Composition for film formation

Abstract

To provide a film-forming composition, a film-manufacturing method and a kit for forming a film in order to form an excellently compatible film.SOLUTION: A film-forming composition is electrostatically sprayed on a subject film-forming site directly or indirectly to form a film made of deposit containing fiber. The film-forming composition includes a first polymer and a second polymer. The moisture absorption rate of the first polymer under a high-temperature high-humidity environment (under 40°C 90RH% for 24 hours standing) is 1.0% or less. The moisture absorption rate of the second polymer under a high-temperature high-humidity environment (under 40°C 90RH% for 24 hours standing) is 5% or more and 29% or less. When the mass of the first polymer and the mass of the second polymer in the film-forming composition are M1 and M2 respectively, a value of M2 / (M1+M2) is 0.05 or more and 0.60 or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a composition for forming a coating, a method for producing a coating, and a kit for forming a coating. [Background technology]

[0002] A method for forming a coating by electrostatic spraying is known. For example, Patent Document 1 describes that a coating having good adhesion to the skin and good transparency is formed by electrostatically spraying a composition containing a volatile substance, a water-insoluble polymer, and an adhesive polymer directly onto the skin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-177802 Summary of the Invention [Problem to be solved by the invention]

[0004] When a coating is formed on a target site, such as the skin, it is desirable for the coating to have good compatibility with the skin. When a water-soluble polymer compound is used in a film-forming composition to improve skin compatibility, the film may absorb moisture and dissolve. Furthermore, such dissolution of the film tends to occur particularly easily under conditions of high temperature or high humidity, and there is room for improvement in film-forming compositions for forming films by electrostatic spraying.

[0005] The present invention relates to a coating composition, a coating production method, and a coating formation kit for forming a coating that is compatible even under conditions of high temperature or high humidity. [Means for solving the problem]

[0006] A coating composition according to one embodiment of the present invention is used for forming a coating comprising a deposit containing fibers by electrostatically spraying the composition directly or indirectly onto a target site for coating formation. The coating composition includes a first polymer and a second polymer. The first polymer has a moisture absorption of 1% or less in a high temperature and high humidity environment (left to stand at 40°C and 90% RH for 24 hours). The second polymer has a moisture absorption of 5% or more and 29% or less in a high-temperature and high-humidity environment (left to stand at 40°C and 90% RH for 24 hours).

[0007] A coating manufacturing method according to one embodiment of the present invention is a method for forming a coating on a coating formation target portion. The coating manufacturing method includes a coating formation step. In the coating formation step, a coating composition is electrostatically sprayed directly or indirectly onto a target area to form a coating made of a deposit containing fibers. The coating composition includes a first polymer and a second polymer. The first polymer has a moisture absorption of 1% or less in a high temperature and high humidity environment (left to stand at 40°C and 90% RH for 24 hours). The second polymer has a moisture absorption of 5% or more and 29% or less in a high-temperature and high-humidity environment (left to stand at 40°C and 90% RH for 24 hours).

[0008] A coating formation kit according to one embodiment of the present invention includes the coating formation composition and a formulation. The preparation is applied to the skin before or after forming a film with the film-forming composition. [Effects of the Invention]

[0009] According to the coating composition, coating production method, and coating formation kit of the present invention, a coating that is well-fitting can be obtained even under conditions of high temperature or high humidity. [Brief explanation of the drawings]

[0010] [Figure 1]1 is a schematic diagram showing the configuration of an electrostatic spray device preferably used in the present invention. [Figure 2] 1 is a schematic diagram showing the formation of a coating on skin by electrostatic spraying using the electrostatic spray device. FIG. [Figure 3] 1 is a schematic diagram of a coating formation kit according to one embodiment of the present invention. [Figure 4] 1 is a graph showing the relationship between the proportion of the second polymer in the composition for forming a coating and the overall average usability score of the coating after storage at high temperature and humidity. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention relates to improving the conformability of a coating formed on a target area by electrostatic spraying. The present invention will be described below based on preferred embodiments thereof.

[0012] In the present invention, a coating is formed by applying a coating composition containing predetermined components directly or indirectly to a target area for coating formation by electrostatic spraying. In the present invention, by configuring the composition for forming a coating to contain predetermined components, it is possible to improve the compatibility of the coating with the target area for coating formation. By using the electrostatic spray method, it is possible to form a coating of deposited fibers (so-called nanofibers) with a fiber diameter on the order of nanometers. The target site for film formation is typically human skin, but may also be human teeth, gums, the skin, teeth, gums of non-human mammals, plant surfaces such as branches and leaves, etc. In the following explanation, an example of forming a film on human skin will be given. In the following description, an example is given in which a coating is formed directly on human skin by electrostatic spraying, but a coating can also be formed on the skin by forming a coating by electrostatic spraying on an applicator, which is an intermediate coating formation target, and then transferring the coating to the skin. This mode of forming a coating on an intermediate coating formation target and then transferring the coating to the coating formation target area is referred to as "forming a coating indirectly on the coating formation target area by electrostatic spraying." In this specification, the target site on which a coating is ultimately formed is referred to as a “target site for coating formation.” Therefore, in the case where a coating is formed on an applicator and then transferred to the skin, the target site for coating formation is the skin. In this specification, the term "user" refers to the person to whom the film is applied, and the term "assistant" refers to the person who applies the preparation and performs at least part of the film formation on behalf of the user.

[0013] The coating formed using the coating composition of the present invention can be suitably used for wounds and abnormal conditions extending from the skin surface to the basal layer of the epidermis. Specifically, it can be suitably used for improving skin conditions and wound healing, with the objectives of promoting tissue regeneration, promoting basement membrane regeneration, activating epidermal cell proliferation, epithelialization of epidermal cells (promoting keratinization), improving barrier function, improving moisture content, reducing scale, inhibiting crust formation, suppressing inflammation, and inhibiting post-inflammatory pigmentation. The coating is formed on wound healing sites, such as human skin suffering from symptoms such as scales and inflammation, or skin damaged after laser treatment, to protect the skin. Forming a coating on the skin not only protects the skin from external stimuli and foreign substances, but also efficiently heals symptoms such as scales and inflammation, and damage after laser treatment. The film-forming composition of the present invention is typically used in combination with a formulation (described below). By using the formulation in combination, the capillary force of the fibers of the film can be utilized to hold the formulation between the fibers. This allows the formulation to act efficiently and effectively on the skin while protecting the skin. The formulation can be applied to the skin before or after film formation by electrostatic spraying. The following description gives examples of use in which the formulation is applied before film formation. The coating may be used alone without being used in combination with a preparation. By forming a coating on the skin, the skin can be protected from external stimuli and foreign substances. This will be explained in detail below.

[0014] <Film forming composition> The inventors focused on the moisture absorption of polymers used in coating compositions in high-temperature, high-humidity environments, and discovered that by blending a first polymer that has a relatively low moisture absorption rate in high-temperature, high-humidity environments with a second polymer that has a relatively high moisture absorption rate, the coating composition can be used to form a coating that is less affected by the usage environment and has good compatibility. This will be explained in detail below.

[0015] Here, "good adhesion" refers to a state in which the user feels that the formed coating adheres firmly to the skin (the area where the coating is to be formed), and when the user touches the skin on which the coating has been formed with the pads of their fingers or the palm of their hand, the user feels a sense of adhesion such that the entire body part being touched (the pads of their fingers or the palm) adheres evenly to the skin.

[0016] The coating composition of the present invention comprises a first polymer having a moisture absorption rate of 1% or less in a high-temperature, high-humidity environment, a second polymer having a moisture absorption rate of more than 1% and not more than 40% in a high-temperature, high-humidity environment, and a solvent. The solvent evaporates during the coating formation process, and the coating is composed of the first polymer and the second polymer. Although the coating composition is composed of the first polymer, the second polymer, and the solvent, it may also contain other components. The first polymer is the core portion of the coating. The second polymer contributes to modifying the surface of the fibers that make up the coating.

[0017] [Method for measuring moisture absorption of polymers in a high-temperature, high-humidity environment] In this specification, the moisture absorption of a polymer in a high-temperature and high-humidity environment is measured by the measurement method described below. 1 g of the polymer to be measured is left standing in an incubator at 40°C and 90% RH (high temperature and humidity environment) for 24 hours, and the polymer to be measured is subjected to a high temperature and humidity load. The weight of the polymer to be measured before the high temperature and humidity load is measured immediately after leaving it to stand in an environment of 25°C and 50% RH for 1 minute is defined as the "initial weight," and the weight of the polymer to be measured after the high temperature and humidity load is measured immediately after leaving it to stand in an environment of 25°C and 50% RH for 1 minute immediately after taking it out of the incubator is defined as the "weight after high temperature and humidity load." The moisture absorption of the polymer to be measured is calculated using the following formula (1). Moisture absorption = (weight after high temperature and humidity load - initial weight) / initial weight × 100 (%) ... (1) In this specification, unless otherwise specified, "moisture absorption" means "moisture absorption in a high-temperature and high-humidity environment."

[0018] [First polymer] The first polymer has a moisture absorption of 1% or less, more preferably 0.9% or less, from the viewpoint of forming a coating that is less susceptible to the use environment and that is easy to maintain good quality. From the same viewpoint, the moisture absorption is preferably 0.1% or more, more preferably 0.6% or more.

[0019] In addition to the moisture absorption mentioned above, the physical properties of the first polymer can also be explained from the viewpoint of water insolubility. Specifically, the first polymer is preferably a polymer that, when 1 g of the polymer is weighed and immersed in 10 g of deionized water under an environment of 1 atmosphere and 23°C, does not dissolve more than 0.5 g of the immersed polymer after 24 hours.

[0020] More specifically, from the viewpoint of forming a coating that is easy to maintain good quality, it is more preferable to use one or more polymers selected from polyvinyl butyral resin, polyurethane resin, and polylactic acid as the first polymer, and it is even more preferable to use polyvinyl butyral resin.

[0021] [Second polymer] The second polymer has a moisture absorption of more than 5%, preferably 6.5% or more, from the viewpoint of achieving good compatibility and reducing wrinkling of the coating formed on the skin and the inclusion of air bubbles, and from the same viewpoint and also from the viewpoint of preventing nozzle clogging during electrostatic spraying, the moisture absorption of the second polymer is 29% or less, preferably 28.4% or less. The moisture absorption of the second polymer is more than 5% and 29% or less, preferably 6.5% or more and 28.4% or less.

[0022] The second polymer may contain one or more polymers selected from polyvinylpyrrolidone, polyvinylpyrrolidone copolymers, polyalkylene glycols, and silicone structure-containing copolymers. From the viewpoint of improving the compatibility of the coating formed on the skin, it is preferable to use one or more polymers selected from polyvinylpyrrolidone copolymers and polyalkylene glycols. The content of one or more polymers selected from polyvinylpyrrolidone, polyvinylpyrrolidone copolymers, polyalkylene glycols, and silicone structure-containing copolymers relative to the total amount of the second polymer is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 95% by mass or more, from the viewpoint of improving the compatibility of the coating formed on the skin.

[0023] Examples of polyvinylpyrrolidone copolymers include vinyl acetate-vinylpyrrolidone copolymer, vinylpyrrolidone-dimethylaminoethyl methacrylate copolymer diethyl sulfate, and vinylcaprolactam-vinylpyrrolidone-dimethylaminopropyl methacrylamide-methacryloylaminopropyl lauryldimonium chloride copolymer. From the viewpoint of improving the compatibility of the film formed on the skin, it is preferable to use vinyl acetate-vinylpyrrolidone copolymer.

[0024] Vinyl acetate-vinylpyrrolidone copolymer is a copolymer obtained by polymerization of vinyl acetate and vinylpyrrolidone, and contains both vinyl acetate-based and vinylpyrrolidone-based structures. Here, the vinyl acetate-based structure is designated as VP, and the vinylpyrrolidone-based structure is designated as VA. From the viewpoint of achieving good skin compatibility, the VP:VA ratio in the vinyl acetate-vinylpyrrolidone copolymer of the present invention is preferably in the range of VP:VA = 20:80 to 80:20, and more preferably in the range of VP:VA = 25:75 to 65:35. The "ratio" in this section refers to the molar ratio, and the amount of residual monomer relative to the charged monomer composition can be calculated by gas chromatography.

[0025] More specifically, the following commercially available products can be used as polyvinylpyrrolidone and its copolymers. Product name: PVA / VA E735 (Ashland Japan Co., Ltd.) Product name: PLASDONE (registered trademark) S630 (Ashland Japan Co., Ltd.) Product name: PVA / VA E535 (Ashland Japan Co., Ltd.) Product name: PVA / VA E335 (Ashland Japan Co., Ltd.) Product name: Gafquat (registered trademark) 734 (Ashland Japan Co., Ltd.) Product name: Aquastyle300N (Ashland Japan Co., Ltd.)

[0026] Examples of polyalkylene glycols include polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, and polyoxyethylene polyoxypropylene glycol. From the viewpoint of improving the compatibility of the coating formed on the skin, it is preferable to use polyoxyethylene polyoxypropylene glycol.

[0027] The average number of moles of ethylene oxide added in polyoxyethylene polyoxypropylene glycol is preferably 5 to 200, more preferably 10 to 30, from the viewpoint of achieving good compatibility and reducing the wrinkling of the coating formed on the skin and the inclusion of air bubbles. Also, from the same viewpoint, the average number of moles of propylene oxide added is preferably 5 to 100, more preferably 10 to 30. The average number of moles of ethylene oxide added can be calculated, for example, by the method described in "JIS K 0070-1992 7.1 Neutralization titration method." 1 It can be determined using H-NMR.

[0028] More specifically, the following commercially available polyethylene glycol adducts can be used: Product name: Pronon (registered trademark) 124P (NOF Corporation)

[0029] More specifically, the following commercially available products can be used as the silicone structure-containing copolymer. Product name: Silicone KF-6011 (Shin-Etsu Chemical Co., Ltd.)

[0030] [solvent] The solvent contains one or more selected from monohydric alcohols and ketones. Monohydric alcohols and ketones are volatile substances. From the viewpoint of improving the compatibility of the formed coating, the solvent preferably contains one or more monohydric alcohols selected from ethanol, isopropyl alcohol, and butyl alcohol, more preferably ethanol. From the same viewpoint, the solvent preferably contains acetone as a ketone. The type of solvent used can be appropriately determined depending on the type of first polymer, and a solubilizer for the first polymer can be used as the solvent. For example, when polyvinyl butyral resin or polyurethane resin is used as the first polymer, ethanol can be used as the solvent. When polylactic acid is used as the first polymer, acetone can be used as the solvent.

[0031] When ethanol is used as the solvent, the ethanol content in the solvent is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, based on the total amount of the solvent, from the viewpoints of high volatility and compatibility of the formed coating. It is also preferably 100% by mass or less, and more preferably 95% by mass. The ethanol content in the solvent is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, and even more preferably 80% by mass or more and 95% by mass or less, based on the total amount of the solvent.

[0032] The solvent may also contain water. In the examples described below, an example is given in which 99% synthetic alcohol (Nippon Synthetic Alcohol Co., Ltd.), which is an absolute alcohol with an ethanol content of 99.5% by volume or more, is used as the solvent. However, since ethanol easily absorbs moisture from the air and the ethanol content is not 100% by volume, when the above 99% synthetic alcohol is used as the solvent, the solvent will contain moisture. In the description of the ethanol content in the above solvent, ethanol refers to the above absolute alcohol, 99% synthetic alcohol (Nippon Synthetic Alcohol Co., Ltd.).

[0033] From the viewpoint of compatibility of the formed coating, the water content in the solvent is preferably 0.2% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.4% by mass or more, relative to the total amount of the solvent. Also, it is preferably 10% by mass or less, and more preferably 5% by mass or less. The water content in the solvent is preferably 0.2% by mass or more and 10% by mass or less, more preferably 0.3% by mass or more and 10% by mass or less, and even more preferably 0.4% by mass or more and 5% by mass or less, relative to the total amount of the solvent.

[0034] When forming a nanofiber coating using electrostatic spraying, the solvent is evaporated to form the nanofibers, so the main component of the solvent is preferably a volatile substance. The vapor pressure of the volatile substance at 20°C is preferably 0.01 kPa or more and 106.66 kPa or less, more preferably 0.13 kPa or more and 66.66 kPa or less, even more preferably 0.67 kPa or more and 40.00 kPa or less, and even more preferably 1.33 kPa or more and 40.00 kPa or less.

[0035] In a coating formed using the coating composition of the present invention, the content of the first polymer is preferably 40% by mass or more, more preferably 48% by mass or more, even more preferably 54% by mass or more, still more preferably 60% by mass or more, and even more preferably 64% by mass or more, from the viewpoints of good compatibility and reducing wrinkling and air bubble inclusion in the coating formed on the skin, and from the same viewpoint, is preferably 98% by mass or less, more preferably 89% by mass or less, even more preferably 85% by mass or less, still more preferably 82% by mass or less, and even more preferably 79% by mass or less. The content of the first polymer is preferably 40% by mass or more and 98% by mass or less, more preferably 48% by mass or more and 89% by mass or less, even more preferably 54% by mass or more and 85% by mass or less, still more preferably 60% by mass or more and 82% by mass or less, and even more preferably 64% by mass or more and 79% by mass or less.

[0036] In a coating formed using the coating composition of the present invention, the content of the second polymer is preferably 2% by mass or more, more preferably 12% by mass or more, even more preferably 15% by mass or more, still more preferably 18% by mass or more, and even more preferably 21% by mass or more, from the viewpoints of good compatibility and reducing wrinkling and air bubble inclusion in the coating formed on the skin, and from the same viewpoint, is preferably 60% by mass or less, more preferably 52% by mass or less, even more preferably 46% by mass or less, still more preferably 40% by mass or less, and even more preferably 34% by mass or less. The content of the second polymer is preferably 2% by mass or more and 60% by mass or less, more preferably 12% by mass or more and 52% by mass or less, even more preferably 15% by mass or more and 46% by mass or less, still more preferably 18% by mass or more and 40% by mass or less, and even more preferably 21% by mass or more and 34% by mass or less.

[0037] [Mass ratio (blending ratio) of the first polymer to the second polymer in the film-forming composition] From the viewpoint of forming a coating that is less susceptible to the influence of the usage environment and has good compatibility, it is preferable to specify the blending ratio of the first polymer, which has a relatively low moisture absorption in a high temperature and humidity environment, to the second polymer, which has a relatively high moisture absorption, as follows: In the film-forming composition, the proportion of the second polymer in the total polymer, including the first polymer and the second polymer (hereinafter sometimes simply referred to as the "proportion of the second polymer") is preferably 0.05 or more, more preferably 0.11 or more, even more preferably 0.15 or more, even more preferably 0.18 or more, and even more preferably 0.21 or more, from the viewpoint of good compatibility and reducing wrinkling and the inclusion of air bubbles in the film formed on the skin, and from the same viewpoint, is preferably 0.60 or less, more preferably 0.52 or less, even more preferably 0.46 or less, even more preferably 0.40 or less, even more preferably 0.38 or less, and even more preferably 0.34 or less. The ratio of the second polymer to the total polymer, which is the combination of the first polymer and the second polymer, is preferably 0.05 or more and 0.60 or less, more preferably 0.11 or more and 0.52 or less, even more preferably 0.15 or more and 0.46 or less, still more preferably 0.18 or more and 0.40 or less, still more preferably 0.21 or more and 0.38 or less, and still more preferably 0.21 or more and 0.34 or less. The proportion of the second polymer is calculated by the following formula (2), where M1 is the mass (content) of the first polymer in the composition for forming a coating, and M2 is the mass (content) of the second polymer. Ratio of second polymer = M2 / (M1+M2) ... (2)

[0038] In this embodiment, the film-forming composition is a mixture of a first polymer, a second polymer, and a solvent. The solvent evaporates during the film-forming process, and the film is composed of the first polymer and the second polymer.

[0039] The film-forming composition of the present invention is composed of a first polymer with relatively low moisture absorption and a second polymer with relatively high moisture absorption in the above-mentioned blending ratio, and therefore the moisture resistance of the film formed using the film-forming composition is improved. Even in a hot and humid environment such as a bathroom or changing room, the film formed on the skin is less likely to absorb moisture, dissolve, and become distorted, and the film shape is stable, allowing the quality to be maintained. Furthermore, when the area to be coated is a wound on the skin, the coating is placed in a state where it is easily able to absorb exudate, and the area where the coating is to be formed is in an environment where humidity is high. However, by improving the moisture resistance of the coating, the coating is less likely to be dissolved by exudate, and the quality of the coating can be stably maintained. Furthermore, when the area to be coated is inside the oral cavity, such as on the teeth or gums, which is a humid environment, the coating is placed in an environment that makes it easy for it to absorb saliva. However, by improving the moisture resistance of the coating, the coating is less likely to be dissolved by saliva, and the quality of the coating can be stably maintained. Thus, the film formed using the film-forming composition of the present invention maintains its quality with a stable film shape even in a high-temperature or high-humidity environment.

[0040] In addition, by including the second polymer, the adhesion of the coating to the skin can be improved, making it easier to fit to the skin, and the coating can continue to maintain good adhesion even in high temperature or high humidity environments, resulting in a coating that is less susceptible to the use environment and can continue to maintain good fit. Furthermore, since the coating adheres well to the skin, it is less likely to become distorted or have air bubbles mixed in, and the boundary between the skin on which the coating is formed and the skin on which the coating is not formed is difficult to distinguish, resulting in a natural appearance that does not make you feel the presence of the coating. Furthermore, a coating formed using the coating composition of the present invention adheres firmly to the skin, conforming to the irregularities of the skin, even on uneven skin surfaces such as wounds, making it less likely to cause any sensory discomfort on the skin.

[0041] Furthermore, the inclusion of the second polymer improves the compatibility of the coating with the formulation, allowing the formulation to be present throughout the entire coating formed on the skin, and enabling the formulation held between the fibers to remain in good contact with the skin for a long period of time during use, thereby further promoting the penetration of the formulation into the skin and improving the effect of the formulation on the skin. Furthermore, the formed coating has excellent moisture resistance even under high temperature or high humidity conditions, so it is less susceptible to the influence of the usage environment and the film shape is easily maintained stably. As a result, the preparation can be stably retained between the fibers for a long period of time, and the effect of the preparation on the skin can be further improved.

[0042] In this way, by using the coating composition of the present invention, it is possible to form a coating of stable quality that is less affected by the usage environment and can stably maintain a good film shape and good compatibility over a long period of time.

[0043] <About electrostatic spraying> The film is formed by electrostatically spraying the film-forming composition and depositing the fibers onto the skin. The electrostatic spray method is a method in which a positive or negative high voltage is applied to a coating composition to charge the composition, and the charged composition is then sprayed toward an object. The sprayed coating composition spreads into space while repeatedly being atomized by Coulomb repulsion, and during this process, or after the composition has adhered to the target area, the volatile solvent evaporates, forming a coating on the surface of the target area.

[0044] [Electrostatic spray device] FIG. 1 is a schematic diagram showing the configuration of an electrostatic spray device that can be suitably used in the present invention. 1, an electrostatic spray device 10 includes a low-voltage power supply 11, a high-voltage power supply 12, an auxiliary electric circuit 13, a micro gear pump 14 as a liquid feed pump, a container 15, a nozzle 16, a conduit 17, a flexible conduit 18, and a current-limiting resistor 19. Note that the liquid feed pump may be a piston pump instead of a gear pump, and the nozzle and pump may be interchangeable.

[0045] The low-voltage power supply 11 generates a voltage of several volts to several tens of volts. To increase the portability of the electrostatic spray device 10, the low-voltage power supply 11 preferably comprises one or more batteries. Another advantage of using a battery as the low-voltage power supply 11 is that it can be easily replaced as needed. Instead of a battery, an AC adapter or the like can also be used as the low-voltage power supply 11.

[0046] The high-voltage power supply 12 is connected to the low-voltage power supply 11 and includes an electric circuit (not shown) that boosts the voltage generated by the low-voltage power supply 11 to a high voltage. The boosting electric circuit is generally composed of a transformer, a capacitor, semiconductor elements, etc.

[0047] The auxiliary electric circuit 13 is interposed between the low-voltage power supply 11 and the high-voltage power supply 12, and has the function of adjusting (amplifying) the voltage of the low-voltage power supply 11 to ensure stable operation of the high-voltage power supply 12. Furthermore, the auxiliary electric circuit 13 has a function of controlling the rotation speed of the motor provided in the micro gear pump 14. By controlling the rotation speed of the motor, the amount of the coating composition supplied from the coating composition container 15 to the micro gear pump 14 is controlled. A switch SW is installed between the auxiliary electric field 13 and the low-voltage power supply 11. The electrostatic spray device 10 can be operated / stopped by turning the switch SW on and off.

[0048] The nozzle 16 is made of various conductive materials such as metal, and its outer periphery is covered with a non-conductive material such as plastic, rubber, or ceramic. Nozzle 16 has a shape that allows the coating composition to be discharged from its tip. A minute space through which the coating composition flows is formed within nozzle 16 along the longitudinal direction of nozzle 16. The size of the cross section of this minute space, expressed in diameter, is preferably 100 μm or more and 1000 μm or less. The nozzle 16 communicates with the micro gear pump 14 via a conduit 17. The conduit 17 may be conductive or non-conductive. Nozzle 16 is electrically connected to high-voltage power supply 12, making it possible to apply a high voltage to nozzle 16. In this case, nozzle 16 and high-voltage power supply 12 are electrically connected via current-limiting resistor 19 to prevent problematic current from flowing if the human body comes into direct contact with nozzle 16.

[0049] The coating composition is stored in the container 15. The container 15 is preferably a replaceable cartridge type. The container 15 is connected to the micro gear pump 14 via a flexible conduit 18. The micro gear pump 14 functions as a supply device that supplies the coating composition contained in the container 15 to the nozzle 16 . The micro gear pump 14 operates by receiving power from the low voltage power supply 11 . A micro gear pump 14 is controlled by auxiliary electrical circuitry 13 to deliver a predetermined amount of coating composition to a nozzle 16 .

[0050] FIG. 2 shows an example of how the electrostatic spray device 10 is used. In the example shown in Fig. 2, the electrostatic spray device 10 is a handheld type having dimensions that allow it to be held in one hand. The electrostatic spray device 10 has a cylindrical housing 20, and all of the components shown in Fig. 1 are housed within the housing 20. Note that the shape of the housing 20 is not limited to a cylindrical shape, and it can typically have a shape and dimensions that allow it to be easily held in one hand. A nozzle (not shown) is disposed at one longitudinal end 10a of the housing 20. The nozzle is disposed so that the direction in which the coating composition 1 is sprayed coincides with the longitudinal direction of the housing 20 and is convex toward the skin. This makes it difficult for the coating composition to adhere to the housing 20, allowing for stable formation of a coating.

[0051] <Coating production method using electrostatic spraying> A preferred method for producing a coating according to the present invention comprises a formulation application step and a coating formation step. The formulation application step may be carried out before or after the coating formation step.

[0052] [Formulation application process] The formulation application step is a step of applying the formulation to the skin. The formulation is applied by the user or a caregiver, mainly to the area where a film is to be formed. The formulation has a different composition from the film-forming composition, preferably does not contain the first polymer of the present invention, and is preferably applied to the skin by a method other than electrostatic spraying. The preparation preferably has functions such as moisturizing, anti-inflammatory, sterilizing, and anti-hemorrhoidal. The preparation can be appropriately selected depending on the skin condition. Examples of the preparation will be described later. The formulation may be applied to the skin in the form of a liquid, cream, foam, or mist for ease of application to the skin. The formulation is typically applied to the skin before film formation in order to improve adhesion between the film and the skin. By applying the formulation before the coating formation step, the sprayed coating composition can be more easily adhered by electrostatic force and the transparency of the sprayed coating composition can be improved. Improved transparency makes the presence of the coating less noticeable visually, resulting in a natural, skin-like appearance. On the other hand, when the formulation application step is carried out after the coating formation step, the coating formed by electrostatic spraying becomes more compatible with the skin due to the formulation, and the coating adheres more closely to the skin, while also becoming more transparent.

[0053] Here, applying a preparation to the skin refers to a state in which the preparation is attached to, spread on, carried on, or fixed to a target site on the skin. The means for applying the preparation to the skin is not particularly limited. For example, the preparation may be spread using a tool such as fingers or a brush, or may be sprayed using a spray or the like.

[0054] [Film formation process] The film-forming step is a step in which the film-forming composition is electrostatically sprayed directly onto the skin using the electrostatic spray device 10 to form a film made of a deposit containing fibers. By using the formulation in combination with the coating, the capillary force of the fibers forming the coating is believed to prevent the formulation from being unevenly distributed and spread, and to retain the formulation between the fibers and / or on the fiber surface.

[0055] The method of producing a coating by operating the electrostatic spray device 10 is as follows. As shown in Fig. 2, a user U, i.e., a person who forms a coating on their skin by electrostatic spray, holds the electrostatic spray device 10 in their hand and points one end 10a of the electrostatic spray device 10, where a nozzle (not shown) is located, toward the area to be coated with electrostatic spray. Fig. 2 shows the state in which one end 10a of the electrostatic spray device 10 is pointed toward the inside of the forearm of the user U. In this state, the switch of the electrostatic spray device 10 is turned on to perform electrostatic spraying. When the electrostatic spray device 10 is turned on, an electric field is generated between the nozzle and the skin. In the embodiment shown in FIG. 2, a positive high voltage is applied to the nozzle, and the skin serves as the negative electrode. When an electric field is generated between the nozzle and the skin, the film-forming composition at the tip of the nozzle is polarized by electrostatic induction, forming a cone-like tip. Charged droplets of the film-forming composition are ejected from the tip of the cone along the electric field into the air toward the skin. As the solvent evaporates from the charged film-forming composition ejected into space, the charge density on the surface of the film-forming composition becomes excessive, causing the film to spread through space while repeatedly being atomized by Coulomb repulsion, eventually reaching the skin. While being ejected into space, the volatile solvent is evaporated from the film-forming composition, solidifying the solute film-forming polymers (first polymer and second polymer). The potential difference causes the polymers to elongate and deform, forming fibers, which are then deposited on the surface of the skin to form a film. Once electrostatic spraying is completed in this manner, the electrostatic spray device 10 is turned off, thereby eliminating the electric field between the nozzle and the skin.

[0056] During electrostatic spraying, a high potential difference occurs between the nozzle and the skin. However, because the impedance is very large, the current flowing through the human body is extremely small. The inventors have confirmed that the current flowing through the human body during electrostatic spraying is several orders of magnitude smaller than the current flowing through the human body due to static electricity generated in everyday life.

[0057] When forming a fiber deposit by electrostatic spraying, the thickness of the fibers, expressed in equivalent circle diameter, is preferably 10 nm or more, more preferably 50 nm or more. Also, it is preferably 3000 nm or less, more preferably 1000 nm or less. Thus, by forming a coating using electrostatic spraying, a coating can be formed in which fibers on the order of nanometers are deposited. The thickness of a fiber can be measured, for example, by observing the fiber under a scanning electron microscope (SEM) at 10,000 times magnification, removing defects (fiber clumps, fiber intersections, and droplets) from the two-dimensional image, randomly selecting 10 fibers, drawing a line perpendicular to the longitudinal direction of the fiber, and directly reading the fiber diameter.

[0058] [Formulation example] The formulation preferably contains one or more selected from water, polyols, and oils that are liquid at 20°C.

[0059] Preparations containing water include, for example, aqueous liquids such as water, aqueous solutions, and aqueous dispersions. Other examples of preparations containing water include lotions, emulsions such as O / W emulsions and W / O emulsions, compositions and cosmetic creams having a lamellar structure, and aqueous liquids thickened with a thickener. From the viewpoints of moisturizing properties and improving the compatibility of a film adhered to the skin, compositions having a lamellar structure are preferred.

[0060] When the preparation contains a polyol, examples of the polyol include alkylene glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, and 1,3-butanediol; polyalkylene glycols such as diethylene glycol, dipropylene glycol, polyethylene glycol, and polypropylene glycol; and glycerins such as glycerin, diglycerin, and triglycerin. From the viewpoint of improving the compatibility of the coating adhered to the skin, polyols that are liquid at 20°C are preferred.

[0061] When the preparation contains a polyol, the content of the polyol in the preparation is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more from the viewpoint of improving the compatibility of the coating adhered to the skin, and from the same viewpoint, is 40% by mass or less, preferably 30% by mass or less, and more preferably 20% by mass or less. The content of the polyol in the preparation is preferably 3% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 30% by mass or less, and even more preferably 10% by mass or more and 20% by mass or less.

[0062] When the formulation contains an oil that is liquid at 20°C (hereinafter, this oil will also be referred to as "liquid oil"), examples of the oil that is liquid at 20°C include linear or branched hydrocarbon oils, ester oils, higher alcohols of branched or unsaturated fatty acids, and silicone oils.

[0063] Examples of the hydrocarbon oil include liquid paraffin, squalane, squalene, n-octane, n-heptane, cyclohexane, light isoparaffin, and liquid isoparaffin, with liquid paraffin and squalane being preferred from the viewpoint of usability.

[0064] Furthermore, polar oils that are liquid at 20° C. can also be preferably used as the liquid oil, examples of which include ester oils, higher alcohols of branched or unsaturated fatty acids, silicone oils, etc. These liquid oils can be used alone or in combination of two or more.

[0065] Examples of the ester oil include esters of linear or branched fatty acids and linear or branched alcohols or polyhydric alcohols. Specific examples include isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, isocetyl stearate, isocetyl isostearate, cholesteryl 12-hydroxystearate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid esters, and monoisostearate N. -Alkyl glycol, neopentyl glycol dicaprate, diisostearyl malate, glycerin di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, pentaerythrityl tetra-2-ethylhexanoate, glyceryl tri-2-ethylhexanoate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, diethylhexyl naphthalenedicarboxylate, benzoic acid (carbon number 12 or more) 15) Alkyl, Cetearyl Isononanoate, Tri(Caprylic / Capric) Glycerin, (Dicaprylic / Capric) Butylene Glycol, Glyceryl Trilaurate, Glyceryl Trimyristate, Glyceryl Tripalmitate, Glyceryl Triisostearate, Glyceryl Tri-2-heptylundecanoate, Glyceryl Tribehenate, Glyceryl Tri-2-heptylundecanoate, Glyceryl Triisostearate, Glyceryl Cocoate, Castor Oil Fatty Acid Methyl Ester, Oleyl Oleate, Palm Examples of suitable alkyl acrylates include 2-heptylundecyl mitate, diisobutyl adipate, 2-octyldodecyl N-lauroyl-L-glutamate, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, di-2-ethylhexyl succinate, triethyl citrate, 2-ethylhexyl paramethoxycinnamate, and tripropylene glycol dipivalate. The liquid oil may also include a vegetable oil or animal oil containing an ester oil. For example, examples of liquid oils containing an ester oil include vegetable oils such as jojoba oil, olive oil, macadamia nut oil, medfoam oil, castor oil, safflower oil, sunflower oil, avocado oil, canola oil, apricot kernel oil, rice germ oil, and rice bran oil, and animal oils such as liquid lanolin.

[0066] Examples of higher alcohols include liquid higher alcohols having 12 to 20 carbon atoms, and specific examples include isostearyl alcohol and oleyl alcohol.

[0067] Examples of silicone oils include dimethylpolysiloxane, dimethylcyclopolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, and higher alcohol-modified organopolysiloxane.

[0068] When the preparation contains liquid oil, the content of the liquid oil in the preparation is preferably 1% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2% by mass from the viewpoint of improving the compatibility of the coating adhered to the skin, and from the same viewpoint, it is 10% by mass or less, preferably 6% by mass or less, and more preferably 4% by mass or less. The content of the liquid oil in the preparation is preferably 1% by mass or more and 10% by mass or less, more preferably 1.5% by mass or more and 6% by mass or less, and even more preferably 2% by mass or more and 4% by mass or less.

[0069] The preparation may also contain solid fats, and preferably contains pseudoceramides, etc., from the viewpoint of improving the compatibility of the coating adhered to the skin. The pseudoceramides of the present invention include those also called natural (animal) ceramides, human ceramides, and synthetic ceramides. For example, the pseudoceramides are called cetyl PG hydroxyethyl palmitamide as a cosmetic ingredient and N-(hexadecyloxyhydroxypropyl)-N-hydroxyethylhexadecanamide or hexadecyloxy PG hydroxyethylhexadecanamide (abbreviated name) as a quasi-drug.

[0070] <Coating kit> As shown in FIG. 3, the coating formation kit 2 of the present invention comprises a container 15 filled with the coating formation composition and a container 3 filled with a formulation. The container 15 is, for example, in the form of a replaceable cartridge. A user or an attendant can set the container 15 in the electrostatic spray device 10 and use it.

[0071] <Other configurations>

[0072] [Moisture absorption of coating] From the viewpoint of improving the moisture resistance and compatibility of the coating, the moisture absorption of the coating formed using the coating composition is preferably 1% to 10%, more preferably 2% to 9%, and even more preferably 3% to 7%. The moisture absorption of the coatings of each example described below is shown in Tables 1 to 4. The moisture absorption of the film is calculated as a weighted average using the following formula (3). In formula (3), M1 is the mass (content) of the first polymer in the coating, M2 is the mass (content) of the second polymer in the coating, A1 is the moisture absorption of the first polymer, and A2 is the moisture absorption of the second polymer. The moisture absorption is calculated using formula (1) above. The mass ratio of the first polymer to the second polymer in the coating is the same as the mass ratio of the first polymer to the second polymer in the coating composition. Moisture absorption of film = (A1 × M1 + A2 × M2) / (M1 + M2) ... (3)

[0073] [Relationship between moisture absorption of the first polymer and the second polymer] From the viewpoint of improving the moisture resistance and compatibility of the coating formed using the coating composition, it is preferable that the difference in moisture absorption between the first polymer and the second polymer is 5% or more and 30% or less, more preferably 7% or more and 16% or less.

[0074] Although the present invention has been described above based on the preferred embodiments, the present invention is not limited to the above embodiments.

[0075] <Example> The present invention will be further described below with reference to examples, but the scope of the present invention is not limited to such examples.

[0076] <<Test Example 1: Examination of the blending ratio of the first polymer and the second polymer>> In Examples 1 to 12, films were formed using compositions for forming films in which the mass ratio (blending ratio) of the first polymer to the second polymer was varied, and the usability of the films was evaluated before and after exposure to high temperature and humidity. In addition, the moisture resistance of a cast film (also called a polymer coating) formed using the first polymer and the second polymer blended at the mass ratio of each example was evaluated. Although the fibers of the cast film subjected to the moisture resistance evaluation were not nanofiber-shaped, it was confirmed that moisture resistance evaluation results equivalent to those obtained when nanofibers were used were obtained.

[0077] [Preparation of film-forming composition] As the coating-forming compositions of Examples 1 to 12, mixtures of the following first polymer, second polymer, and solvent were prepared. (First polymer) A polyvinyl butyral resin (product name: S-LEC (registered trademark) BH-3, Sekisui Chemical Co., Ltd.) was used as the first polymer. The moisture absorption of the polyvinyl butyral resin calculated by the above formula (1) was 0.9%. (Second polymer) The second polymer used was a vinyl acetate-vinylpyrrolidone copolymer (product name: PLASDONE® S630, Ashland Japan Co., Ltd.). The moisture absorption of this polymer calculated using the above formula (1) was 16.8%. (solvent) As a solvent, 99% synthetic alcohol (Nippon Synthetic Alcohol Co., Ltd.), which is an absolute alcohol with an ethanol content of 99.5% by volume or more, was used. In the following description of the examples, this absolute alcohol will be referred to as "ethanol." As mentioned above, ethanol easily absorbs moisture from the air, so strictly speaking, the solvent contains water. Ethanol was mixed in a proportion of 93 mass % in the composition for forming a coating film.

[0078] In each of Examples 1 to 12, the mass ratio of the first polymer to the second polymer (first polymer:second polymer) in the composition for forming a coating was as follows. (Example 1) 71.4:28.6 (Example 2) 95.2:4.8 (Example 3) 90.9:9.1 (Example 4) 87.0:13.0 (Example 5) 83.3:16.7 (Example 6) 76.9:23.1 (Example 7) 66.7:33.3 (Example 8) 62.5:37.5 (Example 9) 55.6:44.4 (Example 10) 50.0:50.0 (Example 11) 45.5:54.5 (Example 12) 41.7:58.3

[0079] [Usability evaluation] The coatings formed using the coating composition of each example were evaluated by five expert panelists for usability before and after storage at high temperature and humidity. In the evaluation of the film-forming composition before storage at high temperature and humidity, expert panelists electrostatically sprayed the film-forming composition onto the inside of their own forearms using the electrostatic spray device 10 under the film-forming conditions described below to form films, and the films were evaluated according to the evaluation method described below. To evaluate the coating composition after storage at high temperature and humidity, a fiber sheet was first prepared by electrostatically spraying the coating composition onto a substrate layer using the electrostatic spray device 10 described above to form a coating. The fiber sheet was then packaged in breathable packaging and placed in an incubator at 40°C and 90% RH (high temperature and humidity environment) for 24 hours. The expert panelists removed the fiber sheet after storage at high temperature and humidity from the breathable packaging, positioned the fiber sheet so that the coating was in direct contact with the inside of their forearm, and removed the substrate layer to transfer the coating onto the skin, forming a coating. A rayon nonwoven fabric (product name: Omikenshi 45, Omikenshi Co., Ltd.) was used as the substrate layer.

[0080] The conditions for forming the coating by electrostatic spraying are as follows. Applied voltage: 30 kV Distance between nozzle and skin: 130mm Discharge rate of film-forming composition: 4 mL / h Environment: 25℃, 30%RH

[0081] [Evaluation items and evaluation methods] The evaluation items for usability were fit, appearance, and wrinkles / bubbles. The expert panel evaluated the compatibility of the film formed on the skin, the appearance of the film, and whether the film was wrinkled or had air bubbles. The evaluation was carried out without applying the preparation before or after film formation. Five expert panelists evaluated each evaluation item on a five-point scale from 1 to 5 according to the following item evaluation criteria, and based on the overall average score, evaluated the usability of the coating on a four-point scale from A to D according to the following usability evaluation criteria. Table 1 shows the overall average scores for usability of the films formed using the film-forming compositions of each Example before and after storage at high temperature and humidity, the evaluation results based on the scores, and the average scores for each evaluation item.

[0082] (Item evaluation criteria) 5 points...very good 4 points...good 3 points…average 2 points...bad 1 point...very bad

[0083] (Usability evaluation criteria) A: 4.5≦total average score≦5.0 B: 4.0≦total average score<4.5 C: 3.0≦total average score<4.0 D: Overall average score < 3.0

[0084] [Evaluation of moisture resistance of cast film] The moisture resistance of the cast film was evaluated as follows. 0.35 g of the polymer to be evaluated (a mixture of the first polymer and the second polymer in the blending ratio specified in each example) was dissolved in 4.65 g of ethanol to prepare 5 g of polymer solution. The polymer solution was prepared with a ratio of 7% by mass of polymer and 93% by mass of ethanol. The polymer solution was placed in a 5 cm square plastic shell and dried at room temperature for 72 hours to evaporate the ethanol, producing a cast film. Next, the prepared cast film was left to stand in an incubator at 40°C and 90% RH (high temperature and humidity environment) for 24 hours. The weight change rate of the cast film before and after standing in the high temperature and humidity environment was calculated. Based on the weight change rate, the moisture absorption of the cast film was evaluated on a four-point scale (A to D) as follows. The evaluation results are shown in Table 1. A: 0%≦weight change rate≦5% B: 5% < weight change rate ≦ 10% C: 10% < weight change rate ≦ 15% D: 15% < weight change rate

[0085] [Table 1]

[0086] FIG. 4 is a graph prepared based on Table 1, showing the relationship between the proportion of the second polymer (horizontal axis) and the overall average usability score of the coating after storage at high temperature and humidity (vertical axis).

[0087] As shown in Table 1 and Figure 4, when the ratio of the second polymer in the coating composition was 0.05 or more and 0.60 or less, the compatibility of the coating both before and after storage at high temperature and humidity was rated at 3 or more, and the usability was rated at B or more, which was good.

[0088] <<Test Example 2: Examination of the second polymer, part 1>> For Examples 1 (same as Example 1 of Test Example 1), 13, and 14, coating compositions were prepared using the same blending ratio of the first polymer and the second polymer, but materials with different moisture absorption properties were used for the second polymer.The coatings were formed using the coating compositions under the same formation conditions as in Test Example 1, and the usability of the coatings before and after exposure to high temperature and humidity was evaluated using the same method as in Test Example 1. In addition, the moisture resistance of a cast film formed in the same manner as in Test Example 1 using the first polymer and the second polymer in the blending ratio of each Example was evaluated in the same manner as in Test Example 1. In addition, as Comparative Example 1, a composition for forming a film containing only the first polymer as the polymer was prepared, and the usability of a film formed using the composition for forming a film was evaluated. In addition, the moisture resistance of a cast film formed using only the first polymer was evaluated. Table 2 shows the overall average scores for usability of the coatings formed from the coating compositions of each Example and Comparative Example before and after storage at high temperature and humidity, the evaluation results based on the scores, the average scores for each evaluation item, and the evaluation results of the cast films.

[0089] [Preparation of film-forming composition] Mixtures of the following first polymer, second polymer, and solvent were prepared as the film-forming compositions of Examples 1, 13, and 14. In preparing the mixtures, the polymers were blended so that the mass ratio of the first polymer to the second polymer was 71.4:28.6. A mixture of the following first polymer and a solvent was prepared as a film-forming composition of Comparative Example 1. This film-forming composition did not contain a second polymer. (First polymer) A polyvinyl butyral resin (product name: S-LEC (registered trademark) BH-3, Sekisui Chemical Co., Ltd.) was used as the first polymer. The moisture absorption of the polyvinyl butyral resin calculated by the above formula (1) was 0.9%. (Second polymer) The following second polymers were used in each example. ((Example 1)) Vinyl acetate-vinylpyrrolidone copolymer (trade name: PLASDONE (registered trademark) S630, Ashland Japan Co., Ltd.) The moisture absorption of this polymer calculated by the above formula (1) was 16.8%. ((Example 13)) Vinylpyrrolidone-dimethylaminoethyl methacrylate copolymer diethyl sulfate (trade name: Gafquat 734, Ashland Japan Co., Ltd.) The moisture absorption of this polymer calculated by the above formula (1) was 28.4%. ((Example 14)) Vinylcaprolactam·vinylpyrrolidone·dimethylaminopropyl methacrylamide·methacryloylaminopropyl lauryldimonium chloride copolymer (Aquastyle 300N, Ashland Japan Co., Ltd.) The moisture absorption of this polymer calculated by the above formula (1) was 19.8%. (solvent) Ethanol was used as a solvent, and was mixed in a proportion of 93 mass % in the composition for forming a coating film.

[0090] [Table 2]

[0091] <<Test Example 3: Study of the second polymer, part 2>> In Example 1 (the same as Example 1 in Test Example 1) and Examples 15 to 17, films were formed under the same formation conditions as in Test Example 1 using film-forming compositions in which the second polymer was a vinyl acetate-vinylpyrrolidone copolymer with a different composition ratio of vinylpyrrolidone (VP) to vinyl acetate (VA), and the blending ratio of the first polymer to the second polymer was the same.The usability of these films before and after exposure to high temperature and humidity was evaluated using the same method as in Test Example 1. In addition, the moisture resistance of cast films formed using the first polymer and second polymer of each example was evaluated in the same manner as in Test Example 1. Table 3 shows the overall average scores for usability of the coatings formed from the coating composition of each example before and after storage at high temperature and humidity, the evaluation results based on the scores, the average scores for each evaluation item, and the evaluation results of the cast films.

[0092] [Preparation of film-forming composition] Mixtures of the following first polymer, second polymer, and solvent were prepared as the coating compositions of Examples 1, 15 to 17. In preparing the mixtures, the polymers were blended so that the mass ratio of the first polymer to the second polymer was 71.4:28.6. (First polymer) A polyvinyl butyral resin (product name: S-LEC (registered trademark) BH-3, Sekisui Chemical Co., Ltd.) was used as the first polymer. The moisture absorption of the polyvinyl butyral resin calculated by the above formula (1) was 0.9%. (Second polymer) The following second polymers were used in each example. ((Example 1)) Vinyl acetate-vinylpyrrolidone copolymer (trade name: PLASDONE (registered trademark) S630 (composition ratio VP:VA=60:40), Ashland Japan Co., Ltd.) The moisture absorption of this polymer calculated by the above formula (1) was 16.8%. ((Example 15)) Vinyl acetate-vinylpyrrolidone copolymer (trade name: PVP / VA E735 (composition ratio VP:VA=70:30), Ashland Japan Co., Ltd.) The moisture absorption of this polymer calculated by the above formula (1) was 26.2%. ((Example 16)) Vinyl acetate-vinylpyrrolidone copolymer (trade name: PVP / VA S535 (composition ratio VP:VA=50:50), Ashland Japan Co., Ltd.) The moisture absorption of this polymer calculated by the above formula (1) was 14.6%. ((Example 17)) Vinyl acetate-vinylpyrrolidone copolymer (trade name: PVP / VA E335 (composition ratio VP:VA=30:70), Ashland Japan Co., Ltd.) The moisture absorption of this polymer calculated by the above formula (1) was 12.0%. (solvent) Ethanol was used as a solvent, and was mixed in a proportion of 93 mass % in the composition for forming a coating film.

[0093] [Table 3]

[0094] <<Test Example 4: Study of the second polymer, part 3>> For Examples 1 (same as Example 1 in Test Example 1), 18 and 19, and Comparative Examples 2 and 3, coating compositions were prepared using the same blending ratio of the first polymer to the second polymer, but materials with different moisture absorption properties were used for the second polymer.The coatings were formed using the coating compositions under the same formation conditions as in Test Example 1, and the usability of the films before and after exposure to high temperature and humidity was evaluated using the same method as in Test Example 1. Furthermore, the moisture resistance of cast films formed in the same manner as in Test Example 1 using the first polymer and the second polymer of each of the Examples and Comparative Examples was evaluated in the same manner as in Test Example 1. The overall average scores for usability of the coatings formed from the coating compositions of each Example and Comparative Example before and after storage at high temperature and humidity, the evaluation results based thereon, the average scores for each evaluation item, and the evaluation results of the cast films are shown in Table 4. In Table 4, the "-" in the usability column indicates that the coating melted and the evaluation itself could not be performed.

[0095] [Preparation of film-forming composition] Mixtures of the first polymer, second polymer, and solvent shown below were prepared as coating-forming compositions for Examples 1, 18, and 19, and Comparative Examples 2 and 3. In preparing the mixtures, the polymers were blended so that the mass ratio of the first polymer to the second polymer was 71.4:28.6. (First polymer) A polyvinyl butyral resin (product name: S-LEC (registered trademark) BH-3, Sekisui Chemical Co., Ltd.) was used as the first polymer. The moisture absorption of the polyvinyl butyral resin calculated by the above formula (1) was 0.9%. (Second polymer) The following second polymers were used in each of the Examples and Comparative Examples. ((Example 1)) Vinyl acetate-vinylpyrrolidone copolymer Vinyl acetate-vinylpyrrolidone copolymer (trade name: PLASDONE (registered trademark) S630, Ashland Japan Co., Ltd.) The moisture absorption of this polymer calculated by the above formula (1) was 16.8%. ((Example 18)) Polyoxyethylene (20) polyoxypropylene (20) glycol (trade name: Pronon 124P, NOF Corporation) The moisture absorption of this polymer calculated by the above formula (1) was 8.5%. ((Example 19)) PEG-11 methyl ether dimethicone (trade name: Silicone KF6011, Shin-Etsu Chemical Co., Ltd.) The moisture absorption of this polymer calculated by the above formula (1) was 6.5%. (Comparative Example 2) Polyethylene glycol (trade name: PEG400, Wako Pure Chemical Industries, Ltd.) The polyethylene glycol is a polymer having an average molecular weight of 360 to 440. The moisture absorption of the polymer calculated by the above formula (1) was 45.6%. (Comparative Example 3) Polyethylene glycol (trade name: PEG1450, Sanyo Chemical Industries, Ltd.) The polyethylene glycol is a polymer with an average molecular weight of 1450. The moisture absorption of the polymer calculated by the above formula (1) was 42.0%. (solvent) Ethanol was used as a solvent, and was mixed in a proportion of 93 mass % in the composition for forming a coating film.

[0096] [Table 4]

[0097] In addition, the following primer liquid (preparation) formulation is disclosed as an example of a formulation that can be applied before or after the coating formation process. <Primer liquid formulation> Pseudoceramide 1% by mass Glycerin fatty acid ester 0.34% by mass Cetyl alcohol 0.34% by mass Dimethylpolysiloxane 2% by mass Glycerin 10% by mass 1,3-butanediol 3% by mass Distearyldimonium chloride 0.4% by mass Polyoxyethylene sorbitan monostearate (20E.O.) 0.2% by mass Succinic acid 0.005% by mass Methyl parahydroxybenzoate 0.2% by mass The balance was made up with purified water to make the total 100% by mass. [Explanation of symbols]

[0098] 1...Film forming composition

Claims

1. A coating composition for forming a coating that is electrostatically sprayed directly or indirectly onto a target site to form a coating comprising a deposit containing fibers, comprising: The coating composition is a first polymer having a moisture absorption of 1% or less in a high temperature and high humidity environment (when left standing at 40°C and 90% RH for 24 hours); A second polymer having a moisture absorption of 5% or more and 29% or less in a high temperature and humidity environment (left standing at 40°C and 90% RH for 24 hours); Including, the first polymer includes one or more polymers selected from a polyvinyl butyral resin, a polyurethane resin, and a polylactic acid; the second polymer comprises one or more polymers selected from polyvinylpyrrolidone, a copolymer of polyvinylpyrrolidone, a polyalkylene glycol, and a copolymer containing a silicone structure; When the mass of the first polymer in the coating composition is M1 and the mass of the second polymer is M2, the value of M2 / (M1+M2) is 0.05 or more and 0.60 or less. Composition for film formation.

2. The second polymer includes one or more polymers selected from vinyl acetate-vinylpyrrolidone copolymer, vinylpyrrolidone-dimethylaminoethyl methacrylate copolymer diethyl sulfate, vinylcaprolactam-vinylpyrrolidone-dimethylaminopropyl methacrylamide-methacryloylaminopropyl lauryldimonium chloride copolymer, polyoxyethylene polyoxypropylene glycol, and PEG-11 methyl ether dimethicone. The coating composition according to claim 1 .

3. The film-forming composition further contains one or more selected from monohydric alcohols and ketones. The film-forming composition according to claim 1 or 2.

4. The target site for coating is human skin. The film-forming composition according to claim 1 or 2.

5. A coating manufacturing method for forming a coating on a coating formation target portion, comprising: a coating formation step of electrostatically spraying a coating composition directly or indirectly onto a target area to form a coating made of a deposit containing fibers; The coating composition is a first polymer having a moisture absorption of 1% or less in a high temperature and high humidity environment (when left standing at 40°C and 90% RH for 24 hours); A second polymer having a moisture absorption of 5% or more and 29% or less in a high temperature and humidity environment (left standing at 40°C and 90% RH for 24 hours); Including, the first polymer includes one or more polymers selected from a polyvinyl butyral resin, a polyurethane resin, and a polylactic acid; the second polymer comprises one or more polymers selected from polyvinylpyrrolidone, a copolymer of polyvinylpyrrolidone, a polyalkylene glycol, and a copolymer containing a silicone structure; When the mass of the first polymer in the coating composition is M1 and the mass of the second polymer is M2, the value of M2 / (M1+M2) is 0.05 or more and 0.60 or less. Coating manufacturing method.

6. a preparation application step of applying a preparation to the site to be coated before or after the coating formation step; Further provided with The method for producing a coating according to claim 5.

7. The coating composition according to claim 1 or 2, a preparation to be applied to the site to be coated before or after coating formation using the coating composition; A coating formation kit comprising:

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