EP-4740921-A1 - UNDERPANTS-TYPE DISPOSABLE DIAPER

EP4740921A1EP 4740921 A1EP4740921 A1EP 4740921A1EP-4740921-A1

Abstract

An underpants-type disposable diaper (1) comprising an absorbent body (10), a ventral-side waist part (20), a dorsal-side waist part (30), and waist elastic members (23, 33) that can expand and contract in the lateral direction, wherein: the waist elastic members (23, 33) are provided between a skin-side sheet and a non-skin-side sheet; the dorsal-side waist part (30) has openings (50) that penetrate the skin-side sheet (31) and the non-skin-side sheet (32) in the thickness direction of the sheets; the openings (50) overlap an absorbent core (11) in the lateral direction, and are positioned at the upper side of the absorbent core (11) in the vertical direction; the openings (50) overlap at least one waist elastic member (33) in the vertical direction; and the waist elastic member (33) is discontinuous, at the openings (50), in the lateral direction.

Inventors

OHTSUBO, TOSHIFUMI
DANG, Thi Quyen

Assignees

Unicharm Corporation

Dates

Publication Date: 20260513
Application Date: 20241001

Claims (20)

An underpants-shaped disposable diaper having an up-down direction, a lateral direction, and a thickness direction that are orthogonal to one another, the underpants-shaped disposable diaper comprising: an absorbent main body that has an absorbent core; a front waist portion; a back waist portion; and a plurality of waist elastic members that are arranged spaced apart in the up-down direction and at least in the back waist portion, the waist elastic members being capable of stretching/contracting in the lateral direction, wherein the back waist portion has a skin-side sheet and a non-skin-side sheet that is located on a non-skin side relative to the skin-side sheet, the waist elastic members are provided between the skin-side sheet and the non-skin-side sheet, the back waist portion has an opening that penetrates the skin-side sheet and the non-skin-side sheet in the thickness direction, the opening is located at a position that overlaps the absorbent core in the lateral direction and is above the absorbent core in the up-down direction, in the up-down direction, the opening overlap at least one of the waist elastic members, and in the lateral direction, the waist elastic member is discontinuous within the opening.
An underpants-shaped disposable diaper having an up-down direction, a lateral direction, and a thickness direction that are orthogonal to one another, the underpants-shaped disposable diaper comprising: an absorbent main body that has an absorbent core; a front waist portion; a back waist portion; and a plurality of waist elastic members that are arranged spaced apart in the up-down direction and at least in the back waist portion, the waist elastic members being capable of stretching/contracting in the lateral direction, wherein the back waist portion has a skin-side sheet and a non-skin-side sheet that is located on a non-skin side relative to the skin-side sheet, the waist elastic members are provided between the skin-side sheet and the non-skin-side sheet, the back waist portion has an opening that penetrates the skin-side sheet and the non-skin-side sheet in the thickness direction, in the up-down direction, the opening overlap at least one of the waist elastic members, in the lateral direction, the waist elastic member is discontinuous within the opening, the back waist portion includes a back barrier cuff in an upper end portion, in the up-down direction, of the absorbent main body, the back barrier cuff has a base end portion being incapable of standing up, and a standing portion being capable of standing up on a skin side in the thickness direction due to a barrier-cuff elastic member that contracts in the lateral direction using the base end portion as a fulcrum, the standing portion is located below the base end portion in the up-down direction, and the base end portion is located below the opening in the up-down direction.
The underpants-shaped disposable diaper according to claim 1 or 2, wherein a length, in the up-down direction, of the opening is less than 15 mm.
The underpants-shaped disposable diaper according to claim 3, wherein in the stretched state, the opening is a slit extending along the up-down direction.
The underpants-shaped disposable diaper according to claim 3, wherein in the stretched state, the opening is a cutout formed by cutting out a specified range.
The underpants-shaped disposable diaper according to claim 1 or 2, wherein when one of the waist elastic members that overlap the opening in the up-down direction is defined as an overlapping waist elastic member, in the stretched state, a length, in the up-down direction, of the opening is longer than a distance in the up-down direction between the overlapping waist elastic member and another waist elastic member that is adjacent to the overlapping waist elastic member in the up-down direction.
The underpants-shaped disposable diaper according to claim 6, wherein when the waist elastic member that is located above and adjacent to the overlapping waist elastic member in the up-down direction is defined as an upper waist elastic member, and the waist elastic member that is located below the overlapping waist elastic member is defined as a lower waist elastic member, in the stretched state, the length, in the up-down direction, of the opening is longer than a distance in the up-down direction from the upper waist elastic member to the lower waist elastic member.
The underpants-shaped disposable diaper according to claim 1 or 2, wherein a magnitude of force required to stretch the waist elastic member that overlaps the opening in the up-down direction, by a unit length in the lateral direction is greater than a magnitude of force required to stretch the waist elastic member that does not overlap the opening in the up-down direction, by the unit length in the lateral direction.
The underpants-shaped disposable diaper according to claim 1 or 2, wherein in the up-down direction, the opening overlaps at least two of the waist elastic members, the at least two waist elastic members being adjacent in the up-down direction, and in the stretched state, a distance in the up-down direction between the two waist elastic members adjacent in the up-down direction is shorter than a distance the up-down direction between another two of the waist elastic members, the other two waist elastic members being adjacent in the up-down direction and not overlapping the opening in the up-down direction.
The underpants-shaped disposable diaper according to claim 9, wherein the plurality of openings that overlap the two waist elastic members adjacent in the up-down direction are provided space apart in the lateral direction.
The underpants-shaped disposable diaper according to claim 1 or 2, wherein in the up-down direction, the opening is provided in a lower region of an area obtained by bisecting between an upper end of the absorbent main body and an upper end of the back waist portion.
The underpants-shaped disposable diaper according to claim 1 or 2, wherein at least two of the openings are provided spaced apart in the lateral direction, when one of the two openings located on a one side in the lateral direction is defined as a first opening, and the other of the two openings located on another side in the lateral direction is defined as a second opening, in the stretched state, a distance in the lateral direction between an upper end of the first opening and an upper end of the second opening is shorter than a length, in the up-down direction, of the opening, and the first opening and the second opening have an overlapping portion in the up-down direction, or the first opening and the second opening are spaced apart in the up-down direction, and a distance from a lower end of the upper opening of the first and second openings to an upper end of the lower opening of the first and second openings is shorter than the length, in the up-down direction, of the opening.
The underpants-shaped disposable diaper according to claim 12, wherein the back waist portion has an opening group including the first opening and the second opening, a plurality of the opening groups are provided spaced apart in the lateral direction, and in the stretched state, a distance in the lateral direction between two of the opening groups that are adjacent in the lateral direction is longer than the length, in the up-down direction, of the opening.
The underpants-shaped disposable diaper according to claim 12, wherein in the stretched state, the first opening and the second opening are separated in the up-down direction by equal to or more than half the length, in the up-down direction, of the opening.
The underpants-shaped disposable diaper according to claim 1 or 2, wherein a plurality of the openings are provided, and the plurality of openings do not overlap each other in the lateral direction.
The underpants-shaped disposable diaper according to claim 1 or 2, wherein a post-treatment tape that is used to discard the underpants-shaped disposable diaper after use is provided on a non-skin-side face of the back waist portion, and the opening does not overlap the post-treatment tape in the lateral direction.
The underpants-shaped disposable diaper according to claim 2, wherein the opening is provided outside the absorbent core on both sides in the lateral direction.
The underpants-shaped disposable diaper according to claim 2, wherein a lower end, in the up-down direction, of the base end portion of the back barrier cuff is located below an upper end, in the up-down direction, of the absorbent main body.
The underpants-shaped disposable diaper according to claim 2, wherein the front waist portion and the back waist portion are joined by a pair of side joining portions in both side portions in the lateral direction, both side portions, in the lateral direction, of the back barrier cuff are joined by the pair of side joining portions, and in the back barrier cuff, the pair of side joining portions are not fixed between a one-side end and an other-side end in the lateral direction.
The underpants-shaped disposable diaper according to claim 2, wherein a magnitude of force required to stretch the barrier-cuff elastic member by a unit length in the lateral direction is smaller than a magnitude of force required to stretch the waist elastic member that overlaps the opening in the up-down direction, by the unit length in the lateral direction.

Description

FIELD The present invention relates to an underpants-shaped disposable diaper. BACKGROUND An absorbent article such as a diaper include open holes in the waist portion in order to enhance breathability conventionally has been known. For example, Patent Document 1 discloses an absorbent article in which, in the lengthwise direction, through holes overlap with elastic members and, in the transverse direction, the elastic members are discontinuous within the through holes. [CITATION LIST] [PATENT LITERATURE] [Patent Document 1] WO2017/175289 SUMMARY [TECHNICAL PROBLEM] During wearing of an absorbent article such as diaper or the like, areas such as the wearer's back and the cleft of the buttocks (gluteal cleft) tend to accumulate sweat and moisture and are prone to skin problems. Although, for enhancing the ventilation of the absorbent article, there are absorbent articles having through holes at both sides of the waist portion (both side portions), as in Patent Document 1, but on both sides of the waist portion, there are no through holes along the extension of the gluteal cleft, making it difficult to eliminate accumulation of sweat in the gluteal cleft. Moreover, even in a diaper having multiple small holes on the back or a diaper having through holes on the crotch side of the waist portion, small holes likewise make it difficult to prevent sweat from accumulating on the back and in the gluteal cleft, and the through holes located on the crotch side may increase the risk of leakage. Further, when an open hole is provided on the back side of a diaper, there is a risk of anxiety that leakage occurs from the open hole during wear. The present invention is achieved in light of conventional problems such as that described above, an aspect of the present invention is to provide an underpants-shaped disposable diaper that improves breathability, makes it less likely for sweat to accumulate on the wearer's back or the gluteal cleft, while also being less likely to leak. [SOLUTION TO PROBLEM] A main aspect of the present invention of achieving the above-described aspect is an underpants-shaped disposable diaper having an up-down direction, a lateral direction, and a thickness direction that are orthogonal to one another, the underpants-shaped disposable diaper including: an absorbent main body that has an absorbent core; a front waist portion; a back waist portion; and a plurality of waist elastic members that are arranged spaced apart in the up-down direction and at least in the back waist portion, the waist elastic members being capable of stretching/contracting in the lateral direction, wherein the back waist portion has a skin-side sheet and a non-skin-side sheet that is located on a non-skin side relative to the skin-side sheet, the waist elastic members are provided between the skin-side sheet and the non-skin-side sheet, the back waist portion has an opening that penetrates the skin-side sheet and the non-skin-side sheet in the thickness direction, the opening is located at a position that overlaps the absorbent core in the lateral direction and is above the absorbent core in the up-down direction, in the up-down direction, the opening overlap at least one of the waist elastic members, and in the lateral direction, the waist elastic member is discontinuous within the opening. Features of the present invention other than the above will become clear by reading the description of the present specification with reference to the accompanying drawings. [ADVANTAGEOUS EFFECT OF THE INVENTION] According to the present invention, it is possible to provide an underpants-shaped disposable diaper that improves breathability, makes it less likely for sweat to accumulate on the wearer's back or the gluteal cleft, while also being less likely to leak. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic perspective view of an underpants-shaped disposable diaper 1 as seen from the back.FIG. 2 is a schematic plan view of the diaper 1 in an unfolded state and stretched state, as viewed from the skin side.FIG. 3 is a schematic cross-sectional view taken along line A-A in FIG. 2.FIG. 4A is a diagram showing a portion of a strip-shaped back waist member 300 in the stretched state before forming slits S (openings 50), FIG. 4B is a diagram showing a portion of the strip-shaped back waist member 300 in the stretched state when the slits S (openings 50) has been formed, and FIG. 4C is a diagram showing a portion of a back waist portion 30 in a worn state.FIG. 5 is a partial enlarged view of the back waist portion 30 in the worn stateFIG. 6A is a partial enlarged view of the back waist portion 30 in FIG. 2 illustrating the openings 50.FIG. 6B is a diagram illustrating a modified example of the arrangement of a first opening 50a and a second opening 50b.FIG. 6C is a diagram illustrating waist elastic members 33 that are located in the back waist portion 30 and colored in a specified color.FIG. 7A is a schematic plan view showing the back