absorbent articles

Abstract

To provide an absorbent article that allows a user to determine an absorption amount of body fluid from a top sheet side.SOLUTION: An absorbent article includes: a liquid permeable top sheet 10; a liquid impermeable back sheet 30; and an absorber 20 disposed therebetween. The top sheet 10 includes: a cover sheet 70 from which variation in a color of the absorber 20 is visible and which is disposed between the top sheet 10 and the absorber 20 and covers at least a skin side surface of the absorber 20; and an embossed groove 60 extending in a longitudinal direction at a skin side surface of the top sheet 10, reaching the inside of the absorber 20 while being recessed on a non-skin side and having an internal space which the top sheet 10 and the cover sheet 70 enter. The cover sheet 70 is provided with a coloring area 71. The coloring area 71 includes: a water-soluble coloring agent diffusing into the absorber 20 with absorption of body fluid; and a water-soluble binder. The embossed groove 60 includes a joint area 72 where the top sheet 10, the coloring area 71 and the absorber 20 are joined at the bottom surface thereof.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an absorbent article. [Background technology]

[0002] Pad products such as sanitary napkins and light incontinence pads, which are used by fastening the backsheet side to underwear, are known as absorbent articles for absorbing bodily fluids. Pad products are discarded after absorbing a certain amount of bodily fluid, but replacing pad products with low bodily fluid absorption capacity each time increases the economic burden on users. As a method for reducing the economic burden, when the amount of bodily fluid discharge is small, a method is adopted in which a pad product is used until a certain amount of discharge is reached, rather than replacing it with a new one each time a patient discharges. Various technologies have been proposed to allow users to recognize the level of bodily fluid discharge.

[0003] Patent Document 1 describes a liquid-absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body for retaining liquid disposed between the two sheets, with a mesh-like scale on the surface of the top sheet (Claim 1).It is stated that with this liquid-absorbent article, the presence of the mesh-like scale on the surface of the top sheet makes it possible to evaluate the amount of liquid absorbed (mass or volume) by counting the number of meshes occupied by liquid stains (bloodstains, etc.) (by measuring the area of ​​the liquid stains) (Paragraph 0010).

[0004] Patent Document 2 describes a disposable diaper that is divided into a front waistline, a rear waistline, and a crotch area between them, has a pair of leg openings, and is equipped with an absorbent that extends across the crotch area to the front and rear waistline, and is equipped with leg elastic members that extend from the front waistline to the rear waistline along the leg openings, across the crotch area, a waistline holder that extends widthwise through the front and rear waistline to hold the disposable diaper on the wearer's body, and a stretchable crotch stretchable member formed in an area overlapping with the crotch area where the absorbent is located, the crotch stretchable member being spaced apart from the waistline holder and the leg elastic members, non-stretchable regions being provided on the front waistline and rear waistline sides in the longitudinal direction of the crotch stretchable member, and an indicator that extends longitudinally across the crotch stretchable member and changes visually when it comes into contact with moisture, the change being visible from the non-skin-contacting side of the disposable diaper (Claim 1). According to Patent Document 2, a disposable diaper is provided that can be stably attached to a wearer and can cause an indicator to react appropriately (paragraph 0018).

[0005] Patent Document 3 describes an absorbent article that includes a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed therebetween, and that has at least one absorbent region indicating the extent of absorption of bodily fluids by the absorbent body and a numerical value of the absorbent body's absorption capacity in the absorbent region displayed on the outer surface of the back sheet (Claim 1). Patent Document 3 describes that by displaying the absorbent regions and the corresponding numerical values ​​of the absorbent body's absorption capacity on the outer surface of the back sheet of the absorbent article, even numbers with three digits or the like can be clearly displayed, and the specific absorption capacity value of the absorbent article can be easily and reliably visually recognized, allowing the user of the absorbent article or a caregiver to visually recognize how much urine or the like has been absorbed and easily determine whether the absorbent article is still usable or needs to be replaced (paragraph 0006). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-153506 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-094194 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-128531 Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, when urine is excreted, it is difficult to visually determine which markings on the scale the clear urine has reached. In particular, because a hygienic white nonwoven fabric is usually used for the top sheet, even if urine is excreted on the top sheet, it is difficult to determine the state of dispersion of the clear urine on the white top sheet.

[0008] In Patent Documents 2 and 3, the degree of urine absorption must be ascertained from the non-skin side of the back sheet. For example, in the case of pad products such as light incontinence pads and liners in which the back sheet side is attached to underwear, the wearer must take the time to peel the pad product off the underwear or dedicated outerwear while in use to check the amount of urine absorbed.

[0009] As such, the above-mentioned conventional technology has the problem that it is difficult for the user or the person assisting or caring for the user to visually determine how much bodily fluid has been absorbed by the absorbent article, and this is time-consuming.

[0010] An object of the present invention is to provide an absorbent article that allows the amount of absorbed bodily fluid to be determined from the top sheet side. [Means for solving the problem]

[0011] As a result of extensive research to solve the above problems, the inventors have discovered that the body fluid absorbing region of the absorbent body can be visually confirmed as a color change by providing a cover sheet that covers at least the skin-facing surface of the absorbent body, providing a colored area in the cover sheet that is composed of a water-soluble colorant and a water-soluble binder, providing an embossed groove in the skin-facing surface of the top sheet that extends longitudinally along the colored area and reaches the inside of the absorbent body, and joining the top sheet, the colored area, and the absorbent body at the bottom of the embossed groove, and have thus completed the present invention. The present invention provides the following absorbent article.

[0012] (1) An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed therebetween, The top sheet allows a change in color of the absorbent body to be visually recognized, a covering sheet disposed between the top sheet and the absorbent body and covering at least the skin-facing surface of the absorbent body; the top sheet further has an embossed groove extending in the longitudinal direction on the skin-side surface of the top sheet, recessed toward the non-skin side, and reaching the inside of the absorbent body, with the top sheet and the covering sheet entering into the internal space; The covering sheet is provided with a colored area, and the colored area includes a water-soluble colorant that diffuses into the absorbent body upon absorption of body fluids, and a water-soluble binder; An absorbent article, wherein the bottom surface of the embossed groove has a joining region where the top sheet, the colored area, and the absorbent body are joined together. (2) The absorbent article of (1) further comprising a diffusion promoting section disposed on the non-skin side of the colored area in the thickness direction, which promotes the diffusion of the water-soluble colorant into the absorbent body upon absorption of body fluids. (3) The absorbent article according to (2) above, wherein the diffusion-promoting portion is one or more recessed grooves extending in the longitudinal direction on the skin-side surface of the absorbent body and recessed toward the non-skin side. (4) The absorbent article of (2) above, wherein the diffusion-promoting portion is provided on the non-skin side of the colored area at the bottom surface of the embossed groove, and is a low-basis weight area having a basis weight lower than other areas in the absorbent body, and the top sheet, the colored area, and the low-basis weight area are joined to form the joined area. (5) The absorbent article according to any one of (1) to (4) above, wherein the bonding strength in the bonding region is greater than 0 N and not greater than 0.2 N. (6) The absorbent article according to any one of (1) to (5) above, wherein the colored area is composed of a colored portion and a non-colored portion. (7) An absorbent article according to any one of (1) to (6) above, wherein the colored portions and the non-colored portions are arranged alternately in the longitudinal direction, the width direction and / or a diagonal direction intersecting these directions. (8) The absorbent article according to any one of (1) to (7) above, wherein the covering sheet comprises a hydrophilic nonwoven fabric or a pulp sheet. (9) The absorbent article according to any one of (1) to (8) above, wherein the water-soluble colorant is a food additive colorant. (10) The absorbent article according to any one of (1) to (9) above, wherein at least a part of the embossed grooves is heat-sealed. [Effects of the Invention]

[0013] According to the present invention, an absorbent article is provided that allows the amount of absorbed bodily fluid to be determined from the top sheet side. [Brief explanation of the drawings]

[0014] [Figure 1] 1A and 1B are plan views schematically illustrating the configuration of an absorbent article according to the present embodiment, in which (a) shows the state before absorbing body fluids and (b) shows the state after absorbing body fluids. [Figure 2] 2 is a schematic cross-sectional view taken along the XX line in Fig. 1. (a) shows the state before absorbing body fluids, and (b) shows the state after absorbing body fluids. [Figure 3] 10 shows a modified example of the absorbent article according to the present embodiment. [Figure 4] FIG. 10 is a plan view showing a modified example of the colored area. DETAILED DESCRIPTION OF THE INVENTION

[0015] In this specification, "wearing the absorbent article 50" refers to a state in which the absorbent article 50 is attached to the wearer's body, regardless of whether it has absorbed bodily fluids or not. The longitudinal direction of the absorbent article 50 is the direction indicated by Y in the figure, which extends from front to back across the wearer's crotch when the absorbent article 50 is worn; the width direction is the direction indicated by X in the figure, which is approximately perpendicular to the longitudinal direction; and the thickness direction is the direction indicated by Z in the figure, in which the components are stacked. The skin-side surfaces of the absorbent article 50 and its components are the surfaces that contact the wearer's skin or face the skin, and the non-skin-side surfaces are the surfaces that contact the wearer's clothing or face the clothing. Body fluids refer to liquids excreted from the body to the outside, such as urine, blood, and water in loose stools.

[0016] <Absorbent articles> Hereinafter, an absorbent article 50 according to this embodiment will be described with reference to the drawings. Figs. 1 and 2 show the absorbent article 50 according to this embodiment. Figs. 3 and 4 show modified examples of the absorbent article 50. The drawings do not define the shapes of the absorbent article 50 and each of its constituent members, or the relative sizes of the components.

[0017] The absorbent article 50 of this embodiment can be used as a variety of absorbent articles for babies, adults, and the elderly, and is particularly suitable for use as pad products such as light incontinence pads, light incontinence liners, sanitary napkins, and panty liners. The longitudinal dimension of the absorbent article 50 is, for example, in the range of 100 mm to 800 mm, and the width dimension is, for example, in the range of 50 mm to 500 mm. By keeping each dimension within the aforementioned numerical ranges, an absorbent article 50 suitable for use as a pad product can be obtained.

[0018] As shown in Figures 1 and 2, the absorbent article 50 of this embodiment comprises a liquid-permeable top sheet 10 located on the skin side, a liquid-impermeable back sheet 30 arranged opposite the top sheet 10 and located on the non-skin side, an absorbent body 20 arranged between the top sheet 10 and the back sheet 30, a covering sheet 70 arranged between the top sheet 10 and the absorbent body 20 and covering at least the skin-side surface of the absorbent body 20, and an embossed groove 60 extending longitudinally on the skin-side surface of the top sheet 10, recessed toward the non-skin side and reaching the inside of the absorbent body 20, with the top sheet 10 and the covering sheet 70 penetrating into the internal space, and a colored area 71 is provided on the covering sheet 70, and the colored area 71 contains a water-soluble colorant and a water-soluble binder that diffuse into the absorbent body 20 upon absorption of body fluids, and the bottom surface of the embossed groove 60 has a joining region 72 where the top sheet 10, colored area 71, and absorbent body 20 are joined.

[0019] According to this embodiment, when bodily fluids reach the colored areas 71 of the cover sheet 70 during urination, the water-soluble binder in the colored areas 71 is dissolved, followed by the water-soluble colorant, which dissolves and spreads throughout the absorbent body 20, causing the color of the colored areas 71 to lighten, and the wearer can visually recognize this color fading and check the amount of bodily fluid absorbed by the absorbent body 20. When the absorbent article 50 is divided into a front portion that mainly contacts the wearer's lower abdomen, a rear portion that mainly contacts the buttocks, and a crotch portion between the front and rear portions that mainly contacts the wearer's crotch, if bodily fluids such as urine are excreted in the crotch area and the color of not only the colored areas 71 around the crotch area but also the color of the colored areas 71 in the front and rear portions fade, the user can see that the bodily fluids have been absorbed by the entire absorbent body 20, and can visually recognize that it is time to change the absorbent body 20. Furthermore, because this change in color can be seen directly from the top sheet 10 side of the absorbent article 50, the color change (fading of color) can be confirmed from directly above the absorbent article 50 during urination, etc., without having to remove the absorbent article 50 in use from the underwear or dedicated outerwear, and the time to replace the absorbent article can be determined based on the color change. In other words, the amount of urine output can be easily determined in a toilet stall, etc.

[0020] The absorbent article 50 of this embodiment has as its basic constituent units the top sheet 10, absorbent body 20, back sheet 30, embossed grooves 60, and covering sheet 70, and various known modifications can be made thereto, such as the provision of the above-mentioned three-dimensional gathers 40, or covering the absorbent body 20 with a carrier sheet (not shown). Below, the constituent members of the absorbent article 50 of this embodiment will be described in more detail in the order of the top sheet 10, absorbent body 20, embossed grooves 60, covering sheet 70, back sheet 30, and three-dimensional gathers 40.

[0021] <Top sheet> In the industrial field of absorbent articles 50, the top sheet 10 is a very thin sheet-like substrate having a thickness of approximately 0.1 mm to 0.4 mm, and a color change in the absorbent body 20 caused by a water-soluble colorant contained in the colored area 71 of the covering sheet 70 is visible without any special treatment. In this embodiment, the provision of embossed grooves 60, which will be described later, makes the color change in the absorbent body 20 even more clearly visible. The top sheet 10 is a liquid-permeable sheet-like substrate that allows bodily fluids to pass quickly toward the absorbent body 20 and diffuse the bodily fluids in the planar direction of the absorbent body 20. The top sheet 10 is preferably a substrate that is soft to the touch and does not irritate the skin so that it may come into direct contact with the wearer's skin, and the sheet-like substrate is preferably white or translucent in order to facilitate the visibility of the color change.

[0022] Examples of sheet-like substrates constituting the top sheet 10 include hydrophilic sheets, composite nonwoven fabrics which are laminates of the same or different hydrophilic sheets, apertured films such as apertured polyethylene films, and foamed films such as polyethylene foam and urethane foam. Examples of hydrophilic sheets include air-through nonwoven fabrics, thermal-bonded nonwoven fabrics, spunlace nonwoven fabrics, and spunbonded nonwoven fabrics made from synthetic fibers made from synthetic resins such as polypropylene and polyethylene, regenerated fibers such as rayon, and natural fibers such as cotton. Among these, the various nonwoven fabrics are preferred.

[0023] The surface of the top sheet 10 may be embossed or perforated to improve liquid permeability. The top sheet 10 may contain one or more of lotions, antioxidants, anti-inflammatory ingredients, pH adjusters, antibacterial agents, moisturizers, etc. to reduce irritation to the skin. The basis weight of the top sheet 10 is set to, for example, 15 g / m² from the viewpoints of strength, processability, and liquid wetting-back. 2 More than 40g / m 2 The following range or 19g / m 2 More than 35g / m 2 The shape of the top sheet 10 is not particularly limited, and may be any shape that covers part or all of the absorbent body 20, which is necessary to guide bodily fluids to the absorbent body 20 without leakage.

[0024] <Absorbent> The absorbent body 20 has a longitudinal dimension (maximum length) in the range of, for example, 100 mm to 800 mm, 150 mm to 500 mm, or 270 mm to 500 mm. The widthwise dimension (maximum width) of the absorbent body 20 is, for example, 50 mm to 500 mm, 60 mm to 400 mm, or 70 mm to 105 mm. When the absorbent body 20 has an hourglass-shaped planar shape, the longitudinal dimension is in the range of 180 mm to 800 mm, the widthwise dimensions of the front and rear portions that contact the wearer's abdomen and back, respectively, are both in the range of 60 mm to 400 mm, and the widthwise dimension of the central portion that contacts the wearer's crotch is in the range of 90 mm to 250 mm. Examples of planar shapes of the absorbent body 20 include an hourglass shape, an I-shape, a rectangle, a rounded rectangle, and an oval. The absorbent body 20 may be, for example, a fluff absorbent body containing absorbent fibers and a superabsorbent polymer.

[0025] (absorbent fiber) The absorbent fiber is not particularly limited as long as it is one generally used in absorbent articles such as sanitary napkins, disposable diapers, and urine absorption pads, and examples thereof include fluff pulp, cotton, rayon, acetate, tissue, absorbent paper, and hydrophilic nonwoven fabric. Among these, fluff pulp is preferably used from the viewpoint of absorbency. Examples of fluff pulp include wood pulp (e.g., bleached coniferous kraft pulp (N-BKP) such as southern pine or Douglas fir), synthetic fiber, resin fiber, and non-wood pulp defibrated into a cotton-like state. When fluff pulp is used as the absorbent fiber base material in the absorber 20, the basis weight of the absorbent fiber is, for example, 100 g / m2 from the viewpoint of feel on the skin, body fluid absorption capacity, and the like. 2 More than 800g / m 2 The following range: 325g / m 2 More than 615g / m 2 The range is as follows:

[0026] (Superabsorbent polymer) The superabsorbent polymer (hereinafter also referred to as "SAP") is not particularly limited as long as it can absorb body fluids and prevent backflow, and examples thereof include polyacrylates, polyaspartates, (starch-acrylic acid) graft copolymers, (acrylic acid-vinyl alcohol) copolymers, (isobutylene-maleic anhydride) copolymers, and saponified products thereof. Among these, from the viewpoint of absorption per weight, polyacrylates are preferred, alkali metal polyacrylates are more preferred, and sodium polyacrylate is even more preferred. The superabsorbent polymers can be used alone or in combination of two or more.

[0027] The superabsorbent polymer is used in various forms, such as particulate or fibrous, but is preferably used in particulate form for ease of handling. By avoiding the use of a finely powdered superabsorbent polymer with poor powder flowability and using a superabsorbent polymer with a median particle size, basic absorption performance can be improved and the rough feel that occurs when the absorbent body 20 hardens after absorbing body fluids can be reduced. The median particle size of the superabsorbent polymer 12 is, for example, in the range of 50 μm to 600 μm or in the range of 100 μm to 500 μm. The content of the superabsorbent polymer in the absorbent body 20 is in the range of 40 wt % or more, or in the range of 40 wt % to 70 wt % of the total weight of the absorbent body 20.

[0028] In the absorbent body 20, the absorbent fibers and SAP may be in the form of a mixture of SAP particles in absorbent fibers, or an SAP sheet in which SAP particles are fixed between absorbent fibers. In addition to the fluff absorbent body described above, the absorbent body 20 may also be an absorbent sheet containing multiple hydrophilic sheets with a superabsorbent polymer fixed and supported between them. To prevent leakage of SAP particles from the absorbent body 20 and to stabilize the shape of the absorbent body 20, a carrier sheet (not shown) may be provided under the absorbent body 20 or to completely wrap the absorbent body 20. The substrate of the carrier sheet may be any hydrophilic material, including tissue, absorbent paper, and hydrophilic nonwoven fabrics such as air-laid nonwoven fabrics. When multiple carrier sheets are provided, the substrates of the multiple carrier sheets may be the same or different.

[0029] (embossed groove) 1 and 2, the embossed groove 60 of this embodiment is a bottomed groove that extends longitudinally through approximately the center in the width direction of the skin-side surface of the top sheet 10, is recessed from the skin-side surface of the top sheet 10 toward the non-skin side, and has a bottom that reaches the inside of the absorbent body 20. In this embodiment, as shown in Figures 1 and 2, the top sheet 10 and the covering sheet 70 overlap and enter the internal space of the embossed groove 60, thereby forming the inner wall surface and bottom surface of the embossed groove 60. In this embodiment, a relatively darkly colored area 71 of the covering sheet 70 is positioned on the bottom of the embossed groove 60, and the colored area 71 of the top sheet 10 and a part of the absorbent body 20 on the non-skin side in the thickness direction are joined to form a joining region 72, which makes it easier for the wearer to see the darkly colored area 71 of the covering sheet 70 through the top sheet.

[0030] In this embodiment, the colored area 71 is configured such that quadrangular (approximately square) colored and non-colored areas are alternately arranged in the longitudinal and transverse directions. As described below, the colored areas contain a water-soluble colorant and a water-soluble binder. Body fluids are diffused in the longitudinal direction by the embossed grooves 60, and the water-soluble colorant in the colored areas 71 that the body fluid reaches is dispersed uniformly. This eliminates the color difference (contrast ratio) between the colored and non-colored areas, resulting in the formation of relatively thin colored areas 71 with good visibility, as shown in FIGS. 1(b) and 2(b). The depth of the embossed grooves 60 is in the range of 20% to 70% of the thickness of the absorbent body 20. However, as described below, when recessed grooves or low-basis-weight portions are provided in the absorbent body 20 as the diffusion-promoting portions, the depth is not limited to this numerical range.

[0031] The embossed grooves 60 can be formed, for example, using a pair of unheated press rolls. In the aforementioned pair of press rolls, one roll has a convex shape on its surface that corresponds to the internal space shape of the embossed groove, while the other roll has a flat surface. By passing a laminate formed by stacking the top sheet 10, the covering sheet 70, and the absorbent body 20 in this order between the pair of press rolls, the embossed grooves 60 are formed, with the top sheet 10 and the covering sheet 70 recessed toward the absorbent body 20. Furthermore, the top sheet 10, the colored areas 71, and a portion of the absorbent body 20 at the bottom of the embossed grooves 60 are bonded together by a water-soluble binder contained in the colored portions of the colored areas 71. Alternatively, a separate adhesive (e.g., a water-soluble binder) layer may be formed on the non-skin side of the top sheet 10 or the skin-side surface of the absorbent body 20 to bond the top sheet 10, the colored areas 71, and a portion of the absorbent body 20 together. This bonding makes the colored areas 71 formed in the covering sheet 70 more visible through the top sheet 10.

[0032] The bonding strength is not particularly limited, but is, for example, in the range of greater than 0 N and less than 0.2 N. This is because the pair of press rolls is not heated, and bonding is primarily due to the water-soluble binder contained in the colored portion of the colored area 71. If the bonding strength is weak, the force exerted when the absorbent body 20 swells in the thickness direction after urination will cause the top sheet 10 and the cover sheet 70 to peel away, tending to cause the shape of the embossed grooves 60 to collapse and causing the discoloration of the colored area 71 to become blurred. By bonding with an appropriate strength, the embossed grooves 60 are well maintained, allowing the wearer to clearly grasp the state of urine absorption. If the cover sheet 70 and the top sheet 10 are not bonded at the embossed grooves 60 and the top sheet 10 and the cover sheet are separated in the thickness direction, the color change of the colored area 71 will be less visible through the top sheet 10 than if they were bonded, but will still be visible.

[0033] Furthermore, instead of using a pair of unheated press rolls, a channel embossment having a heat-sealed portion may be provided in the region from the top sheet 10 to the absorbent body 20 by a common method such as channel embossing or high-frequency embossing using a heated press roll (one of the convex shapes may have fine irregularities at the tip) In this case, since the bonding strength is relatively strong, the force exerted when the absorbent body 20 swells in the thickness direction after urination makes it difficult for the top sheet 10 and the covering sheet 70 to peel from the absorbent body 20, so peeling does not occur, and the state of urine absorption can be clearly seen from the color change.

[0034] The number of embossed grooves 60 is not limited to one, and may be multiple. The absorbent article 50A shown in FIG. 3 has two longitudinally extending, approximately parallel embossed grooves 60 extending from the skin-side surface of the top sheet 10 to the inside of the absorbent body 20, and formed on its bottom surface by joining the top sheet 10, the colored area 71 of the covering sheet 70, and the skin-side surface of the absorbent body 20. In the absorbent article 50A, the initial relatively dark colored area 71 changes to a relatively light color as bodily fluids are absorbed, and the colored area 71 becomes wider than it was initially. This allows the amount of absorbed bodily fluid to be recognized, and the time to replace the absorbent article with a new one to be accurately determined. The absorbent article 50A allows the degree of bodily fluid absorption to be recognized not only in the longitudinal direction, but also in the width direction.

[0035] (Diffusion Promotion Department) In this embodiment, a diffusion promoter (not shown) may be disposed on the non-skin side of the colored area 70 in the thickness direction to promote diffusion of the water-soluble colorant into the absorbent body 20 upon absorption of body fluids. Examples of the diffusion promoter include one or more grooves (not shown) extending longitudinally on the skin-side surface of the absorbent body 20 and recessed toward the non-skin side, and a low-basis weight region (not shown) provided on the non-skin side of the colored area 71 at the bottom of the embossed groove 60, the low-basis weight region having a lower basis weight than other regions in the absorbent body 20. In an embodiment in which a low-basis weight region is provided, the top sheet 10, the colored area 71, and the low-basis weight region are joined in the thickness direction to form a joined region 72. In an embodiment in which a groove is provided, the groove may be appropriately selected depending on the mechanical strength of the entire absorbent body 20, and may be formed, for example, with a width of 3 mm to 20 mm and a depth of 3 mm to 10 mm. The number of grooves is not particularly limited, and may be, for example, between 1 and 3. The bonding strength in the bonding region between the top sheet 10, the colored area 71, and the low basis weight region is, for example, in the range of greater than 0 N and equal to or less than 0.2 N.

[0036] As described above, the region of the covering sheet 70 where the colored area 71 is formed, and the skin-facing surface of the absorbent body 20 that is in contact with this region in the thickness direction and its surrounding region are made to have a lower basis weight (not shown) than the other regions in the absorbent body 20, and the top sheet 10, the colored area 71, and the low basis weight region are joined to form the joined region 72, which makes it easier for the water-soluble colorant in the colored area 71 to diffuse along the flow of body fluids in the absorbent body 20, improving the visibility of the color change from a relatively dark color tone to a relatively light color tone in the colored area 71. The joining strength is, for example, within the range described above. Alternatively, the embossed groove 60 as described above may be provided, and the inner wall of the embossed groove 60 and the periphery of the bottom surface of the absorbent body 20 may be made to be a low basis weight region. The low basis weight region in the absorbent body 20 may be formed by stacking multiple layers of the absorbent body 20 in the thickness direction (at least the uppermost layer has a slit that penetrates the thickness direction in the center in the width direction), or may be formed by other known methods.

[0037] By providing the above-mentioned diffusion-promoting portion together with the embossed groove 60, bodily fluids are more easily diffused within the absorbent body 20, and the entire absorbent body 20 can be effectively utilized for absorbing bodily fluids. Furthermore, a colored area 71 is provided on the bottom surface of the embossed groove 60 or directly above the low basis weight region, making it possible to visually confirm the extent to which diffusion and absorption has occurred.

[0038] (covering sheet) The covering sheet 70 is positioned between the top sheet 10 and the absorbent body 20, and covers at least the skin-facing surface of the absorbent body 20. The covering sheet 70 may cover the entire absorbent body 20. The covering sheet 70 has a colored area 71 that extends longitudinally through the center of the width of the covering sheet 70 and contains a water-soluble colorant and a water-soluble binder. In this embodiment, the covering sheet 70 is arranged so that the colored area 71 is located on the bottom surface of the embossed groove 60. More specifically, when the absorbent article 50 is divided longitudinally into a front portion that mainly contacts the lower abdomen of the wearer, a crotch portion that is connected to the front portion and mainly contacts the crotch region of the wearer, and a rear portion that is connected to the crotch portion and mainly contacts the buttocks of the wearer, the colored area 71 is provided so as to extend longitudinally mainly in the crotch region. The covering sheet 70 receives body fluids from the top sheet 10 and transmits them to the absorbent body 20, and as the body fluids penetrate the water-soluble colorant in the colored areas 71, which have a relatively dark color, diffuses as the body fluids penetrate into the absorbent body 20, and the relatively dark color of the colored areas 71 spreads and becomes a relatively light color, allowing the amount of body fluid absorbed by the absorbent body 20 at that time to be confirmed and the time to replace it with a new absorbent article 50 to be determined.

[0039] (Colored area) The colored area 71 of the covering sheet 70 may be entirely colored, or may be composed of colored and uncolored areas. In a preferred embodiment, the colored and uncolored areas are arranged alternately in the longitudinal direction, the width direction, and / or a diagonal direction intersecting these directions. In the present embodiment shown in FIGS. 1 and 2, square colored and uncolored areas are arranged alternately in a grid pattern. With this configuration, there is a color contrast between the colored and uncolored areas. However, when the water-soluble colorant diffuses due to absorption of body fluids, the color of the colored area 71 becomes blurred, making the contrast difficult to perceive, and thus making it easier to visually recognize the color change.

[0040] The material of the covering sheet 70 is not particularly limited, but in a preferred embodiment, a hydrophilic covering sheet 70 is used, and examples thereof include hydrophilic nonwoven fabrics and pulp sheets. Examples of hydrophilic nonwoven fabrics include air-through nonwoven fabrics, point-bonded nonwoven fabrics, spunbonded nonwoven fabrics, melt-blown nonwoven fabrics, and air-laid nonwoven fabrics. Examples of pulp sheets include pulp-containing nonwoven fabrics in which a valve layer is integrated on one side of a spunbonded nonwoven fabric, tissue, absorbent paper, and the like. The basis weight of the covering sheet 70 is, for example, 10 g / m 2 More than 30g / m 2 The range is as follows: By using such a covering sheet 70, the water-soluble colorant can be easily retained on the sheet, and since the colorant is water-soluble, the retention of the water-soluble colorant is better than when the covering sheet 70 is made of hydrophobic fibers.

[0041] The water-soluble colorant used herein can be one or more known colorants, and examples of the water-soluble colorant include food additive dyes. The use of various water-soluble colorants for food additives ensures safety even if the colorant eluted by urine adheres to the wearer's crotch area. Any water-soluble binder that does not adversely affect the skin can be used without particular limitation. Examples include natural polysaccharides such as sodium alginate, tolanthus gum, guar gum, xanthan gum, gum arabic, carrageenan, galactomannan, gelatin, casein, albumin, and pulpuran; polysaccharide derivatives such as carboxymethyl cellulose, carboxyethyl cellulose, carboxymethylated starch or salts thereof, starch, methyl cellulose, and ethyl cellulose; polyvinyl alcohol; polyvinyl alcohol derivatives; salts of polymers or copolymers of unsaturated carboxylic acids; and synthetic polymer compounds such as salts of copolymers of unsaturated carboxylic acids and monomers copolymerizable with the unsaturated carboxylic acids.

[0042] FIG. 4 shows a modified example of the colored area 71. As shown in FIGS. 4(a) to 4(d), the colored and non-colored portions may be alternately arranged in the longitudinal, transverse, and / or diagonal directions, and the surface shapes of the colored and non-colored portions are not particularly limited. Furthermore, instead of the regular shapes shown in FIGS. 1 and 4, the size of the pattern (shape) of the colored and non-colored portions may vary in the longitudinal direction. More specifically, for example, if the pattern in the front and back portions is larger than the pattern in the crotch area, it becomes easier to recognize that urine has been initially excreted, and since the edges are also easily visible, it becomes easier to recognize that urine has been absorbed up to the edges.

[0043] <Back seat> The backsheet 30 may be formed using a liquid-impermeable substrate that prevents the body fluids retained by the absorbent sheet 20 from wetting the wearer's clothing. Examples of such substrates include resin films and composite sheets that are laminates of resin films and nonwoven fabrics. The nonwoven fabrics used in the composite sheets may be made by any method, and examples include single-layer nonwoven fabrics such as spunbonded nonwoven fabrics and meltblown nonwoven fabrics, composite nonwoven fabrics such as spunbonded nonwoven fabric / meltblown nonwoven fabric laminates, and spunbonded nonwoven fabric / meltblown nonwoven fabric / spunbonded nonwoven fabric laminates, as well as composite materials thereof. Examples of resin films include polyester, polyvinyl alcohol, polyethylene, polypropylene, and composite films of polyethylene and polypropylene.

[0044] The basis weight of the back sheet 30 is, for example, 15 g / m from the viewpoint of strength and processability. 2 More than 60g / m 2 The range is as follows. In order to prevent stuffiness during wear, it is preferable that the back sheet 30 be breathable. To make the back sheet 30 breathable, for example, a filler may be blended into the resin film of the base material, or the back sheet 30 may be embossed. An example of the filler is calcium carbonate, and the blending method may be any known method without any restrictions.

[0045] <3D gathers> The three-dimensional gathers 40 may be provided at both widthwise ends of the skin-facing surface of the top sheet 10 so as to extend along the longitudinal direction of the absorbent article 50, for example, in order to prevent side leakage of bodily fluids excreted by the wearer of the absorbent article 50. The three-dimensional gathers 40 include an elastic stretchable member 40a and a water-repellent and / or waterproof sheet member 40b.

[0046] The elastically stretchable member 40a is disposed along the longitudinal direction near the free end (other end) of the sheet member 40b, imparting upstanding property to the free end and allowing the free end and its neighboring area of ​​the sheet member 40b to deform to fit the wearer's body shape. In this embodiment, one widthwise end (fixed end) of the sheet member 40b is fixed to near both widthwise ends of the skin-side surface of the backsheet 30, a middle portion in the widthwise direction is fixed to near both widthwise ends of the skin-side surface of the topsheet 10, and the other widthwise end is a free end that is upstanding. The fixing position of the fixed end (one widthwise end) of the sheet member 40b is not limited to this embodiment, and examples include the non-skin-side surface of the backsheet 30, near both widthwise ends of the skin-side surface or non-skin-side surface of the joint between the topsheet 10 and the backsheet 30, which has the absorbent body 20 housed therein, and near both widthwise ends of the skin-side surface of the topsheet 10.

[0047] The sheet member 40b is a water-repellent and / or waterproof sheet, and is made of, for example, a nonwoven fabric. The nonwoven fabric for the first sheet member can be any water-repellent and / or waterproof (liquid-impermeable) nonwoven fabric made of hydrophobic fibers, and examples thereof include spunbond nonwoven fabric, meltblown nonwoven fabric, and composite nonwoven fabric (SMS nonwoven fabric) which is a spunbond nonwoven fabric / meltblown nonwoven fabric / spunbond nonwoven fabric laminate. The basis weight of the sheet member 40b is, for example, 13 g / m 2 More than 20g / m 2 The range is as follows: As the elastic and stretchable member 40a, for example, thread-, string- or band-shaped members made of natural rubber, synthetic rubber, polyurethane or the like can be used as appropriate.

[0048] Although the present invention has been described above using embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope described in the above embodiments and examples. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. Furthermore, it is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention. [Explanation of symbols]

[0049] 10 Topsheet 20 Absorbent 30 Back Seat 40 Three-dimensional gathers 50, 50A, 50B, 50C, 50D, 50E Absorbent articles 60 Embossed groove 70 Covering Sheet 71 Coloring Area 72 Junction area

Claims

1. An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed therebetween, The top sheet allows a change in color of the absorbent body to be visually recognized, a covering sheet disposed between the top sheet and the absorbent body and covering at least the skin-facing surface of the absorbent body; the top sheet further has an embossed groove extending in the longitudinal direction on the skin-side surface of the top sheet, recessed toward the non-skin side, and reaching the inside of the absorbent body, with the top sheet and the covering sheet entering into the internal space; The covering sheet is provided with a colored area, and the colored area includes a water-soluble colorant that diffuses into the absorbent body upon absorption of body fluids, and a water-soluble binder; a bottom surface of the embossed groove has a bonding region where the top sheet, the colored area, and the absorbent body are bonded together by the water-soluble binder contained in the colored area; the colored area on the bottom surface of the embossed groove is composed of a colored portion and a non-colored portion, the absorbent body has a diffusion promoting portion that promotes diffusion of the water-soluble colorant into the absorbent body due to absorption of body fluids, the diffusion promoting portion is provided on the non-skin side of the colored area at the bottom surface of the embossed groove, and is a low basis weight region having a basis weight lower than that of other regions in the absorbent body, An absorbent article, wherein the bonded region is formed by bonding the top sheet, the colored area of ​​the covering sheet, and the low basis weight region of the absorbent body.

2. The absorbent article according to claim 1, wherein the colored portions and the non-colored portions are arranged alternately in the longitudinal direction, the width direction, and / or an oblique direction intersecting these directions.

3. The absorbent article according to claim 1 or 2, wherein the covering sheet comprises a hydrophilic nonwoven fabric or a pulp sheet.

4. The absorbent article according to claim 1 , wherein the water-soluble colorant is a food additive colorant.

5. The absorbent article according to claim 1 , wherein at least a portion of the embossed grooves is heat-sealed.

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