METHOD FOR EVALUATING THE UV PROTECTION PERFORMANCE OF A COSMETIC PRODUCT

Abstract

A method for evaluating the UV protection performance of a cosmetic product includes a preparation step. This step involves preparing a measurement sample to assess the UV protection performance of the target cosmetic product. The preparation step consists of applying a uniform layer of the cosmetic product onto a transparent substrate surface for measuring UV transmittance. This is achieved using an applicator with a non-metallic coating that prevents oil adhesion. According to this method, the UV transmission of the cosmetic product can be easily and accurately evaluated.

Description

Title of the invention: METHOD FOR EVALUATING THE UV PROTECTION PERFORMANCE OF A COSMETIC PRODUCT Field of the invention

[0001] [ ] The present invention relates to a method for evaluating the performance of UV protection of a cosmetic product. Technical background

[0002] [ ] The technical context of the present invention is described below.

[0003] [ ] Currently, in Japan, they are used as indicators of the effect of UV protection in cosmetic products is expressed as the Sun Protection Factor (SPF), which indicates protection against UVB rays with a wavelength between 290 and 320 nm, and the UVA protection factor (UVA-PA), which indicates protection against UVA rays with a wavelength between 320 and 400 nm. When measurement results are given for cosmetic products, the measured values ​​or corresponding protection factors must be stated based on the measurement procedure standards (non-patent literature 1 and non-patent literature 2) specified by the Japan Cosmetic Industry Association.

[0004] [ ] Abroad as well, the indication is fundamentally required in accordance with to the measurement and indication methods (non-patent literature 3) of each region, but the basic measurement methods are almost standardized. In standardized measurement methods, the back of a human being is used, the back is irradiated with strong UV rays, and the UV protection effect is determined from the results of visual observation of the inflammation and darkening reactions that occur on the skin in this case. However, using human subjects is time-consuming and expensive, and the measurement results are slow to obtain.

[0005] [ ] Furthermore, given that the use of human beings poses problems Ethical and medical considerations have led to the study of methods for measuring the protective effect against UV radiation in Japan and Europe, using machines and without human intervention (non-patent literature 4). However, it has been reported that current measurement methods present numerous problems (non-patent literature 5). In studies conducted by the inventors of the present invention, it was found that even when the test is performed with the same sample under the same standards, the SPF values ​​vary by approximately 20 times.

[0006] [ ] The use of the method disclosed in the patent literature makes it possible to solve largely solved this problem. However, studies using this method have highlighted a new problem. This is the phenomenon whereby the use of substrates with different contact angles with water leads to a significant change in the measured values ​​of a sample (non-patent literature 6).

[0007] [ ] In view of the above, it is necessary to develop methods measurement enabling very precise measurements to be made with the least possible effort, and very precise measurements have been made by the inventions associated with the works of literature patent 2 to 7 centered on the works of literature patent 2 and 3 invented by the inventors of the present invention.

[0008] Works of patent literature relating to the prior art

[0009] [ ] Patent Literature 1: International Publication No. 2018 / 047707

[0010] [ ] Literature patent 2: Japanese patent no. 6741261

[0011] [ ] Literature patent 3: Japanese patent no. 6842778

[0012] [ ] Literature patent 4: Japanese patent no. 5825654

[0013] [ ] Patent Literature 5: Publication of the unexamined Japanese patent application No. 2021-65873

[0014] [ ] Patent Literature 6: Publication of the unexamined Japanese patent application No. 2023-57509

[0015] [ ] Patent Literature 7: Publication of the unexamined Japanese patent application No. 2023-95723 Non-patent literature

[0016] [ ] Non-patent literature 1: Japan Cosmetic Industry Association, “UV protection cosmetics and UV protection effects - SPF and PA indication-", 2003, revised version

[0017] [ ] Non-patent literature 2: Japan Cosmetic Industry Association, “Japan Cosmetic Industry Association Standard SPF testmethod » <2007, revised version>.

[0018] [ ] Non-patent literature 3: ISO / TR26369 Cosmetics - "Sun protection test methods — Review and evaluation of methods to as ses s the photoprotection of sun protection products. »

[0019] [] Non-patent literature 4: Colipa Guidelines, “Method for in vitro Determination of UVA protection”, 2009

[0020] [ ] Non-patent literature 5: Rohr, M.; Klette, E.; Ruppert, S.; Bimzcok, R.; Klebon, B.; Heinrich, U.; Tronnier, H.; Johncock, W.; Peters, S.; Pfluecker, F.; Rudolph, T.; Floesser-Mueller, H.; Jenni, K.; Kockott, D.; Lademann, J.; Herzog, B.; Bielfeldt, S.; Mendrok-Edinger, C.; Hanay, C.; Zastrow, L. “in vitro Sun Protection Factor: Still a Challenge with No Final Answer” Skin Pharmacol. Phys. 2010, 23(4), 201-212.

[0021] [ ] Non-patent literature 6: K. Asakura, A. Kuroda, IFSCC Magazine 21(2), 53-57 (2018). Summary of the invention

[0022] [ ] Cosmetic products have different physical properties, such as Hydrophilicity, lipophilicity, and intermediate properties between hydrophilicity and lipophilicity depend on their composition. When cosmetic products are applied to a single type of substrate with a fixed contact angle with water, even if some of the cosmetic products can be applied uniformly, other cosmetic products may not be applied uniformly, and the cosmetic products may undergo phase separation or be repelled from part of the substrate surface, resulting in the formation of a non-uniform coating film, for example, with part of the substrate surface exposed.

[0023] [ ] For this reason, even if the measurement accuracy is improved, the properties These properties can only be assessed by preparing substrates with many different contact angles for measurement in advance and plotting the measured values ​​on a graph. Measuring a single product can be very time-consuming; for example, measurements may be required for substrates with several different types of contact angles.

[0024] [ ] This process is extremely time-consuming compared to the in vivo method, of so that it is not a practical alternative process.

[0025] [ ] Furthermore, when more than 200 cosmetic products are commercially available And from products sourced worldwide, measured using related techniques, it was found that some cosmetic products behaved differently than expected, so we conducted research to determine the cause. According to the results, since the applicator is made of metal, in a cosmetic product with a strong affinity for a lipophilic metal, a phase separation of the cosmetic product occurs between a portion of the applicator's surface and a portion of its front surface. This results in a phenomenon where most of the cosmetic product adheres to the applicator face, and almost no product remains on the surface to be coated with the substrate.In addition, also in a preparation where such a phenomenon does not occur, an infrared imaging microscope was used to examine a change in the amount of UV absorbent in a coating film whose uniform thickness was This was confirmed using a rotating film thickness gauge. Consequently, it was found that when a four-sided stainless steel applicator was used, there were areas where the concentration of the UV absorber increased periodically; that is, the concentration of the UV absorber could become irregular depending on the position of the coating film. This implies that it is not possible to perform accurate measurements by measuring only the film thickness.

[0026] [ ] Furthermore, when corona discharge treatment is performed for When preparing a superhydrophilic substrate, a corona discharge treatment device generates strong electromagnetic noise; therefore, the device may not be suitable for use in office buildings or similar environments. Furthermore, when a cosmetic product is applied to the substrate surface, the resulting coating film may exhibit a broad, striped pattern with irregularities. In this case, if a rotating wet film thickness gauge is used to measure the coating film thickness, the measured value and the actual film thickness will differ considerably. Moreover, values ​​obtained using the calculation formulas specified in the ISO processes described in non-patent literature may differ from data obtained from human subjects.

[0027] [ ] An object of the present invention is to provide a method for evaluating a UV transmission ratio of a cosmetic product, the process solving the problems described above.

[0028] [ ] By adopting the configuration described below, an applicator, in which a a layer of material (obtained, for example, by winding a resin film) having an oil adhesion prevention property is formed on the surface of a cylindrical applicator, is used instead of an applicator having a metal surface (stainless steel), to particularly suppress excessive adhesion of an oily component of a cosmetic product to the applicator.

[0029] [ ] In addition, several types of transmission ratio evaluation substrates UV substrates with varying contact angles, such as a transparent UV transmittance measurement substrate with superhydrophilic properties, obtained by coating a quartz plate or similar surface with various materials like inulin after corona discharge, were adopted instead of a corona-discharged quartz plate itself. A uniform cosmetic product application layer is formed on each surface of these substrates using a cosmetic product and an applicator with a surface made of a material that prevents oil adhesion. Therefore, experimentally, regardless of the product's properties (such as hydrophilicity, lipophilicity, and intermediate properties between hydrophilicity and lipophilicity, as well as liquid, solid, creamy, and sticky consistency), the product... In cosmetics, a thin layer of the cosmetic product can be uniformly formed on at least one of the various substrate types for evaluating UV transmission ratio. Adopting this method eliminates the need for a corona discharge device for surface treatment of the substrates at the test site. Consequently, more accurate measurements can be performed by comparing the absorbance value of a coated cosmetic product layer at a specific wavelength, measured by a spectrophotometer, to an absorbance value at the same specific wavelength measured using a 100 µm thick assembled cell. The thickness of the cosmetic product layer can then be determined by calculation, instead of using a rotating wet film thickness gauge. Thus, a simpler and more accurate method for evaluating the UV transmission ratio of a cosmetic product has been developed.Furthermore, since the formulas for calculating SPF and UVA-PF values ​​from absorbance are not formulas specified by ISO methods, it was possible to obtain measurement results with a higher correlation to human test data. It should be noted that, hereafter, a substrate for evaluating UV transmission ratio may simply be referred to as "substrate," as appropriate.

[0030] [ ] 1. Method for evaluating the UV protection performance of a cosmetic product, the process comprising a step of preparing a measurement sample to evaluate the UV protection performance of a cosmetic product, wherein the preparation step is a step comprising the formation of a uniform application layer of the cosmetic product on a transparent substrate surface for measuring UV transmittance by means of an applicator having a layer of material with a surface having an oil adhesion prevention property.

[0031] [ ] 2. Method for evaluating the UV protection performance of a cosmetic product according to point 1, in which the layer of material whose surface has the property of preventing oil adhesion is a layer formed of one or more films selected from a polyethylene naphthalate (PEN) film, a hydrophilized polyester film, a hydrophilized polyethylene terephthalate film, and a fluorinated resin film, which have the property of preventing oil adhesion.

[0032] [ ] 3. Method for evaluating the UV protection performance of a cosmetic product according to point 1 or 2, comprising the following steps A to D in which:

[0033] A: The preparation step includes a step of preparing a plurality of measurement samples of a type of cosmetic product to evaluate the UV protection performance of the cosmetic product by forming a plurality of uniform application layers of the cosmetic product on the surfaces of a plurality of types of transparent substrates for measuring UV transmittance having different contact angles, respectively, using the applicator comprising the layer of material whose surface has the property of preventing oil adhesion;

[0034] B: a step consisting of determining the absorbance of the cosmetic product at a reference thickness using an assembled cell, and determining an SPF (sun protection factor) value and a UVA-PF (degree of protection against UVA) value for each measurement sample, using the following formulas or their equivalents:

[0035] an SPF value obtained by performing an integration every 1 nm between 290 and 320 nm using a formula CF x SEE(X) x K / .) x Abs(X),

[0036] a UVA-PF value obtained by performing an integration every 1 nm between 320 and 400 nm using a formula CF x SEE(X) x K / .) x Abs(X),

[0037] where “CF” represents a correction factor (= 10), “EE” represents an erythematous effect spectrum, “I” represents a solar intensity spectrum and “Abs” represents the absorbance of a sun protection product (i.e. each measurement sample);

[0038] C: a step consisting of selecting, on the basis of the SPF values ​​obtained for the plurality of measurement samples, a measurement sample having a maximum SPF value, and of defining the SPF value and the UVA-PF value of the selected measurement sample as an in vitro SPF value and an in vitro UVA-PF value, respectively, of said type of cosmetic product;

[0039] D: a step consisting of determining an equivalent in vivo SPF value of a type of cosmetic product from a predetermined relational expression between an in vivo SPF value and the in vitro SPF value, and further determining an equivalent in vivo UVA-PF value of said type of cosmetic product from a predetermined relational expression between an in vivo UVA-PF value and the in vitro UVA-PF value.

[0040] [ ] 4. Method for evaluating the UV protection performance of a cosmetic product according to point 3, in which the plurality of types of transparent substrates for measuring UV transmittance having different contact angles corresponds to the following three types of substrates: a transparent substrate for measuring UV transmittance having, on one of its surfaces, a layer formed by the application of a polyisocyanate, a transparent substrate for measuring UV transmittance having, on one of its surfaces, a layer formed by the application of inulin, and a transparent substrate for measuring UV transmittance having, on one of its surfaces, a layer formed by the application of a hydroxyalkylcellulose.

[0041] [ ] 5. Method for evaluating the UV protection performance of a cosmetic product according to point 3 or 4, in which the relational expression between The in vivo SPF value and the in vitro SPF value and the relational expression between the in vivo UVA-PF value and the in vitro UVA-PF value are determined by statistical treatment of the relationships between (i) the SPF values ​​and UVA-PF values ​​obtained by in vivo processes or the in vivo UVA-PF values ​​corresponding to a PA classification (degree of protection against UV-A), of cosmetic products whose properties are known (e.g., commercially available cosmetic products), and (ii) the SPF values ​​and UVA-PF values ​​of cosmetic products determined in accordance with steps A to D.

[0042] [ ] 6. Method for evaluating the UV protection performance of a cosmetic product according to any one of points 1 to 5, in which the cosmetic product is a powdered cosmetic product, a stick-shaped cosmetic product, or a paste-like substance obtained by mixing a non-volatile oil with a solid cosmetic product.

[0043] It should be noted that the present invention (which generally refers to the present disclosure and may refer to certain embodiments) can also be applied to a system for evaluating the UV protection performance of a cosmetic product.

[0044] [ ] The adoption of the method for evaluating the UV transmission ratio of a product The cosmetic product according to the present invention has an advantageous effect in that, among the various forms of cosmetic products such as cosmetic solutions, cosmetic emulsions, powdered cosmetics, paste cosmetics, and stick cosmetics, there is no form of cosmetic product that cannot be evaluated, and more precise, accurate, and stable measured values ​​are obtained for any form of cosmetic product. In particular, powdered cosmetics and stick cosmetics have not been subjected to high-precision measurements until now, and this method is the first to allow the measurement of all the different forms of cosmetic products mentioned above. Brief description of the drawings

[0045] [ ] The [Fig.1] is a flowchart of an evaluation process.

[0046] [ ] Fig. 2 is a graph illustrating an example of heating time and change in absorbance.

[0047] [ ] Fig. 3 is a photograph of the exterior of an assembled cell placed in a template for installation in a spectrophotometer.

[0048] [ ] Fig. 4 is a perspective view of a metal applicator.

[0049] [ ] The [Fig.5] is a view of a metal applicator, seen from below.

[0050] [ ] The [Fig.6] is a cross-sectional view of a metal applicator.

[0051] [ ] Fig. 7 is a cross-sectional view of an application device used in a step application 2.

[0052] [ ] The [Fig.8] is a perspective view of a cylindrical applicator.

[0053] [ ] The [Fig.9] is a cross-sectional view of a cylindrical applicator.

[0054] [ ] Figure 10 is an example of an observation using an infrared imaging microscope of a coating film applied using a cylindrical stainless steel applicator.

[0055] [ ] Figure 11 is an example of an observation using an infrared imaging microscope of a coating film applied using a cylindrical applicator in which a hydrophilized polyethylene terephthalate film is fixed to a surface which comes into contact with a cosmetic product during application.

[0056] [ ] Figure 12 is an example of an observation using an infrared imaging microscope of a coating film applied using a cylindrical applicator in which a non-hydrophilized polyethylene terephthalate film is fixed to a surface which comes into contact with a cosmetic product during application.

[0057] [ ] Figure 13 is an example of an infrared imaging microscope observation of a coating film applied using a cylindrical applicator in which a polyimide ribbon is fixed to a surface which comes into contact with a cosmetic product during application.

[0058] [ ] Figure 14 is an example of an observation using an infrared imaging microscope of a coating film applied using a cylindrical applicator in which a polyvinyl chloride ribbon is fixed to a surface which comes into contact with a cosmetic product during application.

[0059] [ ] Figure 15 is an example of an observation using an infrared imaging microscope of a coating film applied using a cylindrical applicator in which silicone rubber is fixed to a surface which comes into contact with a cosmetic product during application.

[0060] [ ] Figure 16 is an example of an observation using an infrared imaging microscope of a coating film applied using a cylindrical applicator in which a film of ethylene polynaphthalate is fixed to a surface which comes into contact with a cosmetic product during application.

[0061] [ ] Figure 17-1 is the table in ANNEX I of the non-patent literature 4.

[0062] [ ] Figure 17-2 is the table in ANNEX I of the non-patent literature 4.

[0063] [ ] Figure 17-3 is the table in ANNEX I of the non-patent literature 4. Description of symbols

[0064] [ ] 1: spreading device

[0065] [ ] 2: spreading element

[0066] [ ] 3: support part

[0067] [ ] 4: substrate

[0068] [ ] 5: excess cosmetic product

[0069] [ ] 6: tip part of spreading element

[0070] [ ] 7: cylindrical applicator

[0071] [ ] 8: support part

[0072] [ ] 9: spreading device

[0073] [ ] B: base

[0074] [ ] P: support

[0075] [ ] S: resin sponge-shaped coating tool Detailed description of the implementation methods

[0076] [ ] The present invention is described in detail below.

[0077] [ ] A method for evaluating a UV transmission ratio, the method comprising A step in preparing a measurement sample to evaluate the UV protection performance of a cosmetic product, according to the present invention, is a measurement method for obtaining very precise and stable UV protection factors for various cosmetic products such as emulsions including hydrophilic and lipophilic emulsions, lotions, emulsified foundations, powder cosmetics, oil-based cosmetics, and sprays.

[0078] [ ] As illustrated in [Fig. 1], in the present invention, a plurality For example, three types of substrates—an inulin-treated substrate (hydrophilic substrate), a hydroxyalkylcellulose-treated substrate (intermediate substrate), and a polyisocyanate-treated substrate (hydrophobic) (lipophilic substrate)—are prepared as transparent substrate surfaces for measuring UV transmittance (hereafter referred to as "UV transmittance measurement transparent substrate surfaces"). A cosmetic product to be evaluated is applied to the substrates by sequentially implementing, for example, coating steps 1, 2, and 3. The spectra of UV light transmitted through the substrates are measured. These are corrected to obtain spectra where the thickness of the cosmetic product is, for example, 20 pm. In this case, the spectra are determined with reference to the absorbance when the thickness of the cosmetic product is 100 pm, the absorbance being determined separately using an assembled cell.

[0079] [ ] Subsequently, among the three types of substrates, a substrate having a value The highest SPF is selected.

[0080] [ ] The method is based on obtaining values ​​equivalent to the SPF factor in vivo and the UVA-PF degree in vivo using predetermined formulas based on the SPF value and UVA value obtained when the substrate with the highest SPF value is used.

[0081] <Produits cosmétiques>

[0082] [ ] The cosmetic products of the present invention correspond to a wide range of cosmetic products, including makeup products and basic cosmetic products.Specific examples include makeup cosmetics such as hydrophilic emulsified sunscreens (O / W), lipophilic emulsified sunscreens (W / O), multilayer emulsified sunscreens (O / W / O, W / O / W), and emulsified foundations; makeup bases, sunscreen creams, multilayer separating sunscreens, non-chemical sunscreens, day essences, day care lotions, hand creams; powder cosmetics such as solid foundations, whitening powders, blushes, and eyeshadows; oil-based cosmetics such as lipsticks and stick sunscreens; spray sunscreens and roll-on sunscreens.Formulation types include liquids, emulsions, creams, lotions, essences, multi-layered separations, oils, powders, and sheets. However, cosmetic products with a clearly defined UV transmission rate of 0% or 100% are not included. This cosmetic product and similar products are applied to the skin, preferably at least on the face, body, limbs, etc., to achieve UV protection.

[0083] [ ] In general, this UV protection effect is represented by an SPF value corresponding to UV B rays with a wavelength of 290 to 320 nm, a UVA-PF value corresponding to UV A rays with a wavelength of 320 to 400 nm, a UVA-PF value in vivo corresponding to the PA classification or a PPD value, but it can be represented by any other index indicating the protective effect of these wavelengths.

[0084] [ ] An added UV absorbent to exhibit UV absorptivity may be Any UV absorbent added to cosmetic products. Examples of such UV absorbents include oil-soluble UV absorbents such as cinnamic acid-based, triazine-based, benzophenone-based, benzoic acid-based, salicylic acid-based, and dibenzoylmethane-based. These absorbents can be used alone or in combination with two or more of them. Water-soluble UV absorbents may include, for example, benzophenone-based UV absorbents or phenylbenzimidazole sulfonic acid and / or 2-hydroxy-4-methoxybenzophenone sulfonic acid. Examples of room-temperature solid UV absorbents include methylene bis-benzotriazolyl tetramethylbutylphenol trisbiphenyltriazine, etc.

[0085] [ ] Examples of pigments that may be contained in the products cosmetics and which diffuse and absorb UV rays include fine-particle titanium dioxide, fine-particle zinc oxide, fine-particle cerium oxide, titanium dioxide, zinc oxide, titanium hydroxide sol, aluminum powder and gold foil powder.

[0086] [ ] In addition, cosmetic products contain, as ingredients other than these UV absorbers and / or pigments, various ingredients that can be mixed into cosmetic products.

[0087] <Surface de substrat transparent de mesure de transmittance des UV>

[0088] [ ] As transparent substrate surfaces for measuring UV transmittance, Several types of UV transmittance ratio evaluation substrates with different contact angles are used. In particular, two or more substrate types selected from three types (a lipophilic substrate, an intermediate substrate, and a hydrophilic substrate) are used. For example, these three substrate types are used to obtain a plurality of measurement samples. The three substrate types have different contact angles with pure water. The contact angle of each of the UV transmittance ratio evaluation substrates in the present invention is a contact angle at 25°C with pure water on the substrate surface. Hereafter, in some cases, a transparent substrate surface for measuring UV transmittance is referred to as a "UV transmittance ratio evaluation substrate."

[0089] [ ] The UV transmission ratio evaluation substrates are formed of a A plurality of plates are produced by processing, for example, ultra-smooth treated quartz plates, and which, on surfaces possibly subjected to hydrophilic, lipophilic, or similar pretreatment, exhibit a lipophilic layer, a hydrophilic layer, and a contact angle adjustment layer with intermediate properties, presenting a contact angle between their properties. In particular, the three aforementioned substrate types are preferred and transmit UV rays in the 290 to 400 nm range. Excellent long-term stability is also required.

[0090] [ ] Hydrophilic pretreatment is carried out by subjecting a plate to a treatment by physical means, such as plasma treatment, arc discharge treatment, or corona discharge treatment, to provide a hydrophilic substrate having a contact angle with pure water between 0° and 20°, preferably between 0° and 10°, and more preferably between 0° and 5°. The detailed conditions of these treatments, such as the applied voltage and treatment duration, can be determined as appropriate depending on the desired contact angle. Furthermore, with regard to the atmosphere, discharge treatment by Corona discharge treatment in air or plasma discharge treatment in a vacuum or in an oxygen or argon atmosphere can be carried out. In particular, a quartz substrate is preferably subjected to corona discharge treatment.

[0091] [ ] Lipophilic pretreatment can be carried out by coating a plaque surface of a compound to exhibit lipophilicity or by subjecting a plate surface to plasma treatment, arc discharge treatment, corona discharge treatment or similar treatment in an atmosphere of reactive compound exhibiting lipophilicity.

[0092] [ ] It should be noted that a plate made of a material easily A material deformed by an external force, such as polymethyl methacrylate, is not preferable because the plate is susceptible to deformation during the application of a cosmetic product or washing, and it may prove impossible to prepare or use a stable substrate for evaluating UV transmission ratios. Therefore, it is preferable to use a plate that exhibits high mechanical strength and transmits UV rays uniformly across the entire wavelength range in the 290–400 nm range, such as a quartz plate.

[0093] [ ] In order to obtain the three aforementioned types of substrates on the basis of the plates, Three different types of contact angle adjustment layers are formed for each of the three plates in order to obtain transparent substrates for measuring UV transmittance.

[0094] [ ] It should be noted that in the present invention, to evaluate with To ensure UV transmittance accuracy, each of the three types of contact angle adjustment layers formed on the plate surfaces must be smooth. Regarding the degree of smoothness, based on the results determined by the following inspection procedure, the height of any irregularities should preferably be 1 µm or less.

[0095] (Method for inspecting irregularities)

[0096] [ ] A test liquid (27% by weight of isononyl isononanoate, 6% by weight ethylhexyl methoxycinnamate, 15 wt% titanium dioxide dispersion, 50 wt% petrolatum, and 2 wt% sorbitan isostearate) was applied as a thin layer to a quartz plate. Subsequently, a stainless steel applicator with a 1 µm gap and a 10 cm width was placed on the applied layer of the test liquid and moved slightly parallel to the plate surface to adjust the applicator surface to the applied layer of the test liquid. After precisely leveling the applied layer using the applicator at a speed of 5 mm / s, the resulting coating film was observed under light. If the resulting coating film shows no shadows, the plate surface is considered free of irregularities and a lipophilic substrate, an intermediate substrate, and Hydrophilic substrates prepared as described below also do not exhibit irregularities, and the plate is considered satisfactory upon inspection.

[0097] (Lipophilic substrate)

[0098] [ ] The lipophilic substrate is obtained by smoothing the above plate surface, in Performing a lipophilic pretreatment if necessary, and forming a lipophilic treatment layer such that the contact angle at 25°C with pure water is between 75° and 85°. Typical urethane resins and urethane acrylates, as the lipophilic treatment layer, exhibit higher contact angles; therefore, it is necessary to mix in another component that lowers the contact angles. Acrylic resins are also unsuitable, as the acrylic resin grades that can be used for coatings often have UV absorption in the 290–400 nm wavelength range. Similarly, UV-curable resins are unsuitable because, after curing, these resins often exhibit absorption in the 290–400 nm wavelength range.

[0099] [ ] In view of the above, acrylic-based polyisocyanates, the Polyurethanes, polyurethane acrylates, and moisture-curable thiol / isocyanate / acrylate copolymers are preferably adopted as resins that can be applied smoothly and whose contact angles with pure water can be adjusted by modifying the components and adding other components. These resins have, in a portion of their molecular structure, a hydrophilic polyol, an acrylate, or an acrylate containing a hydroxy group. Adjusting the mixing ratio of this polyol, acrylate, or acrylate containing a hydroxy group allows the contact angle with pure water to be adjusted between 75° and 85°.

[0100] (Intermediate substrate)

[0101] [ ] The intermediate substrate is obtained by smoothing the above plate surface, in Performing a hydrophilic pretreatment, a lipophilic pretreatment, or a similar pretreatment as required, and forming a layer with intermediate hydrophilicity and lipophilicity. The surface of the intermediate substrate preferably has a contact angle of 25° with pure water in the range of 50° to 60°. In the intermediate substrate, where the contact angle changes immediately after the formation of the layer with intermediate hydrophilicity and lipophilicity, it is necessary to apply a cosmetic product immediately after the formation of this layer.

[0102] [ ] The layer having the property intermediate between hydrophilicity and lipophilicity necessary to obtain such an intermediate substrate is preferably formed from a hydroxyalkylcellulose (with a contact angle immediately after application) from 51° to 52°). Alternatively, one or more compounds may be selected from the following and applied to the plate surface to form the layer: compounds having a sugar skeleton, such as mannose, galactose, xylose, glucose, maltose, lactose, sucrose, trehalose, fructose, cellulose, cellulose derivatives such as hydroxyethylcellulose, hydroxypropylcellulose and carboxymethylcellulose, trisaccharides such as maltotriose and raffinose, tetrasaccharides such as inulin, oligosaccharides, glucan, agar, α-cyclodextrin, maltodextrin, corn starch, kudzu starch, tapioca starch, potato starch, wheat starch, hydroxyethyl starch, hydroxypropyl starch, tamarind gum, xanthan gum, native gellan gum, and gellan gum, which are solubilized if necessary.

[0103] [ ] It should be noted that sugar alcohols such as erythritol and xylitol, Sugar-derived compounds and other non-sugar compounds may be mixed as long as the effects of the present invention are not altered or cannot be mixed.

[0104] [ ] Furthermore, from the point of view of the composition of the layer, the compounds are Preferably solid at normal temperature and pressure, not deliquescent, and not insoluble in water at room temperature. The term "not insoluble" refers to a solubility in water at room temperature equal to or greater than 1 g / 100 mL. Furthermore, compounds with a solubility of 5 g / 100 mL or more are preferable.

[0105] (Hydrophilic substrate)

[0106] [ ] The hydrophilic substrate is obtained by selecting from among the different compounds and a plurality of combinations of the different compounds used to obtain the intermediate substrate, and by forming a layer on the plate.

[0107] [ ] In particular, a layer exhibiting hydrophilicity can be formed using of a tetrasaccharide such as inulin, or of a hydroxyalkylcellulose. When inulin is used, the contact angle at 25°C with pure water immediately after application is 23° to 26°, and the contact angle five minutes immediately after application is 0° to 2.5°. Long-term stability is also excellent.

[0108] [ ] In the process of evaluating UV protection performance In the preparation of a cosmetic product according to the present invention, a cosmetic product is applied in a thin layer onto three types of substrates (a lipophilic substrate, an intermediate substrate, and a hydrophilic substrate), which are substrates for evaluating UV transmission ratio, to prepare measurement samples. The method is based on measuring the samples using a spectrophotometer. The main features of the measurement method are illustrated in [Fig. 1] and are described with reference to a case of an emulsion sunscreen product.

[0109] [ ] [A. Preparation step consisting of preparing a plurality of samples measurement to evaluate the UV protection performance of a cosmetic product by forming a uniform application layer of cosmetic product on surfaces of a plurality of substrate types; evaluation of UV transmission ratio having different contact angles using a type of cosmetic product with an applicator comprising a layer of material with a surface having an oil adhesion prevention property].

[0110] <Revêtement de substrats d’évaluation de rapport de transmission UV avec un produit cosmétique>

[0111] [ ] A coating step 1 and / or a coating step 2 described below, etc., are carried out as appropriate, and a coating step 3 described below is then performed as a preparation step. Measurement samples are thus prepared.

[0112] (Coating step 1)

[0113] [ ] For a surface of a substrate for evaluating UV transmission ratio, a The cosmetic product is applied to the UV transmission ratio evaluation substrate using a metal applicator with a spacing of 500 sq m to 1000 sq m. In this case, the UV transmission ratio evaluation substrate is placed on, for example, a support substrate made of extra super duralumin or similar material with a thickness between 4 and 10 mm, and the coating is applied at a speed of 1 to 10 mm / sec relative to the metal applicator, for example, 5 mm / sec. The cosmetic product can be pre-spread onto the UV transmission ratio evaluation substrate using a paint spatula or similar tool, and then leveled as needed using the metal applicator.

[0114] [ ] As an example of the metal applicator, the one illustrated in Figures 4 to 6 can be adopted.

[0115] [ ] The metal applicator is moved, for example, by a spreading device 1 illustrated in [Fig.4].

[0116] [ ] The spreading device 1 is a device comprising a spreading element 2 and support parts 3 which support both ends of the spreading element 2.

[0117] [ ] The spreading element 2 is configured to be supported relative to the parts support 3 by a structure (not shown), for example, by inserting pins supplied to the two end parts of the spreading element into grooves extending in the vertical direction and supplied in the support parts 3, so that the spreading element 2 can move freely up and down and resist the drag received from the cosmetic product to be spread by the self-weight of the spreading element in order to apply the cosmetic product evenly on the substrate.

[0118] [ ] For the spreading device 1 illustrated in [Fig. 4], other elements are not not illustrated for the sake of explanation; however, in order to integrate as a spreading device, for example, an element angle which connects the two support parts 3 can be provided.

[0119] [ ] Furthermore, [Fig. 5] is a view of the spreading device 1 seen from the surface lower (view when upper spreading element 2 is viewed from the side of base B in [Fig.6]), and a tip portion of spreading element 6 is located at the tip portion of spreading element 2.

[0120] [ ] The material of the spreading element 2 and the support parts 3 included in The spreading device 1 is preferably made of metal, in particular preferably a material with good dimensional accuracy and which can be machined, such as stainless steel or duralumin. The spreading element used in the present invention preferably has a polygonal cross-section.

[0121] [ ] Fig. 6 is a cross-sectional view illustrating a state during coating with The metal applicator. In [Fig. 6], a base B for attaching a substrate 4 is provided. Furthermore, as illustrated in [Fig. 6], the angle formed by a surface of the spreading element, the surface being oriented in the direction of movement of the spreading device indicated by the arrow, and the surface of the substrate 4 to be coated, must be 30° or more. If the angle is less than 30°, the film thickness may not be uniform due to the drag applied to the spreading element by a cosmetic product 5, and the measurement accuracy may be reduced depending on the cosmetic product.Similarly, as in the case where the spreading element has a cylindrical or cylindrical elliptical shape, when the spreading element has a shape in which the angle formed by a part of the spreading element closest to the substrate and the surface of the substrate to be coated is close to 0°, the film thickness is not uniform due to the drag applied to the spreading element.

[0122] [ ] The height of a space formed between the tip part of the spreading element 6 and substrate 4 is preferably in the range of 500 qm to 1000 qm during coating step 1.

[0123] [ ] When the spreading element is used alone, the mass of the spreading element is preferably equal to or greater than 100 g, and more preferably equal to or greater than 250 g. If the mass is too low, the spreading element may be affected by drag, which can prevent the formation of a smooth film. Similarly, if the mass is too high, the substrate and the substrate support plate are deformed, and the substrate is no longer flat, which can lead to a change in film thickness depending on the coated area. It is difficult to say exactly what mass can be applied because it also depends on the strength of the substrate and the support plate. However, in the case of using extra super duralumin with a thickness of 5 mm, it has been observed that when a load is applied from the top of the spreading element and the combined load with the self-weight exceeds 2 kg, the deformation of the substrate appears as a non-negligible quantity.

[0124] (Coating step 2)

[0125] [ ] An application device used in the coating step 2 comprises a A cylindrical support P with a diameter of 30 to 40 mm is attached to one end of a rotating shaft, as shown in [Fig. 7]. A shaft passing through the center of the circular end faces at both ends of the cylindrical support is connected to the rotating shaft. A resin sponge coating tool S, having, for example, a rectangular parallelepiped shape with a width of 8 to 12 mm, a length of 30 to 35 mm, and a height of 8 to 12 mm, is attached to the support. In this case, the surface of the resin sponge coating tool S is a flat surface, and this flat surface is parallel to the surface of a substrate with a UV transmission ratio of 4.Subsequently, while the resin sponge-shaped coating tool is rotated (e.g., at 200 or 250 rpm in the R direction), leveling is performed for a predetermined time so that the resin sponge-shaped coating tool is in contact with the layer (present between the resin sponge-shaped coating tool S and the UV transmission ratio evaluation substrate 4, although not illustrated in [Fig.7]) formed from the cosmetic product applied to the surface of the UV transmission ratio evaluation substrate 4 during coating step 1, thus transforming the cosmetic product layer formed during coating step 1 into a thinner coating layer.It should be noted that, in this case, the surface area of ​​the resin sponge coating tool preferably has a larger surface area than that of the UV transmission ratio evaluation substrate, or the length of the resin sponge coating tool S is preferably longer than the width or diameter of the UV transmission ratio evaluation substrate, so that the end portions of the resin sponge coating tool do not come into contact with the coating layer of the cosmetic product (in [Fig. 7], both ends of the resin sponge coating tool S protrude from the end portions of the UV transmission ratio evaluation substrate 4). The sponge coating tool is preferably made of a urethane sponge.

[0126] (Coating step 3 (Preparation step))

[0127] [ ] As a preparation step, for the product application layer surface cosmetic obtained in coating step 2, a layer (layer of material that prevents grease and oil from selectively adhering to the surface of the applicator) formed of a material with a surface having an adhesion-preventing property A coating of oil, a material possessing the necessary properties to maintain the dispersion of an oil contained in the cosmetic product or of an oil used to manufacture the cosmetic product in a measurement sample, and of another substance dispersed with these oils (a material possessing the property to substantially maintain the dispersion of these oils and the other dispersed substance), is formed on, for example, the surface of a cylindrical applicator. Hereafter, this layer is referred to as a "coating" or "film" that prevents oil adsorption. Furthermore, the coating is applied at a speed of approximately 5 mm / s using a modified applicator, i.e., an applicator whose film is attached with double-sided tape and which has a gap of 20 to 30 µm from the surface of the substrate for evaluating the UV transmission ratio, in order to prepare a measurement sample.Here, the layer or film that prevents oil adsorption is formed from a material whose surface has an oil adhesion-preventing property. This coating step 3 makes it possible to obtain a measurement sample comprising a more uniform cosmetic product application layer.

[0128] [ ] It should be noted that since the coating step 3 is a step To form a thin film of cosmetic product layer, it is necessary to limit the material of the applicator surface as described above. Coating steps 1 and 2 are steps for forming a thicker layer of cosmetic product. Therefore, for application devices used in coating steps 1 and 2, unlike in coating step 3, the material of the applicator surface is not limited to a water-repellent material or one capable of substantially maintaining the dispersion of oils and other dispersed substances.

[0129] [ ] The material whose surface has an oil adhesion prevention property The material used in coating step 3 must have the property described above, namely, a uniform film thickness when formed into a single layer, and must not tear or wrinkle during coating. Based on the material review results presented in Table 1, hydrophilized films and coatings such as hydrophilized polyester films and coatings and hydrophilized polyethylene terephthalate films and coatings, as well as films and coatings made from a fluorinated resin such as polyvinylidene fluoride or polyethylene naphthalate (PEN), are preferred. Regarding fluorinated resins, in addition to polyvinylidene fluoride, tetrafluoroethylene, fluorinated ethylene-propylene polymers, perfluoroalkoxy polymers, ethylene tetrafluoroethylene copolymers, ethylene chlorotrifluoroethylene copolymers, polychlorotrifluoroethylene, and polyvinyl fluoride are also preferred.Layers made of any of these materials can be used, and a polyethylene naphthalate (PEN) film with particularly high durability was the most preferred. The layers. Coatings made with fluorinated resins have also given good results. Although stainless steel has a 90° contact angle with water, it can destroy, for example, the emulsion of an emulsion-based cosmetic product, and therefore it may not be possible to form a uniform coating film.

[0130] [ ] The water contact angles shown in Table 1 are angles of contact with pure water at 25°C.

[0131] [ ] Subsequently, an applicator was prepared by applying a resin film such that a PEN film (as a material with an oil-resistant surface) 25 µm thick and with an irregularity height of 1.0 µm or less was applied to a cylindrical stainless steel applicator with a 100 µm gap using NICETACK manufactured by NICHIBAN Co., Ltd. (low adhesive, 60 µm thick) to ensure there were no creases, and the surface was smoothed with a plastic scraper. Furthermore, the applicator coated with a resin film such as a PEN film had a light weight of 266 g, and the phenomenon of the applicator floating during coating in a high-viscosity cosmetic product, resulting in uneven film thickness, was confirmed. As a result, a stainless steel block weighing 248 ga was placed on the applicator, and the coating was carried out for a total weight of 508 g.In particular, since the height of the irregularities was 1.0 µm or less, a cosmetic product layer with a smooth surface could be formed. It should be noted that the smoother the surface of the resin film, the smoother the surface of the resulting cosmetic product layer, and the more the subsequent measurement accuracy can be improved. It should also be noted that this property remains unchanged even when the cosmetic products have different properties, such as being liquid and solid. Furthermore, all the materials described above as having a surface with oil adhesion prevention properties gave results similar to those obtained in the examples described below, such as polyethylene naphthalate (PEN).

[0132] [ ] It should be noted that the metal applicator with a 500 µm gap at 1 The 000 pm used in coating step 1 does not require any special treatment. The problem of applicator wobble during coating becomes apparent when the applicator gap is narrow and is therefore likely to occur in coating step 3, but coating step 1, which is carried out with a large gap, does not require any special measures.

[0133] [ ] Fig. 8 illustrates an example of the cylindrical applicator.

[0134] [ ] A cylindrical applicator 7 is moved by, for example, a device 9 spread illustrated in [Fig.8].

[0135] [ ] The spreading device 9 is a device comprising a cylindrical applicator 7 and support parts 8 which support both ends of the cylindrical applicator 7. The spreading device 9 is supported by the support parts 8 or similar so as to be fixed to a frame (not shown) or similar or to permit movement necessary for spreading.

[0136] [ ] The cylindrical applicator 7 is supported relative to the support parts 8 by A structure (not shown), for example, by inserting pins provided at both end portions of the cylindrical applicator 7 into grooves extending vertically and provided in the support portions 8, or by forming the entire assembly so that the cylindrical applicator 7 can move freely up and down. The cylindrical applicator 7 is configured to resist the drag received from the cosmetic product to be spread by the applicator's own weight in order to apply the cosmetic product evenly to the substrate. Alternatively, the cylindrical applicator 7 can be fixed to the support portions 8. The cylindrical applicator 7 can be obtained, for example, by cutting a single block of metal to obtain a seamless block, or can be obtained, for example, by assembling suitable components.

[0137] [ ] For the spreading device 9 illustrated in [Fig.8], other elements are not not illustrated for the sake of explanation; however, in order to integrate as a spreading device 9, for example, an element angle which connects the two support parts 8 can be provided.

[0138] [ ] The cylindrical applicator 7 illustrated in [Fig. 8] has a shape in which the spreading element 2 of the metal applicator described above is replaced by the cylindrical applicator 7.

[0139] [ ] In the cylindrical applicator 7, the shape of a cross-section The cross-section perpendicular to the length of the cylinder may or may not be strictly circular. The cylindrical applicator 7 may have a circular shape, a four-corded shape within a circular shape in which the cords are flat, as illustrated in [Fig. 9], or a fan shape. Furthermore, instead of the circular shape illustrated in [Fig. 9], the cross-section may be elliptical or a shape in which two circles, ellipses, or other shapes overlap and which has a partially flat surface. It is sufficient that a portion of the cross-section that comes into contact with a cosmetic product be a gentle curve or a horizontal surface.The cylindrical shape of the part that comes into contact with the cosmetic product is not particularly limited; however, the shape of the part that comes into contact with the cosmetic product during application may be a curved surface that reflects a cylindrical shape with a cross-sectional diameter of 10 to 30 mm, or a curved surface that reflects a cross-section. transversal close to such a curved surface and which is not a circle, such as an elliptical shape. In the case of a horizontal surface, the width of a minor axis (in [Fig.9], with respect to the smooth curve described above or to the horizontal surface facing a base B, a length L in a direction parallel to the arrow indicating a direction in which the cylindrical applicator moves relative to the substrate) is preferably 1.0 to 5.0 mm, more preferably 1.0 to 3.0 mm.

[0140] [ ] Fig. 9 is a view illustrating a state in which the cylindrical applicator 7 is displaced in the direction of the arrow during the application of a cosmetic product using the cylindrical applicator 7. As with the metal applicator (Figures 4-6), the applicator is displaced relative to the surface of a layer of applied cosmetic product. The part corresponding to the tip of the spreading element 6 in the metal applicator is the substantially horizontal part of the lower end of the cylindrical applicator 7 in [Fig. 9], and when the cylindrical applicator moves in the direction of the arrow with its lower end, an excess cosmetic product 5 consequently also moves in the same way. In this case, the space formed by the cylindrical applicator 7 and the surface of a substrate 4 is preferably in the range of 500 µm to 1000 µm during the coating step 1.

[0141] [ ] Although the film described above inhibits the adsorption of oil on the surface If the cylindrical applicator is not shown in [Fig. 8], the film can cover the surface of the cylindrical applicator 7 so as to wrap around the entire cylindrical applicator 7 in [Fig. 8], or so as to cover only a portion that also comes into contact with the excess cosmetic product 5 in a lower part of the cylindrical applicator 7 in [Fig. 8]. When the surface of the cylindrical applicator is covered with a layer made of a material whose surface has an oil-preventing surface property, for example, the film wrapped around the surface of the cylindrical applicator can be fixed with double-sided adhesive tape only in an upper part of the cylindrical applicator 7 that does not come into contact with the excess cosmetic product 5.Even if only the lower part of the cylindrical applicator 7, the part that also comes into contact with the excess cosmetic product 5, is covered with the film, the film can be fixed using double-sided adhesive tape only in the part that does not come into contact with the excess cosmetic product 5. It should be noted that, as means of fixing the film to the cylindrical applicator, other known means of fixing a film to an object (such as clips and fixing with an adhesive) can be adopted instead of fixing with double-sided adhesive tape.

[0142] [ ] The reason why it is essential that the surface be formed of a film or The preparation of a layer of material with oil adhesion-preventing properties is described here. A coating film is prepared by applying a sunscreen product to a superhydrophilic quartz plate made by corona discharge using a stainless steel applicator of the shape shown in [Fig. 4], and by verifying that the film thickness is uniform using a rotating film thickness gauge. Imaging at 2852 cm⁻¹, one of the absorption wavenumbers of a UV absorber, was performed on this coating film using an infrared imaging microscope (all-in-one FT-IR microspectrometer with infrared imaging system, iNIO MX, manufactured by Thermo Fisher Scientific), and it was confirmed that the concentration of the UV absorber changed depending on the location.This means that the assumption that a cosmetic product's film thickness is uniform, and therefore the composition of the sunscreen in the product is uniform regardless of the coating film's location, has been invalidated. In other words, when using a stainless steel applicator, the measured values ​​contain significant errors. If the coating can be made from a material in which the concentration of a UV absorber does not change depending on the location, the errors can be significantly reduced, and accurate measurements can be made. With this in mind, the coating was applied using different materials, and the distribution of a UV absorber in the resulting coating films was measured using an infrared imaging microscope.Consequently, it was found that the concentration of the UV absorber did not change depending on the location, or changed only slightly when materials with a surface exhibiting oil adhesion prevention properties were used. Conversely, since the uniformity of the coating film was maintained by these materials, the reason for the change in UV absorber concentration depending on the location is considered to be the following phenomenon: because stainless steel is lipophilic, an oily ingredient of the sunscreen product gradually adsorbs onto the stainless steel surface as the applicator moves, and when the amount of adsorption becomes equal to or greater than a certain level, the oily ingredient falls to the substrate side.

[0143] (Regarding coating steps in general)

[0144] [ ] Coating step 1 is a pre-coating step for the step Coating step 2. The stability of the film thickness that can be applied by an applicator in coating step 2 tends to depend on the amount of cosmetic product on the front face of the applicator. Therefore, coating step 1 is performed to ensure a uniform amount of cosmetic product. The user When a cosmetic product, such as sunscreen, is spread with fingers or hands during actual use, the coating step 2 is performed to replicate this physical effect, such as shearing, to reduce thickness. However, if the coating step 2 is prolonged, the volatile ingredients of the cosmetic product evaporate, and the non-volatile ingredients concentrate. For this reason, the coating time is 8 to 14 seconds, ensuring that even a cosmetic product that is difficult to apply can be applied evenly. The coating step 3 transforms the cosmetic product, which became uneven during the coating step 2, into a uniform coating film.

[0145] [ ] [Table 1] Contact angle with pure water (°) Stainless steel 90 Polyethylene (medical adhesive tape) 107 Polyimide 95 Polyvinyl chloride 100 Polyethylene terephthalate 83 Silicone rubber 105 Rayon (medical adhesive tape) 139 Paper (medical adhesive tape) 131 Urethane (medical adhesive tape) 127 Cotton (medical adhesive tape) 141 Hydrophilized polyethylene terephthalate 10 Polyethylene naphthalate 95 Hydrophilized polyester 7 Polyvinylidene fluoride 110 (Drying stage)

[0146] [ ] After the coating step 3, the resulting sample is left to rest in a Place in a cool, dark place for one to one and a half hours. During this time, UV rays can be applied.

[0147] [ ] In countries other than Japan, the SPF values ​​of protective products Commercially available solar panels cost between 100 and 150, and for To measure these cosmetic products, the performance of current SPF analyzers is insufficient. An ultrasensitive spectrophotometer capable of stably measuring absorbance up to approximately 5.5 is required, and in such an ultrasensitive spectrophotometer, the sample must be positioned vertically due to the arrangement of the integrating sphere and optical path. Consequently, a drying step of some duration is necessary to prevent a coated sample from running.

[0148] [ ] [Measurement of the UV absorption spectrum of the measurement sample]

[0149] (Step of measuring the absorption spectrum of the cosmetic product applied to each substrate using an ultrasensitive spectrophotometer)

[0150] [ ] A 150 mm integrating sphere was installed in a spectrophotometer A UV-visible LAMBDA 850+ (measurement sensitivity, absorbance 8) manufactured by PerkinElmer was used. A cell assembled for a measurement sample was mounted to fit into a hole in the center of an alumite-treated aluminum jig in [Fig. 3], as shown in the photograph of the exterior of an assembled cell placed in a jig for installation in the spectrophotometer in [Fig. 3]. This jig was attached to the exterior of a light-receiving portion of the integrating sphere using double-sided tape so as to be parallel to an opening in the integrating sphere. The absorbance in the 290–400 nm range was measured using this device.

[0151] [ ] The reason why this LAMBDA 850+ UV visible spectrophotometer was The article "Materials Characterization: UV / Vis / NIR Spectroscopy; A Spectroscopic in vitro Method for the Calculation of Sunscreen SPF Values" (available at resources.perkinelmer.com) describes examples of measurements using the LAMBDA 1050+ spectrophotometer, which has performance in the UV region equivalent to that of the LAMBDA 850+ manufactured by PerkinElmer. This is because concrete examples of UV protection measurement using this instrument already exist.

[0152] [ ] This operation was performed for each of the three types of samples of measurement (the lipophilic substrate, the intermediate substrate, and the hydrophilic substrate). It should be noted that it is preferable to acquire data at three different measurement points per measurement sample. Samples with a reference thickness (reference film thickness) are obtained as described below.

[0153] [ ] [B. Step for determining the absorbance of the cosmetic product at the thickness of reference using an assembled cell, and determination of the SPF value and UVA-PF value using the formulas below (cosmetic products other than solid cosmetic products)].

[0154] (Filling the assembled cell with the sample)

[0155] [ ] A template capable of fixing an assembled cell (composed of a pair of Assembled quartz plates that are separable, one of which has a recess of a predefined depth to accommodate a sample (T-20-UV-0.1, demountable cell with removable window, manufactured by Tosoh Corporation), with an internal cavity thickness of 100 µm, were prepared, and a female mold of the assembled cell (the cell with the recess) was placed in the jig. A sample was poured into the 100 µm recess of the cell, and a flat, smooth quartz plate measuring 100 x 100 mm was then gently pressed from above to remove air bubbles from the sample. Since the cell and the quartz plate were parallel to each other in this state, the quartz plate was moved horizontally to obtain a reference film thickness sample formed from the assembled cell filled with the sample to a thickness of 100 pm.The periphery and rear surface of the cell were subsequently cleaned. The reason the thickness was fixed at 100 µm is that when an emulsion is measured at a thickness of 50 µm, the measured absorbance often varies considerably depending on the measurement position. This is because the composition of the ingredients in the emulsion differs significantly depending on the measurement position at a thickness of 50 µm. On the other hand, at a thickness of 500 µm, even when various cosmetic products are measured, the absorbance does not vary depending on the measurement position. However, cosmetic products with high SPF values ​​may have excessively high absorbance, and the Lambert-Beer law may not be satisfied.At a thickness of 100 pm, although a variation in absorbance was observed depending on the measurement position, the variation can be corrected by performing the measurement several times, and an assembled cell with a thickness of 100 pm was therefore selected as the reference thickness.

[0156] [ ] The reason why the process in which the cell and the quartz plate The smooth, parallel surfaces are used as a method for filling the assembled cell with a sample, as follows. When the surface of the assembled cell was scraped using a scraping process (a process of leveling the surface of the assembled cell by obliquely applying a quartz plate), some cosmetic products were scraped off in a quantity greater than the original amount. It was found that, in such cases, the thickness was approximately 80 to 90 µm, and the above process was therefore developed to avoid this problem.

[0157] (Heating step of the reference film thickness sample)

[0158] [ ] A precision heating plate was prepared and stabilized at 60 °C. The above reference film thickness sample was placed on the hot plate and left to stand for 15 minutes. After 15 minutes, the sample was A sample is taken to obtain a reference film thickness. Typically, when multiple reference film thickness samples are measured as part of a task, approximately 10 assembled cells are placed on a hot plate simultaneously. Therefore, it is necessary to use a laboratory hot plate capable of precisely regulating the temperature to avoid uneven heating, and it is preferable to use a large hot plate device to prevent the collection of an incorrect sample.

[0159] [ ] One reason why the reference film thickness sample is heated The following is true: given that the cosmetic product in the reference film thickness sample has a thickness of 100 µm, even if the reference film thickness sample is left unheated for one hour, its state differs from that of the cosmetic product on each of the aforementioned coated substrates. In particular, a change occurs in the residual amount of volatile ingredients. Consequently, measurements were performed using specific cosmetic products. For example, as shown in [Fig. 2], illustrating the relationship between heating time at 60 °C and the absorbance of a sunscreen product, after five minutes of heating, volatile ingredients such as water and ethanol largely evaporate, and subsequently, the absorbance does not change significantly in many cases. In [Fig. 2], the absorbance was measured at different heating times.It should be noted that two samples were heated for 15 minutes and the absorbance of each sample was measured. However, since it was found that some cosmetics required slightly more time, to allow for a margin of error, the heating was carried out for 15 minutes to sufficiently eliminate volatile ingredients in the cosmetic products. It should be noted that in [Fig. 2], the measurement was taken only twice for a heating time of 15 minutes. The reason why the absorbance decreases considerably after five minutes of heating may be as follows: in a milky lotion, since a portion of the water is scattered due to refraction at the water-oil interface (which therefore appears white in visible light), when the water is removed by heating, this scattered light diminishes, resulting in a decrease in absorbance.

[0160] (Step of measuring reference film thickness sample using a spectrophotometer)

[0161] [ ] The assembled cell cannot be placed directly into a spectrophotometer due to its small size of 12.5 x 45 mm. Therefore, a black plastic jig such as the one shown in [Fig. 3] was developed and positioned so that the assembled cell could be placed in close contact with the aperture of The integrating sphere of the spectrophotometer. The assembled cell was placed in an opening of the black plastic jig, and the absorbance at a wavelength of 400 nm was measured. It should be noted that the reason the assembled cell is placed in close contact with the opening of the integrating sphere is that, since some cosmetic products scatter light, the influence of the scattered light cannot be sufficiently reflected if the assembled cell is not in close contact with the integrating sphere.

[0162] [ ] The reason why 400 nm light was used is that this light is closest to visible light in the 290-400 nm wavelength range used for measuring UV radiation, and it is the wavelength least affected by light scattering from fine particles or other sources. A wavelength of 660 nm, for example, can also be used if only the whiteness of cosmetic products is being measured; however, separate measurements in the 290-400 nm wavelength range are necessary when measuring substrates. Therefore, given that substrates must be measured within one to one and a half hours after coating, using the 400 nm wavelength is efficient. Furthermore, depending on the cosmetic product, there are products such as lotions that neither absorb nor scatter light at a 400 nm wavelength.In such a case, the measurement wavelength is progressively shifted towards shorter wavelengths, for example 380 nm, 360 nm, 340 nm, 320 nm and 300 nm, and a wavelength that produces a significant absorbance difference is selected.

[0163] [ ] In the assembled cell, in order to correct measurement variations, the absorbance Absorbance is preferably measured at two different positions within the assembled cell. Furthermore, it has been observed that some cosmetic products exhibit variations in the preparation of a reference film thickness sample; therefore, it is also necessary to prepare a reference film thickness sample multiple times. In a preferred example, two reference film thickness samples are prepared, the absorbance is measured at two positions within each assembled cell to obtain four absorbance data points, and the standard deviation / mean value of the data is determined. If this value is greater than 0.2, a further reference film thickness sample is added, and the six-point mean absorbance value is then determined. This mean value can be defined as the absorbance of the product corresponding to a thickness of 100 µm.

[0164] [ ] The absorbance of the sample corresponding to 100 pm is determined by the operation above. Subsequently, this value is multiplied by 0.2 to convert it to a value at 20 µm. This is a comparison of values ​​at a thickness of 20 µm, which corresponds to 2 mg / cm², because in the measurement process SPF in vivo, a cosmetic product is applied to the back of a human being at a rate of 2 mg / cm2 and measured values ​​are obtained.

[0165] [ ] [C. Selection step, based on the SPF values ​​obtained for a plurality measurement samples, a measurement sample exhibiting the maximum SPF value, and the definition of the SPF value and UVA-PF value of the measurement sample as an in vitro SPF value and an in vitro UVA-PF value, respectively, of a type of cosmetic product (cosmetic products other than solid cosmetic products)].

[0166] [ ] Absorbance data at a total of nine points were obtained for the substrates described above. Therefore, if, for example, the absorbance at 400 nm is used as a reference, the absorbance values ​​at 400 nm at the nine points are compared to the absorbance values ​​at 20 pm measured using the assembled cell in order to correct the entire measurement data to obtain values ​​at 20 pm. Regarding the correction procedure, the values ​​can be simply calculated proportionally for each wavelength from the ratio of the absorbance at 400 nm to the absorbance at 20 pm. The average value of the correction data for each wavelength is determined for each substrate to obtain spectral data for each substrate, and an in vitro SPF value and an in vitro UVA-PF value are determined by calculations using these spectral data.Subsequently, among the three substrates, one substrate with the highest SPF value is selected, and the SPF value and UVA-PF value of the substrate are defined as the product values.

[0167] [ ] Suppose that a layer of a cosmetic product after application is affected A substrate's surface properties, such as hydrophilicity (lipophilicity), determine whether the cosmetic product undergoes phase separation or demolding. Consequently, the substrate is likely to transmit UV rays as a whole. In other words, a substrate with a uniform cosmetic product layer and minimal UV transmittance is the substrate with the maximum SPF (UV transmission ratio evaluation substrate). Such a substrate is one on which a cosmetic product layer has been formed without altering the properties of the cosmetic composition compared to other substrates. Therefore, the initial properties of the cosmetic product can be accurately measured by selecting the substrate with the maximum SPF and then determining both the SPF and UVA-PF values.

[0168] [ ] [D. Step for determining the equivalent value of SPF in vivo of said type of cosmetic product from the relational expression between the in vivo SPF value and the in vitro SPF value, and subsequent determination of the equivalent UVA-PF value in vivo of said type of cosmetic product from the expression relation between the UVA-PF value in vivo and the UVA-PF value in vitro (common to cosmetic products other than solid cosmetic products, powder cosmetic products and stick cosmetic products)].

[0169] [ ] Here, to determine by calculations the in vitro SPF value and the UVA- value PF in vitro from spectral data, the cosmetics industry often uses calculation formulas from ISO standards described in non-patent literature 4. However, a study conducted by the inventors of the present invention (Miyuki Fujishiro, Shoichi Yahagi, Akihiro Kuroda, Taisuke Banno, Kouichi Asakura, “Investigation on the validity of in vitro UVA-PF evaluation method for sunscreen samples”, The 2nd World Congress on Oleo Science, (WCOS 2022)) demonstrates that the calculation formulas of the ISO processes cannot appropriately reflect the difference in absorbance in the UVB region in some cases.Furthermore, it was found that when the relationships between the UV protection values ​​or indices indicated on products using ISO standard calculation formulas and the calculated values ​​obtained by the present invention were examined using measurement results from 206 commercially available sunscreen products from around the world, for both SPF and UVA-PF values, the coefficient of determination (R-squared value) of the linear regression model was very poor. Meanwhile, before the ISO standard calculation formulas were proposed (in 1979), other calculation formulas had been proposed, mainly in the Middle East and South America (Elizangela Abreu Dutra et al., "Determination of sun protection factor (SPF) of sunscreens by UV Spectrophotometry," Brazilian Journal of Pharmaceutical Sciences, 40, 3, 381-385, 2004).Specifically, an SPF for each wavelength is determined using the following formula: SPF = CF x SEE(X) x I(X) x Abs(X) (Formula 1).

[0170] [ ] The SPF determined for each wavelength is determined in the range from 290 to 320 nm, and the values ​​are integrated. Here, "CF" represents a correction factor (= 10), "EE" represents an erythematous effect spectrum, "I" represents a solar intensity spectrum, and "Abs" represents the absorbance of a sunscreen product. CF, EE, and I are constants, and with regard to EE, the values ​​for each wavelength are given as the erythematous action spectrum in the table in Annex I of the non-patent literature 4 illustrated in Figure 17, and with regard to I, the numerical values ​​for each wavelength are given as the UV-SSR Wm 2nm1 source in the same table. These values ​​were therefore used. When the SPF values ​​were calculated using formula 1, a much higher coefficient of determination was obtained than that obtained using the ISO standard calculation formula.Furthermore, the results obtained by formula 1 being more consistent with the values ​​measured in humans, . This formula 1 was used in the present invention (whereas the coefficient of determination of the ISO standard was 0.5336, the coefficient of determination of formula 1 was 0.6792).

[0171] [ ] In addition, a UVA for each wavelength is determined using the The following formula is used: UVA = CF x SEE(X) x K / .) x Abs(X) (Formula 2)

[0172] [ ] The UVA determined for each wavelength is determined within the range of 320 to 400 nm, and the values ​​determined at each wavelength are integrated.

[0173] [ ] Here, CF, EE and I are the same as in formula 1 above, “EE” represents an erythematous effect spectrum, “I” represents a solar intensity spectrum, and “Abs” represents the absorbance of a sunscreen product. These values ​​are indicated in the same way in the table in ANNEX I of the non-patent literature 4 illustrated in Figure 17. When UVA was determined using formula 2, a much higher coefficient of determination than that obtained with the ISO standard calculation formula was obtained (while the ISO standard coefficient of determination was 0.5767, the coefficient of determination of formula 2 was 0.7900). Therefore, in the present invention, the values ​​obtained using this calculation formula and by modifying the wavelength range from 320 to 400 nm were also used for UVA-PF.

[0174] [ ] The in vitro SPF value and the in vitro UVA-PF value obtained above do not These values ​​cannot be compared to conventional in vivo SPF and in vivo UVA-PF values, respectively, as they stand. To perform a comparison, relational expressions showing the correlations are required. The following relational expressions (the relational expression between in vivo and in vitro SPF values ​​and the relational expression between in vivo and in vitro UVA-PF values) obtained from the measurement results (the ratio between in vitro and in vivo SPF values ​​and the ratio between in vitro and in vivo UVA-PF values) of more than 200 commercially available sunscreen products worldwide are the following relational expressions, respectively; therefore, an equivalent in vivo SPF value and an equivalent in vivo UVA-PF value are determined using these relational expressions.

[0175] [ ] Relational expression between the in vivo SPF value and the in vitro SPF value: equivalent value of SPF in vivo = SPF value in vitro / Q, 101 (Formula 3)

[0176] [ ] Relational expression between the in vivo UVA-PF value and the in UVA-PF value in vitro: equivalent value of UVA-PF in vivo = UVA-PF value in vitro / 2.13 (Formula 4)

[0177] [ ] It should be noted that, in the measurement results of more than 200 products of commercially available sun protection products from around the world, a comparison was made using, as the solar light spectrum, both The solar light spectrum specified by the American Association of Textile Chemists and Colorists (AATCC) and the UV-SSR specified by 1TSO were used. Based on the results, although there was no significant difference in the UVA-PF results, the AATCC coefficient showed a slightly higher value. It is considered that using either one does not present any major problems. If the calculation is performed using the UV-SSR light source specified in the ISO process, a relational expression UVA-PF: equivalent in vivo UVA-PF value = in vitro UVA-PF value / 3.6680 can be used.

[0178] [ ] Here, the methods of determining expressions (relational expression The relationship between the in vivo SPF value and the in vitro SPF value, and the relationship between the in vivo UVA-PF value and the in vitro UVA-PF value, obtained from the measurement results (ratio between the in vitro SPF value and the in vivo SPF value, and ratio between the in vitro UVA-PF value and the in vivo UVA-PF value) of more than 200 commercially available sunscreen products from around the world, are now described. These relationships are determined by statistically analyzing the relationships between the SPF and UVA-PF values ​​determined in steps A to D described above and the UVA-PF values ​​indicated on the products. Currently, in vivo values, all measured on humans, are used internationally for SPF.For UVA-PF, some manufacturers indicate actual numerical values ​​on packaging, while others indicate the PA classification. In both cases, these are in vivo values ​​measured on humans. When a UVA-PF value is indicated, it can be used as is. When the PA classification is indicated, the range of its in vivo UVA-PF value is specified. Therefore, in the present invention, since the in vivo UVA-PF value corresponds to the PA classification, a value in the middle of the range was chosen to represent the product's UVA-PF value. More specifically, for PA+, the in vivo UVA-PF value was set at 3; for PA++, the value was set at 6; for PA+++, the value was set at 12; and for PA++++, the value was set at 24.The in vitro SPF values ​​of all products were determined by the method according to the present invention. The figures were plotted on the vertical axis, and the in vivo SPF values ​​indicated on the packaging were plotted on the horizontal axis. A linear approximation through the origin was performed to determine the approximate expression and the coefficient of determination. The relationship between the in vivo SPF value and the in vitro SPF value of formula 3 above was determined based on this method. Similarly, the in vitro UVA-PF values ​​of all products were determined, the figures were plotted on the vertical axis, and the in vivo UVA-PF values ​​indicated on the packaging were plotted. on the horizontal axis. A linear approximation through the origin was performed to determine the approximate expression and the coefficient of determination. Finally, the relational expression between the in vivo UVA-PF value and the in vitro UVA-PF value of formula 4 above was determined.

[0179] [ ] With the processes described above, for emulsions, lotions and products in For typical sprays, including cosmetic makeup products such as liquid foundations, it is possible to perform the preparation and measurement of the absorbance of a reference film thickness sample of 100 µm thickness using an assembled cell.

[0180] [ ] Furthermore, the equivalent value of SPF in vivo and the equivalent value of UVA- PF in vivo can be determined by selecting the substrate with the maximum SPF value and performing the calculations according to formulas (1) to (4) above.

[0181] [ ] Specific procedures for measuring a powdered cosmetic product, such A powder foundation and a stick-shaped cosmetic product, which are not fluids, are now described. The subsequent procedure for determining the equivalent in vivo SPF value and the equivalent in vivo UVA-PF value is the same as for the aforementioned fluid cosmetic products.

[0182] [ ] [B. Step for determining the absorbance of the cosmetic product at the thickness of reference using an assembled cell, and determination of the SPF value and UVA-PF value using the formulas below (powder cosmetic products)].

[0183] (Filling the assembled cell with the sample)

[0184] [ ] A glass plate or a ceramic plate is placed on a balance and a A powdered cosmetic product in a donut shape is placed on the plate. The glass or ceramic plate is preferably approximately 12 cm² in size and has a smooth surface, as such a plate is lightweight and facilitates handling. The dispersed powder is carefully removed beforehand using a brush. The weight of powdered cosmetic product required for each substrate is approximately 1.5 g, and this weight is accurately measured and recorded. Approximately 1.5 g of a non-volatile oil that does not absorb in the UV region is added dropwise to a portion of the donut-shaped cavity, and this weight is accurately measured and recorded. The non-volatile oil that does not absorb in the UV region is preferably a non-polar oil or an ester oil that mixes easily with powdered cosmetic products, particularly squalene, which is available worldwide and of stable quality.The non-volatility standard refers to low or zero volatility at normal temperature and pressure, and a non-volatile substance refers to a substance whose weight changes by 0.1% or less over approximately 10 minutes. The viscosity of the non-volatile oil used in the present invention is not particularly limited, but a non-volatile oil having a viscosity of . 6 to 1000 es, for example, is easy to handle. A balanced scale capable of measuring 1 mg is preferably used. After weighing, the mixture is thoroughly stirred on the glass or ceramic plate using a paint spatula until no lumps remain and a homogeneous paste is obtained. It is important to mix gradually, avoiding mixing the entire mixture at once. A powdered cosmetic product that has not been sufficiently mixed can stick to the back of the spatula, so it is necessary to check it at the end of the process. Once the paste is mixed, it is poured onto the substrate, and the coating steps 1 to 3 described above are carried out sequentially.On a surface of the applicator used in coating step 3, the height of irregularities on the surface of a part that comes into contact with the cosmetic product is 1.0 pm or less. Subsequently, the drying step is omitted and the measurement step using a spectrophotometer is carried out.

[0185] [ ] The same applies to solid cosmetic products which do not present in powder form.

[0186] [ ] With regard to the reference film thickness sample, a paste The mixture is prepared as in the case of a liquid cosmetic product described above, except that the quantity of powdered cosmetic product is approximately 1 g, and the quantity of non-volatile oil that does not absorb in the UV region is also approximately 1 g. Subsequently, as in the case of a liquid cosmetic product, the paste is placed in a hollow of an assembled cell and left to stand for several minutes. A flat plate of the assembled cell is then placed on top and secured by applying pressure. The short side of the assembled cell is held with the fingers, and the paste protruding around the edges is wiped away. Force is slowly applied from one long side of the flat plate of the assembled cell to eliminate as many air bubbles as possible.The main cause of variations in measured values ​​during the preparation of samples of a powdered cosmetic product is the presence of air bubbles mixed in during kneading. Therefore, when the obtained sample is exposed to light, if bubbles are present, the step of measuring a 100 µm reference film thickness sample using a spectrophotometer is performed without measuring such a portion. When placing the paste in the hollow of the assembled cell, placing a large excess of paste, followed by pressure on the flat plate, easily eliminates air bubbles. Regarding the reference film thickness sample, two or more sets of samples are prepared.

[0187] [ ] Subsequently, for each substrate and each film thickness sample For the reference, the measured values ​​for the powdered cosmetic product are obtained as in the step of measuring a reference film thickness sample with a spectrophotometer for a cosmetic product other than a solid cosmetic, except that an adjusted absorbance determined by dividing the obtained absorbance value by the value of "weight of powdered cosmetic product / (weight of non-volatile oil + weight of powdered cosmetic product)" is used as the sample absorbance. The equivalent in vivo SPF value and the equivalent in vivo UVA-PF value are then determined.

[0188] [ ] [B. Step for determining the absorbance of the cosmetic product at thickness reference using an assembled cell, and determination of the SPF value and UVA-PF value using the formulas below (stick-shaped cosmetic products)] (Filling the assembled cell with the sample)

[0189] [ ] The procedures for measuring a stick-shaped cosmetic product, Products such as lipstick or sunscreen in stick form are now described. In the case of a stick-shaped cosmetic product, preferably, a substrate measurement is performed first, followed by a measurement of a reference film thickness sample. This is because many cosmetic products do not absorb or scatter light at a wavelength of 400 nm, and therefore the measurement wavelength used to measure the reference film thickness sample must be determined from the substrate measurement results. A glass or ceramic plate is placed on a balance, approximately 0.6 g of a stick-shaped cosmetic product is rubbed against the plate to obtain a square frame shape using a spatula, and the quantity of cosmetic product is accurately measured and recorded.Subsequently, approximately 2.4 g of a non-volatile oil with no UV absorption is added dropwise to the center of the square frame, and the weight is measured and recorded in the same manner. The cosmetic product and the oil are gradually mixed using a paint spatula. Once thoroughly mixed, the paste is transferred to a container such as a disposable aluminum food cup and heated to 60 °C for 15 minutes using a hot plate. At this point, any cosmetic product that has not been sufficiently mixed may adhere to the back surface of the spatula, so it is necessary to check this. If phase separation is observed after heating, the mixture is sufficiently mixed while still hot. The entire paste is poured onto the substrate, and coating steps 1 to 3 described above are carried out sequentially.On a surface of the applicator used in coating step 3, the height of the irregularities on the . The surface area of ​​any part that comes into contact with the cosmetic product is 1.0 pm or less. Subsequently, the drying step is omitted and the measurement step using a spectrophotometer is performed.

[0190] [ ] With regard to the reference film thickness sample, a paste The mixture is prepared as in the case of the preparation of the reference film thickness sample of the powdered cosmetic product described above, except that the quantity of stick-shaped cosmetic product applied is approximately 0.3 g, and the quantity of non-volatile oil that has no absorption in the UV region is approximately 1.2 g. Two or more sets of reference film thickness samples are prepared as in the case of the powdered cosmetic product.

[0191] [ ] Subsequently, for each substrate and each film thickness sample For the reference, the measured values ​​of the stick-shaped cosmetic product with a film thickness of 100 µm are obtained as in the process for preparing a reference film thickness sample of the powdered cosmetic product, except that an adjusted absorbance determined by dividing the obtained absorbance value by the value of "weight of powdered cosmetic product / (weight of non-volatile oil + weight of powdered cosmetic product)" is used as the sample absorbance. At this stage as well, the height of irregularities is 1.0 µm or less.

[0192] [ ] Here, in the present invention, an extremely sensitive measuring device comprising a main body with a measurement sensitivity reaching absorbance 8, is used in the measurement step with a spectrophotometer; however, in the cosmetics industry, a measurement device called an SPF analyzer has been used until now. There are two typical models: one with an absorbance measurement sensitivity of approximately 2 and the other with an absorbance measurement sensitivity of approximately 3. On the other hand, there are examples of measurements with an absorbance of 8 as described above. It is considered that, although there are differences between products, for products with an SPF value less than or equal to 15, the method according to the present invention can be carried out without sensitivity problems, even using the two existing models. In the case of products with higher SPF values, some measured values ​​are obtained, but it must be considered that these include significant error factors.As stated in the WCOS 2022 article above, we confirmed that when absorbance exceeds 2, the readings vary considerably depending on the measuring instrument. Therefore, the objectivity of the measured values ​​can only be guaranteed if the measurement process is carried out while acknowledging the sensitivity issues of the measuring instruments.

[0193] [ ] A problem related to the smoothness of a substrate is now also described here. In the cosmetics industry, development has progressed by considering that, since human skin has texture and irregularities, a measurement substrate must also exhibit irregularities. Furthermore, a feature of the present invention lies in the fact that the relationships between the measured values ​​obtained by the in vivo SPF measurement method and the in vivo UVA-PF measurement method and the in vitro SPF and UVA-PF values ​​obtained by the method according to the present invention (the formula for calculating the equivalent in vivo SPF value and the formula for calculating the equivalent in vivo UVA-PF value) are determined, and the equivalent in vivo SPF and UVA-PF values ​​are determined without using the in vitro SPF and UVA-PF values ​​as they stand. In the in vivo methods, the measurement is performed by firmly pressing a UV irradiation probe against the human's back. [See https: / / solarlight.]The catalog at com / product / model-601-multiport-spf-testing-6-output-solar-simulator / presents a description of a UV irradiation device most commonly used for controlled measurements, and outlines the use of a series of six irradiation probes. The UV irradiation portion of the probes is cylindrical and has a structure in which UV rays, guided by an optical fiber, are applied from the center. When the 8 mm cylinder is pressed firmly against human skin, the skin is stretched to its maximum and flattened. In the present invention, since the relationship to measurement results obtained in this flattened state is determined, the measurement substrates used are also smooth substrates.A plate exhibiting irregularities is relevant for measuring the effects of UV radiation to which consumers are exposed in real life, rather than using the in vivo measurement methods described above, and presumably, it is essentially difficult to compare with existing in vivo measurement methods. Examples

[0194] [ ] The present invention is now described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0195] [ ] [Reason why the surface of the applicator used in the coating step 3 which comes into contact with the cosmetic product must be formed of a layer of material having an oil adhesion prevention property].

[0196] [ ] Confirmation test of the change in the coating film in the case where a a layer of material having an oil adhesion prevention property is provided or not on the coating part of the applicator

[0197] (Measurement conditions)

[0198] [ ] An infrared imaging microscope (all-in-one FT-IR microspectrometer with The iNIO MX infrared imaging system (manufactured by Thermo Fisher Scientific) was used; the measurement interval was 100 pm x 100 pm; the number of measurement waves The concentration was 2,852 cm³. A liquid nitrogen transmission measurement was performed, integration was carried out 16 times for each measurement point, and a quartz plate made of synthetic quartz was used as a reference. Regarding the measurement range, a 70 mm range was measured in the direction in which an applicator moved. This device initially provides color-matching analysis results, but in the present patent, white areas indicate a higher concentration (lower transmittance).

[0199] [ ] Measurement sample: Milky lotion composed of water, zinc oxide, ethanol, ethylhexyl methoxycinnamate, isocetyl myristate, glycerin, propylene glycol, bisethylhexyloxyphenol methoxyphenyl triazine, polyhydroxystearic acid, phenoxyethanol, methicone, xanthan gum, perfume, EDTA-2Na, biosaccharide gum-1, pigment, copolymer (Na acrylate / Na acryloyldimethyltaurate), isohexadecane, polysorbate 80 and sorbitan oleate (preparation obtained by selecting and adjusting the ingredients from the infrared spectrum of each ingredient so that the behavior of a UV absorber (oil layer) becomes clear when infrared observation).

[0200] [ ] Applicator: a cylindrical applicator with a stainless steel surface and cylindrical applicators in which various layers of materials have been fixed to their surfaces have been used.

[0201] [ ] Coating conditions: a coating was applied at a speed of 5 mm / s at with the help of a precision coating device.

[0202] [ ] Substrate used for the coating: the surface of a quartz plate made up A 10 x 10 cm synthetic quartz slab was treated for 90 seconds using a corona discharge device (BD-20AC Laboratory Corona Treater, manufactured by Electro-Technic Products, Inc.). The treatment was performed using a robot to ensure uniformity across the entire surface.

[0203] [ ] Film thickness measurement: the measurement was carried out using a gauge of rotating film thickness.

[0204] (Test results)

[0205] [ ] Figure 10 shows the results of the observation of a coating film applied using a cylindrical stainless steel applicator, obtained using an infrared imaging microscope under the measurement conditions described above. The area to the right of -15,000 is a region of the coating film that is typically used for a UV protection performance evaluation test. Uniform film thickness in this area was confirmed using a rotating film thickness gauge. In [Fig. 10], the areas appearing white are regions where the concentration of the UV absorber is relatively high. This shows that even if the coating film appears to have a uniform thickness, the concentration of the UV absorber is not uniform.

[0206] [ ] Figure 11 shows the results of the observation of an applied coating film Using an applicator identical to the cylindrical applicator, except that a hydrophilized polyethylene terephthalate film was applied to the surface in contact with the cosmetic product, the results were obtained using an infrared imaging microscope. Areas with high concentrations of UV absorber were not particularly observed, indicating that a stable coating was achieved.

[0207] [ ] Furthermore, [Fig. 12] shows the results of the observation in the case of The use of a non-hydrophilized polyethylene terephthalate film, obtained using an infrared imaging microscope, revealed that when hydrophilization was not performed, shadowing of the UV absorber concentration occurred.

[0208] [ ] Figure 13 shows the results of the observation of an applied coating film using an applicator to which a polyimide tape had been attached, obtained using an infrared imaging microscope. It was observed that the shadowing of the UV absorber concentration occurred significantly.

[0209] [ ] Figure 14 shows the results of the observation of an applied coating film using an applicator to which a polyvinyl chloride ribbon had been attached, images were obtained using an infrared imaging microscope. It was observed that significant shadowing of the UV absorber concentration occurred.

[0210] [ ] Figure 15 shows the results of the observation of an applied coating film using an applicator to which a silicone rubber was attached, obtained using an infrared imaging microscope. It was observed that the shadowing of the UV absorber concentration occurred significantly.

[0211] [ ] Figure 16 shows the results of the observation of an applied coating film using an applicator to which a PEN film had been attached, obtained with an infrared imaging microscope. Areas of high concentration of the UV absorber were not particularly observed, indicating that a stable coating was achieved.

[0212] [ ] Various materials were selected in this way based on the presence or the absence of a high concentration zone, and polyethylene naphthalate (PEN), hydrophilized polyethylene terephthalate, etc., have proven excellent in terms of coating film uniformity.

[0213] (Example 1)

[0214] [ ] A description is now given of an example of a series of operations for to obtain, using a cosmetic emulsion composed of ingredients listed in Table 2, an equivalent in vivo SPF value and an equivalent in vivo UVA-PF value of the product. It should be noted that when the performance of UV protection of the milky lotion described in Table 2 was measured on humans, the SPF value was 56 and the UVA-PF value was 19.9.

[0215] [ ] The spectrophotometer used was a LAMBDA UV-visible spectrophotometer 850+ (measurement sensitivity, absorbance 8) manufactured by PerkinElmer and comprising a 150 mm integrating sphere, and the assembled cell used was T-20-UV-0.1 manufactured by Tosoh Corporation.

[0216] [ ] The drying time for each substrate is one hour. As in the step of In coating step 1, the emulsion cosmetic product was leveled using a 500 µm four-sided stainless steel applicator. Subsequently, in coating step 2, a sponge-like urethane (15 mm wide, 10 mm high, and 35 mm long) was used as the coating tool attached to the tip of a rotary device, and spreading was performed for 12 seconds at a rotary coating speed of 260 rpm. Polyethylene naphthalate (PEN) was used as the coating material for a cylindrical applicator (in which the cross-section of an area in contact with the cosmetic product during application was a curved surface reflecting a circle with a diameter of 12 mm) used in coating step 3, and the gap with each substrate was 25 µm.Three types of substrates were used: a plate treated with acrylic polyisocyanate (contact angle after one week of acrylic polyisocyanate application: 80°), a plate treated with hydroxyalkylcellulose (contact angle after one week of hydroxyalkylcellulose application: 51° to 52°), and an inulin-coated plate (quartz plate coated with inulin) (contact angle after one week of inulin application: 23° to 26°). It should be noted that these contact angles are for pure water at 25°C.

[0217] [ ] [Table 2] Names of ingredients Water Ethyl methoxycinnamate BG Diethylamino hydroxybenzoyl hexyl benzoate Ethanol Ethylhexyl triazone Bis-ethylhexyloxyphenol methoxyphenyl triazine Dimethicone Diisopropyl adipate Methyl methacrylate crosspolymer Cross-polymer (HDI / trimethylol hexyllactone) PEG-20 Glyceryl Triisostearate Ethylhexylglycerin Glyceryl caprylate Sorbitan sesquiisostearate Scent Copolymer (acrylates / beheneth-25 methacrylate) Potassium hydroxide PPG-8-ceteth-20 Tocopherol EDTA-2Na Citrus junos fruit extract Gum-1 Biosaccharide Phenoxyethanol

[0218] [ ] As a plurality of report evaluation substrate types UV transmission, a plate treated with moisture-curable, lipophilic acrylic-based polyisocyanate (simply referred to as "polyisocyanate" in the tables), a plate coated with hydroxyalkylcellulose, and a plate coated with inulin were prepared. In coating step 1, the milky lotion described in Table 2 was applied to the plate using a stainless steel applicator with a space of 500 µm. Subsequently, in coating step 2, the milky lotion was immediately spread at 260 rpm for 12 seconds using a rotating device to which a urethane sponge was attached. Subsequently, in coating step 3, a coating film was immediately formed using the PEN-coated cylindrical applicator described above. The plates were stored in a cool, dark place for one hour, and the absorbance was measured at three points for each plate using a spectrophotometer.

[0219] [ ] Two sets of assembled cells with a depth of 100 pm, prepared Separately, the assembled cells were filled with the milky lotion described in Table 2. After filling, the assembled cells were left to rest for 15 minutes on a precision hot plate heated to 60 °C, then allowed to cool to room temperature. Absorbance at 400 nm was measured at two points for each assembled cell using a spectrophotometer to obtain a total of four measured values. The actual measured values ​​of 1.174941, 1.159418, 1.277993, and 1.155809 were obtained as absorbance values; the mean absorbance was 1.19204, the standard deviation was 0.0579, and the mean absorbance standard deviation was 4.9%. The standard deviation / mean absorbance being 4.9%, i.e. 20% or less, the measurement was carried out at four points.

[0220] [ ] The average absorbance of 1.19204 being a value at 100 pm, for the value For 20 pm, multiplying this value by 0.2 gives 0.238408. Using this value as a reference, the spectrum corresponding to a film thickness of 20 pm was determined by proportional calculation from the absorbance values ​​at 400 nm measured at the nine points on the plates.

[0221] [ ] The spectral data equivalent to 20 pm from the nine measurement points were obtained as described above. These data were used to determine, as Example 1, the SPF and UVA-PF values ​​determined according to formulas (1) and (2), respectively, and, as Comparative Example 1, the SPF and UVA-PF values ​​based on ISO standard processes determined according to non-patent literature 4. It should be noted that, in the calculation formulas for formulas (1) and (2), the values ​​determined using, as the solar light spectrum, the data from the solar light spectrum specified by the AATCC are indicated. Tables 3 and 4 present the results.

[0222] [ ] [Table 3] UV transmission ratio evaluation substrate SPF Value determined by formula (1) Value determined by ISO standard Lipophilic polyisocyanate treated plate 4.682821079 146.1796068 Hydroxyalkylcellulose coated plate 6.83223345 296.0188865 Inulin coated plate 6.453689161 265.303419

[0223] [ ] [Table 4] UV transmission ratio evaluation substrate UVA-PF Value determined by formula (2) Value determined by ISO standard Lipophilic polyisocyanate treated plate 34.23424469 21.12210293 Hydroxyalkylcellulose coated plate 45.86799382 26.60630364 Inulin coated plate 43.25500714 24.56087138

[0224] [ ] With reference to Table 3, it is noted that the plate showing the SPF value The highest value determined by formula 1 is the hydroxyalkylcellulose-coated plate, and the in vitro SPF value of this product is approximately 6.8. The in vitro UVA-PF value determined similarly by formula 2 is approximately 45.9, measured using the same plate. The equivalent in vivo SPF value determined from formula 3 using this in vitro SPF value is 67.7, and similarly, the equivalent in vivo UVA-PF value determined from formula 4 using this in vitro UVA-PF value is 21.6. In the case of ISO processes, the values ​​must be used as is; therefore, the in vitro SPF value is 296 and the in vitro UVA-PF value is 26.6. There is thus a large difference between the two values.In contrast, as described above, the in vivo measured values ​​of this product are an SPF of 56 and a UVA-PF of 19.9, which shows that the measurement methods according to the present invention indicate values ​​extremely close to those measured by the in vivo methods compared to the ISO methods, which are comparative examples.

[0225] [ ] Furthermore, even when a film is formed, instead of ethylene polynaphthalate (PEN) above, hydrophilized polyester, hydrophilized polyethylene terephthalate, polyvinylidene fluoride, tetrafluoroethylene, fluorinated ethylene propylene polymer, perfluoroalkoxy polymer, ethylene tetrafluoroethylene copolymer, ethylene chlorotrifluoroethylene copolymer, polychlorotrifluoroethylene, and polyvinyl fluoride was adopted, respectively, a thin layer composed of the milky lotion shown in Table 2 and having the same properties as the original properties of this milky lotion can be formed on a plate coated with hydroxyalkylcellulose, as in the case of the use of ethylene polynaphthalate (PEN).

[0226] (Example 2)

[0227] [ ] Measurements were carried out using a powdered cosmetic product commercially available (face powder). It should be noted that the packaging of the commercially available product indicated an SPF value of 32 and a PA classification of +++ (equivalent to 8 to 16 in terms of UVA-PF) (in vivo UVA-PF value corresponding to PA classification: 12) and included the labeling of the ingredients below.

[0228] [ ] Talc, perlite, titanium dioxide, ethylhexyl methoxycinnamate, dimethicone, aluminium hydroxide, stearic acid, silica, methicone, caprylyl glycol, ethylhexylglycerin, BHT, cetyl PEG / PPG-10 / 1 dimethicone, tocopherol, pentaerythrityl tetra-di-t-butyl hydroxyhydrocinnamate, (+ / -) titanium dioxide, mica, iron oxides.

[0229] [ ] A plate treated with hardenable lipophilic acrylic-based polyisocyanate In humid conditions, a plate coated with hydroxyalkylcellulose and a plate coated with inulin, identical to those described above, were prepared. On a 12 cm² surface-hardened glass plate, the powdered cosmetic product was finely scraped with a spatula and placed in a donut-like shape. The weight of the powdered cosmetic product was 1.5 g. To the powdered cosmetic product, 1.5 g of squalene was added and thoroughly mixed with a paint spatula, and the resulting paste was spread onto a substrate. This operation was repeated three times to prepare samples formed from each of the substrates onto the surface of which the paste was spread. Subsequently, during coating step 1, the mixed paste was leveled similarly using a 500 pm stainless steel four-sided applicator, as in Example 1.Subsequently, in coating step 2, the mixed paste was immediately spread at 260 rpm for 12 seconds using the same rotary device to which a urethane sponge was attached as that used in Example 1. Subsequently, in coating step 3, a coating film was immediately formed using the same PEN-coated cylindrical applicator as that used in Example 1. Absorbance was measured at three points for each plate using a spectrophotometer.

[0230] [ ] Three sets of assembled cells having an obvious depth Each 100 µm vessel was filled with the mixed paste prepared in the same way as above and having a powdered cosmetic product / (powdered cosmetic product + squalene) value of 0.615. The absorbance at 400 nm was measured in two points for each cell assembled using a spectrophotometer to obtain measured values ​​at a total of six points. It should be noted that, although there are no issues even with four points, the data for six points are presented here to demonstrate the extent of variation that occurs when the powdered cosmetic product is actually measured by this method. The actual measured values ​​of 4.779588, 4.715465, 4.95402, 4.692718, 5.403312, and 4.901608 were obtained as absorbance values; the mean absorbance was 4.907785167, the standard deviation was 0.263589873, and the standard deviation / mean absorbance = 5.4%. This mean absorbance is measured using the diluted powdered cosmetic product; Therefore, assuming that the powdered cosmetic product is not diluted, dividing the average absorbance value by the above mixing ratio gives 7.980.

[0231] [ ] Tables 5 and 6 show the results obtained by correcting using this value, in relation to the film thickness, the absorbance values ​​determined beforehand in a total of nine points.

[0232] [ ] [Table 5] UV transmission ratio evaluation substrate SPF Value determined by formula (1) Value determined by ISO standard Lipophilic polyisocyanate treated plate 5.355232258 100.6848401 Hydroxyalkylcellulose coated plate 4.428813801 67.02088636 Inulin coated plate 4.499381589 94.85938376

[0233] [ ] [Table 6] UV transmission ratio evaluation substrate UVA-PF Value determined by formula (2) Value determined by ISO standard Lipophilic polyisocyanate treated plate 23.4704833 13.41072424 Hydroxyalkylcellulose coated plate 22.00354695 12.18088692 Inulin coated plate 25.16421589 15.51185452

[0234] [ ] With reference to Tables 5 and 6, the plate with the highest SPF value determined by formula 1 was the lipophilic plate. The in vitro SPF value of this product is 5.4, and the in vitro UVA-PF value determined in the same way by formula 2 is 23.5, measured using the same plate. The equivalent in vivo SPF value determined from formula 3 using this in vitro SPF value is 53.3, and similarly, the equivalent in vivo UVA-PF value determined from The value of formula 4 using this in vitro UVA-PF is 11.0. In the case of ISO processes, the values ​​must be used as is; therefore, the in vitro SPF value is 100.6 and the in vitro UVA-PF value is 13.4. Regarding the in vitro UVA-PF value, both values ​​are within the same range as the value indicated on the product; however, regarding the SPF value, a more significant difference was observed with the ISO process.

[0235] (Example 3)

[0236] [ ] The measurements were carried out using a sun protection product in commercially available stick. It should be noted that the packaging of the commercially available product indicated an SPF value of 50+ and a PA classification of ++++ (equivalent to 16 to 32 in terms of UVA-PF) (in vivo UVA-PF value corresponding to PA classification: 24) and included the labeling of the ingredients below.

[0237] [ ] Triethylhexanoin, Isononyl isononanoate, Polymethylsilsesquioxane, Dimethicone, Nylon-12, Ethylhexyl Methoxycinnamate, Polyethylene, Synthetic Wax, Trimethylpentanediol / Dipic Acid / Glycerin Crosspolymer, Butyl Methoxydibenzoylmethane, Dimethicone / Vinyl Dimethicone Crosspolymer, Sucrose Polysearate, Polysilicone-15, Menthol, Alumina, Tocopherol, Water, Butylene Glycol, Saxifraga Sarmentosa Extract, Geranium Robertianum Extract, Vaccinium Myrtillus Leaf Extract, Cynara Scolymus (Artichoke) Leaf Extract, BHT, Fragrance

[0238] [ ] A plate treated with hardenable lipophilic acrylic-based polyisocyanate In humid conditions, a plate coated with hydroxyalkylcellulose and a plate coated with inulin, identical to those described above, were prepared. On a 12 cm² surface-cured glass plate, the cosmetic product was rubbed against the plate to create a square frame shape using a spatula. The weight of the cosmetic product was 0.600 g. In the center of the square frame, 2.400 g of squalene were added dropwise and thoroughly mixed with a spatula. The resulting paste mixture was placed in a disposable aluminum food-grade cup, heated to 60 °C for 15 minutes, and then poured onto the plate. This process was repeated three times to prepare samples of each substrate onto the surface of which the paste mixture was spread.Subsequently, in coating step 1, the mixed paste was leveled similarly using a 500 µm four-sided stainless steel applicator, as in Example 1. Subsequently, in coating step 2, the mixed paste was immediately spread as in Example 1 at 260 rpm for 12 seconds using a rotary device to which a urethane sponge was attached. Subsequently, in coating step 3, a coating film was formed using the applicator. cylindrical plate coated with PEN, as in example 1. Absorbance was measured at three points for each plate using a spectrophotometer.

[0239] [ ] Two sets of assembled cells with a depth of 100 pm were Each was filled with the mixed paste prepared in the same way as above and having a value of 0.208 (cosmetic powder / (cosmetic powder + squalene)) of 0.208. It should be noted that the above measurement revealed that this cosmetic product had virtually no absorption at a wavelength of 400 nm but sufficient adsorption at a wavelength of 360 nm; therefore, the measurement wavelength was changed to 360 nm. The values ​​of 3.883449, 3.774979, 3.804809, and 3.645621 at four points were obtained as the actual measured absorbance values. The mean absorbance was 3.777215, the standard deviation was 0.098943, and the standard deviation / mean absorbance was 2.6%. This average absorbance is measured using the diluted cosmetic product; therefore, assuming the cosmetic product is not diluted, dividing the average absorbance value by the above mixing ratio gives 18.2.Tables 7 and 8 show the results obtained by correcting, with respect to film thickness, the absorbance values ​​previously determined over a total of nine points.

[0240] [ ] [Table 7] UV transmission ratio evaluation substrate SPF Value determined by formula (1) Value determined by ISO standard Lipophilic polyisocyanate treated plate 2.854731581 16.95899725 Hydroxyalkylcellulose coated plate 3.165587076 19.47276036 Inulin coated plate 3.031010476 18.80183919

[0241] [ ] [Table 8] UV transmission ratio evaluation substrate UVA-PF Value determined by formula (2) Value determined by ISO standard Lipophilic polyisocyanate treated plate 11.97693823 3.506189836 Hydroxyalkylcellulose coated plate 12.02769372 3.461358974 Inulin coated plate 12.30134862 3.572286152

[0242] [ ] With reference to Table 7, the plate with the highest SPF value determined by formula 1 was the hydroxyalkylcellulose-coated plate. The in vitro SPF value of this product is approximately 3.2, and similarly, the in vitro UVA-PF value is approximately 12.0, measured using the same plate. The equivalent in vivo SPF value determined from formula 3 using this in vitro SPF value is 31.8, and similarly, the equivalent in vivo UVA-PF value determined from formula 4 using this in vitro UVA-PF value is 5.6. In the case of ISO processes, the values ​​should be used as is; therefore, the in vitro SPF value is 19.5 and the in vitro UVA-PF value is 3.5. Compared to the values ​​indicated on the product, according to formula 3 and formula 4, the SPF value was slightly lower and the UVA-PF values ​​were the same, whereas they were both considerably lower according to the ISO standard processes.

[0243] (Comparative example 1 and example 4)

[0244] [ ] Measurements were taken using a sunscreen spray at commercially available pressure. It should be noted that the packaging of the commercially available product indicated an SPF value of 100 and included the ingredient labeling below.

[0245] [ ] avobenzone (3%), homosalate (10%), octisalate (5%), octocrylene (10%), oxybenzone (6%), denatured alcohol, isobutane, VA / butyl maleate / isobomyl acrylate copolymer, caprylyl glycol, cyclopentasiloxane, cyclohexasiloxane, parfum, polyglyceryl-3 stearate / isostearate / dilinoleate dimer crosspolymer, lauryl PEG-8 dimethicone, phenylisopropyl dimethicone, ascorbyl palmitate, methyl dihydroabietate, tocopheryl acetate, mineral oil, panthenol, water, Aloe barbadensis leaf extract.

[0246] [ ] A plate treated with hardenable lipophilic acrylic-based polyisocyanate In humid conditions, a plate coated with hydroxyalkylcellulose and a plate coated with inulin, identical to those described above, were prepared. In a single coating step, the sunscreen product was sprayed from above, and a four-sided stainless steel applicator with a 20 µm gap was used to form a coating film by moving the applicator at a speed of 5 mm / s. Subsequently, an attempt was made to measure the film thickness using a rotary film thickness gauge, but it was not possible to measure the film thickness because the cosmetic product was transparent.

[0247] [ ] In view of the above, measures have been taken in accordance In Example 1, based on the results, the hydroxyalkylcellulose-coated plate was selected. The in vitro SPF value was 4.8, and similarly, the in vitro UVA-PF value was 35.6, measured using the same plate. The equivalent in vivo SPF value determined from formula 3 using this in vitro SPF value was 47.8, and similarly, the equivalent in vivo UVA-PF value determined from formula 4 using this in vitro UVA-PF value was 16.7. The method for measuring film thickness using an assembled cell was employed. in the present invention is very well suited to cosmetic products such as transparent lotions and cosmetic products which provide coating films with many irregularities.

[0248] (Comparative example 2 and example 5)

[0249] [ ] Measurements were taken using a sunscreen product commercially available. It should be noted that the packaging of the commercially available product indicated an SPF value of 8 and included the ingredient labeling below.

[0250] [ ] Water, alcohol, phenylbenzimidazole sulfonic acid, triethanolamine, extract of Camellia Sinensis leaf, Rosmarinus Officinalis (rosemary) leaf extract, Coix Lacryma-JobiMa-yuen seed extract, Aloe Barbadensis leaf extract, Dipotassium Glycyrrhizate, PEG-12 Dimethicone, Dipropylene Glycol, PEG / PPG-30 / 10 Dimethicone, Dimethicone, Phenyl Trimethicone, Butylene Glycol, Potassium Hydroxide, Menthol, Parfum.

[0251] [ ] A plate treated with acrylic-based lipophilic polyisocyanate and a plate Coated with hydroxyalkylcellulose, identical to those described above, as well as a superhydrophilic plate subjected to corona discharge treatment, were prepared. The sunscreen product was applied from above, and in coating step 1, the cosmetic product was coated as in Example 1 using a four-sided stainless steel applicator with a 500 µm gap. Subsequently, in coating step 2, the product was immediately spread as in Example 1 at 260 rpm for 12 seconds using a rotary device to which a urethane sponge was attached. Subsequently, in coating step 3, a coating film was immediately formed using a four-sided stainless steel applicator with a 20 pm gap, moving the applicator at a speed of 5 mm / s, and the film thickness was then measured using a rotary film thickness gauge.The film thicknesses were 5, 2, and 1 µm in the order of the plates. The SPF values ​​equivalent to a 20 µm thickness, determined by the ISO process, were 9, 32, and 63, respectively. Regarding the treatment state of the superhydrophilic plate subjected to corona discharge treatment, most of the cosmetic product adhered to the stainless steel applicator, and a coating film formed in which some of the ingredients were phase-separated. A similar state was also generated in the hydroxyalkylcellulose-coated plate. The reason for this is likely as follows: since metal is lipophilic, if the sunscreen product is a cosmetic with a strong affinity for metal, even when an applicator with a narrow gap is moved, the... sun protection product is not properly distributed from top to bottom and most of the sun protection product is distributed on the metal side.

[0252] [ ] In view of the above, the test of this product was carried out as in Example 1. It follows that such a problem did not occur in the cylindrical applicator coated with PEN, and that uniform coating films were formed, thus demonstrating the effect of a polyethylene naphthalate film. The test was also carried out with a hydrophilized polyester film, a hydrophilized polyethylene terephthalate film, a polyvinylidene fluoride film, and a typical fluorinated resin film. The result was that coating films were formed in each case, and the effectiveness of the aforementioned films was confirmed. In contrast, for the other film-type materials presented in Table 1, there was, in each case, a problem with the uniformity of the coating films or, for example, a problem with incorrect applicator movement.

[0253] [ ] The results of the above tests demonstrate that the examples in the present inventions solve the problems of comparative examples and are excellent as measurement methods applicable to a wide range of cosmetic products.

Claims

Demands

1. A method for evaluating the UV protection performance of a cosmetic product, comprising a preparation step consisting of preparing a measurement sample to evaluate the UV protection performance of a target cosmetic product, wherein the preparation step is a step comprising the formation of a uniform application layer of the cosmetic product on a transparent substrate surface for measuring UV transmittance, using a surface of an applicator having a layer made of a non-metallic material constituting the surface which has an oil adhesion prevention property.

2. . A method for evaluating the UV protection performance of a cosmetic product according to claim 1, wherein the layer of material whose surface has the oil adhesion prevention property is a layer formed of one or more layers selected from the group consisting of a polyethylene naphthalate (PEN) film, a hydrophilized polyester film, a hydrophilized polyethylene terephthalate film, and a fluorinated resin film, which have the oil adhesion prevention property.

3. . Method for evaluating the UV protection performance of a cosmetic product according to claim 1 or 2, comprising the following steps A to D, wherein: A: the preparation step comprises a step of preparing a plurality of measurement samples of the target cosmetic product to evaluate the UV protection performance of the cosmetic product, by forming a plurality of uniform cosmetic product application layers on the surfaces of a plurality of types of transparent UV transmittance measurement substrates having different contact angles, respectively, using the applicator comprising the layer of material whose surface has the property of preventing oil adhesion;B: a step consisting of determining the absorbance of the cosmetic product at a reference thickness using an assembled cell and a spectrophotometer to determine the thickness of each measurement sample by comparison, and to determine; an SPF (sun protection factor) value and a UVA-PF (degree of protection against UVA) value of each measurement sample based on the determined thickness, using the following formulas or their equivalents: an SPF value obtained by performing an integration every 1 nm between 290 and 320 nm using a formula CF x SEE(X) x 1(7.) x Abs(X), a UVA-PF value obtained by performing an integration every 1 nm between 320 and 400 nm using a formula CF x SEE(X) x 1(7.) x Abs(X), where "CF" represents a correction factor (= 10), "EE" represents an erythematous effect spectrum, "I" represents a solar intensity spectrum and "Abs" represents an absorbance, of each measurement sample;C: a step consisting of selecting, on the basis of the SPF values ​​obtained for the plurality of measurement samples, a measurement sample exhibiting a maximum SPF value, and of defining the SPF value and the UVA-PF value of the selected measurement sample as an in vitro SPF value and an in vitro UVA-PF value, respectively, of the cosmetic product; D: a step consisting of determining an equivalent in vivo SPF value of the cosmetic product from a predetermined relational expression between an in vivo SPF value and the in vitro SPF value, and further determining an equivalent in vivo UVA-PF value of the cosmetic product from a predetermined relational expression between an in vivo UVA-PF value and the in vitro UVA-PF value.

4. . Method for evaluating the UV protection performance of a cosmetic product according to claim 3, wherein the plurality of transparent substrates for measuring UV transmittance having different contact angles are the following three substrates: a transparent substrate for measuring UV transmittance having, on one of its surfaces, a layer formed by the application of a polyisocyanate, a transparent substrate for measuring UV transmittance having, on one of its surfaces, a layer formed by the application of inulin, and a transparent substrate for measuring UV transmittance having, on one of its surfaces, a layer formed by the application of a hydroxyalkylcellulose.

5. . Method for evaluating the UV protection performance of a cosmetic product according to claim 3 or 4, wherein the predetermined relational expression between the in vivo SPF value and the in vitro SPF value and the predetermined relational expression between the in vivo UVA-PF value and the in vitro UVA-PF value are predetermined by statistical processing of the relationships between (i) the SPF values ​​and the UVA-PF values ​​obtained by in vivo processes or the in vivo UVA-PF values ​​corresponding to a PA classification (degree of protection against UV-A), of cosmetic products whose properties are known, and (ii) the SPF values ​​and the UVA-PF values ​​of the cosmetic products determined in accordance with steps A to D.

6. . Method for evaluating the UV protection performance of a cosmetic product according to any one of claims 1 to 5, wherein the cosmetic product is a powdered cosmetic product, a stick-shaped cosmetic product, or a paste-like substance obtained by mixing a non-volatile oil with a solid cosmetic product.

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