Patent Application
20200289341
The present invention relates to an absorbent article such as a disposable diaper.
Conventionally, improving absorption performance for loose stools has been one technical problem of absorbent articles. Loose stools are often the case particularly with babies that are a few months old, and have high viscosities and are likely to flow. Accordingly, loose stools are unlikely to be absorbed into a diaper, and loose stools remaining on the topsheet may flow along the topsheet and leak to the outside.
There are known absorbent articles in which a liquid permeable intermediate sheet is provided between a topsheet and an absorbent member in order to improve absorbing performance of the absorbent member. The intermediate sheet in this case is a sheet that forms a layer different from the absorbent member, and is called a sublayer or a second sheet. For example, Patent Literature 1 discloses an absorbent article in which an uneven second sheet is provided between an absorbent member and a topsheet made of a liquid permeable material, the second sheet having a plurality of recessed grooves on both the front face side and the back face side thereof. Furthermore, Patent Literature 2 discloses an absorbent article in which an uneven second sheet is provided between an absorbent member having an absorbent member core and a liquid permeable topsheet, the second sheet having at least either a plurality of projections projecting toward the topsheet or a plurality of recesses recessed toward the absorbent member core.
Patent Literature 1: JP 2010-17342A
Patent Literature 2: JP 2012-61014A
The present invention is directed to an absorbent article including a liquid permeable topsheet, a liquid retentive absorbent member, and a liquid permeable intermediate sheet arranged between the topsheet and the absorbent member. A non-skin-facing surface of the intermediate sheet has a plurality of contact portions that are in contact with the absorbent member adjacent to the intermediate sheet, and a non-contact portion that is not in contact with the absorbent member. When the intermediate sheet is pressed from the absorbent member side in a thickness direction at a pressure of 30 gf/cm2, a proportion of a total area of contact faces, on which the plurality of contact portions located on a pressed face that has been pressed are in contact with the absorbent member, with respect to the pressed face, is 80% or less.
Patent Literatures 1 and 2 make no mention whatsoever of body pressure or the like that will be applied to an absorbent article when a baby that is a few months old wears the absorbent article. The absorbent articles disclosed in Patent Literatures 1 and 2 include an uneven second sheet, but Patent Literatures 1 and 2 make no mention whatsoever of the properties of the uneven second sheet when the absorbent articles are worn.
Accordingly, the present invention relates to an absorbent article that can effectively absorb loose stools, and suppresses attachment of loose stools to the wearer's skin.
Hereinafter, the absorbent article according to the present invention will be described based on a preferred embodiment thereof with reference to the drawings.
As shown in
Note that, in this specification, “skin-facing surface” is a surface that faces the wearer's skin, that is, the side relatively close to the wearer's skin when the absorbent article is worn, of the absorbent article or its constituent member (e.g., the topsheet 2), and “non-skin-facing surface” is a surface that faces the side (clothing side) opposite to the skin, that is, the side relatively distant from the wearer's skin when an absorbent article is worn, of the absorbent article or its constituent member. Note that “when worn” means a normal and proper worn position, that is, a state in which the correctly worn position of the absorbent article is maintained, and does not encompass a state in which the absorbent article is not in the correctly worn position.
Each of the topsheet 2 and the backsheet 3 has a size larger than that of the absorbent member 4, and extends outward from the outer edge of the absorbent member 4. The topsheet 2 will be described later in detail. The backsheet 3 forms an outer shape of the diaper 1 in its open and uncontracted state as shown in
In a plan view as shown in
The absorbent core 40 has a monolayer structure, and, in a plan view as shown in
The intermediate sheet 5 is a sheet that is different from the absorbent member 4 and is interposed between the topsheet 2 and the absorbent member 4, and is a sheet that is also called a sublayer or a second sheet. The intermediate sheet 5 is rectangular in a plan view as shown in
Side sheets 6 are respectively provided on the right and left sides in the longitudinal direction X of the topsheet 2. Each of the side sheets 6 includes an inner edge portion that extends in the longitudinal direction X, and an outer edge portion that is located on the outer side in the lateral direction Y with respect to the inner edge portion, and extends in the longitudinal direction X. In a plan view as shown in
The diaper 1 is a so-called open type disposable diaper, and, as shown in
Next, the intermediate sheet 5 described above will be described in detail with reference to
As shown in
There is no particular limitation on the arrangement of the skin-side projections 51 and the non-skin-side projections 52, but, in the diaper 1, in a plan view of the intermediate sheet 5 as shown in
As shown in
As shown in
In a plan view of the intermediate sheet 5 from the absorbent member 4 side, which is the non-skin-facing surface side, the adjacent distance between adjacent contact portions 54S that are the closest to each other is preferably 0.5 mm or more, and more preferably 1 mm or more, is preferably 10 mm or less, and more preferably 8 mm or less, and, specifically, is preferably from 0.5 to 10 mm, and more preferably from 1 to 8 mm, from the viewpoint of improving the dispersibility of loose stools that have shifted.
In a plan view of the intermediate sheet 5 from the topsheet 2 side, which is the skin-facing surface side, the adjacent distance between adjacent skin-side contact portions 53S that are the closest to each other is preferably 0.5 mm or more, and more preferably 1 mm or more, is preferably 10 mm or less, and more preferably 8 mm or less, and, specifically, is preferably from 0.5 to 10 mm, and more preferably from 1 to 8 mm, from the viewpoint of stocking loose stools that have shifted. The adjacent distance between is measured using the following measuring method.
The adjacent distance between adjacent contact portions 54S on the non-skin-facing surface of the intermediate sheet 5 or the adjacent distance between adjacent skin-side contact portions 53S on the skin-facing surface can be measured using the following method.
First, a cut sample with a size of 50 mm (CD direction)×50 mm (MD direction) is cut out from the intermediate sheet 5. The cut sample is placed without applying pressure such that the side that is to be measured (e.g., the non-skin-facing surface on the absorbent member 4 side) is oriented upward, a transparent acrylic plate with a weight of 50 g is placed from above, and a weight of 700 g is further installed on the acrylic plate. In a state in which a load of 30 gf/cm2 is applied, the surface shape of the cut sample is measured in a range of 40 mm (CD direction)×40 mm (MD direction) using a high-precision shape measurement system KS-1100 manufactured by Keyence at a measurement pitch of 50 μm and a movement speed of 10 cm/s, and an image is captured. Next, the captured image is analyzed using a shape analysis application KS-Analyzer manufactured by Keyence, a portion that extends from a position with the largest thickness to a portion with a thickness smaller by 500 μm than the largest thickness is extracted and subjected to binarization processing, and thus an image of a portion that is in contact with a member (the absorbent member 4) adjacent to the non-skin-facing surface is obtained. This image is captured by an Image-Pro Plus (manufactured by Nippon Roper K.K.), the black and white contrast is set to 100 by emphasizing the contrast, and noise is removed through filtering processing (median, 5×5 is performed five times). Subsequently, a line connecting centers of gravity of adjacent contact portions 54S is drawn. The center of gravity of a contact portion 54S is obtained as follows: a perpendicular line that is perpendicular to the Feret diameter of one contact portion 54S is drawn so as to pass through the center of the Feret diameter length, and the center between two points at which the perpendicular line intersects the contour of the contact portion is taken as the center of gravity. In this manner, a line connecting centers of gravity of contact portions that are the closest to each other is drawn, the distance of the non-contact portion 54N on that line is measured, and the thus obtained measurement value is taken as the adjacent distance between the contact portions 54S. Note that the adjacent distance between the skin-side contact portions 53S is measured as follows: the cut sample is placed such that the side that is to be measured (e.g., the skin-facing surface on the topsheet 2 side) is oriented upward, and measurement is performed in a similar way to that of the adjacent distance between the contact portions 54S. The load 30 gf/cm2 is assumed to be pressure (pressure that is to be withstood) that will be applied to the rear portion of the diaper 1 when a baby that is a few months old and wearing the diaper is sleeping lying face up.
When viewed in a cross-section of the diaper 1, a height H1 (see
Furthermore, when viewed in a cross-section of the diaper 1, a height H2 (see
As shown in
In a plan view from the skin-facing surface side of the intermediate sheet 5, the wall portions 51W of the skin-side projections 51 have ring-like structures respectively about the top portions 51T of the skin-side projections 51. Furthermore, in a plan view from the non-skin-facing surface side of the intermediate sheet 5, the wall portions 52W of the non-skin-side projections 52 have ring-like structures respectively about the top portions 52T of the non-skin-side projections 52. As shown in
Furthermore, when taking the “ring-like” structure as a three-dimensional shape, examples thereof include any ring-like structures having the shapes of a circular cylinder, an oblique circular cylinder, an elliptic cylinder, a truncated cone, a truncated oblique cone, a truncated elliptic cone, a truncated quadrangular pyramid, a truncated oblique quadrangular pyramid, and the like, but it is preferable to have the shape of a circular cylinder, an elliptic cylinder, a truncated cone, or a truncated elliptic cone, from the viewpoint of maintaining the internal spaces even when pressure is applied thereto.
As described above, the intermediate sheet 5 is formed from an uneven nonwoven fabric in which the plurality of skin-side projections 51 and the non-skin-side projections 52 are arranged in the longitudinal direction X and the lateral direction Y as shown in
From the viewpoint of making it possible to effectively absorb loose stools, improving the dispersibility of loose stools that have been absorbed, suppressing return of loose stools to the topsheet 2, and suppressing attachment of loose stools to the wearer's skin, when the intermediate sheet 5 is pressed from the absorbent member 4 side in the thickness direction at a pressure of 30 gf/cm2, the proportion of the total area of contact faces T54, on which the plurality of contact portions 54S located on a pressed face Ta that has been pressed are in contact with the absorbent member 4, with respect to the pressed face Ta ((the total area of the contact faces T54/the pressed face Ta)×100) (a non-skin-side contact area percentage R54) is 80% or less, preferably 75% or less, and more preferably 70% or less, is preferably 20% or more, and more preferably 25% or more, and, specifically, is preferably from 20 to 75%, and more preferably from 25 to 70%. In this example, the pressed face Ta means a certain face in a predetermined range that is pressed at a pressure of 30 gf/cm2, and, in a later-described method for measuring the contact area percentage, it is a face in a range that is pressed by an acrylic plate that is a non-deformable member. In other words, it is also an area of a sample that is pressed by an acrylic plate. Note that the pressure 30 gf/cm2 is assumed to be pressure (pressure that is to be withstood) that will be applied to the rear portion of the diaper 1 when a baby that is a few months old and wearing the diaper is sleeping lying face up. The non-skin-side contact area percentage R54 is measured using the following measuring method.
From the viewpoint of making it possible to effectively absorb loose stools and to easily stock loose stools that have been absorbed, suppressing return of loose stools to the topsheet 2, and suppressing attachment of loose stools to the wearer's skin, when the intermediate sheet 5 is pressed from the topsheet 2 side in the thickness direction at a pressure of 30 gf/cm2, the proportion of the total area of contact faces T53, in which the plurality of skin-side contact portions 53S located on a pressed face Ta that has been pressed are in contact with the topsheet 2, with respect to the pressed face Ta ((the total area of the contact faces T53/the pressed face Ta)×100) (a skin-side contact area percentage R53) is preferably larger than the proportion of the total area of the contact faces T54 on which the contact portions 54S are in contact with the absorbent member 4 (the non-skin-side contact area percentage R54). Specifically, the ratio of the skin-side contact area percentage R53 with respect to the non-skin-side contact area percentage R54 is preferably 1.1 or more, and more preferably 1.5 or more, is preferably 10 or less, and more preferably 7 or less, and, specifically, is preferably from 1.1 to 10, and more preferably from 1.5 to 7.
From similar viewpoints, the skin-side contact area percentage R53 is preferably 90% or less, and more preferably 85% or less, is preferably 20% or more, and more preferably 30% or more, and, specifically, is preferably from 20 to 90%, and more preferably from 30 to 85%. The skin-side contact area percentage R53 is measured using the following measuring method.
The contact area between the intermediate sheet 5 and a member (the topsheet 2) adjacent to the skin-facing surface of the intermediate sheet 5 or a member (the absorbent member 4) adjacent to the non-skin-facing surface can be measured using the following method.
First, a cut sample with a size of 50 mm (CD direction)×50 mm (MD direction) is cut out from the intermediate sheet 5. The cut sample is placed without applying pressure such that the side that is to be measured (e.g., the non-skin-facing surface on the absorbent member 4 side) is oriented upward, a transparent acrylic plate with a weight of 50 g is placed from above, and a weight of 700 g is further installed on the acrylic plate. In a state in which a load of 30 gf/cm2 is applied, the surface shape of the cut sample is measured in a range of 40 mm (CD direction)×40 mm (MD direction) using a high-precision shape measurement system KS-1100 manufactured by Keyence at a measurement pitch of 50 μm and a movement speed of 10 cm/s, and an image is captured. Next, the captured image is analyzed using a shape analysis application KS-Analyzer manufactured by Keyence, a portion that extends from a position with the largest thickness to a portion with a thickness smaller by 500 μm than the largest thickness is extracted and subjected to binarization processing, and thus an image of a portion that is in contact with a member (the absorbent member 4) adjacent to the non-skin-facing surface is obtained. This image is captured by an Image-Pro Plus (manufactured by Nippon Roper K.K.), the black and white contrast is set to 100 by emphasizing the contrast, noise is removed through filtering processing (median, 5×5 is performed five times), and counting processing is performed to measure the black and white areas. Subsequently, the total black area, which is the total area of the contact faces T54 on which the plurality of contact portions 54S are in contact with the absorbent member 4, is divided by the measurement range area (40 mm (CD direction)×40 mm (MD direction)), which is the total of the black and white areas, so that the non-skin-side contact area percentage R54 is calculated. Note that the skin-side contact area percentage R53 is measured as follows: the cut sample is placed such that the side that is to be measured (e.g., the skin-facing surface on the topsheet 2 side) is oriented upward, and measurement is performed in a similar way to that of the non-skin-side contact area percentage R54.
Furthermore, the basis weight of the intermediate sheet 5 may be selected as appropriate according to the application, and, when a sheet is used as an intermediate sheet for a disposable diaper, the average value of the entire sheet is preferably from 10 to 80 g/m2, and more preferably from 15 to 70 g/m2.
The intermediate sheet 5 described above can be produced, for example, using an air-through nonwoven fabric or the like having a monolayer structure or a multilayer structure in which multiple layers are layered as a raw material nonwoven fabric, by placing the air-through nonwoven fabric or the like on a support member having a large number of protrusions, and applying warm air to the air-through nonwoven fabric or the like on the support member, thereby shaping the through nonwoven fabric or the like into an uneven shape. Note that the shape of the protrusions is a shape corresponding to the projecting shape of the skin-side projections 51 and the non-skin-side projections 52, and examples thereof include shapes of cones such as a circular cone, a truncated cone, a pyramid, a truncated pyramid, and an oblique cone. Aspects of the method for producing the intermediate sheet 5 not specifically described may be similar to those of the methods described, for example, in JP 2013-133574A, JP 2012-149370A, JP 2012-149371A, or the like.
Next, as the topsheet 2, a flat nonwoven fabric and the like conventionally used as a topsheet to form this type of absorbent article can be used without particular limitation. It is more effective to use a nonwoven fabric or the like with a specific uneven shape according to the application of the above-described characteristic configuration of the intermediate sheet 5. The uneven topsheet 2 may be formed from one sheet member, but in the diaper 1 it is formed from a layered member of a first sheet 21 and a second sheet 22 as shown in
It is sufficient that the plurality of projections 24 are arranged at least in the crotch portion 1M, but in the diaper 1 they are arranged over the entire range from the front portion 1F to the rear portion 1R. The projections 24 of the topsheet 2 preferably have the following configuration.
A height T24 (see
A thickness T21 (see
A thickness T22 (see
Furthermore, the number of projections 24 per area of 10 cm2 on the uneven topsheet 2 is preferably from 10 to 150, and more preferably from 30 to 120.
As sheet materials for forming the first sheet 21 and the second sheet 22, various sheet materials known as a material for forming a topsheet in absorbent articles such as disposable diapers or sanitary napkins can be used, but it is preferable to use a nonwoven fabric from the viewpoint of improving the liquid permeability and the feel on the skin. As constituent fibers of a nonwoven fabric, heat fusible fibers are preferably used. A nonwoven fabric may contain, in addition to heat fusible fibers, fibers that are not heat fusible (e.g., cotton fibers, etc.) as constituent fibers. The basis weight of the first sheet 21 and the second sheet 22 may be selected as appropriate according to the application, and, when a sheet is used as the topsheet 2 for a disposable diaper, the basis weight is preferably 5 g/m2 or more, and more preferably 10 g/m2 or more, is preferably 40 g/m2 or less, and more preferably 30 g/m2 or less, and is preferably from 5 to 40 g/m2, and more preferably from 10 to 30 g/m2.
The plurality of joined regions 23 can be formed using various methods. If the first sheet 21 and the second sheet 22 contain heat fusible fibers, it is possible to use fusion-bonding using heat, ultrasonic waves, high frequency, or the like. Regardless of the material for the first sheet 21 and the second sheet 22, it is possible to use bonding using an adhesive. At the joined regions 23, the first sheet 21 and the second sheet 22 are pressed in one piece, and the sheets 21 and 22 have a density higher than that in the other portions. Preferably, the sheets 21 and 22 are bonded to each other though thermal fusion-bonding in which a constituent resin of one or both of the sheets are melted and then cured.
As shown in
Method for Measuring Area Over which Holes 25 and Skin-Side Non-Contact Portions 53N Overlap Each Other
A transparent acrylic plate with a weight of 50 g is placed from above on the topsheet 2, and an image viewed from above with a load of 30 gf/cm2 applied thereto is captured. Then, a hole area S25 of the holes 25 of the topsheet 2 and an area S53N of the skin-side non-contact portions 53N, of the intermediate sheet 5, that overlap the holes 25 are measured from the captured image viewed from above, the area percentage ((S53N/S25)×100) is calculated from the measured values, and this value is obtained as the area over which the holes 25 and the skin-side non-contact portions 53N overlap each other. Note that, in other words, the area S53N of the skin-side non-contact portions 53N that overlap the holes 25 is a value obtained by subtracting the area of the skin-side contact portions 53S that overlap the holes 25 from the hole area S25 of the holes 25.
In the topsheet 2 described above, for example, the first sheet 21 is shaped into an uneven shape by guiding the first sheet 21 into a portion in which a first roller whose circumferential face has an uneven shape meshes with a second roller whose circumferential face has an uneven shape that conforms to the uneven shape of the first roller. While the first sheet 21 shaped into an uneven shape is held with the uneven shape being maintained on the circumferential face of the first roller through suction, the second sheet 22 is placed over the first sheet 21 shaped into an uneven shape, and the second sheet 22 is joined to the first sheet 21 at positions on the projections of the first roller, so that the joined regions 23 are formed, and, at the same time, the holes 25 are formed at the joined regions 23. Accordingly, the topsheet 2 can be produced. Aspects of the method for producing the topsheet 2 not specifically described may be similar to the method for producing a topsheet described in JP 2004-174234A or the method for producing a composite sheet described in JP 2008-106420A.
The absorbent article according to the present invention may be, for example, the diaper 1 according to an embodiment shown in
In the diaper 1 shown in
The intermediate sheet 5 shown in
The absorbent article according to the present invention was described above based on preferred embodiments thereof, but the absorbent article according to the present invention is not limited to the foregoing embodiments, and various changes may be made.
For example, the absorbent article according to the present invention is not limited to the above-described open-type disposable diaper, and may also be a pull-on disposable diaper.
1. An absorbent article comprising a liquid permeable topsheet, a liquid retentive absorbent member, and a liquid permeable intermediate sheet arranged between the topsheet and the absorbent member,
wherein a non-skin-facing surface of the intermediate sheet has a plurality of contact portions that are in contact with the absorbent member adjacent to the intermediate sheet, and a non-contact portion that is not in contact with the absorbent member, and
when the intermediate sheet is pressed from the absorbent member side in a thickness direction at a pressure of 30 gf/cm2, a proportion of a total area of contact faces, on which the plurality of contact portions located on a pressed face that has been pressed are in contact with the absorbent member, with respect to the pressed face, is 80% or less.
2. The absorbent article as set forth in clause 1, wherein, in a plan view of the absorbent article, the plurality of contact portions are separate from each other in one direction.
3. The absorbent article as set forth in clause 1, wherein, in a plan view of the absorbent article, the plurality of contact portions are separate from each other in two directions.
4. The absorbent article as set forth in any one of clauses 1 to 3,
wherein a skin-facing surface of the intermediate sheet has skin-side contact portions that are in contact with the topsheet, and
when the intermediate sheet is pressed from the topsheet side in the thickness direction at a pressure of 30 gf/cm2, a proportion of a total area of contact faces, on which the plurality of skin-side contact portions located on a pressed face that has been pressed are in contact with the topsheet, with respect to the pressed face, is larger than the proportion of the total area of the contact faces, on which the contact portions on the non-skin-facing surface side are in contact with the absorbent member, with respect to the pressed face.
5. The absorbent article as set forth in any one of clauses 1 to 4,
wherein the topsheet comprises a layered member comprising a first sheet and a second sheet, a plurality of joined regions are formed by partially joining the first sheet and the second sheet in the layered member, and the first sheet projects in a direction away from the second sheet in regions other than the joined regions, and forms a plurality of projections projecting toward the wearer's skin-side, and
a non-skin-facing surface of the second sheet has a flat face.
6. The absorbent article as set forth in clause 5, wherein the joined regions of the topsheet have holes that extend through the joined regions.
7. The absorbent article as set forth in clause 6, wherein a skin-facing surface of the intermediate sheet has a skin-side non-contact portion that is recessed so as to project toward the non-skin-facing surface side and that is not in contact with the topsheet.
8. The absorbent article as set forth in clause 7, wherein the holes of the topsheet and the skin-side non-contact portion of the intermediate sheet overlap each other in the thickness direction.
9. The absorbent article as set forth in any one of clauses 1 to 8,
wherein, on the skin-facing surface of the intermediate sheet, skin-side contact portions that are in contact with the topsheet are separate from each other in both of a longitudinal direction and a lateral direction, and
each of the skin-side contact portions is surrounded by a skin-side non-contact portion that is not in contact with the topsheet.
10. The absorbent article as set forth in any one of clauses 1 to 9, wherein, in a plan view of the intermediate sheet from the absorbent member side, which is the non-skin-facing surface side, an adjacent distance between adjacent contact portions that are the closest to each other is preferably 0.5 mm or more, and more preferably 1 mm or more, is preferably 10 mm or less, and more preferably 8 mm or less.
11. The absorbent article as set forth in any one of clauses 1 to 10, wherein, in a plan view of the intermediate sheet from topsheet side, which is the skin-facing surface side, an adjacent distance between adjacent skin-side contact portions that are the closest to each other is is preferably 0.5 mm or more, and more preferably 1 mm or more, is preferably 10 mm or less, and more preferably 8 mm or less.
12. The absorbent article as set forth in any one of clauses 1 to 11,
wherein the intermediate sheet has a plurality of skin-side projections projecting toward the skin-facing surface side and having internal spaces, a skin-side recess positioned between the plurality of skin-side projections, a plurality of non-skin-side projections projecting toward the non-skin-facing surface side and having internal spaces, and a non-skin-side recess positioned between the plurality of non-skin-side projections, and
the skin-side projections and the non-skin-side projections are arranged such that, in a plan view of the intermediate sheet, the skin-side projections and the non-skin-side projections are alternately arranged in a successive manner in two different directions that intersect each other.
13. The absorbent article as set forth in clause 12, wherein the two different directions are such that a first direction in the plane, and a second direction intersecting the first direction intersect each other at an angle of 30 to 90 degrees.
14. The absorbent article as set forth in clause 12 or 13, wherein the skin-side projections and the non-skin-side projections are alternately arranged in a successive manner along a longitudinal direction and a lateral direction.
15. The absorbent article as set forth in any one of clauses 1 to 14,
wherein the intermediate sheet has a plurality of skin-side projections projecting toward the skin-facing surface side and having internal spaces, and
when viewed in a cross-section of the absorbent article, a height of the internal spaces between the skin-side projections and the absorbent member is preferably 0.5 mm or more, and more preferably 1 mm or more, is preferably 20 mm or less, and more preferably 10 mm or less.
16. The absorbent article as set forth in any one of clauses 1 to 15,
wherein the intermediate sheet has a plurality of non-skin-side projections projecting toward the non-skin-facing surface side and having internal spaces, and
when viewed in a cross-section of the absorbent article, a height of the internal spaces between the non-skin-side projections and the topsheet is preferably 0.5 mm or more, and more preferably 1 mm or more, is preferably 20 mm or less, and more preferably 10 mm or less.
17. The absorbent article as set forth in any one of clauses 1 to 16,
wherein the intermediate sheet has a plurality of skin-side projections projecting toward the skin-facing surface side and having internal spaces, a skin-side recess positioned between the plurality of skin-side projections, a plurality of non-skin-side projections projecting toward the non-skin-facing surface side and having internal spaces, and a non-skin-side recess positioned between the plurality of non-skin-side projections,
the skin-side projections respectively have wall portions having ring-like structures and located between top portions thereof and opening portions of the internal spaces, and
the non-skin-side projections respectively have wall portions having ring-like structures and located between top portions thereof and opening portions of the internal spaces.
18. The absorbent article as set forth in any one of clauses 1 to 17,
wherein the intermediate sheet has a plurality of skin-side projections projecting toward the skin-facing surface side and having internal spaces, a skin-side recess positioned between the plurality of skin-side projections, a plurality of non-skin-side projections projecting toward the non-skin-facing surface side and having internal spaces, and a non-skin-side recess positioned between the plurality of non-skin-side projections, and
the skin-side projections and the non-skin-side projections are formed in the shape of truncated pyramids in which top portions thereof are flat.
19. The absorbent article as set forth in clause 17, wherein the wall portions of the skin-side projections have ring-like structures respectively about the top portions of the skin-side projections.
20. The absorbent article as set forth in any one of clauses 1 to 19, wherein, when the intermediate sheet is pressed from the absorbent member side in the thickness direction at a pressure of 30 gf/cm2, a non-skin-side contact area percentage, which is a proportion of a total area of contact faces, on which the plurality of contact portions located on a pressed face that has been pressed are in contact with the absorbent member, with respect to the pressed face((the total area of the contact faces/the pressed face)×100), is 80% or less, preferably 75% or less, and more preferably 70% or less, is preferably 20% or more, and more preferably 25% or more.
21. The absorbent article as set forth in clause 20, wherein, when the intermediate sheet is pressed from the topsheet side in the thickness direction at a pressure of 30 gf/cm2, a ratio of a skin-side contact area percentage with respect to the non-skin-side contact area percentage is preferably 1.1 or more, and more preferably 1.5 or more, is preferably 10 or less, and more preferably 7 or less, the skin-side contact area percentage being a proportion of a total area of contact faces on which the plurality of skin-side contact portions located on a pressed face that has been pressed are in contact with the topsheet, with respect to the pressed face ((the total area of the contact faces/the pressed face)×100).
22. The absorbent article as set forth in clause 21, wherein the skin-side contact area percentage is preferably 90% or less, and more preferably 85% or less, is preferably 20% or more, and more preferably 30% or more.
23. The absorbent article as set forth in any one of clauses 1 to 22,
wherein the topsheet comprises a layered member comprising a first sheet and a second sheet,
the topsheet has a plurality of joined regions formed by partially joining the first sheet and the second sheet,
the first sheet projects in a direction away from the second sheet in regions other than the joined regions, the regions being surrounded by the joined regions, and forms a plurality of projections projecting toward the wearer's skin-side, and
a height of the projections is preferably 0.3 mm or more, and more preferably 0.5 mm or more, is preferably 3 mm or less, and more preferably 2.5 mm or less.
24. The absorbent article as set forth in any one of clauses 1 to 23,
wherein the topsheet comprises a layered member comprising a first sheet and a second sheet, and a plurality of joined regions are formed by partially joining the first sheet and the second sheet in the layered member,
the joined regions have holes that extend through the joined regions, and
the holes of the topsheet and a skin-side non-contact portion that is not in contact with the topsheet on the skin-facing surface of the intermediate sheet overlap each other in the thickness direction over an area of preferably 20% or more, and more preferably 30% or more.
25. The absorbent article as set forth in clause 24, wherein it is preferable that the percentage of holes that overlap, over an area of 20% or more, the skin-side non-contact portions is larger with respect to all holes, is more preferably 30% or more with respect to all holes.
26. The absorbent article as set forth in any one of clauses 1 to 25, including a front portion that is located on a wearer's ventral side, a rear portion that is located on a dorsal side when worn, and a crotch portion that is positioned between the front portion and the rear portion, and having a longitudinal direction extending from the front portion via the crotch portion to the rear portion and corresponding to a front-rear direction of a wearer, and a lateral direction orthogonal to the longitudinal direction,
the intermediate sheet is rectangular in plan view, has a lengthwise direction thereof matching the longitudinal direction, and covers preferably 30 to 70%, more preferably 40 to 60% of a skin-facing surface of the absorbent member.
27. The absorbent article as set forth in clause 26, wherein the intermediate sheet is arranged so as to be positioned at the crotch portion.
Hereinafter, the present invention will be described in more detail by way of examples, but the invention is not limited to these examples.
As an intermediate sheet, an uneven intermediate sheet with a basis weight of 40 g/m2 was prepared in which the skin-side projections 51 and the non-skin-side projections 52 were alternately arranged in a successive manner along the longitudinal direction X and the lateral direction Y. The prepared intermediate sheet had an adjacent distance between adjacent contact portions 54S that were the closest to each other of 5 mm, a height H1 (see
Next, as an open-type disposable diaper, a Merries tape-type diaper, S size (manufactured in 2017, registered trademark) manufactured by Kao Corporation was prepared. A topsheet of the prepared diaper was peeled away by curing a hot melt bonding the materials through cold spraying. Then, the prepared uneven intermediate sheet was arranged such that the skin-side projections 51 were located on the topsheet side and the non-skin-side projections 52 were located on the absorbent member side, the peeled topsheet was arranged on and fixed to the intermediate sheet, so that a disposable diaper of Example 1 as shown in
The adjacent distance and the non-skin-side contact area percentage R54 were measured using a method similar to the above-described measuring methods.
A disposable diaper of Example 2 was produced in a similar way to that of the disposable diaper of Example 1, except that an uneven air-through nonwoven fabric with a basis weight of 40 g/m2 was used as an intermediate sheet. The intermediate sheet had an adjacent distance between adjacent contact portions 54S that were the closest to each other of 4 mm, a height H1 (see
A disposable diaper of Example 3 was produced in a similar way to that of the disposable diaper of Example 1, except that an uneven air-through nonwoven fabric with a basis weight of 40 g/m2 was used as an intermediate sheet. The intermediate sheet had an adjacent distance between adjacent contact portions 54S that were the closest to each other of 5 mm, a height H1 (see
A disposable diaper of Example 4 was produced in a similar way to that of the disposable diaper of Example 1, except that an uneven air-through nonwoven fabric with a basis weight of 40 g/m2 was used as an intermediate sheet. The intermediate sheet had an adjacent distance between adjacent contact portions 54S that were the closest to each other of 2 mm, a height H1 (see
A disposable diaper of Example 5 was produced in a similar way to that of the disposable diaper of Example 1, in which a topsheet obtained by forming holes through recesses of the uneven topsheet used in Example 1 was used as a topsheet and an intermediate sheet used in Example 1 was used as an intermediate sheet.
A disposable diaper of Example 6 was produced in a similar way to that of the disposable diaper of Example 1, except that the topsheet having holes used in Example 5 was used as a topsheet and the intermediate sheet used in Example 2 was used as an intermediate sheet.
A disposable diaper of Example 7 was produced in a similar way to that of the disposable diaper of Example 1, except that the topsheet having holes used in Example 5 was used as a topsheet and the intermediate sheet used in Example 3 was used as an intermediate sheet.
A disposable diaper of Example 8 was produced in a similar way to that of the disposable diaper of Example 1, except that the topsheet having holes used in Example 5 was used as a topsheet and the intermediate sheet used in Example 4 was used as an intermediate sheet.
A Merries tape-type diaper, S size (manufactured in 2017, registered trademark) manufactured by Kao Corporation without having an intermediate sheet was used as a diaper of Comparative Example 1.
A disposable diaper of Comparative Example 2 was produced in a similar way to that of the disposable diaper of Example 1, except that a flat air-through nonwoven fabric not having an uneven shape with a basis weight of 40 g/m2 was used as an intermediate sheet.
A disposable diaper of Comparative Example 3 was produced in a similar way to that of the disposable diaper of Example 1, except that an uneven air-through nonwoven fabric with a basis weight of 40 g/m2 was used as an intermediate sheet. The intermediate sheet had an adjacent distance between adjacent contact portions 54S that were the closest to each other of 2 mm, a height H1 (see
A Merries tape-type diaper, S size (manufactured in 2017, registered trademark) manufactured by Kao Corporation without having an intermediate sheet was prepared. A topsheet of the prepared diaper was peeled away by curing a hot melt bonding the materials through cold spraying, a topsheet obtained by forming holes through recesses of the peeled uneven topsheet (the same sheet as the topsheet having holes used in Example 5) was arranged and fixed, so that a disposable diaper of Comparative Example 4 was produced.
A disposable diaper of Comparative Example 5 was produced in a similar way to that of the disposable diaper of Example 1, except that the topsheet having holes used in Example 5 was used as a topsheet and the intermediate sheet used in Comparative Example 2 was used as an intermediate sheet.
A disposable diaper of Comparative Example 6 was produced in a similar way to that of the disposable diaper of Example 1, except that the topsheet having holes used in Example 5 was used as a topsheet and the intermediate sheet used in Comparative Example 3 was used as an intermediate sheet.
The diapers of Examples 1 to 8 and Comparative Examples 1 to 6 were evaluated as follows. Each diaper was spread out in a planar shape and horizontally placed such that the skin-facing surface side (topsheet side) was oriented upward. Then, 10 g of pseudo-loose stool (viscosity 40 mPa·s) was injected at a time using a metering pump at a flow rate of 6 g/sec to a region distanced 30 mm rearward from the center in the longitudinal direction of the diaper. A liquid impermeable resin film with a size of 10×10 cm was placed over the injection position, and a weight was further placed on the resin film, so that the injection position was pressed at 30 gf/cm2 for one minute. The load 30 gf/cm2 is assumed to be pressure (pressure that is to be withstood) that will be applied to the rear portion of the diaper when a baby that is a few months old and wearing the diaper is sleeping lying face up. Furthermore, the pseudo-loose stool used was a suspension prepared by dissolving or dispersing bentonite in water. The viscosity was adjusted to 40 mPa·s, by adjusting the bentonite concentration. After the pressurization, the weight and the resin film were removed, and the weight of pseudo-loose stool attached to the film was measured. Three measurement samples were prepared for each type of diaper that was to be measured, and were subjected to the above-described measurement. An average of the measured values was taken as the amount of loose stools attached to the diaper. A smaller attachment amount meant better loose stool absorbing performance, which resulted in a higher evaluation result.
Next, after the pressurization, the areas of pseudo-loose stool dispersed on a topsheet and a core-wrap sheet were transferred to OHP sheets, and images thereof were captured by an Image-Pro Plus (manufactured by Nippon Roper K.K.) through scanning. Thus, the area of stools dispersed on each sheet member was obtained. Table 1 shows the results.
As shown in Table 1, it is seen from a comparison between the amounts of loose stools attached to the diapers of Examples 1 to 8 and the amounts of loose stools attached to the diapers of Comparative Examples 1 to 6 that the amounts of loose stools attached to the disposable diapers of Examples 1 to 8 were smaller than those to the disposable diapers of Comparative Examples 1 to 6. Furthermore, regarding the ratio of the area of stools dispersed on a core-wrap sheet with respect to the area of stools dispersed on a topsheet, the values of the disposable diapers of Examples 1 to 8 were significantly larger than those of the disposable diapers of Comparative Examples 1 to 6, and it is seen that, in the examples, loose stools are likely to be dispersed more on the absorbent member side than on the topsheet side, and return of loose stools to the topsheet can be suppressed. Accordingly, compared with the disposable diapers of Comparative Examples 1 to 6, the disposable diapers of Examples 1 to 8 can effectively absorb loose stools and suppress attachment of loose stools to the wearer's skin, and thus they are expected to reduce occurrence of wearer's skin issues. Moreover, as shown in Table 1, compared with the diapers of Examples 1 to 4 using a topsheet without having holes, the amounts of loose stools attached to the diapers of Example 5 to 8 using a topsheet having holes were significantly smaller, and the values of the ratio of the area of stools dispersed on a core-wrap sheet with respect to the area of stools dispersed on a topsheet were larger, and thus it is seen that, in these examples, loose stools can be more effectively absorbed, and attachment of loose stools to the wearer's skin can be more reliably suppressed.
According to the absorbent article according to the present invention, it is possible to effectively absorb loose stools, and suppress attachment of loose stools to the wearer's skin.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-229369 | Nov 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/042537 | 11/16/2018 | WO | 00 |
