JP2023080446A - absorbent article - Google Patents

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

The present invention relates to absorbent articles.

Pad products such as sanitary napkins and light incontinence pads, which are used with the back sheet side fixed to underwear, are known as absorbent articles for absorbing bodily fluids. Pad products are discarded after absorbing a certain amount of bodily fluids, and if pad products that absorb less bodily fluids are replaced each time, the economic burden on the user increases. As a method to reduce the economic burden, when the amount of bodily fluid discharge is small, instead of replacing with a new pad product each time it is discharged, a method of continuing to use until the amount of discharge reaches a certain level and then replacing it is taken. ing. Various techniques have been proposed for allowing a user to recognize the degree of bodily fluid discharge.

In Patent Document 1, a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body for retaining liquid disposed between the two sheets are provided, and a mesh-like structure is provided on the surface of the top sheet. (Claim 1). According to this absorbent article, since there is a mesh-like scale on the surface of the top sheet, by counting the number of meshes occupied by liquid stains (blood stains, etc.) (by measuring the area of the liquid stains), It is described that it becomes possible to evaluate the amount of absorbed liquid (mass or volume) (paragraph 0010).

Patent Document 2 discloses a disposable absorbent body that is divided into a front waistline, a back waistline, and a crotch therebetween, has a pair of leg openings, and extends across the crotch to the front waistline and the back waistline. In the diaper, leg elastic members straddling the crotch and extending from the front waistline to the back waistline along the leg openings, and a waistline holding part extending in the width direction from the front waistline and the back waistline to hold the disposable diaper on the body of the wearer. and a stretchable crotch stretchable part formed in a region overlapping with the crotch where the absorbent body is arranged, the crotch stretchable part is provided apart from the waist circumference holding part and the leg elastic member, and the crotch stretchable part is provided in the longitudinal direction of the crotch stretchable part A non-stretchable region is provided on the front waistline side and the back waistline side of the disposable diaper, extends longitudinally across the crotch stretch part, and is provided with an indicator that visually changes when it comes into contact with moisture, and the change is caused by the non-skin contact of the disposable diaper. Disposable diapers that are visible from the surface side are described (claim 1). According to Patent Document 2, it is described that a disposable diaper is provided that can be stably worn by a wearer and can appropriately react indicators (paragraph 0018).

In Patent Document 3, a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed therebetween are provided, and the outer surface side of the back sheet is provided with an absorbent material for absorbing body fluids. An absorbent article is disclosed in which at least one absorbent area showing a spread and the numerical value of the amount of body fluid absorbed by the absorbent in the absorbent area are displayed (claim 1). According to Patent Document 3, by displaying the numerical value of the absorbent area and the corresponding absorption amount of the absorbent body on the outer surface of the back sheet of the absorbent article, even numerical values such as three digits can be displayed clearly. By making it possible to easily and reliably visualize the value of the specific absorption amount of the absorbent article, the user or caregiver of the absorbent article can visually confirm how much urine, etc., has been absorbed. , it is possible to easily determine whether it is still usable or when it is time to replace it (Paragraph 0006).

JP-A-2002-153506 JP 2014-094194 A JP 2015-128531 A

In Patent Document 1, when urine is excreted, there is a problem that it is difficult to visually recognize where the transparent urine has reached on the scale. In particular, since the top sheet is usually made of sanitary white non-woven fabric, even if urine is excreted on the top sheet, it is difficult to recognize the transparent state of urine diffusion on the white top sheet. There is

In Patent Documents 2 and 3, it is necessary to grasp the degree of urine absorption from the non-skin side of the back sheet. If there is, it is necessary for the wearer to take the trouble of peeling off the pad product in use from the underwear or the exclusive outerwear and checking it.

As described above, in the conventional technology described above, when a user or a person who assists or cares for a user recognizes how much body fluid has been absorbed by the absorbent article, it is difficult to visually recognize it. There is a problem that it takes time and effort.

SUMMARY OF THE INVENTION An object of the present invention is to provide an absorbent article in which the body fluid absorption amount can be determined from the top sheet side.

As a result of intensive studies to solve the above problems, the inventors of the present invention have provided a cover sheet covering at least the skin-side surface of the absorbent body, and the cover sheet is composed of a water-soluble colorant and a water-soluble binder. and an embossed groove extending in the longitudinal direction along the colored area on the skin-side surface of the top sheet and reaching the inside of the absorbent body, and the bottom surface of the embossed groove separates the top sheet, the colored area, and the absorbent body. The inventors have found that by bonding, the bodily fluid absorbing region of the absorbent body can be visually confirmed as a change in color, and have completed the present invention. The present invention provides the following absorbent articles.

(1) An absorbent article comprising a liquid-permeable topsheet, a liquid-impermeable backsheet, and an absorbent body disposed therebetween,
In the top sheet, a change in color of the absorber is visible,
a covering sheet disposed between the top sheet and the absorbent body and covering at least the skin-side surface of the absorbent body;
an embossed groove extending in the longitudinal direction on the skin-side surface of the top sheet, recessed toward the non-skin side, reaching the interior of the absorbent body, and the top sheet and the covering sheet entering the internal space;
A colored area is provided on the covering sheet, and the colored area contains a water-soluble colorant that diffuses into the absorbent body by absorption of bodily fluids, and a water-soluble binder,
The absorbent article, wherein the bottom surface of the embossed grooves has a joint region where the top sheet, the colored area, and the absorber are joined.
(2) Absorbency according to (1) above, further comprising a diffusion promoting part disposed on the non-skin side in the thickness direction of the colored area and promoting diffusion of the water-soluble colorant into the absorbent body due to absorption of bodily fluids. Goods.
(3) The absorbent article according to (2) above, wherein the diffusion promoting portion is one or a plurality of concave grooves extending longitudinally on the skin-side surface of the absorbent body and concave toward the non-skin side.
(4) The diffusion promoting part is a low basis weight region provided on the bottom surface of the embossed groove on the non-skin side of the colored area and having a basis weight lower than that of other regions in the absorbent body, and the top The absorbent article according to (2) above, wherein the sheet, the colored area, and the low basis weight area are bonded to form the bonded area.
(5) The absorbent article according to any one of (1) to (4) above, wherein the joint strength in the joint region is greater than 0N and equal to or less than 0.2N.
(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) Any one of (1) to (6) above, wherein the colored portion and the non-colored portion are alternately arranged in the longitudinal direction, the width direction, and/or the diagonal direction intersecting these directions. absorbent article.
(8) The absorbent article according to any one of (1) to (7) above, wherein the covering sheet includes 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 part of the embossed grooves is heat-sealed.

ADVANTAGE OF THE INVENTION According to this invention, the absorbent article which can determine the bodily fluid absorption amount from the top sheet side is provided.

1 is a plan view schematically showing the structure of an absorbent article according to this embodiment; FIG. (a) shows the state before absorption of body fluid, and (b) shows the state after absorption of body fluid. FIG. 2 is a schematic cross-sectional view taken along the line XX shown in FIG. 1; (a) shows the state before absorption of body fluid, and (b) shows the state after absorption of body fluid. 4 shows a modification of the absorbent article according to the present embodiment. It is a top view which shows the modification of a coloring area.

In the present specification, wearing the absorbent article 50 refers to the state in which the absorbent article 50 is worn on the wearer's body, regardless of whether it is before or after absorption of bodily fluids. The longitudinal direction of the absorbent article 50 is the direction indicated by Y in the drawing that extends from front to back through the crotch of the wearer when the absorbent article 50 is worn, and the width direction is the direction relative to the longitudinal direction. The thickness direction is the direction indicated by Z in the drawing, in which the constituent members are laminated. The skin-side surface of the absorbent article 50 and its constituent members is the surface that contacts or faces the wearer's skin, and the non-skin-side surface is the surface that contacts or faces the clothing of the wearer. is the surface. Body fluids refer to liquids excreted from the body to the outside of the body, such as water in urine, blood, and loose stools.

<Absorbent article>
Hereinafter, an absorbent article 50 according to this embodiment will be described with reference to the drawings. 1 and 2 show an absorbent article 50 according to this embodiment. 3 and 4 show modifications of the absorbent article 50. FIG. Each drawing does not define the shape of the absorbent article 50 and each constituent member, the size relationship of the dimensions, and the like.

The absorbent article 50 of the present embodiment can be used as various absorbent articles for babies, adults, and elderly people. It can be used particularly preferably as a product. The lengthwise dimension of the absorbent article 50 is, for example, in the range of 100 mm or more and 800 mm or less, and the widthwise dimension is in the range of, for example, 50 mm or more and 500 mm or less. When each dimension is within the numerical range described above, an absorbent article 50 suitable for pad products is obtained.

As shown in FIGS. 1 and 2, the absorbent article 50 of the present embodiment comprises a liquid permeable top sheet 10 positioned on the skin side and a liquid permeable top sheet 10 positioned opposite the top sheet 10 and positioned on the non-skin side. An impermeable back sheet 30, an absorbent body 20 disposed between the top sheet 10 and the back sheet 30, and a skin side surface of the absorbent body 20 disposed between the top sheet 10 and the absorbent body 20 A covering sheet 70 covering at least and embossed grooves extending in the longitudinal direction on the skin side surface of the top sheet 10, recessed toward the non-skin side, reaching the inside of the absorbent body 20, and the top sheet 10 and the covering sheet 70 entering the internal space. 60 , the covering sheet 70 is provided with a colored area 71 , the colored area 71 contains a water-soluble coloring agent and a water-soluble binder that diffuse into the absorbent body 20 by absorption of bodily fluids, and the bottom surface of the embossed groove 60 has a bonding area 72 where the top sheet 10, the colored area 71, and the absorbent body 20 are bonded.

According to this embodiment, when bodily fluid reaches the colored area 71 of the covering sheet 70 during urination, the water-soluble coloring agent melts out following the water-soluble binder in the colored area 71 and spreads into the absorbent body 20 to disperse the colored area 71 . Since the color of the absorbent body 20 becomes lighter, the wearer can visually recognize that the color becomes lighter and can confirm the body fluid absorption amount of the absorbent body 20 . The absorbent article 50 is arranged on the front portion that mainly contacts the lower abdomen of the wearer, the rear portion that mainly contacts the buttocks, and the crotch portion that is interposed between these and mainly contacts the crotch portion of the wearer. When the body fluids such as urine are excreted into the crotch portion, not only the colored area 71 around the crotch portion but also the colored area 71 on the front side or the back side become blurred. The user can visually recognize that it has been absorbed and that it is time for replacement.
In addition, since this color change can be seen directly from the top sheet 10 side of the absorbent article 50, the absorbent article 50 in use can be seen from directly above without peeling off the absorbent article 50 from undergarments or special outerwear when urinating. , color change (color fading) can be confirmed, and replacement time can be grasped based on the color change. That is, it is possible to easily grasp the degree of urination in a private toilet room or the like.

The absorbent article 50 of this embodiment has the top sheet 10, the absorbent body 20, the back sheet 30, the embossed grooves 60, and the covering sheet 70 as basic structural units, and includes, for example, the arrangement of the three-dimensional gathers 40 as described above, the carrier Various known modifications such as covering the absorbent body 20 with a sheet (not shown) can be added. Hereinafter, 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, the absorbent body 20, the embossed grooves 60, the covering sheet 70, the back sheet 30, and the three-dimensional gathers 40.

<Top sheet>
In the industrial field of the absorbent article 50, the top sheet 10 is a very thin sheet-like base material having a thickness of about 0.1 mm to 0.4 mm, and the water-soluble colorant contained in the colored area 71 of the cover sheet 70 absorbs the water. A change in the color of the body 20 is visible without special processing. In this embodiment, by providing embossed grooves 60, which will be described later, the color change of the absorber 20 can be visually recognized more clearly. The top sheet 10 is a liquid-permeable sheet-like base material that allows bodily fluids to pass quickly toward the absorbent body 20 and diffuse the bodily fluids in the surface direction of the absorbent body 20 . The top sheet 10 is preferably a base material that has a soft feel and does not irritate the wearer's skin, so that it may be directly in contact with the wearer's skin. Alternatively, it is preferably translucent.

Examples of the sheet-like substrate constituting the top sheet 10 include a hydrophilic sheet, a composite nonwoven fabric which is a laminate of hydrophilic sheets of the same or different types, an open film such as an open polyethylene film, a polyethylene foam, a urethane foam, and the like. A foamed film and the like can be mentioned. Hydrophilic sheets include, for example, synthetic fibers made of synthetic resins such as polypropylene and polyethylene, regenerated fibers such as rayon, and natural fibers such as cotton. A spunbond nonwoven fabric etc. are mentioned. Among these, each nonwoven fabric is preferable.

The surface of the top sheet 10 may be embossed or perforated from the viewpoint of improving liquid permeability. From the viewpoint of reducing irritation to the skin, the top sheet 10 may contain one or more of lotions, antioxidants, anti-inflammatory ingredients, pH adjusters, antibacterial agents, moisturizers, and the like. The basis weight of the top sheet 10 is, for example, in the range of 15 g/m ² or more and 40 g/m ² or less, or in the range of 19 g/m ² or more and 35 g/m ^{2 or} less, from the viewpoint of strength, workability, and liquid return amount. . The shape of the top sheet 10 is not particularly limited as long as it covers part or all of the absorbent core 20, which is necessary for guiding bodily fluids to the absorbent core 20 without leakage.

<Absorber>
The absorber 20 has a longitudinal dimension (maximum length) of, for example, 100 mm or more and 800 mm or less, 150 mm or more and 500 mm or less, or 270 mm or more and 500 mm or less. The widthwise dimension (maximum width) of the absorbent body 20 is, for example, in the range of 50 mm or more and 500 mm or less, 60 mm or more and 400 mm or less, or 70 mm or more and 105 mm or less. In addition, when the absorbent body 20 has an hourglass shape in plan view, the longitudinal dimension is in the range of 180 mm or more and 800 mm or less, and the width dimension of the front part and the rear part, which contact the wearer's abdomen and back, respectively, is 60 mm or more. It is in the range of 400 mm or less, and the width direction dimension of the central portion that contacts the crotch portion of the wearer is in the range of 90 mm or more and 250 mm or less. Examples of the planar shape of the absorber 20 include an hourglass shape, an I shape, a rectangle, a square with rounded corners, and an ellipse.
The absorbent body 20 includes, for example, a fluff absorbent body containing absorbent fibers and a superabsorbent polymer.

(absorbent fiber)
Absorbent fibers are not particularly limited as long as they are generally used for absorbent articles such as sanitary napkins, paper diapers, and incontinence pads. nonwoven fabrics and the like. Among these, fluff pulp is preferably used from the viewpoint of absorbability. Examples of fluff pulp include wood pulp (for example, bleached softwood kraft pulp (N-BKP) such as southern pine and Douglas fir), synthetic fiber, resin fiber, non-wood pulp, etc., which are defibrated into cotton. can. When fluff pulp is used as the absorbent fiber as the base material of the absorbent body 20, the basis weight of the absorbent fiber is, for example, 100 g/m ² or more and 800 g/m ² or less from the viewpoint of the touch and body fluid absorption amount. range of 325 g/m ² or more and 615 g/m ² or less.

(super absorbent 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 polyacrylates, polyaspartates, (starch-acrylic acid ) graft copolymers, (acrylic acid-vinyl alcohol) copolymers, (isobutylene-maleic anhydride) copolymers and saponified products thereof. Among these, polyacrylates are preferred, alkali metal polyacrylates are more preferred, and sodium polyacrylate is even more preferred, from the viewpoint of absorption per weight. A superabsorbent polymer can be used individually by 1 type or in combination of 2 or more types.

The superabsorbent polymer is used, for example, in the form of particles, fibers, etc., but is preferably used in the form of particles from the viewpoint of ease of handling. At this time, by avoiding the use of a fine powder superabsorbent polymer with poor fluidity as a powder and using a superabsorbent polymer having a medium particle size, the basic performance related to absorption is improved, and the absorbent body 20 It is possible to reduce the rugged feel caused by hardening after absorbing body fluids. The median particle size of the superabsorbent polymer 12 is, for example, in the range of 50 μm or more and 600 μm or less or in the range of 100 μm or more and 500 μm or less. The content of the superabsorbent polymer in the absorbent body 20 is in the range of 40% by weight or more, or in the range of 40% by weight or more and 70% by weight or less of the total weight of the absorbent body 20 .

In the absorbent body 20, the absorbent fibers and the SAP may be formed by mixing SAP particles in the absorbent fibers, or may be an SAP sheet in which the SAP particles are fixed between the absorbent fibers. Absorbent sheets containing a plurality of hydrophilic sheets and a superabsorbent polymer fixedly supported therebetween can also be used as the absorbent body 20 other than the fluff absorbent body described above. From the viewpoint of preventing leakage of SAP particles from the absorbent body 20 and stabilizing the shape of the absorbent body 20, a carrier sheet may be provided under the absorbent body 20 or so as to entirely wrap the absorbent body 20 (not shown). The base material of the carrier sheet may be any material as long as it is hydrophilic, and examples thereof include hydrophilic nonwoven fabrics such as tissues, absorbent paper, and air-laid nonwoven fabrics. When a plurality of carrier sheets are provided, the substrates of the plurality of carrier sheets may be the same or different.

(embossed groove)
As shown in FIGS. 1 and 2 , the embossed grooves 60 of the present embodiment extend longitudinally at substantially the center of the skin-side surface of the top sheet 10 in the width direction, and are recessed from the skin-side surface of the top sheet 10 toward the non-skin side. , the bottom surface of which is a bottomed groove reaching the inside of the absorbent body 20 . In this embodiment, the top sheet 10 and the cover sheet 70 are overlapped and enter the internal space of the embossed grooves 60 to constitute the inner wall surface and the bottom surface of the embossed grooves 60, as shown in FIGS. In this embodiment, a relatively dark colored area 71 of the cover sheet 70 is positioned on the bottom surface of the embossed groove 60, and the top sheet 10, the colored area 71, and the absorber 20 on the non-skin side in the thickness direction are arranged. By joining a part to form a joining region 72, the wearer can easily visually recognize the darkly colored area 71 of the cover sheet 70 through the top sheet.

Further, in the present embodiment, the colored area 71 is configured such that rectangular (substantially square) colored portions and non-colored portions are alternately arranged in the longitudinal direction and the width direction. Also, as described later, the colored portion contains a water-soluble colorant and a water-soluble binder. The body fluid is diffused in the longitudinal direction by the embossed grooves 60, and the water-soluble colorant in the colored area 71 reached by the body fluid is dispersed almost uniformly. A relatively thin colored area 71 with good visibility is formed as shown in FIG. 1(b) and FIG. 2(b). The depth of the embossed grooves 60 is in the range of 20% or more and 70% or less of the thickness of the absorbent body 20 . On the other hand, as will be described later, when grooves or low basis weight portions are provided in the absorber 20 as diffusion promoting portions, the numerical range is not limited to this range.

The embossed grooves 60 can be formed, for example, using a pair of unheated press rolls. In the pair of press rolls described above, one roll has a convex shape on its surface corresponding to the shape of the internal space of the embossed grooves, and the other roll has a flat surface. By passing a laminate in which the top sheet 10, the covering sheet 70, and the absorbent body 20 are superimposed in this order, between the pair of press rolls, the top sheet 10 and the covering sheet 70 are recessed toward the absorbent body 20 side. An embossed groove 60 is formed. In addition, the top sheet 10, the colored area 71, and a part of the absorbent body 20 are joined together on the bottom surface of the embossed grooves 60 with the water-soluble binder contained in the colored portion of the colored area 71, but the non-skin side of the top sheet 10 is bonded. Alternatively, another adhesive (for example, a water-soluble binder) layer may be formed on the skin-side surface of the absorbent body 20 to join the top sheet 10, the colored area 71, and part of the absorbent body 20 together. By this bonding, the colored area 71 formed on the covering sheet 70 can be easily seen through the top sheet 10 .

At this time, the bonding strength is not particularly limited, but is, for example, in the range of greater than 0N and 0.2N or less. This is because the pair of press rolls is not heated, and the bonding is mainly due to the water-soluble binder contained in the colored portion of the colored area 71 . If the bonding strength is weak, the top sheet 10 and the cover sheet 70 will separate due to the force when the absorbent body 20 swells in the thickness direction after urination, and the shape of the embossed grooves 60 will tend to collapse, resulting in coloration. Discoloration blurring of area 71 tends to occur. By bonding with an appropriate strength, the embossed grooves 60 are maintained well, and the wearer can clearly grasp the state of urine absorption. If the cover sheet 70 and the top sheet 10 are not joined in the embossed grooves 60 and are separated from each other in the thickness direction, the change in color of the colored area 71 through the top sheet 10 will cause the joining. It's harder to see than if you did it, but it's still visible.

In addition, a general method such as channel embossing or high-frequency embossing using a heated press roll (fine unevenness may be provided at the tip of one convex shape) instead of a pair of unheated press rolls. Therefore, a channel embossment having a heat-sealed portion may be provided in the area from the top sheet 10 to the absorbent body 20 . In this case, since the bonding strength is relatively high, the top sheet 10 and the covering sheet 70 are difficult to separate from the absorbent body 20 due to the force when the absorbent body 20 swells in the thickness direction after urination. It is possible to clearly grasp the state of urine absorption from the change in color.

The number of embossed grooves 60 is not limited to one, and may be plural. The absorbent article 50A shown in FIG. 3 extends from the skin side surface of the top sheet 10 to the inside of the absorbent body 20, and the top sheet 10, the colored area 71 of the covering sheet 70, and the skin side surface of the absorbent body 20 are joined to the bottom surface of the absorbent article 50A. Two embossed grooves 60 extending in the longitudinal direction are formed substantially parallel to each other. In the absorbent article 50A as well, the initially relatively dark colored area 71 changes to a relatively lighter color due to the absorption of bodily fluids, and becomes the colored area 71 over a wider area than the initial area, so that the absorbed amount of bodily fluid can be recognized. Therefore, it is possible to almost accurately determine when to replace the battery with a new one. According to the absorbent article 50A, it is possible to recognize the degree of bodily fluid absorption not only in the longitudinal direction but also in the width direction.

(Diffusion promoting part)
In this embodiment, a diffusion promoting portion (not shown) may be arranged on the non-skin side of the colored area 70 in the thickness direction to promote the diffusion of the water-soluble colorant into the absorbent body 20 due to body fluid absorption. As the diffusion promoting part, for example, one or more concave grooves (not shown) extending in the longitudinal direction on the skin side surface of the absorbent body 20 and concave to the non-skin side, and the bottom surface of the embossed groove 60, the non-skin area of the colored area 71 A low basis weight region (not shown) provided on the side of the absorbent body 20 and having a basis weight lower than that of other regions in the absorbent body 20 may be used. In embodiments in which the low basis weight regions are provided, the topsheet 10 , the colored areas 71 and the low basis weight regions are joined together in the thickness direction to form the joint regions 72 . In the embodiment in which the concave groove is provided, the concave groove may be appropriately selected according to the mechanical strength of the entire absorber 20, and is formed in the range of, for example, a width of 3 mm or more and 20 mm or less and a depth of 3 mm or more and 10 mm or less. Although the number of concave grooves is not particularly limited, it is, for example, about one or more and three or less. Further, 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 0N and less than or equal to 0.2N.

As described above, the region where the colored area 71 of the cover sheet 70 is formed, the skin-side surface of the absorbent body 20 that is in contact with the region in the thickness direction, and the peripheral region thereof are separated from the other regions in the absorbent body 20. is also a low basis weight region (not shown), and the top sheet 10, the colored area 71, and the low basis weight region are joined to form a joint region 72, so that the water-soluble colorant in the colored area 71 is transferred to the absorber 20. It becomes easy to diffuse along the flow of bodily fluid, and the visibility of the color change from a relatively dark color tone to a relatively light color tone of the colored area 71 is improved. The bonding strength is, for example, within the range described above. Alternatively, the embossed grooves 60 as described above may be provided, and the absorbent body 20 around the inner wall and bottom surface of the embossed grooves 60 may be a low basis weight region. The low basis weight region in the absorbent body 20 is the absorbent body 20 formed by laminating a plurality of layers in the thickness direction (at least the uppermost layer is provided with a slit penetrating in the thickness direction at the center in the width direction). It may be configured, but may also be formed by other known methods.

By providing the diffusion promoting portion as described above together with the embossed grooves 60, body fluid can be easily diffused in the absorbent body 20, and the entire absorbent body 20 can be effectively utilized for absorbing body fluid. A colored area 71 is provided on the bottom surface of or immediately above the low basis weight area, so that it is possible to visually confirm the degree of diffusion and absorption.

(coating sheet)
The covering sheet 70 is positioned between the top sheet 10 and the absorbent body 20 and covers at least the skin-side surface of the absorbent body 20 . The covering sheet 70 may cover the entire absorbent body 20 . The cover sheet 70 has a colored area 71 extending longitudinally in the center of the width direction of the cover sheet 70 and containing a water-soluble colorant and a water-soluble binder. In this embodiment, the cover sheet 70 is arranged so that the colored area 71 is positioned on the bottom surface of the embossed groove 60 . More specifically, the colored area 71 is arranged in the longitudinal direction of the absorbent article 50 in a front side portion that mainly contacts the lower abdomen of the wearer and a crotch portion that is connected to the front side portion and mainly contacts the crotch portion of the wearer. and a rear side portion connected to the crotch portion and mainly contacting the buttocks of the wearer so as to extend longitudinally mainly in the region of the crotch portion. The covering sheet 70 receives bodily fluids from the top sheet 10 and transfers them to the absorbent body 20 . permeation, and the relatively dark color of the colored area 71 spreads to become a relatively light color, so that the body fluid absorption amount of the absorbent body 20 at that time can be confirmed, and the absorbency of the new product can be confirmed. It is possible to determine when the article 50 should be replaced.

(colored area)
The colored area 71 of the cover sheet 70 may be colored in its entirety, or may be composed of a colored portion and a non-colored portion. In a preferred embodiment, the colored portions and the non-colored portions are alternately arranged in the longitudinal direction, the width direction and/or the diagonal direction intersecting these directions. In this embodiment shown in FIGS. 1 and 2, square colored portions and square non-colored portions are alternately arranged in a grid pattern. According to this configuration, there is a color contrast between the colored portion and the non-colored portion, but when the water-soluble colorant diffuses due to absorption of body fluid, the color of the colored area 71 becomes blurred and the contrast becomes difficult to recognize. Therefore, it becomes easy to visually perceive the change in color.

Although the material of the cover sheet 70 is not particularly limited, a hydrophilic cover sheet 70 is used in a preferred embodiment, and examples thereof include hydrophilic nonwoven fabric and pulp sheets. Examples of hydrophilic nonwoven fabrics include air-through nonwoven fabrics, point-bonded nonwoven fabrics, spunbonded nonwoven fabrics, meltblown nonwoven fabrics, and air-laid nonwoven fabrics. Pulp sheets include, for example, pulp-containing nonwoven fabric obtained by integrating a valve layer on one side of a spunbond nonwoven fabric, tissue, absorbent paper, and the like. The basis weight of the cover sheet 70 is, for example, in the range of 10 g/m ² or more and 30 g/m ² or less. By using such a cover sheet 70, the water-soluble colorant can be easily retained on the sheet, and since the colorant is water-soluble, compared to the case where the cover sheet 70 is made of hydrophobic fibers, Better retention of water-soluble coloring agents.

One or more of known water-soluble colorants can be used here, and examples of water-soluble colorants include dyes for food additives. By using various water-soluble dyes for food additives, safety can be ensured even if the coloring agent eluted with urine adheres to the wearer's crotch region. As the water-soluble binder, one that does not adversely affect the skin can be used without any particular limitation. Saccharides, carboxymethyl cellulose, carboxyethyl cellulose, carboxymethylated starch or salts thereof, starch, polysaccharide derivatives such as methyl cellulose and ethyl cellulose, polyvinyl alcohol, polyvinyl alcohol derivatives, salts of unsaturated carboxylic acid polymers or copolymers, unsaturated carboxylic acids Synthetic polymer compounds such as salts of copolymers of acids, unsaturated carboxylic acids, and copolymerizable monomers are included.

FIG. 4 shows a modification of the colored area 71. As shown in FIG. As shown in FIGS. 4(a) to (d), it is sufficient that the colored portions and the non-colored portions are alternately formed in the longitudinal direction, the width direction and/or the oblique direction. The shape is not particularly limited. Moreover, instead of the regular shape shown in FIGS. 1 and 4, for example, the sizes of the patterns (shapes) of the colored portion and the non-colored portion may be changed in the longitudinal direction. More specifically, for example, if the pattern of the front side and the back side is made stronger than the pattern of the crotch part, it is easy to recognize that the urine is excreted in the early stage, and the end part is also easy to see. Absorption becomes easier to recognize.

<Back seat>
The back sheet 30 may be formed using a liquid-impermeable base material that does not allow body fluids held by the absorbent sheet 20 to wet the clothes of the wearer. A film, a composite sheet which is a laminate of a resin film and a nonwoven fabric, and the like can be mentioned. The nonwoven fabric used for the composite sheet is not particularly limited in manufacturing method, and examples thereof include single-layer nonwoven fabrics such as spunbond nonwoven fabrics and meltblown nonwoven fabrics, spunbond nonwoven fabric/meltblown nonwoven fabric laminates, spunbond nonwoven fabric/meltblown nonwoven fabric/spunbond nonwoven fabric laminates. Composite nonwoven fabrics such as bodies, composite materials thereof, and the like. Examples of resin films include polyester, polyvinyl alcohol, polyethylene, polypropylene, composite films of polyethylene and polypropylene, and the like.

The basis weight of the backsheet 30 is, for example, in the range of 15 g/m ² or more and 60 g/m ^{2 or} less from the viewpoint of strength and workability. In addition, it is preferable that the back sheet 30 has air permeability in order to prevent stuffiness during wearing. In order to make the back sheet 30 air-permeable, for example, a filler may be added to the base resin film, or the back sheet 30 may be embossed. Calcium carbonate can be used as a filler, and a known method can be used without limitation as a method for blending the filler.

<Three-dimensional gather>
For example, the three-dimensional gathers 40 extend in the longitudinal direction of the absorbent article 50 at both widthwise ends of the skin-side surface of the top sheet 10 in order to prevent sideways leakage of bodily fluid excreted by the wearer of the absorbent article 50. You may provide so that it may extend along. The three-dimensional gathers 40 include an elastic stretchable member 40a and a water-repellent and/or waterproof sheet member 40b.

The elastic stretchable member 40a is arranged in the vicinity of the free end (the other end) of the sheet member 40b along the longitudinal direction, and provides the free end with uprightness so that the free end of the sheet member 40b and the area near the seat member 40b can be used by the wearer. Make it deformable according to the body shape of. In the present embodiment, the sheet member 40b has one widthwise end (fixed end) fixed near both widthwise ends of the skin side surface of the back sheet 30, and a widthwise intermediate portion fixed near both widthwise ends of the skin side surface of the top sheet 10. and the other end in the width direction is a free end having an upright property. The fixing position of the fixed end (one end in the width direction) of the sheet member 40b is not limited to this embodiment. all or part of each edge of the joined body, near both width direction ends of the skin side or non-skin side of the joined body, near both width direction ends of the skin side of the top sheet 10, and the like.

The sheet member 40b is a water-repellent and/or waterproof sheet, and is made of, for example, non-woven fabric. As the nonwoven fabric for the first sheet member, a water-repellent and/or waterproof (liquid-impermeable) nonwoven fabric made of hydrophobic fibers can be used without particular limitation. Composite nonwoven fabrics (SMS nonwoven fabrics), which are nonwoven fabric/meltblown nonwoven fabric/spunbond nonwoven fabric laminates, and the like can be mentioned. The basis weight of the sheet member 40b is, for example, in the range of 13 g/m ² or more and 20 g/m ² or less. As the elastic stretchable member 40a, for example, a string-like, string-like, or belt-like member made of natural rubber, synthetic rubber, polyurethane, or the like can be used as appropriate.

Although the present invention has been described using the 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 is obvious to those skilled in the art that various modifications or improvements can be made to the above embodiments. In addition, it is clear from the description of the scope of the claims that forms with such modifications or improvements can also be included in the technical scope of the present invention.

REFERENCE SIGNS LIST 10 top sheet 20 absorber 30 back sheet 40 three-dimensional gathers 50, 50A, 50B, 50C, 50D, 50E absorbent article 60 embossed groove 70 covering sheet 71 colored area 72 joining area

Claims (10)

An absorbent article comprising a liquid-permeable topsheet, a liquid-impermeable backsheet, and an absorbent body disposed therebetween,
In the top sheet, a change in color of the absorber is visible,
a covering sheet disposed between the top sheet and the absorbent body and covering at least the skin-side surface of the absorbent body;
an embossed groove extending in the longitudinal direction on the skin-side surface of the top sheet, recessed toward the non-skin side, reaching the interior of the absorbent body, and the top sheet and the covering sheet entering the internal space;
A colored area is provided on the covering sheet, and the colored area contains a water-soluble colorant that diffuses into the absorbent body by absorption of bodily fluids, and a water-soluble binder,
An absorbent article, wherein a bottom surface of the embossed grooves has a joint region where the top sheet, the colored area, and the absorbent body are joined. 2. The absorbent article according to claim 1, further comprising a diffusion promoting part disposed on the non-skin side in the thickness direction of said colored area and promoting diffusion of said water-soluble colorant into said absorbent body due to body fluid absorption. 3. The absorbent article according to claim 2, wherein said diffusion promoting part is one or a plurality of concave grooves provided so as to extend longitudinally on the skin-side surface of said absorbent body and concave toward the non-skin side. The diffusion promoting portion is a low basis weight region provided on the bottom surface of the embossed groove on the non-skin side of the colored area and having a basis weight lower than that of other regions in the absorbent body, wherein the top sheet and the 4. The absorbent article of claim 2 or 3, wherein the colored area and the low basis weight region are joined to form the joined region. The absorbent article according to any one of claims 1 to 4, wherein the joint strength in the joint region is greater than 0N and equal to or less than 0.2N. 6. The absorbent article according to any one of claims 1 to 5, wherein said colored area comprises a colored portion and a non-colored portion. 7. The colored portion and the non-colored portion according to any one of claims 1 to 6, wherein the colored portion and the non-colored portion are alternately arranged in a longitudinal direction, a width direction, or an oblique direction intersecting these directions. absorbent article. The absorbent article according to any one of claims 1 to 7, wherein the covering sheet comprises a hydrophilic nonwoven fabric or a pulp sheet. The absorbent article according to any one of claims 1 to 8, wherein the water-soluble colorant is a food additive colorant. 10. The absorbent article according to any one of claims 1 to 9, wherein at least part of said embossed grooves is heat-sealed.

Images