further comprising a step of calculating an ultraviolet transmittance of the entire coating film based on a histogram of a distribution of the ultraviolet transmittance of the obtained ultraviolet protective cosmetic coating film.   The evaluation method according to claim 1, wherein the substrate is inserted between an ultraviolet light source and a camera having sensitivity in the ultraviolet region.   The evaluation method according to any one of claims 1 to 4, further comprising a diffusion illumination unit that uniformizes light such as a diffuser plate, an integrating sphere, or an optical fiber bundle between the substrate and the ultraviolet light source.   The evaluation method according to claim 1, wherein a PMMA substrate, a quartz plate, a medical tape, or a cut skin is used as the substrate. The evaluation method of the ultraviolet protection performance of the ultraviolet protective cosmetics based on the evaluation method of any one of Claims 1 thru | or 6 . A screening method for ultraviolet protective cosmetics using the evaluation method according to any one of claims 1 to 6 .