Skin patch sheet and manufacturing method of skin patch sheet

Abstract

To provide a skin patch sheet capable of easily maintaining an antioxidative action at a position where a user imparts the antioxidative action, and a method for manufacturing the skin patch sheet.SOLUTION: A skin patch sheet 10 includes: a sheet body 10B including a polyurethane resin-containing base material layer 11 and an adhesive layer 12 laminated on the base material layer 11; a protection layer 13 laminated on the base material layer 11 on a side opposite to the adhesive layer 12 with respect to the base material layer 11; and a release layer 14 laminated on the adhesive layer 12 on a side opposite to the base material layer 11 with respect to the adhesive layer 12. The adhesive layer 12 from which the release layer 14 has been peeled off is attached to the skin. The sheet body 10B satisfies at least one of a condition that a radical trapping ratio of the sheet body 10B after 6 hours is 25% or more, and a condition that a radical trapping ratio of the sheet body 10B after 24 hours is 60% or more in an antioxidation test using 2, 2-diphenyl-1-bicrylhydrazyl.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a skin adhesive sheet and a method for manufacturing a skin adhesive sheet. [Background technology]

[0002] When free radicals contained in the air come into contact with the skin, they steal electrons from molecules located on the surface of the skin. This causes the molecules that have lost electrons to oxidize, resulting in wrinkles and age spots on the skin. Cosmetics that are applied to the skin are used to prevent wrinkles and age spots caused by oxidation. Cosmetics are usually in liquid form. Examples of liquid cosmetics include lotions and beauty creams (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-136172 Summary of the Invention [Problem to be solved by the invention]

[0004] However, liquid cosmetics applied to the skin are easily removed when the user puts on clothing or when the cosmetics come into contact with the skin, making it difficult for the cosmetics to remain applied to the skin, and as a result, the antioxidant effect on the skin is also difficult to maintain. [Means for solving the problem]

[0005] The skin adhesive sheet for solving the above problems comprises a sheet body including a base layer containing a polyurethane resin and an adhesive layer laminated on the base layer, and the adhesive layer is attached to the skin. In an antioxidant test using 2,2-diphenyl-1-bicrylhydrazyl, the sheet body satisfies at least one of the following: a radical scavenging rate of 25% or more after 6 hours, and a radical scavenging rate of 60% or more after 24 hours.

[0006] A method for producing a skin patch sheet for solving the above problems includes forming a base layer containing a polyurethane resin on a protective layer, forming an adhesive layer on a release layer, and laminating the adhesive layer on the base layer. In an antioxidant test using 2,2-diphenyl-1-bicrylhydrazyl, the sheet body including the base layer and the adhesive layer satisfies at least one of the following: a radical scavenging rate of the sheet body after 6 hours is 25% or more, and a radical scavenging rate of the sheet body after 24 hours is 60% or more.

[0007] According to the above-mentioned skin adhesive sheet and method for manufacturing the skin adhesive sheet, the sheet body has a radical scavenging ability that lasts for a certain period of time, so that oxidation caused by radicals is suppressed for a certain period of time at the site of the skin where the sheet body is attached. Moreover, since the sheet body is in a solid form, even if the user touches the sheet body, it is less likely to shift position relative to the skin or be removed from the skin than a liquid cosmetic. This makes it easier to maintain the antioxidant effect at the site where the user applied the antioxidant effect.

[0008] In the above-mentioned skin patch sheet, the polyurethane resin may include an ether-based polyurethane resin. The above-mentioned skin adhesive sheet makes it possible to obtain a base layer that is resistant to hydrolysis even when in contact with water.

[0009] In the above-mentioned skin patch sheet, the thickness of the base material layer may be 5 μm or more and 30 μm or less. According to the above-mentioned skin adhesive sheet, it is possible to maintain the high conformability of the base layer to the skin while increasing the reliability of suppressing the penetration of radicals into the area where the sheet body is attached in the thickness direction of the base layer. [Effects of the Invention]

[0010] According to the skin patch sheet and the method for producing the skin patch sheet of the present disclosure, the antioxidant effect is likely to be maintained at the location where the user has imparted the antioxidant effect. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing the structure of a skin adhesive sheet. [Figure 2] FIG. 2 is a plan view showing the structure of the skin adhesive sheet. [Figure 3] FIG. 3 is a flowchart illustrating the steps of forming the base layer. [Figure 4] FIG. 4 is a flowchart illustrating the steps of forming the adhesive layer. [Figure 5] FIG. 5 is a flowchart illustrating the steps of forming a skin patch sheet. [Figure 6] FIG. 6 is a table showing the results of the antioxidant test for each test example. [Figure 7] FIG. 7 is a graph showing the change over time in the radical scavenging rate in each test example. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of a skin adhesive sheet and a method for manufacturing the skin adhesive sheet will be described with reference to FIGS. [Skin patch sheet] The skin adhesive sheet will be described with reference to FIGS.

[0013] As shown in Fig. 1, the skin adhesive sheet 10 comprises a sheet body 10B, a protective layer 13, and a release layer 14. The sheet body 10B includes a base layer 11 containing a polyurethane resin, and an adhesive layer 12 laminated on the base layer 11. The protective layer 13 is laminated on the base material layer 11 on the side opposite the adhesive layer 12 from the base material layer 11. The release layer 14 is laminated on the adhesive layer 12 on the side opposite the adhesive layer 12 from the base material layer 11. After the release layer 14 is peeled off, the adhesive layer 12 of the skin adhesive sheet 10 is attached to the skin.

[0014] The sheet body 10B satisfies at least one of the following conditions 1 and 2 in an antioxidant test using 2,2-diphenyl-1-pycrylhydrazyl. (Condition 1) The radical scavenging rate of the main sheet body 10B after 6 hours is 25% or more. (Condition 2) The radical scavenging rate of the main sheet body 10B after 24 hours is 60% or more.

[0015] Because the base layer 11 containing polyurethane resin has radical scavenging ability that lasts for a certain period of time, oxidation by radicals is suppressed for a certain period of time at the area of ​​the skin where the sheet body 10B is attached. Moreover, since the sheet body 10B is in a solid form, even when the user touches the sheet body 10B, it is less likely to shift position relative to the skin or be removed from the skin than a liquid cosmetic. This makes it easier to maintain the antioxidant effect at the area where the user applied the antioxidant effect. Note that, from the perspective of maintaining the antioxidant effect of the sheet body 10B for a long period of time, it is preferable that the sheet body 10B satisfy both conditions 1 and 2.

[0016] Furthermore, according to the skin adhesive sheet 10, the sheet body 10B is attached to a part of the skin. Therefore, the part of the skin to which the sheet body 10B is attached is prevented from being subjected to physical irritation such as rubbing by clothing. This prevents deterioration of the skin caused by physical irritation. Examples of skin deterioration include wrinkles and blemishes.

[0017] 2,2-Diphenyl-1-pycrylhydrazyl (DPPH), represented by the following chemical formula (1), is an example of a free radical. DPPH has an absorption maximum at 520 nm, giving it a purple color.

[0018] [ka]

[0019] When DPPH reacts with a radical scavenger, it turns into 2,2-diphenyl-1-pycrylhydrazine (DPPH-H), which is shown in the following chemical formula (2). DPPH-H has a lower absorbance at 520 nm than DPPH, and is therefore colorless.

[0020] [ka]

[0021] To measure the radical scavenging rate of the skin adhesive sheet 10, a rectangular test piece measuring 10 mm in the short direction and 30 mm in the long direction is first cut out from the skin adhesive sheet 10. A DPPH solution is obtained by dissolving DPPH in hexane to a concentration of 25 mg / L. Spectroscopic measurement of the DPPH solution is then performed to obtain a first absorbance A1 of the DPPH solution before it comes into contact with the test piece.

[0022] After peeling the release layer from the adhesive layer of the test specimen, the test specimen is folded so that the second portion of the adhesive layer overlaps the first portion. The protective layer is then peeled off from the base layer to obtain a test specimen. After immersing the test specimen in the DPPH solution, spectroscopic measurements are performed on the DPPH solution in which the test specimen is immersed 6 hours and 24 hours after the start of immersion. This yields the second absorbance A2 of the DPPH solution after it has come into contact with the test specimen.

[0023] The radical scavenging rate (%) can be calculated by substituting the first absorbance A1 and the second absorbance A2 into the following formula (1).

[0024]

number

[0025] Polyurethane resin is synthesized by polymerization of a compound having an isocyanate group and a compound having a hydroxyl group. For example, polyurethane resin is synthesized by polymerization of a diisocyanate monomer (OCN-R 1 -NCO) and diol monomer (HO-R 2 Polyurethane resins are synthesized by polymerization of hydroxypropyl methylcellulose (OH). Polyurethane resins have the following structure:

[0026] [ka]

[0027] In the repeating units of polyurethane resin, hydrogen atoms bonded to nitrogen atoms are easily abstracted by other radicals. In an oxygen environment containing oxygen radicals, the repeating units of polyurethane resin are easily radicalized by abstracting hydrogen atoms bonded to nitrogen atoms. When the repeating units of polyurethane resin are radicalized, the oxygen radicals react with the hydrogen atoms abstracted from the polyurethane resin to generate water, which causes the oxygen radicals to become inactive. This gives polyurethane resin an antioxidant effect.

[0028] The base layer 11 has a surface 11S which is the surface opposite to the surface which contacts the adhesive layer 12. The protective layer 13 is in contact with the surface 11S of the base layer 11. The adhesive layer 12 has an adhesive surface 12S which is the surface opposite to the surface which contacts the base layer 11. The release layer 14 is in contact with the adhesive surface 12S. The adhesive surface 12S is the surface which is attached to the skin, the target surface, after the release layer 14 is peeled off from the adhesive layer 12.

[0029] The polyurethane resin forming the base layer 11 may further include a polyurethane resin having radical scavenging ability. The polyurethane resin forming the base layer 11 may include, for example, a diphenylmethylene skeleton. A polyurethane resin including a diphenylmethylene skeleton is an example of a polyurethane resin having radical scavenging ability. Furthermore, an example of a polyurethane resin having radical scavenging ability may include a diphenylamine skeleton or a phenylnaphthylamine skeleton.

[0030] Skin patch sheets containing polyurethane resins with radical scavenging ability usually contain an antioxidant to prevent yellowing of the skin patch sheet, which would change the appearance of the skin patch sheet or make it difficult to see the information provided on the skin patch sheet. In contrast, in the skin patch sheet 10 of the present disclosure, the base layer 11 does not contain an antioxidant, so that the base layer 11 itself can scavenge radicals, thereby preventing oxidation of the skin to which the base layer 11 is applied.

[0031] An example of a polyurethane resin having radical scavenging ability may be formed from an aromatic diisocyanate containing a benzene skeleton and a polyol. That is, an example of a polyurethane resin having radical scavenging ability may contain a first unit structure derived from an aromatic diisocyanate as a repeating unit. Examples of aromatic diisocyanates are diphenylmethane diisocyanate and tolylene diisocyanate. When the repeating unit contains the first unit structure, the benzene skeleton contained in the first unit structure further has radical scavenging ability.

[0032] The polyurethane resin forming the substrate layer 11 may contain an ether-based polyurethane resin. This makes it possible to obtain a substrate layer 11 that is resistant to hydrolysis even when in contact with water. The polyurethane resin may be an ether-based polyurethane resin and may contain any of a diphenylmethylene skeleton, a diphenylamine skeleton, and a phenylnaphthylamine skeleton. When the polyurethane resin is an ether-based polyurethane resin and contains any of the above-mentioned skeletons, the substrate layer 11 can achieve both water resistance and radical scavenging ability. The polyurethane resin may contain at least one of an ester-based polyurethane resin and a carbonate-based polyurethane resin.

[0033] The thickness of the base layer 11 may be, for example, 5 μm or more and 30 μm or less, which can increase the reliability of suppressing radical penetration into the area where the sheet body 10B is attached in the thickness direction of the base layer 11 while maintaining the high conformability of the base layer 11 to the skin.

[0034] The thin base layer 11 is made of polyurethane resin and stretches well even when a small external force is applied to the base layer 11 to stretch the base layer 11. Therefore, the base layer 11 has high conformability to the skin to which the sheet body 10B is attached, and can also have high adhesion to the skin.

[0035] The tensile elongation at break of the substrate layer 11 may be, for example, 130% or more. The tensile elongation at break can be determined in accordance with JIS K 7161-1:2014 (ISO 527-1) "Plastics - Determination of tensile properties - Part 1: General rules" and JIS K 7127:1999 (ISO 527-3) "Plastics - Test methods for tensile properties - Part 3: Test conditions for films and sheets." If the object to be measured does not have a yield point, the tensile breaking strain is measured. If the object to be measured has a yield point, the nominal tensile strain at break is measured. The tensile elongation at break can be determined using these measured values.

[0036] The tensile strength at 100% elongation of the substrate layer 11 may be, for example, 4 N / cm or less. The tensile strength at 100% elongation is the value obtained by dividing the magnitude of the force measured when the strain reaches a specified value (100%), as defined in JIS K 7161-1:2014 (ISO 527-1) "Plastics - Determination of tensile properties - Part 1: General rules," by the width of the test piece. The tensile strength at 100% elongation (T) (N / cm) can be calculated using the following formula:

[0037] T = F / W In the above formula, F is the magnitude of the measured force (N), and W is the width of the test piece (cm).

[0038] The protective layer 13 is formed from a synthetic resin. The protective layer 13 may contain, for example, a polypropylene resin. The protective layer 13 may be formed from, for example, a base sheet and a release layer. In this case, the release layer is laminated on the base sheet. When the protective layer 13 includes a base sheet and a release layer, the release layer is in contact with the base layer 11. The base sheet may be formed from either a polyolefin resin or a polyester resin. The polyolefin resin may be, for example, a polypropylene resin. The polyester resin may be, for example, a polyethylene terephthalate resin. The base sheet is preferably formed from a polyolefin resin. The base sheet may be any of a uniaxially oriented sheet, a biaxially oriented sheet, and a non-oriented sheet. The release layer may be formed from, for example, a silicone resin.

[0039] The protective layer 13 may be composed of only the above-mentioned base sheet. In this case, the contact surface of the base sheet that comes into contact with the base layer 11 may be processed to make it easier to peel the base layer 11 from the base sheet. The processing of the contact surface of the base sheet may be, for example, embossing. The thickness of the protective layer 13 may be, for example, 30 μm or more and 400 μm or less.

[0040] The adhesive layer 12 may be formed from various types of adhesives. The adhesive for forming the adhesive layer 12 may be, for example, any one of a rubber-based adhesive, an acrylic-based adhesive, a silicone-based adhesive, and a urethane-based adhesive. The adhesive layer 12 may be formed from a two-component adhesive. When the adhesive layer 12 is formed from a urethane-based adhesive, the polyurethane resin contained in the urethane-based adhesive may contain any one of a diphenylmethylene skeleton, a diphenylamine skeleton, and a phenylnaphthylamine skeleton. This allows the adhesive layer 12 to also have radical scavenging ability. The thickness of the adhesive layer 12 may be, for example, 5 μm or more and 30 μm or less.

[0041] The release layer 14 may be configured so that the peel strength between the release layer 14 and the adhesive layer 12 is smaller than the peel strength between the protective layer 13 and the base layer 11. The release layer 14 is made of a synthetic resin. The release layer 14 is made of, for example, a base sheet and a release layer. The release layer is laminated on the base sheet. When the release layer 14 comprises a base sheet and a release layer, the release layer is in contact with the adhesive layer 12. The base sheet may be made of, for example, a polyethylene terephthalate resin. The base sheet may be any of a uniaxially oriented sheet, a biaxially oriented sheet, and a non-oriented sheet. The release layer may be made of, for example, a silicone resin.

[0042] The release layer 14 may be composed of only the above-mentioned base sheet. In this case, the contact surface of the base sheet that comes into contact with the adhesive surface 12S of the adhesive layer 12 may be processed to make it easier to peel the adhesive layer 12 from the base sheet. The processing of the contact surface of the base sheet may be, for example, embossing. The thickness of the release layer 14 may be, for example, 12 μm or more and 350 μm or less.

[0043] FIG. 2 shows the planar structure of the skin adhesive sheet 10 as seen from a viewpoint opposite to the XY plane defined by the X direction and the Y direction perpendicular to the X direction. As shown in Figure 2, the skin adhesive sheet 10 has a rectangular shape extending along the X direction when viewed from a perspective opposite to the plane on which the skin adhesive sheet 10 extends. Of the layers included in the skin adhesive sheet 10, the protective layer 13 is the largest, and the base layer 11, adhesive layer 12, and release layer 14 have the same size. Each layer has a rectangular shape extending along the X direction. In the X direction, the length of the protective layer 13 is equal to the length of the base layer 11, the length of the adhesive layer 12, and the length of the release layer 14. In contrast, in the Y direction, the length of the protective layer 13 is longer than the length of the base layer 11, the length of the adhesive layer 12, and the length of the release layer 14.

[0044] 2, the outer edge of the protective layer 13 is composed of a first long side, a second long side, a first short side, and a second short side. The first long side and the second long side extend along the X direction, and the first short side and the second short side extend along the Y direction.

[0045] The protective layer 13 includes a first region 13R1 and a second region 13R2. The second region 13R2 is a region of the protective layer 13 that contacts the base layer 11. In contrast, the first region 13R1 is a region of the protective layer 13 that does not contact the base layer 11. The regions 13R1 and 13R2 extend along the X direction, and the first region 13R1 and the second region 13R2 are aligned along the Y direction. The length of the first region 13R1 along the Y direction may be, for example, 5 mm or more and 20 mm or less.

[0046] The protective layer 13 has two slits 13B in the first region 13R1. The protective layer 13 may have only one slit 13B, or may have three or more slits 13B. Each slit 13B extends from the outer edge of the protective layer 13 toward the base layer 11. The slits 13B have a length that does not reach the base layer 11. In the example shown in FIG. 2, each slit 13B extends along the Y direction. Because the protective layer 13 has the slits 13B, when peeling the protective layer 13 from the base layer 11, it is possible to peel the protective layer 13 from the base layer 11 by splitting the protective layer 13 along the slits 13B. This makes it easy to peel the protective layer 13 from the base layer 11.

[0047] The distance D13B between the slits 13B in the X direction may be, for example, 3 mm or more and 40 mm or less. This makes it easy to grip the portion located between the slits 13B. The center of the skin adhesive sheet 10 in the X direction may be located between the slits 13B. This makes it possible to split the protective layer 13 at approximately the center in the X direction by splitting the protective layer 13 along the slits 13B.

[0048] As described above, the base layer 11, the adhesive layer 12, and the release layer 14 have the same shape, and the entire adhesive layer 12 and the entire release layer 14 overlap the entire base layer 11. Therefore, in the following, the sizes of the protective layer 13 and the base layer 11 will be compared, and a comparison of the sizes of the adhesive layer 12 and the release layer 14 with the size of the protective layer 13 will be omitted. In addition, in the following, the position of the base layer 11 relative to the protective layer 13 will be described, and a description of the positions of the adhesive layer 12 and the release layer 14 relative to the protective layer 13 will be omitted.

[0049] When viewed from a viewpoint opposite to the plane on which the skin adhesive sheet 10 extends, the base layer 11 is located within the protective layer 13. When viewed from a viewpoint opposite to the plane on which the skin adhesive sheet 10 extends, part of the outer edge of the base layer 11 overlaps part of the outer edge of the protective layer 13. When viewed from a viewpoint opposite to the plane on which the skin adhesive sheet 10 extends, the outer edge of the base layer 11 overlaps part of the first long side and each short side of the outer edge of the protective layer 13. In the base layer 11, the length LLS of the long side along the X direction may be, for example, 100 mm or more and 150 mm or less. In the base layer 11, the length LSS of the short side along the Y direction may be, for example, 50 mm or more and 100 mm or less.

[0050] [Manufacturing method of skin patch sheet] A method for producing the skin adhesive sheet 10 will be described with reference to FIGS. The method for producing the skin adhesive sheet 10 of the present disclosure includes forming a base layer 11 containing a polyurethane resin on a protective layer 13, forming an adhesive layer 12 on a release layer 14, and laminating the adhesive layer 12 on the base layer 11. The sheet body 10B of the skin adhesive sheet 10 satisfies at least one of the above-mentioned conditions 1 and 2. The method for producing the skin adhesive sheet 10 will be described below with reference to Figs. 3 to 5.

[0051] As shown in FIG. 3, when forming the base layer 11, first, a first coating film is formed using a first coating liquid for forming the base layer 11 (step S11). At this time, the first coating film is formed on one surface of the protective layer 13. Next, the first coating film is dried (step S12). The thickness of the first coating film after drying may be, for example, 5 μm or more and 30 μm or less. Thereafter, the first coating film is aged to obtain the base layer 11 from the first coating film, and as a result, it is possible to obtain a first laminate composed of the base layer 11 and the protective layer 13 (step S13). Note that the thickness of the base layer 11 obtained after aging is equal to the thickness of the first coating film after drying.

[0052] 4, when forming the adhesive layer 12, first, a second coating film is formed using a second coating liquid for forming the adhesive layer 12 (step S21). At this time, the second coating film is formed using the second coating liquid on one surface of the release layer 14. Thereafter, the second coating film is dried, thereby obtaining the adhesive layer 12 from the second coating film (step S22). In this way, a second laminate composed of the adhesive layer 12 and the release layer 14 can be obtained.

[0053] As shown in Fig. 5, when obtaining the skin patch sheet 10, first, the adhesive layer 12 of the second laminate is bonded to the base layer 11 of the first laminate (step S31). Next, the laminate composed of the first laminate and the second laminate is aged (step S32). This allows the skin patch sheet 10 to be obtained. In the obtained skin patch sheet 10, the protective layer 13, base layer 11, adhesive layer 12, and release layer 14 are laminated in the order listed.

[0054] [Test example] A test example will be described with reference to FIGS. [Skin patch sheet] A biaxially oriented polypropylene (OPP) film (Futamura Chemical Co., Ltd., FOR-MP) with one matte surface facing the other in the thickness direction was prepared as a protective layer. An aqueous polyurethane containing an ether-based polyol (Mitsui Chemicals, Inc., Takelac WS-6021) (Takelac is a registered trademark) was prepared as a first coating liquid. The first coating liquid was applied to the matte surface to form a first coating film. The first coating film was dried to obtain a first coating film with a thickness of 15 μm. The first coating film was then aged at room temperature for 48 hours to obtain a substrate layer. This resulted in a first laminate consisting of a protective layer and a substrate layer.

[0055] Separately, a release film (Cerapeel WZ, manufactured by Toray Advanced Film Co., Ltd.) (Cerapeel is a registered trademark) composed of a PET film and a release layer was prepared as a release layer. A urethane adhesive (Cyabain SP-205, manufactured by Toyochem Co., Ltd.) (Cyabain is a registered trademark), a curing agent (T-501B, manufactured by Toyochem Co., Ltd.), and a dilution solvent (NC401 Solvent C, manufactured by Toyo Ink Co., Ltd.) were also prepared. The viscosity of the base agent was adjusted by adding twice the amount of dilution solvent to the base agent. Next, the curing agent was added to the base agent, and the mixture of the base agent and curing agent was stirred to obtain a second coating liquid for forming an adhesive layer. The second coating liquid was then applied to the release layer provided on the release layer to form a second coating film, and the second coating film was dried to obtain an adhesive layer with a thickness of 15 μm. This resulted in a second laminate composed of a release layer and an adhesive layer.

[0056] The adhesive layer of the second laminate was bonded to the base layer of the first laminate to obtain a laminate in which the base layer and adhesive layer were sandwiched between a protective layer and a release layer, and the laminate was then aged at 50°C for 72 hours to obtain a skin patch sheet.

[0057] [Evaluation method] [DPPH radical scavenging activity measurement method] A DPPH solution was obtained by dissolving DPPH in hexane to a concentration of 25 mg / L, and the first absorbance A1 was obtained by performing spectroscopic analysis on the DPPH solution.

[0058] In Test Example 1, a rectangular test piece measuring 10 mm in the short direction and 30 mm in the long direction was cut out from the skin patch sheet. Next, the release layer was peeled off from the adhesive layer of the test piece, and the test piece was folded so that the second portion of the adhesive layer was in contact with the first portion. Thereafter, the protective layer was peeled off from the base layer to obtain a test piece for measurement.

[0059] In Test Example 2, a rectangular test piece measuring 10 mm in the short direction and 30 mm in the long direction was cut out from the first laminate for forming the skin patch sheet, thereby obtaining a test piece for measurement.

[0060] In Test Example 3, a rectangular test piece measuring 10 mm in the short direction and 30 mm in the long direction was cut out from the base layer of the first laminate for forming the skin patch sheet, thereby obtaining a test piece for measurement.

[0061] In Test Example 5, a rectangular test piece measuring 10 mm in the short direction and 30 mm in the long direction was cut out from the protective layer for forming the skin patch sheet, thereby obtaining a test piece for measurement.

[0062] After immersing each test specimen in a different DPPH solution, spectroscopic measurements were performed on the DPPH solution containing the test specimen at a predetermined time after the start of immersion. This yielded the second absorbance A2 of the DPPH solution at the predetermined time after the DPPH solution contacted the test specimen. The radical scavenging rate for each test example was calculated by substituting the first absorbance A1 and the second absorbance A2 into the above-mentioned formula (1). In Test Example 4, the second absorbance A2 was measured at a predetermined time after the first absorbance A1 was measured for the DPPH solution without the test specimen. A spectrophotometer (Hitachi High-Technologies Corporation, variable-angle absolute reflectance measurement device U4100) was used to measure the spectral characteristics of the DPPH solution and the DPPH solution containing the test specimen.

[0063] [Evaluation results] In each test example, the radical scavenging rate after 6 hours and the radical scavenging rate after 24 hours were as shown in FIG.

[0064] 6, the radical scavenging rate after 6 hours was 32% in Test Example 1, 35% in Test Example 2, and 29% in Test Example 3. The radical scavenging rate after 6 hours was 2% in Test Example 4 and 7% in Test Example 5.

[0065] The radical scavenging rate after 24 hours was found to be 82% in Test Example 1, 74% in Test Example 2, and 68% in Test Example 3. The radical scavenging rate after 24 hours was found to be 14% in Test Example 4 and 12% in Test Example 5.

[0066] According to the evaluation results of Test Examples 1 to 5, it was found that the radical scavenging rate of the measurement test piece including the base material layer was higher than the radical scavenging rate of the measurement test piece not including the base material layer both after 6 hours and after 24 hours.

[0067] 7 is a graph showing the results of measuring the radical scavenging rate for each test example after 0 hours, 2 hours, 4 hours, 6 hours, and 24 hours. In FIG. 7, the measurement results for Test Example 1 are shown with open circles (○), the measurement results for Test Example 2 are shown with open triangles (△), and the measurement results for Test Example 3 are shown with open squares (□). In FIG. 7, the measurement results for Test Example 4 are shown with open diamonds (◇), and the measurement results for Test Example 5 are shown with crosses (×).

[0068] 7, the evaluation results of Test Examples 1 to 3 showed that the measurement test piece including the base layer maintained its radical scavenging ability for 24 hours. Furthermore, the evaluation results of Test Examples 1 to 3 showed that the measurement test piece including the base layer had a particularly high rate of radical scavenging from 0 to 2 hours after the test.

[0069] As described above, according to one embodiment of the skin adhesive sheet and the method for manufacturing the skin adhesive sheet, the following effects can be obtained. (1) Because the sheet body 10B has radical scavenging ability that lasts for a certain period of time, oxidation caused by radicals is suppressed for a certain period of time at the site of the skin where the sheet body 10B is attached. Moreover, because the sheet body 10B is solid, even when the user touches the sheet body 10B, it is less likely to shift position relative to the skin or be removed from the skin than a liquid cosmetic. This makes it easier to maintain the antioxidant effect at the site where the user applied the antioxidant effect.

[0070] (2) When the polyurethane resin contains an ether-based polyurethane resin, it is possible to obtain a substrate layer 11 that is resistant to hydrolysis even when in contact with water.

[0071] (3) When the base layer 11 has a thickness of 5 μm or more and 30 μm or less, the base layer 11 can maintain a high degree of conformability to the skin, while increasing the reliability of suppressing the penetration of radicals into the area where the sheet body 10B is attached in the thickness direction of the base layer 11. [Explanation of symbols]

[0072] 10...Skin adhesive sheet 11...Base material layer 12...adhesive layer 13…Protective layer 14...Release layer

Claims

1. A skin adhesive sheet comprising a sheet body including a base layer containing a polyurethane resin and an adhesive layer laminated on the base layer, wherein the adhesive layer is attached to the skin, In an antioxidant test using 2,2-diphenyl-1-bicrylhydrazyl, the sheet body satisfies at least one of the following: a radical scavenging rate of the sheet body after 6 hours is 25% or more; and a radical scavenging rate of the sheet body after 24 hours is 60% or more. Skin adhesive sheet.

2. The polyurethane resin includes an ether-based polyurethane resin. The skin patch sheet according to claim 1.

3. The thickness of the substrate layer is 5 μm or more and 30 μm or less. The skin patch sheet according to claim 1 or 2.

4. forming a base layer containing a polyurethane resin on the protective layer; forming an adhesive layer on the release layer; and laminating the adhesive layer on the base layer; The sheet body including the base layer and the adhesive layer satisfies at least one of the following in an antioxidant test using 2,2-diphenyl-1-bicrylhydrazyl: a radical scavenging rate of the sheet body after 6 hours of 25% or more; and a radical scavenging rate of the sheet body after 24 hours of 60% or more. A method for manufacturing a skin patch sheet.

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