Absorbent article and package for absorbent article

Abstract

The present invention provides an absorbent article capable of easily handling pulp having colored cellulose fibers. An absorbent article (1) is provided with an absorbent core (31) having pulp (33). The pulp has colored cellulose fibers (34). The color difference ΔＥ between the pulp that has been subjected to an ultraviolet irradiation test for 48 hours and the pulp that has not been subjected to the ultraviolet irradiation test is 10.0 or less.

Description

Absorbent article and packaging of absorbent article

[0001] The present invention relates to an absorbent article comprising pulp having colored cellulose fibers.

[0002] An absorbent article has pulp as a material for absorbing body fluids. Generally, bleached pulp that has been bleached is used as the pulp of the absorbent article. Since bleached pulp is obtained by whitening colored wood, it generally has a problem of high environmental impact. In order to reduce such an environmental load, thermomechanical pulp manufactured by mechanically grinding and shredding wood has been provided (see, for example, Patent Document 1).

[0003] Japanese Patent Laid-Open No. 56-53745

[0004] According to such thermomechanical pulp, the environmental load is small. However, thermomechanical pulp generally has a certain degree of residual components derived from wood that discolor upon ultraviolet irradiation, which may make it difficult to handle.

[0005] The present invention has been made in view of such problems, and an object thereof is to provide an absorbent article that can easily handle pulp having colored cellulose fibers.

[0006] An absorbent article according to one aspect includes an absorbent core having pulp. The pulp has colored cellulose fibers. The color difference ΔE between the pulp subjected to a 48-hour ultraviolet irradiation test and the pulp not subjected to the ultraviolet irradiation test is 10.0 or less.

[0007] An absorbent article according to another aspect includes an absorbent core having pulp, a topsheet disposed closer to the skin side than the absorbent core and contacting the wearer's skin, and a core wrap sheet covering at least the skin-side surface of the absorbent core. The pulp has colored cellulose fibers. The core wrap sheet is colored. The absorbent article has a recess in which both the topsheet and the absorbent core are recessed toward the non-skin side of the absorbent article. Each of the recesses has a recess wall portion that extends in the thickness direction and is continuous with the topsheet and the absorbent core, and a bottom portion that constitutes the non-skin-side surface of the recess.

[0008] An absorbent article according to yet another embodiment comprises an absorbent core having pulp, and a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin. The pulp has colored cellulose fibers. The absorbent core has a fiber mass which is an aggregate of fibers piled up in a mass. Both the top sheet and the absorbent core have recesses that are indented toward the non-skin side of the absorbent article. Each of the recesses has a recessed wall portion that extends in the thickness direction, connected to the top sheet and the absorbent core, and a bottom portion that constitutes the non-skin side surface of the recess.

[0009] A package for an absorbent article according to one embodiment comprises an absorbent article and a packaging sheet for individually packaging the absorbent article. The packaging sheet has a packaging embossed portion formed by compressing the packaging sheet in the thickness direction. In a plan view of the package for the absorbent article, the brightness of the wall portion of the recess is lower than the brightness of the packaging embossed portion.

[0010] Figure 1 is a plan view of the absorbent article as seen from the skin side. Figure 2 is a cross-sectional view along the line A-A 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. Figure 5 is a plan view of the packaging of the absorbent article.

[0011] (1) Outline of Embodiments The following matters will become clear from the description in this specification and the accompanying drawings. The invention according to Embodiment 1 is an absorbent article. The absorbent article comprises an absorbent core having pulp. The pulp has colored cellulose fibers. The color difference ΔE between pulp that has undergone a 48-hour ultraviolet irradiation test and pulp that has not undergone an ultraviolet irradiation test is 10.0 or less. According to this embodiment, the color difference ΔE between pulp that has undergone a 48-hour ultraviolet irradiation test and pulp that has not undergone an ultraviolet irradiation test is 10.0 or less, so discoloration due to ultraviolet irradiation, i.e., over time can be suppressed, making it easy to maintain a consistent quality such as appearance, and making the pulp easy to handle.

[0012] In a preferred embodiment, the invention according to Embodiment 2 may have the following features in the invention according to Embodiment 1: The water absorption ratio of the pulp is 22 times or more and 28 times or less. The water absorption ratio of the pulp is high, at 22 times or more, and can sufficiently absorb bodily fluids. Therefore, the absorption performance of the pulp can be improved. In addition, since the water absorption ratio of the pulp is 28 times or less, the amount of bodily fluids absorbed can be suppressed, and twisting of the absorption core caused by excessive absorption can be suppressed.

[0013] 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 water retention ratio of the pulp is 5 times or more and 7 times or less. According to this embodiment, the water retention ratio of the pulp is high at 5 times or more, so it can sufficiently retain bodily fluids, and because the water retention ratio of the pulp is 7 times or less, twisting after absorption can be further suppressed.

[0014] In a preferred embodiment, the invention according to Embodiment 4 may have the following features in the invention according to any one of Embodiments 1 to 3: The average fiber length of the pulp is less than 3.0 mm. According to this embodiment, the average fiber length of the pulp is less than 3.0 mm, and because the fiber length is relatively short, it is easy to secure the surface area of ​​the pulp that comes into contact with bodily fluids, and it is easy to further improve the absorption performance of the pulp.

[0015] In a preferred embodiment, the invention according to Embodiment 5 may have the following features in the invention according to any of Embodiments 1 to 4: a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin, and an embossed portion formed by compressing at least the top sheet and the absorbent core in the thickness direction. In a plan view of the absorbent article, the brightness of the outer edge of the embossed portion is lower than the brightness of the central portion inside the outer edge of the embossed portion. According to this embodiment, the color of the outline (outer edge) of the embossed portion is darker, creating a contrast in the plan view of the absorbent article, which can give the user an image of bodily fluid absorption. Also, the distance between fibers is shorter at the darker outer edge than at the central portion. Therefore, the thickness of the central portion is greater than the thickness of the outer edge, and in a cross-sectional view, the surface of the embossed portion tends to be convex, with the central portion bulging more than the outer edge. Bodily fluids guided to such an embossed portion are guided along the convex surface to the outer edge side of the embossed portion and are easily guided to the absorbent core surrounding the embossed portion.

[0016] 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 absorbent article comprises a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin, and a core wrap sheet covering at least the skin-side surface of the absorbent core. The color of the core wrap sheet, the color of the top sheet, and the color of the cellulose fibers are brown. The brightness of the core wrap sheet and the brightness of the colored cellulose fibers are lower than the brightness of the top sheet. According to this embodiment, because the color of the core wrap sheet, the color of the top sheet, and the colored cellulose fibers are brown, it is easy for the user to recognize that the absorbent article has a reduced environmental impact. Furthermore, because the color of the core wrap sheet, which is located on the non-skin side of the top sheet, and the color of the colored cellulose fibers in the pulp are darker, it is possible to give the user the image that bodily fluids are drawn to the non-skin side.

[0017] In a preferred embodiment, the invention according to embodiment 7 may have the following features in the invention according to any of embodiments 1 to 6. The absorbent article has a top sheet and an absorbent core, both having recesses that are indented toward the non-skin side of the absorbent article. Each of the recesses has a recessed wall portion that extends in the thickness direction, connected to the top sheet and the absorbent core, and a bottom portion that constitutes the non-skin side surface of the recess. In a plan view of the absorbent article, the brightness of the bottom portion is lower than the brightness of the recessed wall portion. According to this embodiment, since the color of the bottom portion is darker than the color of the recessed wall portion, a color gradient can be provided in the cross-sectional direction, giving the user the impression that the darker bottom portion absorbs more. The user can gain a sense of security regarding the absorption performance from the image of bodily fluids being drawn toward the non-skin side.

[0018] In a preferred embodiment, the invention according to embodiment 8 may have the following features in the invention according to embodiment 7. The absorbent article has a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin, and an embossed portion formed by compressing at least the top sheet and the absorbent core in the thickness direction. In a plan view of the absorbent article, the brightness of the bottom of the recess is lower than the brightness of the bottom of the non-skin side surface of the embossed portion. According to this embodiment, because the color of the bottom of the recess is relatively dark, the user can gain a greater sense of security regarding the absorption performance by imagining that bodily fluids are drawn to the non-skin side by the recess.

[0019] In a preferred embodiment, the invention according to embodiment 9 may have the following features in the invention according to embodiment 7 or embodiment 8: It has a top opening that penetrates only the top sheet. In a plan view of the absorbent article, the brightness of the bottom of the recess is lower than the brightness of the top opening. According to this embodiment, because the brightness of the top opening is low, the user perceives the area where the top sheet is placed as a bright area and easily associates the top sheet with ventilation. Because the brightness of the bottom of the recess is low, the user easily associates the recess with absorption.

[0020] In a preferred embodiment, the invention according to embodiment 10 is a package for an absorbent article. The package for an absorbent article comprises an absorbent article according to any one of embodiments 7 to 9 and a packaging sheet for individually packaging the absorbent article. The packaging sheet has a packaging embossed portion formed by compressing the packaging sheet in the thickness direction. In a plan view of the unfolded state of the package for the absorbent article, the brightness of the recessed portion is lower than the brightness of the packaging embossed portion. According to this embodiment, the packaging embossed portion of the packaging sheet is light in color, prioritizing a sense of unity throughout the packaging sheet and giving a hygienic image, while the recessed portion is dark in color, evoking an image of absorption.

[0021] The invention according to embodiment 11 is an absorbent article. The absorbent article comprises an absorbent core having pulp, a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin, and a core wrap sheet covering at least the skin-side surface of the absorbent core. The pulp has colored cellulose fibers. The core wrap sheet is colored. The absorbent article has recesses in both the top sheet and the absorbent core that are recessed toward the non-skin side of the absorbent article. Each of the recesses has a recessed wall portion extending in the thickness direction, connected to the top sheet and the absorbent core, and a bottom portion that constitutes the non-skin side surface of the recess. The skin side of the absorbent core is covered with a colored core wrap sheet. Therefore, even if the colored cellulose fibers change color over time, the discoloration becomes less noticeable, making it easier to maintain a consistent appearance and other quality, and making the pulp easier to handle. Furthermore, the absorbent article is provided with recesses. The recessed area, where both the top sheet and the absorbent core are indented toward the non-skin side of the absorbent material, is easily visible to the user when viewing the absorbent material from the skin side, making it easy for the user to notice. By focusing on the recessed area, even if the colored cellulose fibers change color over time, the discoloration becomes less noticeable, making it easier to maintain a consistent appearance and quality, and making the pulp easier to handle.

[0022] The invention according to embodiment 12 is an absorbent article. The absorbent article comprises an absorbent core having pulp and a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin. The pulp has colored cellulose fibers. The absorbent core has fiber masses, which are aggregates of fibers piled up in a mass. Both the top sheet and the absorbent core have recesses that are indented toward the non-skin side of the absorbent article. Each of the recesses has a recessed wall portion that extends in the thickness direction, connected to the top sheet and the absorbent core, and a bottom portion that constitutes the non-skin side surface of the recess. The absorbent core has fiber masses. Fiber masses are aggregates of fibers piled up in a mass, and are easily noticeable compared to the surrounding fibers, making them easy for the user to notice. Furthermore, the recesses, both the top sheet and the absorbent core, are indented toward the non-skin side of the absorbent article, making them easily noticeable when viewed from the skin side of the absorbent article by the user, and thus easy for the user to notice. By having the user focus on at least one of the recesses and the fiber masses, even if the colored cellulose fibers change color over time, the discoloration becomes less noticeable, making it easier to maintain a consistent appearance and quality, and making the pulp easier to handle.

[0023] (2) Absorbent Articles According to Embodiments Hereinafter, absorbent article 1 according to embodiments will be described 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 description. 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. Absorbent article 1 of the embodiment is a sanitary napkin.

[0024] 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 the line A-A 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, for example, 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.

[0025] The absorbent article 1 comprises at least an absorbent body 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 a woven fabric. The top sheet 10 is located on the skin side T1 of the absorbent body 30 (absorbent core 31) and 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 arranged on the wing 7.

[0026] The top sheet 10 may contain cellulose fibers. Cellulose fibers 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. Here, "mainly" means that the weight ratio of cellulose fibers in the fibers of the top sheet is 50% or more. Oils containing at least one of the naturally derived oils, linoleic acid, palmitic acid, and oleic acid, may be arranged within the cellulose fibers. Linoleic acid, palmitic acid, and oleic acid are oils that exhibit water repellency. Because oils are arranged within the cellulose fibers, 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, and even after repeated absorption of bodily fluids, the water-repellent effect is maintained, suppressing stickiness of the top sheet 10 having cellulose fibers. The backsheet 20 is a liquid-impermeable sheet. The backsheet 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 having pulp as an absorbent material, and a core wrap sheet 32 ​​covering at least the skin-side T1 surface of the absorbent core 31. The composition of the absorbent core 31 will be described in detail later. The core wrap sheet 32 ​​can be made of, for example, nonwoven fabric or tissue sheet. The core wrap sheet 32 ​​may cover both the skin-side T1 surface and the non-skin-side T2 surface of the absorbent core 31. As a modified example, 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 T2 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 on the skin side T1 of the absorbent core 31.

[0029] The absorbent article 1 may have embossed portions 80 formed by compressing at least the top sheet 10 and the absorbent core 31 in the thickness direction. The embossed portions 80 only need to compress at least the top sheet 10 and the absorbent core 31, and in the case of a configuration 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.

[0030] 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.

[0031] In this invention, the outer part is a portion occupying a certain range in the width direction W, including the outer edge in the width direction W, and the outer edge is the outer edge in the width direction W. In this invention, the inner part is a portion occupying a certain range in the width direction W, including the inner edge in the width direction W, and the inner edge is the inner edge in the width direction W. In this invention, the front end and rear end are portions 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 are the edges 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.

[0032] The absorbent article 1 may have an adhesive portion for attaching the absorbent article 1 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 fastening the area overlapping with the absorbent core 31 to the wearer's article, and a wing adhesive portion 62 for fastening the wing 7 to the wearer's article.

[0033] The pulp 33 of the absorbent core 31 contains colored cellulose fibers 34. The pulp 33 only needs to mainly contain colored cellulose fibers 34, but may also contain non-colored cellulose fibers. Here, "mainly" means that the weight ratio of colored cellulose fibers in the pulp is 50% or more. Preferably, the pulp 33 may be composed only of colored cellulose fibers 34. The color of the cellulose fibers may be due to residual components derived from wood in the pulp, and does not have to be a color achieved by dyes, etc. Colored cellulose fibers containing residual components derived from wood have a lower environmental impact compared to bleached pulp (white pulp) that has undergone bleaching treatment. In addition, by visually identifying the colored cellulose fibers, users can recognize that the absorbent core 31 contains wood-derived materials, making it easier for them to use the absorbent article 1 with peace of mind. Furthermore, cellulose fibers containing residual components derived from wood have a large amount of residue on the surface of the fibers, making it more difficult to form hydrogen bonds compared to bleached pulp, and thus the pulp can be easily crushed into a good state, i.e., finely crushed and that state can be easily maintained. Therefore, it is easier to secure a contact area between the pulp and bodily fluids, and the absorption performance of bodily fluids can be improved.

[0034] The pulp having colored cellulose fibers in this embodiment is configured to be easily handled. There are three main configurations for easily handling the pulp. The absorbent article of the first configuration is configured so that the pulp does not deteriorate easily over time. Specifically, the color difference ΔE between pulp that has undergone a 48-hour UV irradiation test and pulp that has not undergone a UV irradiation test is 10.0 or less. Since this color difference ΔE is 10.0 or less, discoloration due to UV irradiation, i.e., discoloration over time, is suppressed. Because the pulp is less prone to discoloration, it is easier to maintain a consistent quality in terms of appearance, etc., and the pulp becomes easier to handle.

[0035] The color difference ΔE can be measured by the following method. Prepare two 2g samples of the pulp to be measured. Place the first sample in a black plastic bag to protect it from ultraviolet light during the test. Place the second sample in a fade meter without placing it in a black plastic bag. The irradiation conditions for the fade meter should be as follows: Irradiance: 60 W / m ２- Irradiation time: 48 hours (equivalent to 12 days of sunlight irradiation) A 48-hour UV irradiation test will be conducted, and the color difference between Sample 1 and Sample 2 will be calculated using a color difference meter (Color Difference Meter CR-400, manufactured by KONICA MINOLTA). The color difference will be measured at three locations for each sample, and the average value will be used.

[0036] The color difference ΔE can be determined by measuring the color of two points (two regions) to be measured using a commercially available colorimeter and comparing the numerical values ​​obtained based on the CIE 1976 (L*a*b*) color space as defined in JIS Z 8781. Specifically, when the difference in L* values ​​between the two points to be measured is ΔL*, the difference in a* is Δa*, and the difference in b* values ​​is Δb*, the color difference ΔE = [(ΔL*) 2 +(Δa*) 2 +(Δb*) 2 ] 1 / 2 It is determined by [method].

[0037] The pulp may have a low lignin content, which helps to suppress deterioration over time. More specifically, the weight percentage of lignin in the pulp may be 10% or less, preferably 5% or less. Furthermore, the pulp may be oxygen-bleached and not undergo deligninization (chlorine bleaching).

[0038] The second form of the absorbent article has a colored core wrap sheet covering at least the skin-facing side of the absorbent core, and the absorbent article has a recess 90 in which both the top sheet and the absorbent core are recessed toward the non-skin side of the absorbent article. The skin-facing side of the absorbent core is covered with a colored core wrap sheet. Therefore, even if the colored cellulose fibers change color over time, the discoloration becomes less noticeable, making it easier to maintain a consistent appearance and quality, and making the pulp easier to handle. The absorbent article is also provided with a recess. The recess is in which both the top sheet and the absorbent core are recessed toward the non-skin side of the absorbent article, making it easily noticeable when viewed from the skin side of the absorbent article by the user, and easy for the user to focus on. By focusing on the recess, even if the colored cellulose fibers change color over time, the discoloration becomes relatively less noticeable, making it easier to maintain a consistent appearance and quality, and making the pulp easier to handle. The configuration of the recess 90 will be described in detail later.

[0039] The third form of absorbent article comprises an absorbent core having pulp and a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin. The pulp has colored cellulose fibers. The absorbent core has fiber masses, which are aggregates of fibers piled up in a mass. Both the top sheet and the absorbent core have recesses that are indented toward the non-skin side of the absorbent article. Each recess has a recessed wall portion that extends in the thickness direction, connected to the top sheet and the absorbent core, and a bottom portion that forms the non-skin side surface of the recess. The absorbent core has fiber masses. Fiber masses are aggregates of fibers piled up in a mass, making them more noticeable than the surrounding fibers and easier for the user to notice. In particular, fiber masses of colored cellulose fibers are more noticeable because their color is darker than the surrounding fibers. Also, the recesses, both the top sheet and the absorbent core, are indented toward the non-skin side of the absorbent article, making them easily noticeable when viewed from the skin side of the absorbent article by the user, and easy for the user to notice. By having the user focus on at least one of the recesses and the fiber masses, even if the colored cellulose fibers change color over time, the discoloration becomes less noticeable, making it easier to maintain a consistent appearance and quality, and making the pulp easier to handle.

[0040] As shown in Figure 4, the fiber clumps 35 are portions where multiple fibers are clustered together in a ball-like manner. The fiber clumps 35 are portions that, for example, when a pulp sheet is crushed by a saw mill, are separated from the pulp sheet not by the hardwood pulp fibers being broken down one by one, but by the fibers being clustered together in a ball-like manner in a clump (also called a "knot"). The fiber clumps 35 may have a central portion where the fibers are densely clustered, and a napped portion around the central portion where the density is lower than in the central portion. The napped portion 102 is formed when the portions where fibers are intertwined in the pulp sheet are peeled off. In other words, a pulp sheet is formed by the dense clustering of multiple such fiber clumps 35, and when the pulp sheet is scraped by a saw mill, the intertwined portions between adjacent fiber clumps 35 are peeled off, separating them into individual fiber clumps 35, and the peeled portions become napped portions.

[0041] In this embodiment, a sample obtained by crushing a pulp sheet was separated by fiber size using a sieve shaker (for example, a sieve shaker SS-HK60 manufactured by AS ONE Corporation) in accordance with the test method specified in JIS K 0069, and those that met the following conditions were designated as "fiber mass 35". First, the sample was placed on a 14-mesh sieve provided on the sieve shaker. The "mesh" refers to a standard sieving wire mesh as specified in JIS Z8801, and for example, a 14-mesh sieve has an opening of 1.18 mm, a wire diameter of 0.63 mm, and an open area of ​​42.3%. A cylinder with the same diameter as the sieve was placed below the mesh, and a suction device (for example, a Wonder Gun W101 manufactured by Osawa & Company: minimum inner diameter of suction 22 mm, pressure 0.5 MPa) was installed by making holes in the side of the cylinder at a height of 70 mm below the mesh to prevent gaps. Furthermore, an air ejection device (for example, TONE Corporation's Air Duster Gun AG-101: nozzle length 95 mm, nozzle inner diameter 4 mm, pressure 0.5 MPa) is installed 50 mm above the mesh. Next, while shaking for 15 minutes at an amplitude of 70 mm and 60 times / minute, the air ejection device is sprayed evenly, and suction is used to separate the fibers from the sample. After 15 minutes, the material remaining on the sieve (14 mesh) is designated as "fiber clumps 35 (knots)".

[0042] The water absorption rate of the pulp may be 22 times or more and 28 times or less. Since the water absorption rate of the pulp is 28 times or less, the amount of body fluid absorbed can be suppressed, and the sagging of the absorption core 31 caused by excessive absorption can be suppressed. The water absorption rate of the pulp is as high as 22 times or more, and the body fluid can be sufficiently absorbed. Therefore, the absorption performance of the pulp can be improved.

[0043] The water retention rate of the pulp may be 5 times or more and 7 times or less. The water retention rate of the pulp is as high as 5 times or more, and the body fluid can be sufficiently retained. Also, since the water retention rate of the pulp is 7 times or less, the sagging after absorption can be more effectively suppressed.

[0044] The water absorption rate and the water retention rate can be measured by the following method. Prepare two bags. Join three sides of the nylon net forming the bag by heat sealing to form a bag shape. Put 1.0 g of the pulp to be measured into one bag, and do not put pulp into the other bag. Join the unclosed side of each bag by heat sealing. Measure the weight of each bag. Take this weight as the weight before water absorption. Immerse the two bags in ion-exchanged water for 30 minutes. At this time, make sure the bags are completely immersed in the ion-exchanged water. After 30 minutes, take out the pulp from the ion-exchanged water and place it on the net for 5 minutes. After 5 minutes, measure the weight of the bag. Take this weight as the weight after water absorption. Then, use a centrifuge (upper discharge type centrifuge H-130E special) to dehydrate each bag for 1 minute and 30 seconds under the conditions of 150G and 763 rpm. Measure the weight after dehydration, and take this weight as the weight after dehydration. ・Water absorption rate = (weight of the pulp after water absorption - weight of the pulp before water absorption) / weight of the pulp before water absorption Weight of the pulp after water absorption = weight of the bag with pulp after water absorption - weight of the bag without pulp after water absorption Weight of the pulp before water absorption = weight of the bag with pulp before water absorption - weight of the bag without pulp before water absorption ・Water retention rate = (weight of the pulp after dehydration - weight of the pulp before water absorption) / weight of the pulp before water absorption Weight of the pulp after dehydration = weight of the bag with pulp after dehydration - weight of the bag without pulp after dehydration

[0045] The average fiber length of the pulp may be less than 3.0 mm. As described above, by finely pulverizing the pulp and maintaining its pulverized state, the average fiber length can be shortened. Since the average fiber length of the pulp is less than 3.0 mm and the fiber length is relatively short, it is easy to secure the surface area of the pulp that comes into contact with body fluids, and it is easier to improve the absorption performance of the pulp. More preferably, the average fiber length of the pulp may be 0.7 mm or more and less than 3.0 mm. Since the average fiber length of the pulp is 0.7 mm or more, entanglement of the fibers is more likely to occur, and sagging of the pulp can be suppressed. The average fiber length of the fibers is measured in accordance with "A7.1 Method of Measuring Fiber Length" in Appendix A of JIS L 1015: 2010, "A7.1 Method A (Standard Method) Measuring the length of individual fibers on a graduated glass plate". Note that the above method is a test method corresponding to ISO 6989 issued in 1981.

[0046] The absorption core 31 may have a superabsorbent polymer (SAP) in addition to the pulp. Since the average fiber length of the pulp is short, less than 3.0 mm, the SAP is likely to swell. Therefore, the absorption performance of body fluids can be further improved.

[0047] The topsheet 10 and the core wrap sheet 32 may be colored. Since the absorption core 31, the topsheet 10, and the core wrap sheet 32 having colored cellulose fibers are all colored, the color of the overlapping area becomes darker, and it is easy for the user to feel the image that body fluids are drawn into the non-skin side T2.

[0048] The color of the core wrap sheet 32, the color of the topsheet 10, and the color of the colored cellulose fibers may be brown. Since brown is a color that generally reminds people of natural materials, it is easy for the user to recognize that the absorbent article 1 has reduced the environmental load because the color of the core wrap sheet 32, the color of the topsheet 10, and the color of the colored cellulose fibers are brown. Note that the color of the core wrap sheet 32, the color of the topsheet 10, and the color of the colored cellulose fibers may all be colors due to residual components derived from the wood of the pulp, and may not be colors colored with dyes or the like.

[0049] Brown may include the following colors as defined by JIS standard colors (Japanese names) and JIS standard colors (English names): Rust color (#624035), Azuki bean color (#864944, #905D54), Yellowish brown (#B1632A), White brown (#D1B592), Reddish rust color (#6F2D21, #8D3927), Bruno van Dyck (#644045), Brown (#C73422), Cocoa brown (#704B38), Deep orange (#663300), Light withered leaf (#ce944d), Chinese brown (#B47157), Cognac (#AB4A20), Deep reddish purple (#660033), Small chicken yellow (#E6CE84), Tan (#9E6C3F It may be any of the following colors: red, maroon (#800000, #662B2C), golden (#D3B95E, #D68E31), chestnut (#704B38, #5D2917), terre de siena brûlée (#734333), dark sappanwood (#491022), tokigara tea (#DB8E71), vert safari (#888724), black tea (#362519), rouille (#CE481F), or Edo tea (#AB7F5C).

[0050] The brightness of the core wrap sheet 32 ​​and the colored cellulose fibers may be lower than the brightness of the top sheet 10. Users perceive areas with lower brightness as darker. Because the color of the core wrap sheet 32 ​​and the colored cellulose fibers in the pulp are darker than the color of the top sheet 10 (located on the non-skin side T2), it can give the user the image that bodily fluids are being drawn in. In a configuration where the top sheet 10 has a top opening that penetrates only the top sheet 10 in the thickness direction T, the color of the core wrap sheet 32 ​​and other materials visible through the top opening is darker, which can give the user an even stronger image that bodily fluids are being drawn to the non-skin side T2. Furthermore, the brightness of the core wrap sheet 32 ​​may be lower than the brightness of the top sheet 10 and lower than the brightness of the colored cellulose fibers. When measuring the brightness of each material, the materials are disassembled from the absorbent article 1 and measured.

[0051] As shown in Figure 3, in a plan view of the absorbent article 1, the embossed portion 80 has an outer end portion 81 and a central portion 82 located inside the outer end portion 81. The central portion 82 may be a portion that is recessed in the thickness direction compared to the outer end portion 81. In a plan view of the absorbent article 1, the brightness of the outer end portion 81 of the embossed portion may be lower than the brightness of the central portion 82 of the embossed portion 80. Because the color of the outline (outer end portion) of the embossed portion 80 becomes darker, a contrast in shade is created in the plan view of the absorbent article 1, giving the user an image of absorption of bodily fluids. Also, the distance between fibers is shorter in the darker outer end portion 81 than in the central portion 82. Therefore, the thickness of the central portion 82 is thicker than the thickness of the outer end portion 81, and in a cross-sectional view, the surface of the embossed portion 80 tends to be convex, with the central portion 82 bulging more than the outer end portion 81. Body fluids guided to the embossed portion 80 of this shape are guided along the convex surface towards the outer end 81 of the embossed portion 80, and are more easily guided to the absorption core 31 surrounding the embossed portion 80.

[0052] 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 core 31 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 spaced apart 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 recessed wall portion 91 connected to the top sheet 10 and the absorbent core 31, and a bottom portion 93 that constitutes the non-skin side T2 surface of the recess 90. The opening 92 is a region surrounded by a recessed wall portion 91 extending in the thickness direction T. The bottom portion 93 is located on the non-skin side of the opening 92, and the fibers of the top sheet 10 and the absorbent material of the absorbent core 31 are compressed therebefore the opening 92 is formed. Therefore, the bottom portion 93 is provided with a high-density portion 94, which has a higher fiber density than the top sheet 10 and absorbent core 31 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, because the high-density portion 94 is provided at the bottom portion 93, bodily fluids can be drawn into the bottom portion 93 side of the recess 90.

[0053] 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 high fiber density, 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 toward the surrounding area via the inclined peripheral portion 96. Therefore, bodily fluids that have entered the opening 92 can be quickly moved toward the surrounding area of ​​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.

[0054] In a plan view of the absorbent article 1, the brightness of the bottom portion 93 may be lower than that of the concave wall portion 91. According to this embodiment, since the color of the bottom portion 93 is darker than that of the concave wall portion 91, a color gradient can be provided in the cross-sectional direction, giving the user the impression that the darker bottom portion absorbs more. The user can gain a sense of security regarding the absorption performance from the image of bodily fluids being drawn to the non-skin side.

[0055] The bottom 93 of the recess 90 may have a lower brightness than the bottom of the non-skin side of the embossed portion 80. Because the bottom of the recess 90 is relatively dark in color, the user can gain a greater sense of security regarding the absorption performance by imagining that bodily fluids are drawn into the non-skin side T2 by the recess 90. Also, the depth of the recess 90 (the distance in the thickness direction from the skin side of the absorbent article to the bottom) may be deeper than the depth of the embossed portion 80. A relatively deep recess 90 allows it to draw in more bodily fluids.

[0056] The top sheet 10 may have a top opening that penetrates only the top sheet 10. Unlike the recess 90 and the embossed portion 80, the top opening is formed only in the top sheet 10. In a plan view, the maximum dimension of the top opening may be smaller than the maximum dimension of the recess 90. In a plan view of the absorbent article, the brightness of the bottom 93 of the recess 90 may be lower than the brightness of the top opening. The brightness of the top opening is the brightness of the area in which the top opening is formed, and is the brightness of the material placed on the non-skin side T2 of the top sheet 10 through the top opening. According to this embodiment, because the brightness of the top opening is low, the user perceives the area where the top sheet 10 is placed as a bright area, and it is easy to associate the top sheet 10 with breathability. Because the brightness of the bottom 93 of the recess 90 is low, the user is easy to associate the recess 90 with absorption.

[0057] Furthermore, the top sheet 10 has a top opening, which makes it easier to guide bodily fluids to the absorbent core 31 located on the non-skin side T2 via the top sheet 10. The bodily fluids guided to the absorbent core 31 can be further guided to the non-skin side T2 and absorbed via the recess 90, or in areas where the recess 90 is not provided, the bodily fluids can be absorbed by the pulp or guided into the gaps between the pulp, allowing for gradual draw-in of the bodily fluids. This makes it easier to absorb bodily fluids using the entire thickness direction T of the absorbent article, further improving the absorption performance of bodily fluids.

[0058] (3) Packaging for absorbent articles Next, with reference to Figure 5, the packaging for absorbent articles 100 will be described. The packaging for absorbent articles 100 comprises the absorbent article 1 of the above-described embodiment and a packaging sheet 110 that packages the absorbent article 1. The packaging sheet 110 is made of nonwoven fabric and is a sheet that individually packages the absorbent article 1. The packaging sheet 110 contains the absorbent article 1 in a folded state based on a plurality of folds extending in the width direction W. When using, the user unfolds the packaging sheet 110 and the absorbent article 1 and separates the absorbent article 1 from the packaging sheet 110. Figure 5 is a plan view of the unfolded state in which the packaging sheet 110 and the absorbent article 1 have been unfolded. In the unfolded state, the absorbent article 1 and the packaging sheet 110 are not folded by any of the folds.

[0059] The packaging sheet 110 has packaging embossed portions 120 formed by compressing the packaging sheet 110 in the thickness direction T. Multiple packaging embossed portions 120 are provided at intervals across the entire packaging sheet 110. In a plan view, the maximum dimension of the packaging embossed portion 120 may be smaller than the maximum dimension of the recess 90.

[0060] In a plan view of the unfolded state, the brightness of the recess 90 may be lower than that of the packaging embossed portion 120. The packaging embossed portion 120 of the packaging sheet 110 has a lighter color, prioritizing a sense of unity throughout the packaging sheet 110 and giving a hygienic image, while the recess 90, with its darker color, evokes an image of absorption.

[0061] The packaging sheet 110 may be colored. The color of the packaging sheet 110 may be the same brown as the color of the core wrap sheet 32, colored cellulose fibers, etc. By making the entire package, including the absorbent article 1 and the packaging sheet 110, the sense of unity of the entire package can be enhanced, and the impression that it is an environmentally friendly product can be created. The color of the packaging sheet 110 may be the color of residual components derived from wood in the pulp, and does not have to be a color created by dyes, etc.

[0062] 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.

[0063] Furthermore, the entire contents of Japanese Patent Application No. 2024-224819, filed on December 20, 2024, are incorporated herein by reference.

[0064] This invention provides an absorbent article that allows for easy handling of pulp containing colored cellulose fibers.

[0065] 1: Absorbent article 10: Top sheet 15: Side sheet 20: Back sheet 30: Absorbent material 31: Absorbent core 32: Core wrap sheet 33: Pulp 34: Colored cellulose fiber 35: Fiber mass 80: Embossed part 81: Outer end 82: Center part 90: Recess 91: Recessed wall part 92: Opening 93: Bottom part 94: High-density part 100: Packaging for absorbent article 110: Packaging sheet 120: Packaging embossed part L: Front-to-back direction T: Thickness direction T1: Skin side T2: Non-skin side W: Width direction

Claims

1. An absorbent article comprising an absorbent core having pulp, wherein the pulp has colored cellulose fibers, and the color difference ΔE between pulp subjected to a 48-hour ultraviolet irradiation test and pulp not subjected to an ultraviolet irradiation test is 10.0 or less.

2. The absorbent article according to claim 1, wherein the water absorption ratio of the pulp is 22 times or more and 28 times or less.

3. The absorbent article according to claim 1 or claim 2, wherein the water retention ratio of the pulp is 5 times or more and 7 times or less.

4. The absorbent article according to claim 1 or claim 2, wherein the average fiber length of the pulp is less than 3.0 mm.

5. The absorbent article according to claim 1 or 2, comprising: a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin; and an embossed portion formed by compressing at least the top sheet and the absorbent core in the thickness direction, wherein, in a plan view of the absorbent article, the brightness of the outer edge of the embossed portion is lower than the brightness of the central portion inside the outer edge of the embossed portion.

6. The absorbent article according to claim 1 or claim 2, comprising: a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin; and a core wrap sheet covering at least the skin-side surface of the absorbent core, wherein the color of the core wrap sheet, the color of the top sheet, and the colored cellulose fibers are brown, and the brightness of the core wrap sheet and the brightness of the colored cellulose fibers are lower than the brightness of the top sheet.

7. The absorbent article according to claim 1, comprising: a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin; and a recess formed by both the top sheet and the absorbent core toward the non-skin side of the absorbent article, wherein each of the recesses comprises a concave wall portion extending in the thickness direction connected to the top sheet and the absorbent core, and a bottom portion forming the non-skin side surface of the recess, wherein in a plan view of the absorbent article, the brightness of the bottom portion is lower than the brightness of the concave wall portion.

8. The absorbent article according to claim 7, comprising: a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin; and an embossed portion formed by compressing at least the top sheet and the absorbent core in the thickness direction, wherein in a plan view of the absorbent article, the brightness of the bottom of the recess is lower than the brightness of the bottom portion forming the non-skin side surface of the embossed portion.

9. The absorbent article according to claim 7, having a top opening that penetrates only the top sheet, wherein in a plan view of the absorbent article, the brightness of the bottom of the recess is lower than the brightness of the top opening.

10. A package for an absorbent article, comprising an absorbent article according to any one of claims 7 to 9, and a packaging sheet for individually packaging the absorbent article in a folded state based on a plurality of folds, wherein the packaging sheet has a packaging embossed portion formed by compressing the packaging sheet in the thickness direction, and the brightness of the recess is lower than the brightness of the packaging embossed portion.

11. An absorbent article comprising: an absorbent core having pulp; a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin; and a core wrap sheet covering at least the skin-side surface of the absorbent core, wherein the pulp has colored cellulose fibers, the core wrap sheet is colored, and the absorbent article has recesses in both the top sheet and the absorbent core that are recessed toward the non-skin side of the absorbent article, and each of the recesses has a recessed wall portion extending in the thickness direction connected to the top sheet and the absorbent core, and a bottom portion that constitutes the non-skin side surface of the recess.

12. An absorbent article comprising: an absorbent core having pulp; and a top sheet positioned on the skin side of the absorbent core and in contact with the wearer's skin, wherein the pulp has colored cellulose fibers; the absorbent core has a fiber mass which is an aggregate of fibers piled up in a mass; the top sheet and the absorbent core both have recesses that are indented toward the non-skin side of the absorbent article; and each of the recesses has a recessed wall portion extending in the thickness direction connected to the top sheet and the absorbent core, and a bottom portion which constitutes the non-skin side surface of the recess.

Images