Absorbent articles

Abstract

The present invention provides an absorbent article that can suppress deformation of the absorbent core while preventing the outer part of the absorbent core from becoming too rigid. [Solution] The absorbent article (1) has an absorbent body (30) having an absorbent material in a front-to-back direction (L), a width direction (W), and a thickness direction (T) that are perpendicular to each other, and a top sheet (10) that is positioned on the skin side (T1) of the absorbent body and comes into contact with the wearer's skin. The top sheet has cellulose fibers. Within the cellulose fibers are oils containing at least one of the naturally derived oils of linoleic acid, palmitic acid, and oleic acid. The naturally derived oils are oils that exhibit water repellency.

Description

Technical Field

[0001] The present invention relates to an absorbent article comprising a topsheet having a cellulosic fiber.

Background Art

[0002] Patent Document 1 discloses an absorbent article comprising a topsheet having cotton fibers as cellulosic fibers. Since cellulosic fibers are excellent in liquid absorption and liquid retention properties, body fluids do not permeate through the topsheet but are absorbed and retained by the topsheet, which may give the wearer an uncomfortable feeling due to stickiness. In order to reduce the uncomfortable feeling due to stickiness, the absorbent article of Patent Document 1 has a lipophilic glycerin fatty acid ester having a water-repellent effect attached to the topsheet.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] However, the above absorbent article had the following problems. Patent Document 1 discloses a method of attaching a lipophilic glycerin fatty acid ester to a topsheet, in which an emulsion solution of a highly lipophilic glycerin fatty acid ester is attached to a nonwoven fabric by spraying, impregnating, kiss coating, etc., and after the emulsion solution is attached, a drying treatment is performed to attach a predetermined amount of the lipophilic glycerin fatty acid ester, and a method of performing a step of applying a high-pressure water stream and a lipophilic glycerin fatty acid ester by passing a nonwoven fabric containing moisture after the high-pressure water stream treatment through a mangle roll to remove excess moisture and then applying a lipophilic glycerin fatty acid ester emulsion solution by an appropriate method.

[0005] The lipophilic glycerin fatty acid ester described in Patent Document 1 is attached to the surface of the top sheet. Therefore, once bodily fluids such as menstrual blood adhere to the surface of the top sheet, the lipophilic glycerin fatty acid ester peels off, and when bodily fluids adhere to the surface of the top sheet again, the effect of the lipophilic glycerin fatty acid ester may not be obtained.

[0006] This invention has been made in view of these problems, and aims to suppress the stickiness of a top sheet having cellulose fibers even when it repeatedly absorbs bodily fluids. [Means for solving the problem]

[0007] An absorbent article according to one embodiment comprises an absorbent body having an absorbent material in mutually orthogonal directions in the front-to-back direction, width direction, and thickness direction, and a top sheet positioned on the skin side of the absorbent body and in contact with the wearer's skin. The top sheet has cellulose fibers. Within the cellulose fibers, an oil is disposed which contains at least one of the naturally derived oils of linoleic acid, palmitic acid, and oleic acid. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a plan view of an absorbent article as seen from the skin side. [Figure 2] Figure 2 is a cross-sectional view along line AA shown in Figure 1. [Figure 3] Figure 3 is a schematic enlarged view of section B shown in Figure 1. [Figure 4] Figure 4 is a schematic enlarged view of section C shown in Figure 2. [Modes for carrying out the invention]

[0009] (1) Outline of the Embodiment The following matters become clear from this specification and the accompanying drawings: The invention according to Embodiment 1 is an absorbent article. The absorbent article comprises an absorbent body having an absorbent material in front-to-back, width, and thickness directions that are orthogonal to each other, and a top sheet positioned on the skin side of the absorbent body and in contact with the wearer's skin. The top sheet has cellulose fibers. Within the cellulose fibers, an oil containing at least one of the naturally derived oils linoleic acid, palmitic acid, and oleic acid is disposed. The naturally derived oil is an oil that exhibits water repellency. The oil containing the naturally derived oil is disposed within the fibers of the top sheet. In a form in which the oil is applied only to the surface of the top sheet, once bodily fluids adhere to the surface of the top sheet, the oil may peel off, and the effect of the naturally derived oil may not be obtained when bodily fluids adhere to the surface of the top sheet again. However, because the oil is disposed within the cellulose fibers, even if bodily fluids adhere to the surface of the top sheet, the oils within the cellulose fibers stick together, suppressing the shedding of the oil. Therefore, even after repeated absorption of bodily fluids, it exhibits a water-repellent effect and suppresses stickiness of the top sheet, which has cellulose fibers.

[0010] In a preferred embodiment, the invention according to Embodiment 2 may have the following features in the invention according to Embodiment 1: The cellulose fiber comprises unbleached cotton. The unbleached cotton is chlorine-unbleached, has the color of cotton itself, and contains naturally derived oils. Because the top sheet has the color of cotton itself, it can remind the user that the top sheet is made of environmentally friendly, naturally derived materials. Therefore, the user can understand that it is an absorbent article that is gentle on the skin and can use the absorbent article with peace of mind.

[0011] In a preferred embodiment, the invention according to Embodiment 3 may have the following features in the invention according to Embodiment 1 or Embodiment 2: The top sheet has seed hulls. The presence of seed hulls reminds the user that the top sheet is made of environmentally friendly, naturally derived materials. Therefore, the user understands that it is an absorbent article that is gentle on the skin and can use the absorbent article with peace of mind. In addition, the presence of naturally derived oils in the seed hulls themselves provides a water-repellent effect through the oils in the fibers and the oils in the seed hulls, further suppressing the stickiness of the top sheet having cellulose fibers.

[0012] In a preferred embodiment, the invention according to Embodiment 4 may have the following features in the invention according to any of Embodiments 1 to 3: The cellulose fiber is a colored fiber containing residual components derived from wood. The presence of the colored fiber reminds the user that the top sheet is made of environmentally friendly, naturally derived materials. Therefore, the user can understand that it is an absorbent article that is gentle on the skin and can use the absorbent article with peace of mind.

[0013] In a preferred embodiment, the invention according to Embodiment 5 may have the following features in any of the inventions according to Embodiments 1 to 4. The absorbent body comprises an absorbent core made of laminated absorbent material and a core wrap sheet covering at least the skin-facing surface of the absorbent core. The top sheet has more of the naturally derived oil than the core wrap sheet. According to this embodiment, the oil on the top sheet is less likely to fall off, and because the amount of oil on the top sheet is relatively large, bodily fluids are more easily transferred from the top sheet to the core wrap sheet. Therefore, stickiness caused by bodily fluids remaining on the surface of the top sheet can be further suppressed. Furthermore, the presence of a large amount of naturally derived oil on the top sheet can suppress the rewetting of bodily fluids that have been transferred to the core wrap sheet.

[0014] In a preferred embodiment, the invention according to embodiment 6 may have the following features in the invention according to any of embodiments 1 to 5: The top sheet has more naturally derived oil than the absorbent core. At least a portion of the naturally derived oil in the top sheet is arranged within the cellulose fibers, making it less likely to fall off, and because the top sheet has a relatively large weight of oil, bodily fluids are easily transferred from the top sheet to the absorbent core. Therefore, stickiness caused by bodily fluids remaining on the surface of the top sheet can be further suppressed. Furthermore, the presence of a large amount of oil in the top sheet can suppress rewetting of bodily fluids that have been transferred to the absorbent core.

[0015] In a preferred embodiment, the invention according to Embodiment 7 may have the following features in the inventions according to Embodiments 1 to 6: It has a second sheet that abuts against the non-skin side of the top sheet. The water retention ratio of the second sheet is higher than that of the top sheet. The top sheet has high water repellency due to the presence of naturally derived oils, making it difficult to retain body fluids, and can draw body fluids to the second sheet, which has high water retention and abuts against the non-skin side of the top sheet. Therefore, it is possible to suppress liquid residue on the top sheet and further suppress stickiness of the top sheet having cellulose fibers.

[0016] In a preferred embodiment, the invention according to Embodiment 8 may have the following features in the inventions according to Embodiments 1 to 7: The oil content within the cellulose fiber consists solely of naturally derived oil. According to this embodiment, since the oil content within the cellulose fiber consists solely of naturally derived oil, the environmental burden can be reduced. Furthermore, by having only naturally derived oil in the cellulose fiber, changes in absorbency and texture caused by artificially composed oils can be suppressed.

[0017] In a preferred embodiment, the invention according to embodiment 9 may have the following features in the invention according to any of embodiments 1 to 8. The absorbent body comprises an absorbent core on which absorbent materials are laminated, and a core wrap sheet covering at least the skin-facing surface of the absorbent core. The area ratio of the adhesive joining the top sheet and the core wrap sheet is higher than the area ratio of the adhesive joining the core wrap sheet and the absorbent core. Generally, adhesives are hydrophobic. By arranging the adhesive on the top sheet side in a high area ratio, the hydrophobicity of the adhesive makes it difficult for liquid to remain on the top sheet side, improving the transfer of body fluids from the top sheet to the absorbent core side, and suppressing rewetting of body fluids once they have been drawn in.

[0018] In a preferred embodiment, the invention according to embodiment 10 may have the following features in the invention according to any of embodiments 1 to 9: The top sheet has a plurality of openings that penetrate in the thickness direction of the top sheet. According to this embodiment, bodily fluids can be smoothly drawn from the top sheet to the non-skin side through the openings. Therefore, residual liquid on the top sheet can be suppressed, and the stickiness of the top sheet having cellulose fibers can be further suppressed.

[0019] In a preferred embodiment, the invention according to embodiment 11 may have the following features in the invention according to any of embodiments 1 to 10. The absorbent article has a plurality of recesses in both the top sheet and the absorbent body that are recessed toward the non-skin side of the absorbent article. Each of the plurality of recesses has an opening formed by a cross-section connecting the top sheet and the absorbent body, and a bottom portion that constitutes the non-skin side surface of the opening. The top sheet at the bottom portion is provided with a high-density portion that has a higher fiber density than the top sheet surrounding the recess. According to this embodiment, the formation of the opening allows bodily fluids to be smoothly drawn from the top sheet side to the non-skin side. Furthermore, because the high-density portion of the top sheet is provided at the bottom, a large amount of oil can be placed at the bottom of the opening, making it easier to transfer bodily fluids from the side of the opening to the surrounding absorbent core.

[0020] According to a preferred embodiment, the invention according to Embodiment 12 may have the following features in the invention according to any of Embodiments 11. The central portion of the bottom is convex and bulges toward the skin side. The peripheral portion of the bottom is inclined and extends from the central portion of the bottom toward the non-skin side in the lateral direction. The high-density portion is provided in both the central portion and the peripheral portion. In both the central portion and the peripheral portion, a high-density portion with a large amount of oil per unit volume is provided. The high-density portion has a mountain-like shape, and it becomes easier for body fluid to migrate to the surroundings through the inclined peripheral portion while migrating to the non-skin side. Therefore, the body fluid that has entered the opening can be quickly migrated to the periphery of the opening.

[0021] According to a preferred embodiment, the invention according to Embodiment 13 may have the following features in the invention according to any of Embodiments 1 to 12. It has a side sheet that covers the skin-side surface of the side portion in the width direction of the top sheet. The side sheet has thermoplastic fibers. The thermoplastic fibers of the side sheet are arranged among the cellulose-based fibers of the top sheet. According to this embodiment, in the outer portion of the top sheet, a region where cellulose-based fibers and thermoplastic fibers are mixed is provided. The thermoplastic fibers promote the diffusion of body fluid, suppress the accumulation of body fluid between the cellulose-based fibers, promote the diffusion in the front-rear direction in which the side sheet extends, and can suppress the leakage of body fluid.

[0022] According to a preferred embodiment, the invention according to Embodiment 14 may have the following features in the invention according to any of Embodiments 1 to 13. It has a side sheet that covers the skin-side surface of the outer portion in the width direction of the top sheet. In the region where the top sheet and the side sheet overlap, a sheet high-density portion with a higher fiber density of the top sheet than the surroundings is provided. The sheet high-density portion has more oil arranged compared to the surroundings. When body fluid diffuses to the outer portion of the top sheet, further diffusion can be suppressed in the sheet high-density portion with a large amount of oil arranged, and the arrival of body fluid to the side sheet side can be suppressed.

[0023] In a preferred embodiment, the invention according to embodiment 15 may have the following features in the invention according to any of embodiments 1 to 14: The top sheet has an extended region that extends outward in the front-rear direction from the absorbent. The extended region is provided with a high-density end portion where the fiber density is higher than that of the surrounding area. The high-density end portion has a higher oil content compared to the surrounding area. When bodily fluids diffuse to the edge of the top sheet, further diffusion can be suppressed in the high-density end portion where a large amount of oil is present, thereby preventing bodily fluids from reaching the outer edge of the absorbent article.

[0024] (2) Absorptive articles according to the embodiment The absorbent article 1 according to the embodiment will be described below with reference to the drawings. In the following drawings, identical or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and the ratios of each dimension etc. may differ from those of reality. Therefore, specific dimensions etc. should be determined by referring to the following explanation. In addition, there may be parts where the relationships and ratios of dimensions differ between drawings. The absorbent article may be an absorbent article such as a sanitary napkin, panty liner, incontinence pad, or fecal pad. The absorbent article may be an article that is attached to the inside of a worn item such as underwear. The absorbent article 1 of the embodiment is a sanitary napkin.

[0025] Figure 1 is a plan view of the absorbent article 1 as seen from the skin side T1. Figure 2 is a cross-sectional view along line AA shown in Figure 1. Figure 3 is a schematic enlarged view of part B shown in Figure 1. Figure 4 is a schematic enlarged view of part C shown in Figure 2. The absorbent article 1 has a front-to-back direction L, a width direction W, and a thickness direction T, all of which are perpendicular to each other. In the front-to-back direction L of the absorbent article 1, the side that comes into contact with the wearer's lower abdomen is called the "front side," and the side that comes into contact with the wearer's buttocks is called the "back side." In the thickness direction T of the absorbent article 1, the side that comes into contact with the wearer's skin is called the "skin side," and the opposite side is called the "non-skin side." The absorbent article 1 has a crotch area S3, a front area S1, and a back area S2. The crotch area S3 is a region positioned opposite the wearer's excretory opening, such as the vaginal opening. When the absorbent article 1 is attached to the wearer's garment, the crotch area S3 is the area located between the legs of the garment. The front area S1 is located in front of the crotch area S3. The front edge of the front area S1 defines the front edge of the absorbent article 1. The rear area S2 is located behind the crotch area S3. The rear edge of the rear area S2 defines the rear edge of the absorbent article 1.

[0026] The absorbent article 1 comprises at least an absorbent core 30, a top sheet 10, and a back sheet 20, and has a vertically elongated shape. The top sheet 10 is made of any sheet-like material having a structure that allows liquid to pass through, such as a nonwoven fabric or woven fabric. The top sheet 10 comes into contact with the wearer's skin. The top sheet 10 will be described in detail later. The absorbent article may have a side sheet 15 that covers the outer part of the top sheet 10. The side sheet 15 covers the skin-side T1 of the side of the top sheet 10 in the width direction and is positioned on the wing 7. The back sheet 20 is a liquid-impermeable sheet positioned on the non-skin side of the absorbent core. The back sheet 20 can be made of a breathable resin film, spunbond, or a sheet in which a breathable resin film is bonded to a nonwoven fabric such as spunlace.

[0027] The absorbent body 30 may include an absorbent core 31 made of laminated absorbent material and a core wrap sheet 32 ​​that covers at least the skin-facing T1 surface of the absorbent core 31. The absorbent material constituting the absorbent core 31 can be made from, for example, hydrophilic fibers, pulp, and superabsorbent polymers (SAP). The core wrap sheet 32 ​​can be made from, for example, nonwoven fabric or tissue sheet. The core wrap sheet may cover both the skin-facing and non-skin-facing surfaces of the absorbent core. As a modification, the absorbent core 31 may not be covered by the core wrap sheet 32.

[0028] The absorbent article 1 may have a second sheet that contacts the non-skin side T2 of the top sheet 10. The second sheet may be positioned between the top sheet 10 and the absorbent core 31. The second sheet is a sheet for improving the draw-in of bodily fluids to the non-skin side and may be composed of a core wrap sheet 32 ​​or a sheet separate from the core wrap sheet. In this embodiment, the second sheet is composed of a core wrap sheet 32 ​​positioned closer to the skin than the absorbent core 31.

[0029] The absorbent article 1 may have wings 7. The wings 7 may be provided in the crotch area S3. The wings 7 extend outward in the width direction W from the absorbent core 31. The front edge of the wings 7 is defined by the base of the wings 7 and corresponds to the front portion of two recessed portions in the width direction W. The front edge of the wings 7 may define the boundary between the crotch area S3 and the front area S1. The rear edge of the wings 7 is defined by the base of the wings 7 and corresponds to the rear portion of two recessed portions in the width direction W. The rear edge of the wings 7 may define the boundary between the crotch area S3 and the rear area S2. In the case of an absorbent article 1 without wings 7, at the position where the length of the absorbent article 1 in the front-to-back direction L is longest, each of the regions obtained by dividing the absorbent article 1 into three equal parts in the front-to-back direction L may constitute the front area S1, the crotch area S3, and the rear area S2.

[0030] In this invention, the outer part refers to a portion occupying a certain range in the width direction W, including the outer edge in the width direction W, and the outer edge refers to the outer edge in the width direction W. In this invention, the inner part refers to a portion occupying a certain range in the width direction W, including the inner edge in the width direction W, and the inner edge refers to the inner edge in the width direction W. In this invention, the front end and rear end refer to a portion occupying a certain range in the front-rear direction L, including the edge in the front-rear direction L, and the front end edge and rear end edge refer to the edge in the front-rear direction L. The outer end includes the front end and rear end, and the outer end edge includes the front end edge and rear end edge. In addition, the inner edge includes the inner edge and extends along the front-rear direction L. The outer edge includes the outer edge and extends along the front-rear direction L. In this specification, the term "along the front-rear direction L" means a direction with an angle of less than 45° with respect to the front-rear direction L, and the term "along the width direction W" means a direction with an angle of less than 45° with respect to the width direction W.

[0031] The absorbent article 1 may have an adhesive portion for attaching it to the wearer's article. The adhesive portion is provided on the non-skin side T2 of the backsheet 20 and is an area where fastening means for attaching the absorbent article 1 to the wearer's article are provided. The adhesive portion may have at least one of a main adhesive portion 61 for attaching the area overlapping with the absorbent core 31 to the wearer's article, and a wing adhesive portion 62 for attaching the wing 7 to the wearer's article.

[0032] The top sheet 10 has cellulose fibers 11. Cellulose fibers 11 are fibers whose main component (for example, 50% or more by weight) is cellulose, and examples include plant fibers such as cotton and linen, regenerated fibers such as rayon, cupro, and lyocell, and synthetic fibers such as acetate. The top sheet 10 is mainly composed of cellulose fibers 11. Here, "mainly" means that the weight ratio of cellulose fibers 11 in the fibers of the top sheet is 50% or more. Alternatively, the top sheet 10 may be substantially composed only of cellulose fibers 11, and may also contain thermoplastic resin fibers or binder fibers at a weight ratio of less than 10%. As described above, cellulose fibers 11 have excellent liquid absorption and liquid retention properties. Therefore, while the top sheet 10 having cellulose fibers 11 has high liquid absorption and liquid retention properties, it may cause stickiness on the skin. The absorbent article of this embodiment is configured to suppress stickiness of the top sheet 10. Next, the configuration for suppressing stickiness of the top sheet 10 will be described in detail.

[0033] The cellulose fibers 11 contain oils, including at least one of the naturally derived oils linoleic acid, palmitic acid, and oleic acid. Linoleic acid, palmitic acid, and oleic acid are oils that exhibit water-repellent properties. The naturally derived oils are arranged within the fibers of the top sheet 10. In a form where the oil is applied only to the surface of the top sheet 10, once bodily fluids adhere to the surface of the top sheet 10, the oil may peel off, and the effect of the naturally derived oils may not be obtained when bodily fluids adhere to the surface of the top sheet 10 again. However, because the oils are arranged within the cellulose fibers 11, even if bodily fluids adhere to the surface of the top sheet 10, the oils within the fibers stick together, suppressing the shedding of the oils. Even after repeated absorption of bodily fluids, the water-repellent effect is maintained, and the stickiness of the top sheet 10 having cellulose fibers 11 can be suppressed.

[0034] At least one of the naturally derived oils, linoleic acid, palmitic acid, and oleic acid, may be located inside the surface of the cellulose fiber 11, or it may also be located on the surface of the cellulose fiber 11. Whether or not oil is located within the cellulose fiber 11 can be verified by DNA spectroscopy of the cellulose and oil. Because the top sheet 10 contains environmentally friendly naturally derived materials, it is gentle on the skin and reduces the environmental burden.

[0035] The cellulose fiber 11 may contain unbleached cotton. Unbleached cotton is chlorine-free cotton that has not undergone delignin treatment. Unbleached cotton is chlorine-free, has the natural color of cotton, and contains naturally derived oils. The top sheet 10 contains chlorine-free cotton and has the natural color of cotton (brown). Therefore, it can remind the user that the top sheet 10 is made of environmentally friendly, naturally derived materials. Thus, the user can understand that the absorbent article 1 is gentle on the skin and can use the absorbent article 1 with peace of mind.

[0036] As shown in Figure 3, the top sheet 10 may have seed hulls 12. The seed hulls 12 are the seed hulls of plants such as cotton and hemp. The seed hulls 12 are darker in color and more noticeable than the cellulose fibers 11. Therefore, the presence of the seed hulls 12 reminds the user that the top sheet 10 is made of environmentally friendly, naturally derived materials. Thus, the user can understand that the absorbent item 1 is gentle on the skin and use the absorbent item 1 with peace of mind. In addition, the presence of oil in the seed hulls themselves provides a water-repellent effect through the oil in the cellulose fibers 11 and the oil in the seed hulls, suppressing stickiness of the top sheet 10 which has cellulose fibers 11. Furthermore, the color of the seed hulls 12 is not a color that has been colored with dyes, but a naturally derived color, and color unevenness is likely to occur due to differences in the color and intensity of the seed hulls. Therefore, color unevenness is likely to occur in the top sheet 10. The color unevenness of the top sheet 10 makes it easier for the user to recognize that the top sheet 10 contains naturally derived materials.

[0037] The cellulose fiber 11 may be a colored fiber containing residual components derived from wood. The presence of colored fibers reminds the user that the top sheet 10 is made of environmentally friendly, naturally derived materials. Therefore, the user can understand that the absorbent material 1 is gentle on the skin and use the absorbent material with peace of mind. These colored fibers are not fibers colored with dyes, etc., but fibers that have the color of the raw material, wood. Unlike fibers colored with dyes, colored fibers containing naturally derived residual components are prone to color unevenness due to differences in wood color (black, brown, dark brown, etc.). Therefore, color unevenness is likely to occur in the top sheet 10. The color unevenness of the top sheet 10 makes it easier for the user to recognize that the top sheet 10 contains naturally derived materials.

[0038] The top sheet 10 may contain more oil than the core wrap sheet 32. That is, the weight of oil in the top sheet 10 may be greater than the weight of oil in the core wrap sheet 32. The core wrap sheet 32 ​​may contain less oil than the top sheet 10, or it may contain no oil at all. The weight of oil in the top sheet 10 includes naturally derived oils. At least a portion of the oil in the top sheet 10 is contained within the cellulose fibers 11, making it less likely to fall off. Furthermore, because the top sheet 10 contains a relatively large amount of oil, bodily fluids are more easily transferred from the top sheet 10 to the core wrap sheet 32. Therefore, stickiness caused by bodily fluids remaining on the surface of the top sheet 10 can be suppressed. In addition, the presence of a large amount of oil in the top sheet 10 can suppress the re-wetting of bodily fluids that have transferred to the core wrap sheet 32.

[0039] Furthermore, in a configuration in which the top sheet 10 and the core wrap sheet 32 ​​are in contact, the weight of the oil per unit area of ​​the core wrap sheet 32 ​​in contact with the top sheet 10 may be greater than the weight of the oil per unit area of ​​the core wrap sheet 32 ​​in the area located on the non-skin side of the absorbent core (not in contact with the top sheet 10). According to this embodiment, rewetting of bodily fluids that have migrated from the sheets located on the skin side of the absorbent core 31 (top sheet 10 and core wrap sheet 32) towards the absorbent core 31 can be suppressed.

[0040] The top sheet 10 may have more oil than the absorbent core 31. That is, the weight of oil in the top sheet 10 may be greater than the weight of oil in the absorbent core 31. At least a portion of the oil in the top sheet 10 is located within the cellulose fibers 11, making it less likely to fall off, and because the top sheet 10 has a relatively large amount of oil, bodily fluids are more easily transferred from the top sheet 10 to the absorbent core 31. Therefore, stickiness caused by bodily fluids remaining on the surface of the top sheet 10 can be suppressed. Furthermore, the presence of a large amount of oil in the top sheet 10 can suppress rewetting of bodily fluids that have already transferred to the absorbent core 31.

[0041] The weight of naturally derived oil in this invention can be calculated by the following method. The component containing naturally derived oil is impregnated with a solvent. Examples of solvents include toluene, xylene, cyclohexane, dipropyl ether, and acetone. The solvent is then evaporated, and the residue is left to stand for 24 hours in a constant temperature and humidity chamber at a temperature of 20±3°C and a humidity of 65±5%RH. After standing, the weight of the residue is measured.

[0042] The water retention ratio of the second sheet may be higher than that of the top sheet 10. Because the top sheet 10 is highly water-repellent due to the presence of oil, it does not easily retain body fluids, and can draw body fluids to the second sheet, which has higher water retention and is in contact with the non-skin side of the top sheet 10. Therefore, it is possible to suppress the residue of liquid on the top sheet 10 and suppress stickiness caused by body fluids remaining on the surface of the top sheet 10. The water retention ratio of the top sheet 10 may be between 0.5 and 3.5 times. The water retention ratio of the second sheet may be between 0.7 and 6.0 times.

[0043] The water retention ratio can be compared using the following measurement method. Remove the material to be measured from the absorbent material and cut the material to a size of 85 mm x 85 mm. If it is not possible to cut to this size, change the size to 70 mm x 100 mm, etc. Prepare five pieces of each material and measure the weight of the five pieces stacked together. This weight will be taken as the weight before water retention. Immerse in 1 L of distilled water for 30 seconds. Remove the five stacked pieces from the distilled water and place them on a mesh for 5 minutes. Next, using a centrifuge (top discharge type centrifuge H-130E special), dewater the five stacked pieces for 1 minute and 30 seconds under the conditions of 150 G and 763 rpm. After dewatering, measure the weight of the five stacked pieces. This weight will be taken as the weight after dewatering. Water retention ratio = weight after dehydration / weight before water retention

[0044] The oil content within the cellulose fibers 11 of the top sheet 10 only needs to contain at least naturally derived oils, and may also contain other oils. However, preferably, the oil content within the cellulose fibers 11 may contain only naturally derived oils. In other words, the oil content within the cellulose fibers 11 may contain only naturally derived oils and may not contain artificially composed oils. Examples of artificially composed oils other than naturally derived oils include known ones such as paraffin-based and silicone-based oils, and more specifically, those containing thearic acid compounds, such as stearamide, zinc stearate, calcium stearate, stearic acid diethanolamide, and magnesium stearate.

[0045] The top sheet 10 may be a laminated sheet comprising an upper layer mainly containing cotton fibers and a lower layer mainly containing synthetic resin fibers and located on the non-skin side of the upper layer. The upper layer may mainly contain cotton fibers (by weight ratio of 50% or more), preferably 100% by weight of cotton fibers, and more preferably 100% by weight of chlorine-unbleached raw cotton. Having 100% cotton fibers in the upper layer improves the feel against the skin, and having 100% by weight of chlorine-unbleached raw cotton provides the wearer with a sense of security. Furthermore, the lower layer, by containing synthetic resin fibers, makes it easier to suppress the rewetting of bodily fluids guided from the top sheet 10 to the absorbent core 31.

[0046] The absorbent article 1 may have embossed portions 80 formed by compressing at least the top sheet 10 and the absorbent material 30 in the thickness direction. The embossed portions 80 only need to compress at least the top sheet 10 and the absorbent material 30, and in the case of a form having a second sheet, the second sheet may also be compressed. The embossed portions 80 may be provided in pairs on both sides of the center CW in the width direction W of the absorbent article 1. According to this embodiment, bodily fluids can be smoothly drawn from the top sheet 10 to the non-skin side T2 via the embossed portions 80. Therefore, residual liquid on the top sheet 10 can be suppressed, and stickiness of the top sheet 10 having cellulose fibers 11 can be suppressed.

[0047] As shown in Figure 4, the absorbent article 1 may have a plurality of recesses 90 in which both the top sheet 10 and the absorbent material 30 are recessed toward the non-skin side T2 of the absorbent article 1. The recesses 90 are circular in plan view and are provided in a plurality at intervals. In this embodiment, the recesses 90 are spaced apart in the front-to-back direction L and in the width direction W, and are located in at least the crotch area S3. Each of the plurality of recesses 90 may have an opening 92 formed by a cut surface 91 connected to the top sheet 10 and the absorbent material 30, and a bottom portion 93 that constitutes the non-skin side T2 surface of the opening 92. The opening 92 is a region surrounded by a cut surface 91 extending in the thickness direction T. The bottom portion 93 is where the fibers of the top sheet 10 and the absorbent material of the absorbent material 30 are compressed before the opening 92 is formed. Therefore, the top sheet 10 of the bottom portion 93 is provided with a high-density portion 94, which has a higher fiber density than the top sheet 10 surrounding the recess 90. In this embodiment, the formation of the opening 92 allows bodily fluids to be smoothly drawn from the top sheet 10 side to the non-skin side T2. Furthermore, since the high-density portion 94 of the top sheet 10 is provided at the bottom 93, a large amount of oil is placed at the bottom 93 of the recess 90, making it easier to transfer bodily fluids from the cut surface 91 on the side of the opening 92 to the surrounding absorbent core 31. In addition, the absorbent material at the bottom may also have portions with a higher density of absorbent material than the absorbent material surrounding the recess.

[0048] The central portion 95 of the bottom portion 93 is convex, bulging toward the skin side T1, and the peripheral portion 96 of the bottom portion 93 may be inclined, extending laterally from the central portion 95 toward the non-skin side T2. The high-density portion 94 is provided in both the central portion 95 and the peripheral portion 96. In this embodiment, the high-density portion 94, which has a large amount of oil per unit volume, is provided in both the central portion 95 and the peripheral portion 96. The high-density portion 94 has a mountain-like shape, making it easier for bodily fluids to move toward the non-skin side T2 and then to move to the surrounding area via the inclined peripheral portion 96. Therefore, bodily fluids that have entered the opening 92 can be quickly moved toward the area around the opening 92. The high-density portion 94 only needs to be provided in at least a part of the central portion 95 and at least a part of the peripheral portion 96, but preferably it may be provided in the entire bottom portion 93. Although the high-density section 94 is provided in both the central section 95 and the peripheral section 96, the density of the top sheet 10 in the peripheral section 96 may be higher than the density of the top sheet 10 in the central section.

[0049] The area ratio of the adhesive joining the top sheet 10 and the core wrap sheet 32 ​​may be higher than the area ratio of the adhesive joining the core wrap sheet 32 ​​and the absorbent core 31. Generally, adhesives are hydrophobic. By placing the adhesive on the top sheet 10 side in a high area ratio, the hydrophobicity of the adhesive makes it less likely for liquid to remain on the top sheet side, improving the transfer of bodily fluids from the top sheet 10 to the absorbent core 31 side, and suppressing rewetting of bodily fluids that have been drawn in. The area ratio of the adhesive can be calculated by the area of ​​adhesive placed per unit area.

[0050] The adhesive used to bond the top sheet 10 and the core wrap sheet 32 ​​in this embodiment includes both a striped pattern AR1 extending in the front-to-back direction and spaced apart in the width direction, and an Ω-shaped pattern AR2 consisting of a series of Ω shapes extending in the front-to-back direction L and arranged side-by-side in the width direction. The striped pattern AR1 is applied to the non-skin side of the top sheet 10 and is positioned only inside the outer edge of the top sheet 10 in the width direction. The Ω-shaped pattern AR2 is applied to the skin side of the laminate formed by the lamination of the back sheet 20 and the absorber 30, and extends beyond the top sheet 10 outward in the width direction W. The Ω-shaped pattern AR2 bonds the top sheet 10 and the core wrap sheet 32, as well as the side sheet 15 and the back sheet 20. The Ω-shaped pattern AR2 only needs to have a lower adhesive area ratio than the striped pattern AR1, and is not limited to the Ω shape; other shapes (e.g., spiral shape) are also acceptable. Furthermore, in a configuration where both pattern AR1 and pattern AR2 are arranged as an adhesive for joining the top sheet 10 and the core wrap sheet 32, it is sufficient that the combined area ratio of pattern AR1 and pattern AR2 is higher than the area ratio of the adhesive for joining the core wrap sheet 32 ​​and the absorbent core 31.

[0051] Adhesive may be applied between the core wrap sheet 32 ​​and the absorbent core 31. The adhesive joining the core wrap sheet 32 ​​and the absorbent core 31 may have an Ω-shaped pattern that extends in the front-to-back direction L and is arranged in the width direction, but does not have to have a striped pattern. The Ω-shaped pattern between the core wrap sheet 32 ​​and the absorbent core 31 only needs to have a lower adhesive area ratio than pattern AR1, and is not limited to an Ω shape, but may be other shapes (for example, a spiral shape).

[0052] The side sheet 15 may have thermoplastic fibers. The side sheet 15 does not have to have cellulose fibers 11. The thermoplastic fibers of the side sheet 15 may be arranged between the cellulose fibers 11 of the top sheet 10. The side sheet 15 covers the skin-facing surface of the outer part of the top sheet 10, and in the region where the side sheet 15 and the top sheet 10 overlap, some of the thermoplastic fibers of the side sheet 15 may be arranged within the top sheet 10. According to this embodiment, a region in which thermoplastic fibers are mixed is provided on the side of the top sheet 10. The thermoplastic fibers promote the diffusion of body fluids, suppressing the accumulation of body fluids between the cellulose fibers 11, while also promoting diffusion in the front-to-back direction L in which the side sheet 15 extends, thereby suppressing seepage.

[0053] The top sheet 10 may have an extended region R10 that extends outward in the front-to-back direction L from the absorbent 30. The extended region includes R10, a region in front of the front edge of the absorbent 30, and a region behind the rear edge of the absorbent 30. The extended region R10 may be provided with an end-high density portion 13 in which the fiber density is higher than that of the surrounding area. The end-high density portion 13 has a higher oil content compared to the surrounding area. When bodily fluids diffuse to the outer edge of the top sheet 10, further diffusion can be suppressed in the end-high density portion 13 in which oil is concentrated, thereby preventing the bodily fluids from reaching the outer edge of the absorbent article 1. The end-high density portion 13 may be composed of, for example, a welded portion formed by welding the top sheet 10 and the back sheet 20 together.

[0054] In the modified version, the top sheet may have multiple openings that penetrate in the thickness direction of the top sheet. The openings only need to be formed over the entire thickness direction of the top sheet. Preferably, the openings are formed over the entire surface of the top sheet in a plan view, and preferably, it may be a so-called mesh sheet. A mesh sheet is a sheet in which the openings are arranged in the front-to-back direction and also in the width direction. The diameter of the openings is not limited, but preferably it is 1 mm or more and 3 mm or less. The formation of the openings makes it easier to smoothly draw bodily fluids from the top sheet side to the non-skin side. Therefore, it is possible to suppress the residue of fluid on the top sheet and suppress stickiness caused by bodily fluids remaining on the surface of the top sheet.

[0055] In the modified version, the skin-facing surface of the top sheet may be provided with a ridged groove section including ridges and grooves. The ridged groove section is formed by arranging multiple ridges and grooves alternately in a second direction that is both planar and perpendicular to the first direction, with ridges and grooves extending in a first direction along the planar direction. The planar direction is a concept that includes the front-to-back direction L and the width direction W. The ridged groove section is formed regularly by the processing of the sheet and does not include irregularities caused by the fibers that make up the nonwoven fabric. By providing the ridged groove section on the top sheet, bodily fluids can be diffused in the planar direction by the ridged groove section, and the bodily fluids can be guided to the absorbent side over a wide area. Bodily fluids discharged onto the top sheet can be quickly guided to the absorbent side, suppressing the residue of fluid on the top sheet and suppressing stickiness caused by bodily fluids remaining on the surface of the top sheet.

[0056] In the modified example, a high-density sheet area may be provided in the region where the top sheet and the side sheet overlap, where the fiber density of the top sheet is higher than that of the surrounding area. The high-density sheet area has a higher oil content compared to the surrounding area. When bodily fluids diffuse to the side of the top sheet, further diffusion can be suppressed in the high-density sheet area where the oil content is higher, thereby preventing the bodily fluids from reaching the side sheet. The high-density sheet area may be composed of, for example, a compressed sheet area formed by compressing the side sheet 15 and the top sheet 10 in the thickness direction. The high-density sheet area may be composed of, for example, a welded area formed by welding the top sheet 10 and the side sheet together.

[0057] (3) Performance evaluation test of the top sheet Next, the diffusion performance of bodily fluids and the rewetting rate of the top sheet were evaluated using the absorbent article according to the example and the absorbent article according to the comparative example. The top sheet according to the example has cellulose fibers 11, and an oil containing at least one of the naturally derived oils linoleic acid, palmitic acid, and oleic acid is arranged within the cellulose fibers 11. On the other hand, the top sheet according to the comparative example has cellulose fibers 11, and the oil containing at least one of the naturally derived oils linoleic acid, palmitic acid, and oleic acid is applied to the skin-facing surface of the top sheet, rather than within the fibers. The top sheet according to the example and the top sheet according to the comparative example have the same configuration except for the arrangement of the oil.

[0058] First, prepare two samples each for the comparative example and the example. For the comparative example, apply 0.03 g of Cottonseed Oil (manufactured by Fujifilm Wako Pure Chemical Industries) to an area of ​​60 mm in the front-to-back direction and 30 mm in the width direction. Use the Airbrush Workset Meteor (manufactured by AIRTEX) for application. Next, as the first test, drop 2 ml of horse blood (as a bodily fluid) onto each sample and check the penetration time (the time it takes for the bodily fluid dropped onto the top sheet to disappear from the top sheet), the diffusion range in the front-to-back direction, and the diffusion range in the width direction. Then, one minute after the first drop, as the second test, drop 2 ml of horse blood and check the penetration time, the diffusion range in the front-to-back direction, and the diffusion range in the width direction. One minute after the second drop, drop a third time, and thereafter repeat dropping 2 ml and checking every minute, for a total of five drops. One minute after the fifth drop (five minutes after the first drop), filter paper was placed on top of the absorbent material's top sheet, a weight was placed on top of the filter paper, and the rewetting rate was checked after one minute. The rewetting rate was calculated as the weight of the body fluid absorbed by the filter paper divided by the weight of the body fluid dropped.

[0059] The test results are shown in Table 1. [Table 1]

[0060] The absorbent article in the comparative example had a larger diffusion area of ​​body fluid than the absorbent article in the example, regardless of the number of drops. Furthermore, the diffusion area of ​​the absorbent article in the comparative example increased with each additional drop of body fluid, and the ratio of the diffusion area after the fifth drop to the diffusion area after the first drop was 2.75 times. On the other hand, the diffusion area of ​​the absorbent article in the example also increased with each additional drop of body fluid, but the rate of increase was small, and the ratio of the diffusion area after the fifth drop to the diffusion area after the first drop was 1.69 times. In addition, the rewetting rate of the absorbent article in the example was lower than that of the absorbent article in the comparative example.

[0061] Although the present invention has been described in detail using the embodiments described above, it will be clear to those skilled in the art that the present invention is not limited to the embodiments described herein. The present invention can be implemented in modified and altered forms without departing from the spirit and scope of the invention as defined by the claims. Therefore, the description herein is for illustrative purposes only and is not intended to be restrictive in any way to the present invention. [Explanation of Symbols]

[0062] 1: Absorbent articles 10: Top sheet 11: Cellulose fiber 12: Seed husk 13: Edge high density part 15: Side Seat 20: Back seat 30: Absorbent material 31: Absorption core 32: Core Wrap Sheet 90: recess 91: Cut surface 92: Opening 93: Bottom 94: High density area 95: Central part 96: Peripheral area R10: Extended area L: Anteroposterior direction T: Thickness direction T1: Skin side T2: Non-skin side W: width direction

Claims

1. The front-to-back, width, and thickness directions are mutually orthogonal to each other. An absorbent body having an absorbent material, An absorbent article having a top sheet positioned on the skin side of the absorbent material and in contact with the wearer's skin, The aforementioned top sheet has cellulose fibers, An absorbent article wherein an oil containing at least one of the naturally derived oils, linoleic acid, palmitic acid, and oleic acid, is arranged within the cellulose fiber.

2. The absorbent article according to claim 1, wherein the cellulose fiber comprises generated cotton.

3. The absorbent article according to claim 1, wherein the top sheet has seed hulls.

4. The absorbent article according to claim 1, wherein the cellulose fiber is a colored fiber containing residual components derived from wood.

5. The absorbent body comprises an absorbent core made of laminated absorbent material and a core wrap sheet covering at least the skin-facing side of the absorbent core. The absorbent article according to any one of claims 1 to 4, wherein the top sheet has a higher oil content than the core wrap sheet.

6. The absorbent article according to claim 5, wherein the top sheet has a higher oil content than the absorbent core.

7. The top sheet has a second sheet that contacts the non-skin side surface, The absorbent article according to any one of claims 1 to 4, wherein the water retention ratio of the second sheet is higher than that of the top sheet.

8. The absorbent article according to any one of claims 1 to 4, wherein the oil content within the cellulose fiber consists solely of the naturally derived oil.

9. The absorbent body comprises an absorbent core made of laminated absorbent material and a core wrap sheet covering at least the skin-facing side of the absorbent core. The absorbent article according to any one of claims 1 to 4, wherein the area ratio of the adhesive that joins the top sheet and the core wrap sheet is higher than the area ratio of the adhesive that joins the core wrap sheet and the absorbent core.

10. The absorbent article according to any one of claims 1 to 4, wherein the top sheet has a plurality of openings that penetrate in the thickness direction of the top sheet.

11. The absorbent article has a top sheet and an absorbent body, both having a plurality of recesses that are recessed toward the non-skin side of the absorbent article. Each of the plurality of recesses has an opening formed by a cross-section connecting the top sheet and the absorbent, and a bottom portion that constitutes the non-skin side of the opening. The absorbent article according to any one of claims 1 to 4, wherein the top sheet at the bottom is provided with a high-density portion having a higher fiber density than the top sheet surrounding the recess.

12. The central part of the bottom is convex, bulging towards the skin. The peripheral edge of the bottom portion is inclined, extending laterally from the central portion of the bottom portion toward the non-skin side. The absorbent article according to claim 11, wherein the high-density portion is provided in both the central portion and the peripheral portion.

13. The top sheet has side sheets that cover the skin-facing surface of the side portion in the width direction, The aforementioned side sheet has thermoplastic fibers, The absorbent article according to any one of claims 1 to 4, wherein the thermoplastic fibers of the side sheet are arranged between the cellulose fibers of the top sheet.

14. The top sheet has side sheets that cover the skin-facing surface of the side portion in the width direction, The absorbent article according to any one of claims 1 to 4, wherein a high-density sheet portion is provided in the region where the top sheet and the side sheet overlap, in which the fiber density of the top sheet is higher than that of the surrounding area.

15. The top sheet has an extended region that extends outward in the front-rear direction compared to the absorbent, The absorbent article according to any one of claims 1 to 4, wherein the extended region is provided with an end-high-density portion having a higher fiber density than the surrounding area.

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