JP2021081270A - Method of analyzing base makeup films - Google Patents

Abstract

To provide a method of analyzing base makeup films.SOLUTION: A base makeup film analysis method provided herein involves measuring a base makeup film by micro-Raman spectroscopy.SELECTED DRAWING: None

Description

The present invention relates to a method for analyzing a base make-up coating film.

Base makeup formulations include foundations, base colors, makeup bases, finishing powders, concealers, sunscreens and the like. In addition to making the skin look more beautiful, these preparations are required to exhibit various functions such as long-lasting makeup, UV protection ability, and moisturizing effect on the skin. In order to impart these functions to the base makeup formulation, a formulation that combines various inorganic particles, organic particles, and liquid components has been developed so that a functional base makeup coating film is formed on the skin. There is.

Observation of the base make-up coating film formed on the skin or the like is one of the methods often used in the analysis of the base make-up preparation. Generally, the base makeup coating film is composed of inorganic and organic particles having a diameter of about sub μm to 10 μm and a liquid component. Inorganic particles with a high refractive index are the main constituents that exhibit light scattering, which is the most basic function of the base makeup coating film. In addition, iron oxide, which is a kind of inorganic particles, is often used to give a color tone to a base makeup coating film. The organic particles play a role of controlling the feel and finish of the base make-up preparation at the time of application. On the other hand, the liquid component has various structural functions such as being present on the surface of particles in the base makeup coating film or between particles to crosslink the particles, as well as imparting UV protection ability and moisturizing the skin. It has a function. It is important for the development of the base make-up preparation to analyze the internal structure and composition of the base make-up coating film containing these various particles and liquid components.

The base makeup coating film has strong light scattering properties as a basic performance, and is not suitable for optical observation. Therefore, a scanning electron microscope (SEM) has been often used for the analysis of the internal structure of the conventional base make coating film (Patent Documents 1 and 2, Non-Patent Document 1). At this time, it has also been performed to identify the chemical species of inorganic particles by detecting elemental information in combination with energy dispersive X-ray analysis (EDX, EDS). However, the composition information regarding organic substances cannot be obtained in SEM (for example, it is not possible to distinguish between an ultraviolet absorbing oil agent and a normal oil agent), and the internal structure cannot be observed unless the coating film cross section is prepared (the base make film is brittle). Therefore, special techniques are required to prepare the cross section), and it cannot be applied to volatile substances because it is measured in a vacuum environment (low molecular weight substances such as glycerin volatilize during measurement). was there.

The micro-IR method is well known as a general analysis method for organic components and inorganic components inside a coating film along with SEM. However, since the micro-IR method has a spatial resolution of about 10 μm, it is not possible to sufficiently analyze the particle assembly structure of about sub μm to 10 μm and the liquid component between particles, which are important in the base makeup coating film analysis.

Japanese Unexamined Patent Publication No. 2013-101138 Japanese Unexamined Patent Publication No. 2013-253957

J Soc Cosmet Chem Jpn, 2012, 46 (4): 271-286

In order to develop a highly functional base make-up preparation, it is required to observe the particles contained in the base make-up coating film with a spatial resolution of about sub μm to 10 μm. Furthermore, in order to analyze the internal structure and composition distribution of the coating film after application of the base makeup preparation, or their changes due to sebum, etc., the base makeup coating film is analyzed without preparing the cross section and under atmospheric pressure. Is required. It is desired to develop an analysis method for a base makeup coating film that can satisfy these requirements.

We have attempted to apply micro-Raman spectroscopy to the analysis of base makeup coatings. Generally, when micro Raman spectroscopy is used, biological samples (skin, hair, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc.) and composite materials (laminated film, etc. It is possible to observe the internal structure of ABS resin, etc.). However, in the case of the base make coating film, the strong Raman signal of titanium oxide, which is a light scattering component, became an interfering signal in the coating film internal composition analysis in the analysis by the micro Raman spectroscopy. Furthermore, the present inventors have found that in the base makeup coating film analysis by micro-Raman spectroscopy, iron oxide added to impart the color tone of the base makeup generates heat during measurement and the coating film is destroyed. It has been found that problems such as difficulty in distinguishing the sebum that has infiltrated from the outside of the film and the oil component inside the coating film occur.

On the other hand, the present inventors prepare (i) a model-based make-up coating film in which titanium oxide is replaced with other inorganic particles, and (ii) prepare a model-based make-up coating film in which iron oxide is removed from the formulation. It was found that the above problems in observing the internal structure and composition distribution of the base makeup coating film by Raman spectroscopy can be solved by (iii) using a model sebum containing a lipid component labeled with deuterium. ..

Therefore, the present invention provides a method for analyzing a base make-up coating film, which comprises measuring the base make-up coating film by microscopic Raman spectroscopy.

According to the present invention, the internal structure and composition distribution of the base make-up coating film can be observed with high resolution. Further, according to the present invention, it is possible to observe the sebum dynamics inside the base makeup coating film and the change in the internal structure and composition distribution of the base makeup coating film due to the sebum. The present invention is useful for developing a highly functional base makeup preparation that is resistant to, for example, sebum.

Raman spectrum of each component in the base makeup formulation. Continuation of FIG. Raman spectrum of model sebum and its constituents. Optical microscope image of formulation 1 (iron oxide-containing) coating film before and after microscopic Raman spectroscopic measurement. Optical microscope image of formulation 2 (iron oxide-free) coating film before and after microscopic Raman spectroscopic measurement. Formula 2 Raman imaging of the coating film. A) A two-dimensional image of a CH group signal. B) Two-dimensional image of the titanium oxide signal. C) Raman spectrum for 6 points in the measurement area. Raman imaging of formulation 3 coating. A) A two-dimensional image of a CH group signal. B) Raman spectrum for 6 points in the measurement range. Raman imaging (XY) for 6 types of signal components (CH group, silicones, UV absorber, glycerin, talc, zinc oxide) of the formulation 3 coating film. Raman Imaging (XZ) for 6 signal components (CH group, silicones, UV absorber, glycerin, talc, zinc oxide) of Formulation 3 coating. The broken line indicates the boundary position between the coating film and the glass substrate. Raman Imaging (XY) for 6 signal components (CH groups, silicones, UV absorbers, glycerin, talc, zinc oxide) of the formulation 4 coating. Raman imaging (XZ) for 6 signal components (CH groups, silicones, UV absorbers, glycerin, talc, zinc oxide) of formulation 4 coatings. The broken line indicates the boundary position between the coating film and the glass substrate. Sebum diffusion behavior of the coating films of Formulation 3 and Formulation 4. Error bar = ± SD (n = 2). Raman spectrum of the components contained in Formulation 3 and the components contained in the model sebum. The peak in the area surrounded by the dotted line (around 2200 cm ^-1 ) is the signal of CD expansion and contraction vibration. Raman Imaging (XY) for 7 signal components (CH groups, silicones, UV absorbers, glycerin, talc, zinc oxide, and model sebum (CD groups)) in Formulation 3 coatings in the presence of model sebum. Raman imaging (XZ) of 7 signal components (CH group, silicones, UV absorber, glycerin, talc, zinc oxide, and model sebum (CD group)) of the formulation 3 coating in the presence of model sebum. The broken line indicates the boundary position between the coating film and the glass substrate. Raman Imaging (XY) for 7 signal components (CH groups, silicones, UV absorbers, glycerin, talc, zinc oxide, and model sebum (CD groups)) in the formulation 4 coating in the presence of model sebum. Raman imaging (XZ) of 7 signal components (CH group, silicones, UV absorber, glycerin, talc, zinc oxide, and model sebum (CD group)) of the formulation 4 coating in the presence of model sebum. The broken line indicates the boundary position between the coating film and the glass substrate.

The present invention provides a method for analyzing a base make-up coating film using micro-Raman spectroscopy. In the method of the present invention, the base makeup coating film to be analyzed is measured by micro-Raman spectroscopy. Preferably, confocal micro-Raman spectroscopy is used for the measurement. As the micro-Raman spectroscope used in the present invention, for example, a confocal micro-Raman spectroscope as disclosed in Scientific Reports 6, Article number: 35117 (2016) can be used. Further, a commercially available confocal microscope Raman spectroscope such as Nanofinder30 (Tokyo Instruments Co., Ltd.), alpha300 (WITEC), RAMANtouch / RAMANforce (Nanophoton Co., Ltd.) can be used. Alternatively, the micro-Raman spectroscopy used in the method of the present invention is not limited to the detection of spontaneous Raman scattering, for example by the method disclosed in Journal of Raman Spectroscopy, 2015, 46 (8): 727-734. Coherent anti-Stoke Raman scattering, induced Raman scattering, etc. may be detected.

The Raman signal from the base make coating can be detected two-dimensionally (for example, in the horizontal (XY) or vertical (XZ) direction) or three-dimensionally to perform two-dimensional Raman imaging or three-dimensional Raman imaging. This makes it possible to visualize the internal structure of the base make-up coating film and the distribution of each component two-dimensionally or three-dimensionally.

Examples of the base make-up coating material analyzed in the present invention include base make-up preparations such as foundations, base colors, makeup bases, finishing powders, concealers, sunscreens, and the like, and coating materials formed from their model preparations. In the present invention, the base makeup coating film refers to a coating film, deposits, or coating layer formed on the skin or model substrate when the base makeup preparation is applied on the skin or model substrate. To do. Therefore, the base make-up coating film may be a coating film formed on the skin, or may be a coating film formed on a solid base material such as glass, metal, plastic, or urethane sponge. The latter is preferable in terms of convenience, and glass is more preferable in terms of spatial resolution. Further, in the case of analysis using model sebum described later, it is preferable to use the base make-up coating film formed on the above-mentioned solid base material. Preferably, the solid substrate is a flat plate. The thickness of the base material is not limited, but when irradiating the laser beam from the back side of the glass base material, it is preferable that the thickness of the glass base material is about 100 to 250 μm in order to improve the spatial resolution.

The thickness of the base make-up coating film to be analyzed may be the same as the thickness of the coating film obtained when the base make-up preparation is actually applied to the skin for makeup and dried, and may be, for example, about 3 to 30 μm. Not limited to this.

Some components contained in the base makeup coating film cause strong Raman scattering and bury other signal components in the Raman spectral spectrum, which hinders the analysis of the base makeup coating film. Therefore, in the present invention, a model base make coating film is prepared by removing such a component exhibiting strong Raman scattering (hereinafter, also referred to as a strong Raman scattering component) from the base make coating film to be analyzed, and the coating film is analyzed. It is preferable to do so. In the present invention, the strong Raman scattering component refers to a component having a normalized maximum Raman scattering intensity of 1 or more. Here the maximum normalized Raman scattering intensity is mixed in equal weight ratio of the test substance and petrolatum, the該混hydrate in After thoroughly pulverized and mixed in the Raman spectrum obtained by Raman measurements, 300 to 4000 [cm ^{- It} is defined as the value obtained by dividing the maximum value of the Raman signal derived from the test substance in the region of 1] by the maximum value of the Raman signal of 2920 ± 120 [cm ^{-1] derived from the CH stretching vibration derived from Vaseline.} The procedure for measuring the normalized maximum Raman scattering intensity is described in detail in the following examples.

Examples of the strong Raman scattering component that is abundantly contained in the base makeup coating film include a light scattering component of the base makeup coating film, for example, titanium oxide. Therefore, a preferred example of the strong Raman scattering component to be removed is titanium oxide. Another example of the strong Raman scattering component contained in the base makeup coating film is a part of UV absorbers. Therefore, another preferred example of a strong Raman scattering component to be removed is some UV absorbers.

A coating film from which the strong Raman scattering component has been removed can be prepared by preparing and applying a model-based makeup preparation from which the component has been removed. As a means for removing the strong Raman scattering component from the base makeup coating film, at least a part of the strong Raman scattering component contained in the base makeup coating film is replaced with another component having a lower standardized maximum Raman scattering intensity. Can be mentioned. Preferably, all of the strong Raman scattering components are replaced with the other components. For this replacement, it is preferable to use components having similar physical properties such as particle size and fluidity, in addition to having a lower normalized maximum Raman scattering intensity. For example, talc is a component that has a lower normalized maximum Raman scattering intensity than titanium oxide and is the same inorganic particle. For example, a model-based make-up preparation is prepared by replacing part or all of the mass of titanium oxide contained in the original preparation for forming the base make-up coating to be analyzed with talc, and the coating film of the model-based make-up preparation is Raman It may be analyzed by spectroscopic method. Similarly, examples of components that have a lower standardized maximum Raman scattering intensity than liquid UV absorbers and are the same liquid include oils such as liquid paraffin and liquid surfactants.

Iron oxide contained in the base make coating film may generate heat during microscopic Raman spectroscopic measurement and melt, fluidize or volatilize the coating film components such as surrounding oils to destroy the coating film structure. Therefore, it is preferable to remove iron oxide from the base makeup coating film to be analyzed. For example, a model base-makeup preparation in which a part or all of iron oxide is removed from the original preparation for forming the base-makeup coating film to be analyzed may be prepared, and the base-makeup coating film formed from the model-based make-up preparation may be analyzed. It is preferable to add an inorganic powder such as talc or an organic powder instead of the removed iron oxide to adjust the mass of each component in the model base makeup formulation to be the same as that of the original base makeup formulation. ..

Alternatively, a model-based make-up preparation obtained by removing both the strong Raman scattering component and iron oxide described above may be prepared and the coating film thereof may be analyzed.

The sampling interval on the spatial axis in the microscopic Raman spectroscopic measurement is not particularly limited, but in consideration of observing the distribution of particles in the base makeup coating film and the state of sebum, the spectrum is set every 0.2 to 5 μm. It is preferable to measure. From the obtained Raman spectrum, the peak of each component contained in the base makeup coating film can be detected. For example, the peak of 2920 ± 120 [cm ^-1 ] reflects CH stretching vibration and represents the presence of CH groups (organic substances such as fatty acids, triglycerides, surfactants, oils, etc.). The peak of 500 ± 80 [cm ^-1 ] reflects the expansion and contraction vibration of Si—O and indicates the presence of silicones. The peak of 1610 ± 50 [cm ^-1 ] reflects C = C expansion and contraction vibration, and indicates the presence of a UV absorber or the like. The peak of 3400 ± 200 [cm ^-1 ] reflects the OH expansion and contraction vibration and indicates the presence of OH groups (glycerin, etc.). The peak of 3670 ± 60 [cm ^-1 ] reflects the OH expansion and contraction vibration of Si-OH and indicates the presence of talc. The peak of 435 ± 25 [cm ^-1 ] reflects the E2 (high) vibration mode of zinc oxide and indicates the presence of zinc oxide. Based on these peaks, the presence of each component in the base makeup coating film can be detected.

In order to develop a base makeup preparation that does not easily lose its makeup due to sebum, the dynamics of sebum in the base makeup coating film obtained from the preparation, or changes in the internal structure and composition distribution of the base makeup coating film due to sebum are analyzed. This is very important. However, since the base makeup coating film contains many oil agents, it is difficult to distinguish the Raman signal derived from sebum from the Raman signal derived from the lipid component of the oil agent. In the present invention, this problem can be solved by using a model sebum containing a deuterium-labeled lipid component (hereinafter, also referred to as a deuterium-labeled model sebum).

Generally, sebum contains hydrocarbon oil, ester oil, fatty acid and the like. The model sebum in the present invention may refer to those containing hydrocarbon oils, ester oils, or fatty acids, but those containing at least fatty acids are preferable. The composition of the deuterium-labeled model sebum may be the same as the composition of the model sebum used in conventional research on cosmetics, except that it is labeled with deuterium. For example, a deuterium-labeled model sebum can be prepared by labeling at least one of the lipid components in ordinary model sebum, preferably a fatty acid such as oleic acid, with deuterium (D). Deuterium labeling of lipid components can be performed according to normal procedures. Alternatively, a model sebum may be prepared using a commercially available deuterium-labeled fatty acid (for example, deuterium-labeled oleic acid C ₁₈ H ₁₇ D ₁₇ O _{2; Cayman Chemical).}

For example, the above-mentioned deuterium label model sebum may be added to the base make-up coating film, and the microscopic Raman spectroscopic measurement of the coating film may be performed. In the Raman spectrum, the deuterium label model sebum signal can be detected as a peak of ^{2150 ± 250 [cm -1] derived from CD expansion and contraction vibration.} By detecting the signal of CD expansion and contraction vibration, it is possible to distinguish the signal of the deuterium label model sebum in the spectrum from the signal derived from the oil agent and other components of the base makeup coating film. Therefore, by using the deuterium label model sebum, it is possible to analyze the dynamics of sebum in the base makeup coating film, or the effect of sebum on the internal structure and composition distribution of the base makeup coating film, or the base. It is possible to analyze the sebum resistance of the makeup coating film (for example, the resistance to sebum breakage). The composition of the base make-up coating film used in the analysis is not particularly limited, but is a coating film formed from a model-based make-up preparation obtained by removing both the above-mentioned strong Raman scattering component and / or iron oxide. It is preferable to have it. Further, it may contain a sebum absorbing component, a sebum resistant component, and the like.

As an exemplary embodiment of the invention, the following methods are further disclosed herein. However, the present invention is not limited to these embodiments.

[1] A method for analyzing a base make-up coating film, which comprises measuring the base make-up coating film by micro-Raman spectroscopy.
[2] Preferably, at least a part of the component exhibiting strong Raman scattering contained in the base makeup coating film is replaced with another component having a lower normalized maximum Raman scattering intensity, according to the method according to [1]. ..
[3] The method according to [1] or [2], wherein the component exhibiting strong Raman scattering is preferably a component having a normalized maximum Raman scattering intensity of 1 or more.
[4] The method according to any one of [1] to [3], wherein the component exhibiting strong Raman scattering is titanium oxide.
[5] The method according to any one of [2] to [4], wherein the other component having a lower standardized maximum Raman scattering intensity is talc.
[6] Preferably, the base make-up coating film has some or all of iron oxide removed.
More preferably, the method according to any one of [1] to [5], wherein the base makeup coating film does not contain iron oxide.
[7] Preferably, the analysis method of the base make coating film is a method of analyzing the sebum dynamics in the base make coating film, a method of analyzing the influence of sebum on the internal structure or composition distribution of the base make coating film, or It is a method for analyzing the sebum resistance of a base make coating film, and the method further comprises adding a model sebum containing a lipid component labeled with a heavy hydrogen to the base make coating film [1] to [ 6] The method according to any one of.
[8] The method according to any one of [1] to [7], wherein the micro-Raman spectroscopy is preferably a confocal micro-Raman spectroscopy.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

(Raman spectroscope)
Confocal microscope Raman spectrometer: Nanofinder30 (Tokyo Instruments)
Objective lens: Oil-immersed objective lens (Nikon S Fluor, NA: 1.3, 100X, WD: 0.2 mm)
Sample placement: Inverted microscopic measurement (measurement by placing the sample above the objective lens and irradiating the laser through the cover glass)
Laser: 632.8 nm (He-Ne laser, MELLES GRIOT, 05-LHP-928)
Laser output: 8mW (immediately after the objective lens)
Detector: Cooled CCD detector (Andor)
Pinhole diameter: 80 μm
Diffraction lattice: 150 gr / mm
XY Scanner: Galvano Mirror Z Scanner: Piezo Accumulation time: 0.5 seconds / pixel (during imaging measurement)
Spot spacing: 0.5 μm spacing (XY direction), 1.0 μm spacing (Z direction)

(Model sebum)
Squalane, triacylglycerol (TAG, trade name "Cropure OL", cosmetic raw material, Claude Japan Co., Ltd.) and oleic acid were mixed at a ratio of 3: 3: 2 (mass ratio) and used as model sebum.
_{Deuterium-labeled oleic acid (C 18} H ₁₇ D ₁₇ O ₂ , Cayman Chemical) in which a part of H in the alkyl chain of oleic acid was replaced with D was mixed with squalane and TAG in the same ratio as above. A deuterium label model sebum was prepared.

(Base makeup)
The four base makeup preparations (formulations 1 to 4) shown in Table 1 were prepared. The numerical values in Table 1 indicate the content (mass%) of each component in the formulation.

Test 1 Microscopic Raman spectroscopic measurement of the components contained in the base make-up coating film The Raman spectrum of each component of the formulation shown in Table 1 was measured. The results are shown in FIGS. In addition, the normalized maximum Raman scattering intensity was calculated for the five components shown in Table 2. Each component (test substance) was combined with an equal amount of petrolatum (baby petrolatum, Kenei Pharmaceutical), and well pulverized and mixed using an agate mortar to prepare an equal mass mixture. Raman spectra were randomly measured at 10 locations on the mixture. The integrated spectrum obtained by adding these 10 spectra was defined as the Raman spectrum (Smix (ω), ω is the wave number) of the equal mass mixture. In addition, the Raman spectra (Vaseline: Swas (ω), test substance Ssub (ω)) of each of the two components constituting the equal mass mixture were separately measured. Then, the constants a and b that best satisfy the following (Equation 1) were calculated by the least squares method.
Smix (ω) = aSwas (ω) + bSsub (ω) (Equation 1)
Then, by dividing ^{the maximum value of bSsub (ω) in the region of 300 to 4000 [cm -1} ] by the maximum value of aSwas (ω) in the region of 2920 ± 120 [cm ^-1 ], the normalized maximum Raman The scattering intensity was calculated. The results are shown in Table 2.

Test 2 Microscopic Raman spectroscopic measurement of model sebum The Raman spectrum of model sebum, deuterium label model sebum, and their components alone was measured. The results are shown in FIG.

Test 3 Microscopic Raman spectroscopic measurement of the base makeup coating film The base makeup of Formulations 1 to 4 is applied to a cover glass (170 μm thick, Matsunami Glass Ind.) To a thickness of 100 μm, dried for 1 day or more, and then Raman. The spectrum was measured.

1) Microscopic Raman spectroscopic measurement of formulation 1 coating film (high-skin-resistant formulation / without titanium oxide / with iron oxide) Strong fluorescence and luminescence different from Raman scattered light were observed, and Raman spectrum could not be measured. FIG. 4 shows an optical microscope image of the prescription 1 coating film before and after the microscopic Raman spectroscopic measurement. The coating film in the area irradiated with the laser (center of the screen) was deformed. This means that the coating film was destroyed by the heat generated by the laser irradiation.

2) Formulation 2 Microscopic Raman spectroscopic measurement of coating film (high-skin-resistant formulation / with titanium oxide / without iron oxide) Formulation 2 is a formulation excluding iron oxide, which is the main component that absorbs light, in order to prevent heat generation by the laser. Is. An optical microscope image of the prescription 2 coating film before and after the microscopic Raman spectroscopic measurement is shown in FIG. It was confirmed that there was no change in the coating film structure before and after the measurement. From this, it was found that the destruction of the base makeup coating film by Raman spectroscopy can be avoided by removing the iron oxide.
The results of two-dimensional Raman imaging (horizontal direction (XY), 20 μm × 20 μm) for the formulation 2 coating film are shown in FIG. FIG. 6A) shows a two-dimensional image of the CH group signal (peak area at 2800 to 3040 [cm ^-1 ]), and FIG. 6B) ^{shows a two-dimensional image of the titanium oxide signal (peak area at 550 to 650 [cm -1]).} Raman spectra at 6 points in the measurement range are shown in FIG. 6C). In the five spectra other than Spot-5, the titanium oxide signal ( ^{peak at 450 ± 50 [cm -1} ] and 610 ± 60 [cm ^-1 ]) containing only 8% by mass in the formulation is extremely high. It appeared strongly and interfered with the signal detection of the signal of the component having a silicone skeleton ( ^{peak at 500 ± 80 [cm -1} ]) and the signal of zinc oxide (peak at 435 ± 25 [cm ^-1]). ..

3) Microscopic Raman spectroscopic measurement of formulation 3 coating film (high-sebum resistant formulation / no titanium oxide / no iron oxide) Formulation 3 replaces titanium oxide in formulation 2 with talc. The results of two-dimensional Raman imaging (horizontal direction (XY), 20 μm × 20 μm) for the formulation 3 coating film are shown in FIG. FIG. 7A) shows a two-dimensional image of the CH group signal ( ^{peak area at 2800 to 3040 cm -1).} The Raman spectra at 6 points in the measurement range are shown in FIG. 7B). The signal of the UV absorber appeared in common in 1610 ± 50 [cm ^-1 ] and 1165 ± 25 [cm ^-1 ], but the spectra in the other wavenumber regions differed greatly depending on the site. For example Spot-2 and Spot-5 435 ± 25 indicating the presence of zinc oxide in [cm ^-1] peak could be seen in, 500 ± 80 indicate the presence of a component having a silicone skeleton in Spot-6 [cm ^{- 1} ] peak could be observed. By replacing titanium oxide with talc in this way, it became possible to clearly observe the difference in Raman spectrum locally in the coating film.
It was expected that more detailed composition information could be read by replacing the UV absorber, which has the highest standardized Raman intensity next to titanium oxide, with another oil agent in Formulation 3. However, on the other hand, since the distribution information peculiar to the UV absorber disappears, the replacement of the UV absorber was not performed in this example.
Raman imaging of 6 types of signal components (CH group, silicones, UV absorber, glycerin, talc, zinc oxide) of the formulation 3 coating film is shown in FIGS. 8 to 9. FIG. 8 is XY imaging, and FIG. 9 is XZ imaging. The broken line in FIG. 9 indicates the boundary position between the coating film and the glass substrate. By comparing the distribution or presence site of each component from the Raman signal, the three main liquid components of base makeup (silicone, UV absorber, glycerin) do not mix well in the coating film, and each has an independent domain. Was found to form.

4) Microscopic Raman spectroscopic measurement of formulation 4 coating (low-skin-resistant formulation / no titanium oxide / no iron oxide) 6 types of signal components (CH group, silicones, UV absorber, glycerin, Raman imaging for talc, zinc oxide) is shown in FIGS. 10-11. FIG. 10 is XY imaging, and FIG. 11 is XZ imaging. The broken line in FIG. 11 indicates the boundary position between the coating film and the glass substrate. Similar to the coating film of Formulation 3, in Formulation 4, the three main liquid components (silicone, UV absorber, and glycerin) of the base makeup were not mixed well and formed independent domains.

Test 4 Evaluation of sebum diffusivity of the base makeup coating film Formulation 3 and Formulation 4 were each coated on a cover glass (170 μm thick, Matsunami Glass Ind.) To a thickness of 100 μm. 0.2 μL of model sebum was added dropwise to the base make-up coating film after drying for 1 day or more, and the permeation distance in the plane direction up to 5 minutes after the addition was measured every 1 minute. This observation was performed under a digital microscope observation, and the penetration distance was determined by the image measurement function. The results are shown in FIG. The coating film of Formulation 3, which is a high sebum-resistant formulation, diffused sebum slower than the coating film of Formulation 4, which is a low-sebum-resistant formulation.

Test 5 Evaluation of sebum resistance of base makeup coating film The sebum resistance of Formulations 1 to 4 was sensory-evaluated. In the evaluation, five expert evaluators visually evaluated the condition of the face after applying each prescription to the face with a finger according to the following five criteria.
Score 5; No sebum shine on the skin 6 hours after application Score 4; No sebum shine on the skin 6 hours after application Score 3; No sebum shine on the skin 6 hours after application Score 3; Slightly shiny due to sebum Score 2; Shiny due to sebum on the skin 6 hours after application Score 1; There is considerable shiny due to sebum on the skin 6 hours after application

Table 3 shows the total score of the evaluation results of the five people. It was confirmed that Formulations 1, 2 and 3 showed similar high sebum resistance, whereas Formula 4 had low sebum resistance. From the results of Formulations 1, 2 and 3, it was shown that the presence or absence of titanium oxide and iron oxide did not significantly affect the sebum resistance of the base makeup coating film. On the other hand, Formula 4, which had a remarkably low evaluation of sebum resistance, had high sebum diffusivity in Test 4, indicating that the sebum resistance of the base makeup coating film corresponds to sebum diffusivity.

Test 6 Comparison of Raman Spectrals of Coating Film-Containing Ingredients and Sebum-Containing Ingredients FIG. 13 shows Raman spectra of the ingredients of Formulation 3 and the model sebum-containing components overwritten (offset display). The model sebum-containing components (squalene, TAG, oleic acid) did not have a distinctly different Raman signal with respect to the components contained in the base make-up coating. A deuterium label model sebum was used as the model sebum in order to clearly distinguish the base makeup coating film from the sebum. As shown in FIG. 13, by using the deuterium label model sebum, the presence of sebum in the base make-up coating film could be clearly detected based on the signal of CD expansion and contraction vibration around ^{2200 cm -1.} ..

Test 7 Microscopic Raman spectroscopic measurement of the base makeup coating film in the presence of sebum A very small amount of deuterium label model sebum was applied to the coating film of Formulation 3 (high sebum resistance) or Formulation 4 (low sebum resistance) in spot form. Raman imaging of seven signal components (CH groups, silicones, UV absorbers, glycerin, talc, zinc oxide, and model sebum (CD groups)) in the outer peripheral portion of the coating film region where the model sebum is diffused. Was acquired. Raman imaging of the formulation 3 coating film is shown in FIGS. 14 to 15, and Raman imaging of the formulation 4 coating film is shown in FIGS. 16 to 17. 14 and 16 are XY imaging, FIGS. 15 and 17 are XZ imaging, and the broken lines in FIGS. 15 and 17 indicate the boundary positions between the coating film and the glass substrate.
In the formulation 3 coating film, there was a part where the CD group was localized in the coating film, and the liquid component (silicone, UV absorber, glycerin) in the formulation and the part where the CD group was present were different. It was confirmed that the sebum component and the base make component were almost immiscible, and that a domain mainly composed of sebum existed. Glycerin, the only hydrophilic component, was present in a spherical cluster in the oil reservoir. On the other hand, in the prescription 4 coating film, the UV absorber and the CD group tended to be separated in XY imaging, but the difference in the presence site of them was not as clear as in the prescription 3 coating film, and further, lipophilicity in XZ imaging. The location of the liquid component (silicone, UV absorber) and the CD group overlapped considerably.
From these results, it was suggested that the ease of mixing the lipophilic liquid component in the coating film with the sebum is the cause of the lower sebum resistance of the formulation 4 coating film than that of the formulation 3 coating film.

Claims (6)

A method for analyzing a base make-up coating film, which comprises measuring by micro-Raman spectroscopy. The method according to claim 1, wherein at least a part of the component exhibiting strong Raman scattering contained in the base makeup coating film is replaced with another component having a lower standardized maximum Raman scattering intensity. The method according to claim 2, wherein the component exhibiting strong Raman scattering is titanium oxide. The method according to any one of claims 1 to 3, wherein the base makeup coating film does not contain iron oxide. The method according to any one of claims 1 to 4, further comprising adding a model sebum containing a deuterium-labeled lipid component to the base make-up coating film. The method according to any one of claims 1 to 5, wherein the micro-Raman spectroscopy is confocal micro-Raman spectroscopy.

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