AU2015265241B2

AU2015265241B2 - Open-type disposable diaper for low-weight infant weighing equal to or less than 3000 grams

Info

Publication number: AU2015265241B2
Application number: AU2015265241A
Authority: AU
Inventors: Tomomi Isogai; Maki MIYAKE; Satoru Sakaguchi
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 2014-05-27
Filing date: 2015-03-10
Publication date: 2018-11-22
Anticipated expiration: 2035-03-10
Also published as: JP2015223254A; CN106456389B; WO2015182210A1; AU2015265241A1; TW201607515A; KR20170009829A; TWI650108B; BR112016024564A2; JP6400945B2; MY179319A; CN106456389A

Abstract

An unfolding-type disposable diaper (1) for infants weighing 3000 grams or less at birth, said diaper (1) having leg-surrounding elastic members (21) for constricting leg-surrounding openings (HL) in the longitudinal direction, the leg-surrounding elastic members (21) each being provided in the longitudinal direction in positions on both sides in the transverse direction in a crotch section (1m). A back-side section (1b) has a waist-surrounding elastic sheet (31) for constricting a waist-surrounding opening (HB) in the transverse direction, the waist-surrounding elastic sheet (31) being provided so as to extend to both sides in the transverse direction. When the diaper (1) is unfolded, end sections in the transverse direction of the waist-surrounding elastic sheet (31) are positioned with respect to the transverse direction at the same positions as end sections on the back side in the longitudinal direction of the leg-surrounding elastic members (21) nearest thereto, or are positioned further outside in the transverse direction relative to the end sections of the leg-surrounding elastic members (21) nearest thereto, and the waist-surrounding elastic sheet (31) is disposed astride longitudinal center positions (C11m) of engaging sections (11m) of fastening tapes (11) in the longitudinal direction.

Description

[DESCRIPTION] [Title of Invention]

OPEN-TYPE DISPOSABLE DIAPER FOR LOW-WEIGHT INFANT WEIGHING

EQUAL TO OR LESS THAN 3000 GRAMS

[Technical Field] [0001]

The present invention relates to an open-type disposable diaper for a low-weight infant weighing equal to or less than 3000 grams.

[Background Art] [0001a]

The following discussion of the background to the invention is intended to facilitate an understanding of the invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any aspect of the discussion was part of the common general knowledge as at the priority date of the application.

[0002]

Conventionally, open-type disposable diapers are known. The same diaper includes an abdomen part, a crotch part, and a back part, which are arranged in the longitudinal direction, and has substantially in an hourglass shape in plan view. Then, fastening tapes provided on both end parts in the lateral direction in a back part engage a target tape in an abdomen part and thereby a waist opening and a pair of leg openings are formed, and the diaper is worn by a diaper user.

[Citation List] [Patent Literature] [0003] [PTL 1] Japanese Patent Application Laid-open Publication No. 2002-253608 [Technical Problem] [0004]

On the other hand, low birth-weight infants weighing equal to or lower than 3000 grams exist. And, such low-weight infants may spend much of their time, after birth, being in a fetus-like flexed posture when in a maternal body. The fetuslike flexed posture is also called a positioning posture, which is such a posture as to hunch the back in C-shape in the side view, as illustrated in Fig. 1A, and also a prone posture with appropriate safety treatment, such as laying them on a cutout cushion not shown, having been undergone. Then, position change to a supine posture or the like is suitably performed, but they spend much of their time spending in the supine posture. Further, depending on a low-weight infant 101, such a concept of minimum handling that it is desirable not to touch his/her body may be applied from a viewpoint of avoiding unnecessary stress. And, the open-type disposable diaper 1' is used for such a low-weight infant.

[0005]

Fig. IB illustrates a B-B arrow view of Fig. 1A, and here, in this positioning posture, the low-weight infant 101 is in such a state as to have his/her knees brought closer to and almost in contact with his/her abdominal area while having his/her legs apart in M-shape. Thus, fastening tapes 11' engaging a target tape 15' in an abdomen part la' have been pushed up, by the knees and thighs, from the leg opening HL' side to the waist opening HB' side. Further, since the infant spends much of his/her time being in such a positioning posture, such a pushing-up force F continues acting over a long period of time. Thus, as illustrated in a schematic side view of Fig. 1C, the tapes 11' are gradually peeled off from the leg opening HL' side to the waist opening HB side (see dotted area in Fig. 1C) , and eventually have been detached. And, in the case of having been detached, the fastening tapes 11' should engage again, but in such a case, no alternative is left but to touch the low-weight infant 101, which goes against the minimum handling.

[0006]

Further, as described above, in the positioning posture, the infant is made in a prone posture in C-shape in the side vide, however, in this posture, since the back is hunched as in Fig. IA, a gap G is created between the back and the back part lb of the diaper 1' . Then, the diaper 1' should be worn again in such a manner as to reduce the gap G, and as a result, no alternative is left but to touch the low-weight infant 101, which goes against the minimum handling, similarly to the above .

[0007]

It is desirable to provide to an open-type disposable diaper for low-weight infants weighing equal to or less than 3000 grams, which is to bring a back part of the diaper into intimate contact with the back while restraining the fastening tapes engaging the abdomen part from being peeled off and detached from the abdomen part.

[Summary of the Invention] [0008]

In one aspect of the invention there is provided an open-type disposable diaper for a low-weight infant weighing equal to or less than 3000 grams, the diaper including an abdomen part arranged along a lateral direction on an abdomen-side of the low-weight infant, a crotch part arranged in crotch of the low-weight infant, and a back part arranged along the lateral direction on the back side of the low-weight infant, the abdomen part, the crotch part and the back part being arranged in a longitudinal direction orthogonal to the lateral direction, the back part having end parts in the lateral direction, which are configured to engage the abdomen part via engagement parts of fastening tapes respectively provided in the end parts, to form a waist opening and a pair of leg openings, the diaper comprising: leg-circumference elastic members provided along the longitudinal direction in positions on both sides in the lateral direction in the crotch part, the leg-circumference elastic members configured to contract the leg openings along the longitudinal direction; and a waist-circumference elastic sheet provided to extend to both sides in the lateral direction in the back part, the waist-circumference elastic sheet configured to contract the waist opening in the lateral direction, wherein in a state where the diaper is unfolded, end parts in the lateral direction in the waist-circumference elastic sheet are respectively located at same positions, with respect to the lateral direction, as positions of back-side end parts in the longitudinal direction of the nearest leg-circumference elastic members or located laterally outside the back-side end parts; and with respect to the longitudinal direction, the waist-circumference elastic sheet is arranged to span, in the longitudinal direction, central positions in the longitudinal direction in the engagement parts of the fastening tapes, an absorbent body extending along the longitudinal direction over the abdomen part, the crotch part, and the back part is included, a direction orthogonal to both the longitudinal direction and the lateral direction is along a thickness direction of the diaper in the unfolded state, the absorbent body includes a back-side low stiffness portion corresponding to a position of the back part, the back-side low stiffness portion having stiffness lower than stiffness of surrounding portion, the back-side low stiffness portion overlaps with the waist-circumference elastic sheet when seen from the thickness direction, the abdomen part includes a target area configured to engage each of the engagement parts of the fastening tapes in the end parts of the back part, the absorbent body includes an abdomen-side low stiffness portion corresponding to a position of the abdomen part, the abdomen-side low stiffness portion having stiffness lower than stiffness of surrounding portion, the abdomen-side low stiffness portion overlaps with the target area when seen from the thickness direction, and the abdomen-side low stiffness portion is smaller than the back-side low stiffness portion, in the longitudinal direction.

[0009]

In summary the present invention relates to an open-type disposable diaper for low-weight infants weighing equal to or less than 3000 grams, and it becomes possible to bring the back part of the diaper to intimate contact with the back while restraining the fastening tapes engaging the abdomen part from being peeled off and detached from the abdomen part.

Other features of the present invention will be made clear through the present specification with reference to the accompanying drawings .

Where any or all of the terms "comprise", "comprises", "comprised" or "comprising" are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other features, integers, steps or components.

[Brief Description of Drawings] [0010]

Fig. IA is a schematic side view illustrating a low-weight infant 101 in a positioning posture, Fig. IB is a B-B arrow view in Fig. IA for explaining a push-up force F acting on fastening tapes 11', and Fig. 1C is a schematic side view illustrating a state in which the fastening tape 11' is peeled off by the push-up force F.

Fig. 2 is a schematic plan view illustrating a disposable diaper 1 in an unfolded state according to a present embodiment.

Figs. 3A, 3B and 3C are cross-sectional views A-A, B-B, and C-C in Fig. 2, respectively.

Fig. 4 is a schematic perspective view illustrating the disposable diaper 1 when worn.

Fig. 5 is a diagram for explaining another improvement which has been made to the disposable diaper 1 according to the present embodiment, and a schematic plan view illustrating the diaper in an unfolded state.

Fig. 6 is an explanatory diagram in a case where engagement positions of fastening tapes 11, 11 engaging a target tape 15 are in such positions as to sandwich a low stiffness portion 3na of an absorbent body 3 from both sides in the lateral direction.

Fig. 7 is a diagram for explaining a contraction effective portion 31a and ineffective portion 31n included in a waist-circumference elastic sheet 31.

Fig. 8 is an explanatory diagram in a case where the fastening tapes 11, 11 engage in a state of overlapping with each other.

Fig. 9 is a diagram for explaining a method for measuring an engagement force (N/10 mm) of the fastening tape 11.

[Description of Embodiments] [0011]

At least the following matters will become clear with reference to this specification and the attached drawings.

An open-type disposable diaper for a low-weight infant weighing equal to or less than 3000 grams, the diaper including an abdomen part arranged along a lateral direction on an abdomen-side of the low-weight infant, a crotch part arranged in crotch of the low-weight infant, and a back part arranged along the lateral direction on the back side of the low-weight infant, the abdomen part, the crotch part and the back part being arranged in a longitudinal direction orthogonal to the lateral direction, the back part having end parts in the lateral direction, which are configured to engage the abdomen part via engagement parts of fastening tapes respectively provided in the end parts, to form a waist opening and a pair of leg openings, the diaper comprising: leg-circumference elastic members provided along the longitudinal direction in positions on both sides in the lateral direction in the crotch part, the leg-circumference elastic members configured to contract the leg openings along the longitudinal direction; and a waist-circumference elastic sheet provided to extend to both sides in the lateral direction in the back part, the waist-circumference elastic sheet configured to contract the waist opening in the lateral direction, wherein in a state where the diaper is unfolded, end parts in the lateral direction in the waist-circumference elastic sheet are respectively located at same positions, with respect to the lateral direction, as positions of back-side end parts in the longitudinal direction of the nearest leg-circumference elastic members or located laterally outside the back-side end parts; and with respect to the longitudinal direction, the waist-circumference elastic sheet is arranged to span, in the longitudinal direction, central positions in the longitudinal direction in the engagement parts of the fastening tapes.

[0012]

According to such an open-type disposable diaper, the end parts in the lateral direction of the waist-circumference elastic sheet are respectively located at the same positions, with respect to the lateral direction, as the positions of the back-side end parts in the longitudinal direction of the nearest leg-circumference elastic members, or located laterally outside the back-side end parts. Thus, the end parts are to be hardly affected by a force created in the leg-circumference elastic members, and thus it is possible to cause their own contractile forces of the end parts of the waist-circumference elastic sheet to swiftly act on the fastening tapes as a tensile force in the lateral direction. Thereby, a shearing force in the lateral direction is added to the engagement part in the fastening tapes, and thus the engagement part can engage the abdomen part with a high engagement force, and as a result, it becomes possible to effectively restrain the fastening tapes from being peeled off and detached.

Further, the waist-circumference elastic sheet is arranged to longitudinally span the longitudinally central position in the engagement part of the fastening tapes, and thus the above-described contractile force can be transferred to the fastening tapes with a substantially uniform distribution, which is longitudinally less-biased, and this also effectively contributes to restraint of

Furthermore, such a waist-circumference elastic sheet is of a sheet form, and thus, as compared with the case where a string-like elastic member is used, a tensile force can act on the fastening tapes with a substantially uniform distribution, which is longitudinally less-biased, and this also contributes to restraint of the above-described peeling off and detaching.

Further, a gap, which may be created between the back hunched in C-shape of the low-weight infant in a positioning posture and the back part of the diaper, is reduced on the basis of the contractile force of the waist-circumference elastic sheet. Thus, the back part of the diaper can be brought into intimate contact with the back of the low-weight infant.

[0013]

In such an open-type disposable diaper, it is desirable that the end parts of the waist-circumference elastic sheet are outer end parts in the lateral direction among the end parts, and are connected to the nearest fastening tapes.

[0014]

According to such an open-type disposable diaper, the waist-circumference elastic sheet is connected to the fastening tapes at the outer end parts in the lateral direction among the end parts. Thus, the contractile force of the end parts can act on the fastening tapes swiftly and reliably.

[0015]

In such an open-type disposable diaper, it is desirable that a direction orthogonal to both the longitudinal direction and the lateral direction is along a thickness direction of the diaper in the unfolded state, an absorbent body extending along the longitudinal direction over the abdomen part, the crotch part, and the back part; and a leak-proof sheet covering the absorbent body from a non-skin side in the thickness direction, are included, and when seen from the thickness direction, the waist-circumference elastic sheet overlaps with both the absorbent body and the leak-proof sheet, and the end parts in the lateral direction in the waist-circumference elastic sheet are located at the same positions as positions of end edges in the lateral direction of both the absorbent body and the leak-proof sheet, or located laterally outside the end edges .

[0016]

In such an open-type disposable diaper, the end parts in the lateral direction in the waist-circumference elastic sheet are located at the same position as the positions of the end edges in the lateral direction of both of the absorbent body and the leak-proof sheet, or located laterally outside the end edges. Thus, when the fastening tapes are pulled in the lateral direction in order that the diaper is worn, the end parts can freely stretch without receiving great resistance from the absorbent body and the leak-proof sheet. Thereby, the contractile force created in the end parts can be swiftly acting on the fastening tapes.

[0017]

In such an open-type disposable diaper, it is desirable that the absorbent body includes a back-side low stiffness portion corresponding to a position of the back part, the back-side low stiffness portion having stiffness lower than stiffness of surrounding portion, and the back-side low stiffness portion overlaps with the waist-circumference elastic sheet when seen from the thickness direction.

[0018]

According to such an open-type disposable diaper, the back-side low stiffness portion overlaps the waist-circumference elastic sheet. Thus, when the fastening tapes are pulled in the lateral direction when the diaper is worn, at least the back-side low stiffness portion in the absorbent body is swiftly contracted in the lateral direction, and the back-side low stiffness portion does not cause great resistance . Thereby, the waist-circumference elastic sheet can be stretched with a small tensile force. As a result, a contractile force can easily be created in the waist-circumference elastic sheet.

Further, the back-side low stiffness portion is easily contracted in the lateral direction. Thus, when worn, the back-side low stiffness portion is swiftly contracted by a contractile force of the waist-circumference elastic sheet. Thus, a gap, which may be created between the back hunched in C-shape of the low-weight infant in a positioning posture and the back part of the diaper, is swiftly reduced on the basis of the contraction of the back-side low stiffness portion.

[0019]

In such an open-type disposable diaper, it is desirable that the abdomen part includes a target area configured to engage each of the engagement parts of the fastening tapes in the end parts of the back part, the absorbent body includes an abdomen-side low stiffness portion corresponding to a position of the abdomen part, the abdomen-side low stiffness portion having stiffness lower than stiffness of surrounding portion, and the abdomen-side low stiffness portion overlaps with the target area when seen from the thickness direction.

[0020]

According to such an open-type disposable diaper, in the case where the engagement positions when worn, at which the engagement parts of the fastening tapes have engaged the target area, are such positions as to sandwich the abdomen-side low stiffness portion from both sides in the lateral direction, the abdomen-side low stiffness portion easily enlarges on the basis of the contractile force of the waist-circumference elastic sheet. Then, the engagement part is slightly moved in the lateral direction in association with this enlargement operation, and thereby the engagement part can be fit and securely engage the target area, which enables firmer engagement between the engagement part and the target area.

[0021]

In such an open-type disposable diaper, it is desirable that the engagement parts of the fastening tapes have a shape having a side positioned inside in the lateral direction, the leg-circumference elastic member is a band-like elastic sheet having a pair of long sides along the longitudinal direction and a pair of short sides along the lateral direction, and a part of the waist-circumference elastic sheet is positioned in a quadrangular area partitioned with the short side positioned on the back side out of the pair of short sides and the side positioned inside in the lateral direction of the engagement part of the fastening tape, the short side and the side serving as opposite sides.

[0022]

According to such an open-type disposable diaper, a part of the waist-circumference elastic sheet is positioned in the above-described quadrangular area. Further, the quadrangular area is a transfer path through which a force can be transferred from the leg-circumference elastic member to engagement part of the fastening tape. Thus, even in the case where such a force as to pull down the engagement part to the leg opening side is transferred from the leg-circumference elastic member, the force is alleviated by a part of the above-described waist-circumference elastic sheet and transferred to the engagement part, thereby being able to effectively restrain the fastening tape from being peeled off due to such a force. [0023]

In such an open-type disposable diaper, the waist-circumference elastic sheet includes an effective portion configured to contract the waist opening in the lateral direction and an ineffective portion configured to not contract the waist opening in the lateral direction, and the ineffective portion is located in the end parts in the lateral direction in the waist-circumference elastic sheet, and is located between the fastening tape and the effective portion.

[0024]

According to such an open-type disposable diaper, the ineffective portion is positioned between the fastening tape and the effective portion. Thus, when pulling the fastening tape in the lateral direction, the ineffective portion is stretched relatively easily. Then, a contractile force created on the basis of such stretch can swiftly act on the fastening tapes as a tensile force in the lateral direction. Thus, the engagement parts of the fastening tapes can engage the abdomen part with an appropriate engagement force.

[0025]

In such an open-type disposable diaper, in a case where a fastening tape of one end part out of the end parts is a first tape, a fastening tape of an other end part is a second tape, the engagement part of the first tape engages the abdomen part, and the engagement part of the second tape engages a surface on a non-engagement part side of the first tape in an overlapping manner, an engagement force between the engagement part of the second tape and the surface on the non-engagement part side of the first tape is equal to or greater than 0. 1 (N/10 mm) , and an engagement force (N/10 mm) between the engagement part of the first tape and the abdomen part and an engagement force (N/10 mm) between the engagement part of the second tape and the abdomen part each are set greater than the engagement force (N/10 mm) between the surface on the non-engagement part side of the first tape and the engagement part of the second tape, and in a case where the engagement part of the second tape engages the surface on the non-engagement part side of the first tape in an overlapping manner while a central position in the longitudinal direction in the first tape and a central position in the longitudinal direction in the second tape are being aligned to coincide with each other, the first tape and the second tape are set in such a form that the engagement part of the second tape extends out from the first tape to both sides in the longitudinal direction.

[0026]

According to such an open-type disposable diaper, an engagement force in the case where the engagement part of the second tape engages the surface on the non-engagement part side of the first tape is equal to or greater than 0.1 (N/lOmm) . Thus, in a form where the fastening tapes overlap with each other (hereinafter, also referred to as a "fastening tape overlapping form") , the first tape and the second tape can reliably engage the abdomen part. That is, the engagement part of the first tape can engage the abdomen part, and the engagement part of the second tape can reliably engage the surface on the non-engagement part side of the first tape.

Further, in the case of the "fastening tape overlapping form", the first and the second tapes can be brought closer to the laterally central portion in the abdomen part, and these first and second tapes can be kept away from the legs of the low-weight infant. As a result, the above-described push-up force given from the legs in M-shape to the first and second tapes is reduced, thereby restraining the first and second tapes from being peeled off and detached.

Furthermore, according to the above described construction, it becomes possible to strengthen the engagement state of the second tape as a whole while enabling easy detachment of the second tape in the fastening-tape overlapping form from the first tape. Details are as follows .

Firstly, as described above, the engagement force (N/lOmm) between the male member of the first tape and the abdomen part is made greater than the engagement force (N/lOmm) between the surface on the non-engagement part side of the first tape and the engagement part of the second tape. Thus, in the case where the second tape is detached from the first tape by holding the tape, it can be effectively prevented that the first tape is also detached from the abdomen part together therewith, and thereby only the second tape can be detached from the first tape on the stable first tape. Thereby, it becomes possible to easily detach the second tape from the first tape, and this effectively contributes to the above-described minimum handling.

On the other hand, in the fastening tape overlapping form, the engagement part of the second tape engages the surface on the on-engagement part side of the first tape as described above, and at this time, the engagement part of the second tape is of such a shape as to extend out from the first tape to both sides in the longitudinal direction. And, such a part as to extend out therefrom engages the abdomen part, and here, the engagement force (N/lOmm) of engaging with the abdomen part is set greater than the engagement force (N/lOmm) of engaging the surface on the non-engagement part side of the first tape. Thus, the engagement force of the engagement part of the second tape can be enhanced by an amount corresponding to such an extending out portion.

[0027] ===Present Embodiment===

Fig. 2 is a schematic plan view illustrating a disposable diaper 1 in an unfolded state according to a present embodiment. Further, Figs. 3A, 3B and 3C are a cross-sectional view A-A, a cross-sectional view B-B, and a cross-sectional view C-C in Fig. 2, respectively. Further, Fig. 4 is a schematic perspective view illustrating the disposable diaper 1 when worn.

[0028]

The diaper 1 is specialized in a diaper for low-weight infants weighing equal to or less than 3000 grams, and is the open-type diaper 1 to be worn by a low-weight infant 101 with the use of fastening tapes 11. Then, the diaper 1 in an unfolded state as in Fig. 2 has a longitudinal direction, a lateral direction, and a thickness direction, as three directions orthogonal to one another. Here, with respect to the longitudinal direction, an abdomen part la, a crotch part lm, and a back part lb, arranged in this order, are included and, in the worn state in Fig. 4, the abdomen part la covers the abdomen side of the low-weight infant 101, the crotch part lm covers the crotch of the infant 101, and the back part lb covers the back side of the infant 101.

[0029]

Note that, in the unfolded state in Fig. 2, the abdomen part la and the back part lb each protrude from the crotch part lm on both sides in the lateral direction. Thus, the external form of the diaper 1 when seen from the thickness direction is substantially in an hourglass shape in plan view. Hereinafter, portions lasf, lasf protruding on both sides in the lateral direction of the abdomen part la are also referred to as "abdomen side flaps lasf", and portions lbsf, lbsf protruding on both sides in the lateral direction of the back part lb are also referred to as "back-side flaps lbsf". Note that the back-side flaps lbsf, lbsf correspond to "end parts in the lateral direction" according to claims. Further, hereinafter, one direction in the thickness direction is also referred to as a "skin side", and the other side is also referred to as a "non-skin side". In this regard, the schematic plan view in Fig. 2 illustrates the diaper 1 in an unfolded state when seen from the skin side.

[0030]

Here, as illustrated in Fig. 2, the fastening tapes 11 are provided to protrude in the lateral direction in tip parts on the outer side of the back-side flaps lbsf in the lateral direction, respectively. Then, the fastening tapes 11 engage a target tape 15 (Fig. 2, Fig. 3A) provided on the non-skin side of the abdomen part la, and thereby, as illustrated in Fig. 4, a waist opening HB and a pair of leg openings HL, HL are formed and the diaper 1 is worn by the low-weight infant 101.

[0031]

The diaper 1 includes: an absorbent body 3 substantially in an oblong shape that absorbs excretory fluid such as urine, etc.; a liquid permeable top sheet 2 that covers the absorbent body 3 from the skin side; a liquid-impermeable leak-proof sheet 4 that covers the absorbent body 3 from the non-skin side; an exterior sheet 5 substantially in an hourglass shape that covers the leak-proof sheet 4 from the non-skin side and forms an external shape of the diaper 1; and a pair of solid gather sheets 6, 6 that are provided side by side in a pair in the lateral direction on the top sheet 2 and form solid gathers 6g, 6g as leakage-proof walls in the end parts in the lateral direction of the absorbent body 3, respectively.

[0032]

As illustrated in Figs. 3A to 3C, the absorbent body 3 includes an absorbent core 3c and a core wrap sheet 3rs that covers substantially the entire outer circumferential surface of the absorbent core 3c.

The absorbent core 3c is obtained by forming liquid-absorbent fibers such as pulp fibers etc., and liquid-absorbent particles such as superabsorbent polymers (hereinafter also referred to as SAP), etc., substantially in an hourglass shape in plan view as an example of a predetermined shape (Fig. 2) . A liquid permeable sheet, such as tissue paper, nonwoven fabric or the like, is used for the core wrap sheet 3rs. Further, portions 3cna, 3cnb, in which structure materials of the absorbent core 3c such as pulp fibers, etc., are not included, are respectively provided in predetermined shapes in both end parts in the longitudinal direction of the absorbent core 3c, which will be described later.

[0033]

The top sheet 2 is made of a nonwoven fabric such as air-through nonwoven fabric, etc., and has such a planar size as to extend out from the absorbent body 3 in both sides in the longitudinal direction and both sides in the lateral direction, as illustrated in Figs. 2 and 3A to 3C. Further, the leak-proof sheet 4 also has such a planar size as to extend out from the absorbent body 3 in both sides in the longitudinal direction and both sides in the lateral direction, and is made of a resin film such as a polyethylene film, etc. Then, these sheets 2, 4 are joined to each other, by bonding, welding, etc., in a part extending out from the absorbent body 3 in the longitudinal direction and the lateral direction, thereby holding the absorbent body 3 between the sheets 2, 4.

[0034]

As illustrated in Fig. 2, the exterior sheet 5 is made of suitable nonwoven fabric, etc., and forms an exterior shape of the diaper 1. Then, on the skin side of the exterior sheet 5, the above sheets 2, 4 and the absorbent body 3 held between the sheets 2, 4 are superposed, with the central positions thereof in the lateral direction being aligned with each other, and are integrated with each other, by bonding, welding or the like (Figs. 3A to 3C) . Note that, in such an integrated state, the absorbent body 3 extends across the abdomen part la, the crotch part lm, and the back part lb (Fig. 2).

[0035]

The solid gather sheets 6, 6 are provided in a pair corresponding to end parts 2e, 2e in the lateral direction of the top sheet 2 so as to respectively cover the end parts 2e, 2e from the skin side. Then, the sheets 6, 6 respectively form, along the longitudinal direction, the solid gathers 6g, 6g standing from the skin-side surface of the top sheet. That is, a plurality of rubber threads 6r, 6r along the longitudinal direction are fixed in a stretched state in the longitudinal direction, by bonding, etc., to the inner end edges in the lateral direction of the solid gather sheet 6, and the sheet 6 is fixed to the top sheet 2 with a predetermined position P6g, positioned laterally outside the inner end edge, serving as a fixed position. Thus, when the stretched state of the rubber thread 6r is loosened, the inner end edge and its neighbouring portion of the solid gather sheet 6 is contracted in the longitudinal direction by a contractile force of the rubber thread 6r, and accordingly, the inner end edge and its neighbouring portion swiftly stand from the skin-side surface of the top sheet 2 with the above fixed position P6g serving as a standing position, thereby forming the solid gather 6g.

[0036]

Note that the solid gather sheet 6, as illustrated in Figs. 2 and 3A to 3C, extend outward in the lateral direction to substantially the same position of the outer end edge of the exterior sheet 5, and is integrated with the exterior sheet 5 by bonding or welding at such end edge or its neighbouring position. Thereby, the solid gather sheet 6 and the exterior sheet 5 are cooperated with each other to form the abdomen side flaps lasf, lasf and the back-side flaps lbsf, lbsf in the abdomen part la and the back part lb, respectively. On the other hand, in the crotch part lm, similarly, the solid gather sheet 6 and the exterior sheet 5 are integrated by bonding or welding at the end edge or neighbouring position, thereby forming leg flaps lmf, lmf over a predetermined range from the end edge to the inner side in the lateral direction.

[0037]

The leg flaps lmf, lmf are portions to be the leg openings HL in the worn state, respectively, that is, portions covering and surrounding the legs of the low-weight infant 101. Then, in the leg flaps lmf, band-like elastic sheets 21 along a straight line in the longitudinal direction are respectively fixed in a stretched state in the longitudinal direction, by bonding, etc., to the leg flaps lmf as leg-circumference elastic members 21, so as to contract the leg flaps lmf in the longitudinal direction to form leg gathers. Thus, when the stretched state of the leg-circumference elastic members 21 is loosened, the leg flaps lmf contract in the longitudinal direction to form a plurality of gathers which will be leg gathers.

Incidentally, in this embodiment, the leg-circumference elastic member 21 is inserted between the exterior sheet 5 and the solid gather sheet 6, as illustrated in Fig. 3B, but it is not limited thereto. For example, the member may be bonded to the non-skin-side surface of the exterior sheet 5, or may be bonded to the skin-side surface of the solid gather sheet 6.

Further, in this embodiment, such band-like elastic sheets 21 are made of stretchable nonwoven fabric (nonwoven fabric including elastomer fiber such as urethane fiber, etc., and having stretchability based on its own elasticity) , but they are not limited thereto. That is to say, other types of sheets may be used if only the sheet has stretchability based on its own elasticity without depending on rubber thread, flat rubber, etc. For example, stretchable film (film including elastomer and having stretchability based on its own elasticity) may be used.

[0038]

As illustrated in Figs. 2 and 3A, fastening tapes 11, 11 are respectively provided in the tip parts in the lateral direction of the pair of back-side flaps lbsf, lbsf. The fastening tapes 11 respectively use laterally long band-like sheets made of nonwoven fabric as tape substrates 11a, and one end part in the lateral direction of each of the tape substrates 11a is fixed to the tip part of the back-side flap lbsf, and the other end part protrudes to the outside of the tip part of the back-side flap lbsf.

Then, a male member 11m (corresponding to an engagement part) of a hook-and-loop fastener is fixed to the skin-side surface of this protruding portion, and further a plurality of engagement protrusions (not shown) are provided to the skin-side surface of the male member 11m. Thus, the engagement protrusions of the male member 11m are hooked by the non-skin-side surface of the target tape 15, thereby engaging the fastening tape 11 with the target tape 15. A known hook-and-loop fastener can be applied for such a male member 11m, and for example, those whose engagement protrusions are in a fish hook shape, T-shape, etc., can be used appropriately.

[0039]

As illustrated in Figs. 2 and 3A, the target tape 15 (corresponding to a target area) is provided on the non-skin-side surface of the exterior sheet 5 which is the non-skin-side surface of the abdomen part la. In this embodiment, the tape 15 is in a laterally long rectangular shape, and then the target tape 15 is fixed, by bonding or welding, to the exterior sheet 5 with their central positions in the lateral direction being aligned to each other. Further, in this embodiment, in order to increase an engagement force with respect to the fastening tape 11, air-through nonwoven fabric in a laterally long rectangular shape having a basis weight equal to or greater than 25 (g/m2) is used for the target tape 15. Thereby, an engagement force required for appropriate engagement is secured. An estimated engagement force required for appropriate engagement can be exemplified as 0.1 (g/lOmm) or more. A method for measuring this engagement force, etc., will be described later.

[0040]

Incidentally, the material of the target tape 15 is not limited to the above-described air-through nonwoven fabric. That is to say, as long as such an engagement force as above can be secured between the fastening tape 11 and the male member 11m, nonwoven fabric other than the above spunbond nonwoven fabric may be used, or a female member, such as loop material, of the known hook-and-loop fastener may be used without using nonwoven fabric. Further, when the exterior sheet 5 is nonwoven fabric, the exterior sheet 5 is used as a target tape, and thereby the dedicated target tape 15 may be omitted.

[0041]

Then, when such diaper 1 is worn by the low-weight infant, a pair of fastening tapes 11, 11 engages the target tape 15 while the diaper 1 is being stretched to both sides in the lateral direction using the pair of fastening tapes 11, 11. Incidentally, in this embodiment, the tape substrates 11a further protrude in the lateral direction to the outside of the male member 11m, these protruding parts llap function as the holding parts llap which are to be held when the fastening tapes 11 are stretched to both sides.

[0042]

Hereinabove, the basic structure of the diaper 1 has been described, and in the present embodiment, several contrivances to solve the previously mentioned problems (such issues of restraining the fastening tapes 11 from peeled off and detached and bringing the back part lb into intimate contact with the back) are made. Hereinafter, this will be described.

[0043]

Fig. 5 is an explanatory diagram of such contrivance, and the schematic plan view in the same unfolded state as in Fig. 2. The first contrivance relates to an elastic member 31 that provides stretchability to the waist opening HB. That is, although not mentioned above, in this example, in order to give stretchability to the waist opening HB, the band-like elastic sheet 31 (hereinafter also referred to as the waist-circumference elastic sheet 31) in a laterally long rectangular shape is provided in the back part lb, which causes a part corresponding to the waist opening HB to be laterally contracted in the back part lb, in a natural state where an external force does notact. More specifically, such elastic sheet 31 extends in both sides in the lateral direction and the sheet 31 is fixed by bonding or welding, in a laterally stretched state, to the members 2, 3, 4, 5 and 6 adjacent to the skin side and the non-skin side in the thickness direction of the sheet 31. Thus, if a stretched state is loosened to bring about a natural state, a part fixed to the elastic sheet 31 is laterally contracted mainly in the back part lb, to form a plurality of gathers. Therefore, the elastic sheet 31 can be swiftly stretched in the lateral direction until such gathers have been stretched tight, and thus the waist opening HB is in such a state that stretchability is given. [0044]

Note that, as understood referring to Figs. 5 and 3A, a member to which the elastic sheet 31 is fixed varies among the above members 2, 3, 4, 5 and 6 adjacent to the non-skin side and the skin side in the thickness direction, depending on the position in the lateral direction and the longitudinal direction. For example, as illustrated in Fig. 3A, the leak-proof sheet 4 is present on the central position side in the lateral direction on the non-skin side in the thickness direction, and thus, at this position, the sheet 31 is fixed to the leak-proof sheet 4. However, since the leak-proof sheet 4 is not present at the position on each end side in the lateral direction, the elastic sheet 31 is fixed to the exterior sheet 5. Further, as illustrated in Figs. 5 and 3A, since the absorbent body 3 is present at the position on the central side in the lateral direction and on the central side in the longitudinal direction on the skin side in the thickness direction, the sheet 31 is fixed to the absorbent body 3 at this position. However, at the position where the absorbent body 3 is not present, the sheet 31 is fixed to the top sheet, and further at the position on each end side in the lateral direction where even the top sheet 2 is not present, the sheet 31 is fixed to the solid gather sheet 6.

[0045]

Then, in the present embodiment, in the diaper 1 in an unfolded state as in Fig. 5, the elastic sheet 31 extends to both sides in the lateral direction at least to the positions in proximity to the fastening tapes 11, 11, and thus end parts 31el, 31el in the lateral direction of the elastic sheet 31 are respectively located at the same positions with respect to the lateral direction as or located laterally outside the closest end parts 21e2, 21e2 on the back side in the longitudinal direction in the leg-circumference elastic members 21, 21.

Thus, the end parts 31el, 31el are to be less affected by a force generated in the leg-circumference elastic members 21, and therefore the end parts 31el, 31el of the waist-circumference elastic sheet 31 can cause their own contractile forces to swiftly act as a tensile force on the closest fastening tapes 11, 11 in the lateral direction, respectively. Thereby, with a shearing force in the lateral direction being added to the male member 11m of the fastening tapes 11, it becomes possible to engage the male members 11m with the target tape 15 of the abdomen part la with a high engagement force, and as a result, the fastening tapes 11 can be effectively restrained from being peeled off and detached.

Incidentally, here, the "unfolded state" represents, as illustrated in Fig. 5, such a state that the fastening tapes 11, 11 are made out of engagement with the target tape 15; the abdomen part la, the crotch part lm, and the back part lb are made in a state arranged in the longitudinal direction; and the diaper 1 is spread out in both the longitudinal direction and the lateral direction, until contraction of a part corresponding to the waist opening HB based on the waist-circumference elastic sheet 31 and contraction of the pair of leg flaps lmf, lmf based on the leg-circumference elastic members 21, 21 disappears.

[0046]

Further, in the unfolded state in Fig. 5, the waist-circumference elastic sheet 31 is provided to longitudinally span central positions Cllm in the longitudinal direction in the male members 11m of the fastening tapes 11. Specifically, the elastic sheet 31 includes, in its all positions in the lateral direction thereof, a line segment LNCllm connecting between the longitudinally central position Cllm in the male member 11m of one fastening tape 11 and the central position Cllm in the male member 11m of the other fastening tape 11. Thus, the elastic sheet 31 can transfer the above-described contractile force to the fastening tapes 11, 11 with a substantially uniform distribution which is longitudinally less-biased, and this also effectively contributes to restraint of the above-described peeling off and detaching.

Incidentally, the inventors have confirmed that, in order to improve this effect, an overlap ratio between the male member 11m and the elastic sheet 31 with respect to the longitudinal direction (a percentage value obtained by dividing a maximum measurement Lllm in the longitudinal direction of the male member 11m into an amount of overlap LOL (mm) between the male member 11m and the elastic sheet 31 with respect to the longitudinal direction) should be made equal to or greater than 70%.

[0047]

Further, the waist-circumference elastic sheet 31 is an elastic film containing a suitable elastomer resin, and thus the sheet 31 itself has elasticity. Therefore, as compared with the case where a plurality of rubber threads or flat rubbers are used, a tensile force can act on the fastening tapes 11 with substantially uniform distribution which is longitudinally less biased, and this also effectively contributes to restraint of the above-described peeling off and detaching. [0048]

Further, a gap G which may be created in a positioning posture illustrated in Fig. IB, that is, the gap G, which may be created between the back of the low-weight infant 101 hunched in C-shape and the back part lb of the diaper 1, is also reduced on the basis of the contractile force of the elastic sheet 31. Thus, the back part lb of the diaper 1 can be brought into intimate contact with the back of the low-weight infant 101.

[0049]

The first contrivance has been described, hereinabove, and such first contrivance is necessary in the diaper 1 according to the present invention. On the other hand, contrivances, which will be described hereinafter, are not necessary, but with such contrivances, the above-mentioned problem can be solved more effectively. Thus, in the diaper 1 according to the present embodiment, the following contrivances are also provided.

[0050]

First, in this embodiment, as illustrated in Fig. 5, the end parts 31el in the lateral direction of the waist-circumference elastic sheet 31 are respectively coupled to the closest fastening tapes 11 in outer end parts 31ele in the lateral direction in the end part 31el.

Thus, the contractile force of the end part 31el can swiftly and reliably act on the fastening tape 11. Then, this also effectively contributes to restraint of the above-mentioned peeling off and detaching.

[0051]

Further, in this example, as illustrated in Fig. 5, the waist-circumference elastic sheet 31 is provided in such a manner as to overlap with both the absorbent body 3 and the leak-proof sheet 4, when seen from the thickness direction. In this case, the end parts 31el, 31el in the lateral direction in the waist-circumference elastic sheet 31 are located at the same positions as that of the end edges in the lateral direction in both the absorbent body 3 and the leak-proof sheet 4, or located laterally outside thereof.

[0052]

Thus, when pulling the fastening tapes 11, 11 to both sides in the lateral direction for the diaper 1 to be worn, at least the end parts 31el, 31el in the waist-circumference elastic sheet 31 can extend freely without receiving great resistance from the absorbent body 3 and the leak-proof sheet 4. Thereby, the contractile force created in the end parts 31el can swiftly act on the fastening tapes 11 as a tensile force in the lateral direction at the time of the engagement of the fastening tape 11 to the target tape 15 and thereafter, and this can also effectively contribute to restraint of the above-mentioned peeling off and detaching.

[0053]

Further, in this embodiment, as illustrated in Fig. 5, the absorbent body 3 includes a low stiffness portion 3nb (corresponding to a back-side low stiffness portion) having a stiffness lower than that in the surrounding parts, corresponding to the position of the back part lb. That is, in this embodiment, a space 3cnb substantially in a triangular shape in plan view without any material of the absorbent core 3c such as pulp fiber, SAP, etc., is formed at the laterally central position in an end part on the back side in the longitudinal direction in the absorbent core 3c, and thereby the above-described low stiffness portion 3nb is formed in the absorbent body 3. Further, the low stiffness portion 3nb overlaps with the waist-circumference elastic sheet 31 when seen from the thickness direction.

[0054]

Thus, in the case of pulling the fastening tapes 11, 11 to both sides in the lateral direction when the diaper 1 is worn, at least the low stiffness portion 3nb in the absorbent body 3 is swiftly contracted in the lateral direction, and the low stiffness portion 3nb does not act as great resistance. Thereby, the waist-circumference elastic sheet 31 can be stretched with a relatively small tensile force, and as a result, a contractile force can easily be created in the waist-circumference elastic sheet 31.

[0055]

However, the portion 3cnb of the absorbent core 3c corresponding to the low stiffness portion 3nb is not limited to the above-described space. That is, as long as the space having a basis weight (g/m2) less than that in its surrounding portion, the above-described effects can be exerted correspondingly, and thus some structure materials of the absorbent core 3c may be contained in the above portion 3cnb.

[0056]

Further, in this embodiment, as illustrated in Fig. 5, the absorbent body 3 includes a low stiffness portion 3na (corresponding to an abdomen-side low stiffness portion) having stiffness lower than that in its surrounding portion, corresponding to the position of the abdomen part la. That is, in this embodiment, the space 3cna in a trapezoid shape in plan view having an upper base and a lower base along the lateral direction is formed at the laterally central position in an end part on the abdomen side in the longitudinal direction of the absorbent core 3c, thereby forming the above low stiffness portion 3na in the absorbent body 3. Further, the low stiffness portion 3na overlaps with the target tape 15 when seen from the thickness direction. [0057]

Thus, as illustrated in Fig. 6, in the case where the engagement positions, at which the male members 11m, 11m of the fastening tapes 11, 11 have engaged the target tape 15 when the diaper 1 is worn, are such positions as to sandwich the low stiffness portion 3na from both sides in the lateral direction, the low stiffness portion 3na is easily enlarged on the basis of a contractile force of the waist-circumference elastic sheet 31. Then, the male members 11m slightly move in the lateral direction with this enlargement operation, and thereby the male members 11m can fit and securely engage the target tape 15, which enables firmer engagement between the male members 11m and the target tape 15.

However, the portion 3cna in the absorbent core 3c corresponding to the low stiffness portion 3na is not limited to the above-described space. That is, as long as the space having a basis weight (g/m2) less than that in its surrounding portion, the above-described effects can be exerted correspondingly, and thus some structure materials of the absorbent core 3c may be contained in the above portion 3cna.

[0058]

Further, in this embodiment, as illustrated in Fig. 5, the male member 11m of the fastening tape 11 in plan view is substantially in a quadrangular shape, and thus includes a side 11ms along the longitudinal direction at the position on the inner side in the lateral direction. On the other hand, since the leg-circumference elastic member 21 is the band-like elastic sheet 21 provided along the longitudinal direction, the external shape thereof has a pair of long sides 21s2, 21s2 along the longitudinal direction and a pair of short sides 21sl, 21sl along the lateral direction. And, a part of the waist-circumference elastic sheet 31 is positioned in a quadrangular area Allm21 (dotted area Allm21 in Fig. 5) whose opposite sides are the short side 21sl located on the back side in the pair of short sides 21sl, 21sl and the side 11ms located laterally inside the male member 11m of the fastening tape 11, and such a quadrangular area Allm21 is a transfer path through which a force may be transferred from the leg-circumference elastic member 21 to the male member 11m of the fastening tape 11.

[0059]

Thus, even in the case where a force to pull down the male member 11m to the leg opening HL side is transferred from the leg-circumference elastic member 21, such force is reduced by the above-mentioned part in the waist-circumference elastic sheet 31 and transferred to the male member 11m, and thereby being able to effectively restrain the fastening tapes 11 from being detached due to such force.

[0060]

Further, in this embodiment, as illustrated in Fig. 7, the waist-circumference elastic sheet 31 includes: an effective portion 31a that contracts the waist opening HB in the lateral direction; and ineffective portions 31n, 31n that do not contract the waist opening HB in the lateral direction. And, the ineffective portions 31n, 31n are located in the end parts 31el, 31el in the lateral direction in the waist-circumference elastic sheet 31, respectively, and also the ineffective portions 31n, 31n are respectively located between the closest fastening tapes 11 and the effective portion 31a. Further, the ineffective portions 31n, 31n are approximately in a natural length state in a natural state where an external force does not act.

Thus, when pulling the fastening tapes 11 in the lateral direction, the ineffective portion 31n is stretched relatively easily and swiftly. Then, a contractile force created on the basis of such stretch can swiftly act on the fastening tapes 11 as a tensile force in the lateral direction. Thus, the male member 11m of the fastening tape 11 can engage the target tape 15 with an appropriate engagement force .

[0061]

Further, in this embodiment, as illustrated in Fig. 8, the pair of fastening tapes 11, 11 are structured to be engageable in a "fastening-tape overlapping form." Thus, in the case of performing engagement in the fastening-tape overlapping form as necessary, the fastening tapes 11, 11 can engage in such a manner as to become closer to the laterally central part in the abdomen part la when worn, and thereby the fastening tapes 11, 11 can be kept away from the legs in M-shape of the low-weight infant 101. As a result, the above-mentioned push-up force F (Fig. IB) given from the legs to the fastening tapes 11, 11 can be reduced, whereby being able to restrain the fastening tapes 11, 11 from being peeled off and detached.

[0062]

The fastening-tape overlapping form will be described, hereinafter, and firstly, for convenience sake, the fastening tape 11 of the back-side flap lbsf located on the left side in Fig. 8 is referred to as a "left-side tape 11-1 (corresponding to a first tape) ," and similarly, the fastening tape 11 of the back-side flap lbsf located on the right side is referred to as a "right-side tape 11-2 (corresponding to a second tape)

Then, as illustrated in Fig. 8, the male member 11m of the skin-side surface of the left-side tape 11-1 engages the target tape 15 of the abdomen part la, while the male member 11m of the skin-side surface of the right-side tape 11-2 engages a non-skin-side surface 11-ls of the left-side tape 11-1 in an overlapping manner. That is, in the fastening-tape overlapping form, the non-skin-side surface 11-ls (corresponding to a surface on a non-engagement part side) of the left-side tape 11-1 is used as a female member with which the male member 11m of the right-side tape 11-2 is to engage. Thus, in this embodiment, the non-skin-side surface 11-ls of the left-side tape 11-1 is made of nonwoven fabric having a relatively large basis-weight, for example, equal to or greater than 50 (g/m2) , and thereby an engagement force between the male member 11m of the right-side tape 11-2 and the non-skin-side surface 11-ls of the left-side tape 11-1 is made equal to or greater than 0.1 (N/10 mm) . Thus, the male member 11m of the right-side tape 11-2 can engage the non-skin-side surface 11-ls of the left-side tape 11-1 with such an engagement force as to be required for the engagement, thereby implementing the fastening-tape overlapping form.

[0063]

Here, it is preferable that the fastening-tape overlapping form is implemented as follows. That is, it is preferable that the engagement force (N/10 mm) between the male member 11m of the left-side tape 11-1 and the target tape 15 and the engagement force (N/10 mm) between the male member 11m of the right-side tape 11-2 and the target tape 15 each are greater than the engagement force (N/10 mm) between the non-skin-side surface 11-ls of the left-side tape 11-1 and the male member 11m of the right-side tape 11-2, and further it is preferable that in the case where the non-skin-side surface 11-ls of the left-side tape 11-1 engages the male member 11m of the right-side tape 11-2 in an overlapping manner while a longitudinally central position Cll-1 in the left-side tape 11-1 and a longitudinally central position Cll-2 in the right-side tape 11-2 are aligned to coincide with each other, the left-side tape 11-1 and the right-side tape 11-2 are set in such a form that the male member 11m of the right-side tape 11-2 extends out to both sides in the longitudinal direction from the non-skin-side surface 11-ls of the left-side tape 11-1.

For example, in this embodiment in Fig. 8, both the left-side and the right-side tapes 11-1, 11-2 are in the same shape, and specifically, are in such a tapering form that the dimension in the longitudinal direction decreases toward the tip end side in the lateral direction. Thus, in the case where the left-side tape 11-1 and the right-side tape 11-2 engage such that the male member 11m of the right-side tape 11-2 engages the non-skin-side surface 11-ls of the left-side tape 11-1 in an overlap manner while the longitudinally central positions Cll-1, Cll-2 are aligned to coincide with each other, the male member 11m of the right-side tape 11-2 is to extend out from the left-side tape 11-1 to both sides in the longitudinal direction at a basal position Pll-2n in the right-side tape 11-2 in the lateral direction.

[0064]

With a structure is made as such, it becomes possible to strengthen the engagement state of the right-side tape 11-2 as a whole while enabling easy detachment of the left-side tape 11-1 in the fastening-tape overlapping form from the right-side tape 11-2.

Details are as follows.

First, as described above, in this embodiment, the engagement force (N/10 mm) between the male member 11m of the left-side tape 11-1 and the target tape 15 is set greater than the engagement force (N/10 mm) between the non-skin-side surface 11-ls of the left-side tape 11-1 and the male member 11m of the right-side tape 11-2. Thus, in the case where the right-side tape 11-2 is detached from the left-side tape 11-1 with holding the holding part llap in the tip part of the tape 11-2, it can be effectively prevented that the left-side tape 11-1 is also detached from the target tape 15 together therewith, and thereby only the right-side tape 11-2 can be detached from the left-side tape 11-1 on the stable left-side tape 11-1. Thus, the right-side tape 11-2 can easily be detached from the left-side tape 11-1, and as a result, it becomes possible to not apply great stress to the low-weight infant 101, when detaching the fastening tapes 11-1, 11-2 at the time of changing the diaper, which contributes to minimum handling.

[0065]

Further, as described above, in the fastening-tape overlapping form, the male member 11m of the right-side tape 11-2 extends out from the left-side tape 11-1 to both sides in the longitudinal direction, at the basal position Pll-2n of the right-side tape 11-2 in the lateral direction. And, such a part as to extend out therefrom engages the target tape 15 in the abdomen part la. Here, the engagement force (N/10 mm) of engaging with the target tape 15 is made greater than the engagement force (N/10 mm) of engaging with the non-skin-side surface 11-ls of the left-side tape 11-1. Thus, the engagement force of the male member 11m of the right-side tape 11-2 can be increased by an amount corresponding to such extending out portion.

Incidentally, measurement of such engagement force (N/10 mm) , is carried out as follows, for example, using an autograph testing machine AG-XIOplus (manufactured by Shimadzu Corporation) as an example of a tensile testing machine. Fig. 9 is a schematic side view illustrating a measurement state.

First, a part of the fastening tape 11 of the diaper 1 is cut out, to form a rectangular sample 11s (hereinafter, referred to as fastening tape sample 11s) in which the tape substrate 11a and the male material 11m are of the same form. Further, a part of the target tape 15 of the diaper 1 is cut out, to form a sample 15s of the target tape 15 (hereinafter, referred to as a target tape sample 15s), and in this case, the size of the target tape sample 15s is set greater in both the longitudinal direction and the lateral direction than that of the fastening tape sample 11s.

[0066]

The male member 11m of the above-described fastening tape sample 11s engages the non-skin-side surface of this target tape sample 15s, thereby forming a measurement sample llsl5s. However, in this engagement, the fastening tape sample 11s is placed onto the non-skin-side surface of the target tape sample 15s, while alignment is being performed such that the lateral direction of the samples are aligned in parallel with each other and the fastening tape sample 11s does not extend out from the non-skin-side surface of the target tape sample 15s, and thereafter, a roller weighing 700 grams not shown is rolled, in the lateral direction as a pulling-off direction, at a speed value of 5 (mm/min) while acting the roller's own weight on both the samples 11s, 15s. Thereby, both the samples 11s, 15s are made in a predetermined engagement state.

[0067]

On the other hand, as illustrated in Fig. 9, the tensile testing machine includes a pair of heads 81u, 81d capable of being separated in the vertical direction. Specifically, one head 81u is the moving head 81u that is movable upward and downward in the vertical direction, and the other head 81d is the fixed head 81d that is provided to be immovable below the moving head 81u. Further, the fixed head 8Id has a flat inclined surface 8Ids on the upper surface thereof, and the surface 81ds is inclined by 135° from the vertical direction.

[0068]

The measurement sample llsl5s is fixed onto the inclined surface 81ds. Note that, in the fixing thereof, the target tape sample 15s is brought into surface contact with the inclined surface 81ds, thereby positioning the fastening tape sample 11s above the target tape sample 15s. Further, arrangement is made such that the lateral direction of the samples 11s, 15s is in parallel with the inclined direction of the inclined surface 81ds. Further, one end part of supplemental grasping sheet 83, which is formed in such a size as to protrude in the longitudinal direction (a direction penetrating the paper surface in Fig. 9) from a lower end edge llsde is fixed to a lower end edge llsde in the oblique direction of the fastening tape sample 11s, and the other end part of the supplemental grasping sheet 83 is grasped by a grasping part 81uc of the moving head 81u.

[0069]

Then, the moving head 81u is moved upward at a predetermined moving speed value of 300(mm/min) while a load value (N) acting on the head 8Id is being measured by a load cell not shown provided to the fixed head 81d, thereby separating the head 81u from the fixed head 81d.

And, the fastening tape sample 11s is sequentially being detached from the target tape sample 15s, and among the load values measured then, a load value P135 when an angle Θ between the direction of a pulling-off force Fh given from the moving head 81u through the supplemental grasping sheet 83 to the fastening tape sample 11s and the inclined direction of the inclined surface 81ds reaches 135 degrees, is recorded. Then, the recorded load value P135 is converted into a load value when the dimension in the longitudinal direction of the fastening tape sample 11s is 10 mm, and this converted value is obtained as the above-described engagement force (N/10 mm) . For example, when the dimension in the longitudinal direction of the fastening tape sample 11s is 20 mm, a value obtained by multiplying, by 10 mm, a value obtained by dividing the above recorded load value P135 by 20 mm (=(P135/20mm) xlOmm) is obtained as the above engagement force (N/10 mm) .

[0070]

Note that, it is clear that measurement of the engagement force in the case of the fastening-tape overlapping form, that is, the engagement force (N/10 mm) between the non-skin-side surface 11-ls of the left-side tape 11-1 and the male member 11m of the right-side tape 11-2 can also be carried out similarly to the above, and thus the description thereof will be omitted.

[0071]

Incidentally, it is described above that the diaper 1 according to the present embodiment is specialized in a diaper for low-weight infants weighing equal to or less than 3000 grams, and considering that the diaper 1 can effectively solve the above-mentioned problems associated with the positioning posture and the minimum handling, the diaper 1 in the present embodiment is further effective in such a case as to further easily become the positioning posture and also be further required for minimum handling. And, such a case is a case where infants weigh further less.

Thus, it is preferable that the diaper 1 of the present embodiment is used for low birth-weight infants weighing less than 2500 grams and equal to or greater than 1500 grams, more preferably, very low birth-weight infants weighing less than 1500 grams and equal to or greater than 1000 grams, and further more preferably, extremely low birth-weight infants weighing less than 1000 grams.

[0072]

Further, since the diaper 1 according to the present embodiment is specialized in a diaper for low-weight infants, it is formed smaller than the existing diaper 1 for a newborn. For example, as compared with a diaper for newborn infants having a product-length of 365 mm and a circumferential length LHB of the waist opening HB in a worn state of 304 mm, the diaper 1 of the present embodiment has a product length LI (Fig. 2) of 210 to 330 mm and a circumferential length LHB of the waist opening HB in a worn state of 160 to 295 mm.

[0073]

Note that a product length LI is the maximum dimension LI in the longitudinal direction in the above-mentioned unfolded state. Further, the above circumferential length LHB of the waist opening HB is measured with the fastening tapes 11-1, 11-2 being made in an engagement state of the fastening-tape overlapping form. Details are as follows.

Firstly, as illustrated in Fig. 8, the male member 11m of the left-side tape 11-1 engages the target tape 15 of the abdomen part la, and thereafter the male member 11m of the right-side tape 11-2 engages the non-skin-side surface 11-ls of the left-side tape 11-1, and at this time, while the longitudinally central positions Cll-1, Cll-2 of these tapes 11-1, 11-2 are being aligned with each other, alignment is performed such that a tip ll-2e of the right-side tape 11-2 coincides with an end lime on the basal side of the male member 11m of the left-side tape 11-1. Thereby, the engagement state in the fastening-tape overlapping form is brought about.

[0074]

Then, the waist opening HB formed on the basis of this engagement state is stretched until contraction based on the waist-circumference elastic sheet 31 disappears. And then, in such a stretched state, the circumferential length LHB of the waist opening HB is measured, thereby obtaining the circumferential length LHB.

[0075]

Incidentally, the product length LI and the circumferential length LHB of the waist opening HB for low birth-weight infants are 310 mm and 273.5 mm, respectively, and the product length LI and the circumferential length LHB of the waist opening HB for very low birth-weight infants are 27 0mm and 220 mm, respectively, and further, the product length LI and circumferential length LHB of the waist opening HB for extremely low birth-weight infants are 230 mm and 219 mm, respectively.

[0076] ===Other Embodiments===

Hereinabove, the embodiments according to the present invention have been described, and the above embodiments are to facilitate understanding of the present invention, and are not for limiting understanding of the present invention. Further, it is needless to say that the present invention may be changed and modified, without departing from the gist thereof, and the present invention includes its equivalents. For example, modifications as indicated below are possible.

[0077]

In the above-described embodiment, the band-like elastic sheet 21 along a straight line in the longitudinal direction is exemplified as the leg-circumference elastic member 21, and the shape of the band-like elastic sheet 21 is not limited to the above. For example, the sheet may be of such a curved shape as to shift inwardly in the lateral direction as it goes inwardly in the longitudinal direction from the back-side end part.

[0078]

In the above described embodiments, elastic film is exemplified as the waist-circumference elastic sheet 31, but this is not limited thereto. That is, as long as the sheet 31 itself has elasticity, the sheet 31 may be a sheet-like member other than elastic film, and may be, for example, stretchable nonwoven fabric (nonwoven fabric including elastomeric fiber such as urethane fiber and having stretchability based on its own elasticity).

[Reference signs list] [0079] 1 disposable diaper, la abdomen part, lasf side flap, lb back part, lbsf side flap (end part), lm crotch part, lmf leg flap, 2 top sheet, 2e end part, 3 absorbent body, 3na low stiffness portion (abdomen-side low stiffness portion), 3nb low stiffness portion (back-side low stiffness portion), 3c absorbent core, 3cna space, 3cnb space, 3rs core wrap sheet, 4 leak-proof sheet, 6 solid gather sheet, 6g solid gather (leakage-proof wall), 6r rubber thread, 11 fastening tape, 11a tape substrate, llap protruding part (holding part), 11m male member (engagement part) , lime end, 11ms side, 11-1 left-side tape (first tape), 11-ls non-skin-side surface, 11-2 right-side tape (second tape), ll-2e tip, 11s fastening tape sample, llsde lower end edge, llsl5s sample, 15 target tape, 15s target tape sample, 21 leg-circumference elastic member, 21el back-side end part, 21e2 end part, 21sl short side, 21s2 long side, 31 waist-circumference elastic sheet, 31el end part, 31ele outer end part, 31a effective portion, 31n ineffective portion, 81u moving head, 81uc grasping part, 81d fixed head, 81ds inclined surface, 83 supplemental grasping sheet, 101 low-weight infant, HB waist opening, HL leg opening, P6g fixed position,

Allm21 quadrangular area,

Cllm central position, Cll-1 central position,

Cll-2 central position,

Pll-2n basal position, LNCllm line segment, G gap, F push-up force, Fh pulling-off force

Claims

[THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:]

1. An open-type disposable diaper for a low-weight infant weighing equal to or less than 3000 grams, the diaper including an abdomen part arranged along a lateral direction on an abdomen-side of the low-weight infant, a crotch part arranged in crotch of the low-weight infant, and a back part arranged along the lateral direction on the back side of the low-weight infant, the abdomen part, the crotch part and the back part being arranged in a longitudinal direction orthogonal to the lateral direction, the back part having end parts in the lateral direction, which are configured to engage the abdomen part via engagement parts of fastening tapes respectively provided in the end parts, to form a waist opening and a pair of leg openings, the diaper comprising: leg-circumference elastic members provided along the longitudinal direction in positions on both sides in the lateral direction in the crotch part, the leg-circumference elastic members configured to contract the leg openings along the longitudinal direction; and a waist-circumference elastic sheet provided to extend to both sides in the lateral direction in the back part, the waist-circumference elastic sheet configured to contract the waist opening in the lateral direction, wherein in a state where the diaper is unfolded, end parts in the lateral direction in the waist-circumference elastic sheet are respectively located at same positions, with respect to the lateral direction, as positions of back-side end parts in the longitudinal direction of the nearest leg-circumference elastic members or located laterally outside the back-side end parts; and with respect to the longitudinal direction, the waist-circumference elastic sheet is arranged to span, in the longitudinal direction, central positions in the longitudinal direction in the engagement parts of the fastening tapes, an absorbent body extending along the longitudinal direction over the abdomen part, the crotch part, and the back part is included, a direction orthogonal to both the longitudinal direction and the lateral direction is along a thickness direction of the diaper in the unfolded state, the absorbent body includes a back-side low stiffness portion corresponding to a position of the back part, the backside low stiffness portion having stiffness lower than stiffness of surrounding portion, the back-side low stiffness portion overlaps with the waist-circumference elastic sheet when seen from the thickness direction, the abdomen part includes a target area configured to engage each of the engagement parts of the fastening tapes in the end parts of the back part, the absorbent body includes an abdomen-side low stiffness portion corresponding to a position of the abdomen part, the abdomen-side low stiffness portion having stiffness lower than stiffness of surrounding portion, the abdomen-side low stiffness portion overlaps with the target area when seen from the thickness direction, and the abdomen-side low stiffness portion is smaller than the back-side low stiffness portion, in the longitudinal direction.
2. The open-type disposable diaper for a low-weight infant weighing equal to or less than 3000 grams according to claim 1, wherein the end parts of the waist-circumference elastic sheet are outer end parts in the lateral direction among the end parts, and are connected to the nearest fastening tapes.
3. The open-type disposable diaper for a low-weight infant weighing equal to or less than 3000 grams according to one of claims 1 and 2, wherein a leak-proof sheet covering the absorbent body from a nonskin side in the thickness direction, is included, and when seen from the thickness direction, the waist-circumference elastic sheet overlaps with both the absorbent body and the leak-proof sheet, and the end parts in the lateral direction in the waist-circumference elastic sheet are located at the same positions as positions of end edges in the lateral direction of both the absorbent body and the leak-proof sheet, or located laterally outside the end edges.
4. The open-type disposable diaper for a low-weight infant weighing equal to or less than 3000 grams according to any one of claims 1 to 3, wherein the engagement parts of the fastening tapes have a shape having a side positioned inside in the lateral direction, the leg-circumference elastic member is a band-like elastic sheet having a pair of long sides along the longitudinal direction and a pair of short sides along the lateral direction, and a part of the waist-circumference elastic sheet is positioned in a quadrangular area partitioned with the short side positioned on the back side out of the pair of short sides and the side positioned inside in the lateral direction of the engagement part of the fastening tape, the short side and the side serving as opposite sides.
5. The open-type disposable diaper for a low-weight infant weighing equal to or less than 3000 grams according to any one of claims 1 to 4, wherein the waist-circumference elastic sheet includes an effective portion configured to contract the waist opening in the lateral direction and an ineffective portion configured to not contract the waist opening in the lateral direction, and the ineffective portion is located in the end parts in the lateral direction in the waist-circumference elastic sheet, and is located between the fastening tape and the effective portion .
6. The open-type disposable diaper for a low-weight infant weighing equal to or less than 3000 grams according to any one of claims 1 to 5, wherein in a case where a fastening tape of one end part out of the end parts is a first tape, a fastening tape of an other end part is a second tape, the engagement part of the first tape engages the abdomen part, and the engagement part of the second tape engages a surface on a non-engagement part side of the first tape in an overlapping manner, an engagement force between the engagement part of the second tape and the surface on the non-engagement part side of the first tape is equal to or greater than 0. 1 (N/10 mm), and an engagement force (N/10 mm) between the engagement part of the first tape and the abdomen part and an engagement force (N/10 mm) between the engagement part of the second tape and the abdomen part each are set greater than the engagement force (N/10 mm) between the surface on the non-engagement part side of the first tape and the engagement part of the second tape, and in a case where the engagement part of the second tape engages the surface on the non-engagement part side of the first tape in an overlapping manner while a central position in the longitudinal direction in the first tape and a central position in the longitudinal direction in the second tape are being aligned to coincide with each other, the first tape and the second tape are set in such a form that the engagement part of the second tape extends out from the first tape to both sides in the longitudinal direction.