Wearing article

Here is disclosed a wearing article made of an elastically stretchable chassis defining a front waist region, a rear waist region and a crotch region. This sheet is composed of a first elastic segment extending, substantially in parallel to peripheral portions destined to form leg-holes, from a transversely middle zone of the crotch region to lateral portions of the front and rear waist regions, and a second elastic segment defined by the remaining portion except for the first elastic segment wherein the first elastic segment has a stretch stress higher than that of the second elastic segment.

BACKGROUND OF THE INVENTION

The present invention relates to a wearing article suitable for a disposable diaper, pants for an incontinent patient, sanitary shorts or the like.

The disposable diaper provided in its crotch region with a depression adapted to receive feces is well known. For example, Japanese Utility Model Registration No. 2523711B (DOCUMENT 1) discloses the disposable diaper formed around the feces receiving depression with a flexible protrusion.

Japanese Publication of Translated version No. 1997-504194A (DOCUMENT 2) discloses the sanitary pants provided with elastic means (elastic member) extending over its crotch region further to respective edges of the front and rear waist regions in the longitudinal direction of the sanitary pants so that the absorbent core may be tightly placed against the wearer's body as the elastic means contract.

However, the disposable diaper provided with the protrusion disclosed by above-cited DOCUMENT 1 has the problem left behind how this protrusion can be placed in tight contact with the wearer's body. The sanitary pants disclosed by above-cited DOCUMENT 2 is accompanied with the inconvenience that the contractile force of the elastic means certainly functions to place the absorbent core closely against the wearer's body but simultaneously functions to pull the waist surrounding end portion of the pants downward.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a wearing article improved to overcome these problem and inconvenience.

According to the present invention, there is provided a wearing article comprising an elastically stretchable chassis having a front waist region, a rear waist region and a crotch region extending therebetween.

The chassis is composed of a first elastic segment extending substantially along peripheral portions forming leg-holes, from a transversely middle zone of the crotch region to the lateral portions of the front and rear waist regions and a second elastic segment defined by a remaining portion of the chassis except for the first elastic segment wherein the first elastic segment has a stretch stress higher than that of the second elastic segment.

The present invention includes the following embodiments.

(1) The lateral portions of the front and rear waist regions are releasably engaged with each other to define the waist-hole and the leg-holes.

(2) The lateral portions of the front and rear waist regions are permanently joined together to define the waist-hole and the leg-holes.

(3) The transversely middle zone of the crotch region is formed on its inner side with an annular protrusion adapted to surround at least one of anus and urethral of a wearer and the first elastic segment extends along the leg-surrounding peripheral portions from the annular protrusion to the respective lateral portions of the front and rear waist regions.

(4) The first elastic segments formed in the front and rear waist regions become contiguous to each other on the lateral portions of the front and rear waist regions as the front and rear waist regions are joined together along the lateral portions of the waist regions.

(5) The wearing article is one of an open-type disposable diaper, a pull-on disposable diaper, a diaper cover and sanitary shorts.

(6) The chassis is provided along at least one of a waist-hole's peripheral portion and leg-holes' peripheral portions with an elastic member or elastic members extending outside the first elastic segment along the peripheral portion or portions.

(7) The first elastic segment exhibits a stretch stress of 0.25 N/width of 15 mm or higher at a stretch ratio of 15% and a stretch stress of 0.6 N/width of 15 mm at a stretch ratio of 40% and the stretch stress of the first elastic segment is at least 1.5 times of the stretch stress of the second elastic segment.

(8) The second elastic segment comprises at least a single elastic sheet extending over the front and rear waist region and the crotch region and the first elastic segment is formed by overlaying and joined an elastic sheet to the single elastic sheet forming the second elastic segment.

(7) The elastic sheet to be overlaid and joined to the single elastic sheet forming the second elastic segment comprises a pair of sheets extending from the transversely middle zone of the crotch region substantially along the leg-holes' peripheral portions to the lateral portions of the front and rear waist regions, respectively, and describing substantially circular arcs which are convex inward in a transverse direction wherein the pair of sheets are overlapped and joined together in the middle zone of the crotch region.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Details of the wearing article according to the present invention will be more fully understood from the description of the disposable diaper as a specific embodiment of the invention given hereunder with reference to the accompanying drawings.

FIG. 1is a perspective view of a disposable diaper1as put on a wearer's body andFIG. 2is a partially cutaway plan view showing this diaper. This diaper1is of open-type having a waist-hole15and a pair of leg-holes16formed as the diaper is put on the wearer's body. The diaper1has a transverse direction indicated by a double-headed arrow A and a longitudinal direction indicated by a double-headed arrow B in the plan view. The diaper1presenting an hourglass-shape in its developed plan view includes a chassis5which is elastically stretchable in the transverse direction A as well as in the longitudinal direction B. The chassis5comprises an elastically stretchable topsheet2destined to come in contact with the wearer's body and an elastically stretchable backsheet3destined to come in contact with a wearer's garment, wherein these two sheets2,3are intermittently joined together by use of an adhesive or a suitable welding technique. The diaper1is composed of, in the longitudinal direction B, a front waist region6, a rear waist region7and a crotch region8extending between the front and rear waist regions6,7. The diaper1is substantially contoured by front and rear end portions11,12extending in the transverse direction A and transversely opposite lateral portions13extending in the longitudinal direction B wherein these lateral portions13curve inward, in the crotch region8, to define leg-surrounding lateral portions14. Along the rear end portion12and the leg-surrounding lateral portions14, a waist-surrounding elastic members17each comprising a plurality or rubber threads and leg-surrounding elastic members18each comprising a plurality of rubber threads are interposed between the topsheet2and the backsheet3and bonded to at least one of these two sheets2,3in a stretched or unstretched state. In a transversely middle zone of the crotch region8, the diaper1is formed on its inner side with an annular protrusion21so that a space surrounded by this annular protrusion21may define a feces receiving pocket22. This protrusion21is formed at a location in the crotch region8put aside toward the rear waist region7so that the protrusion21may come in contact with the wearer's body around the anus as the diaper1is put on the wearer's body.

The chassis5in the diaper1formed in this manner comprises, as seen inFIG. 2, a zonal high elasticity segment26extending from the periphery of the annular protrusion21toward the lateral portions13in the front waist region6as well as toward the lateral portions13in the rear waist region7so as to describe a substantially X-like shape and a low elasticity segment27defined by the remaining segment of the chassis5. When the diaper1is put on the wearer's body, a higher stretching force is necessary for the high elasticity segment26than a stretching force necessary for the low elasticity segment27. The high elasticity segment26extends along the respective leg-surrounding lateral portions14.

Such high elasticity segment26is formed by an elastically stretchable sheet28interposed between the top- and backsheets2,3and bonded to at least one of these sheets2,3. This elastic sheet28preferably has a stretch stress equal to or higher than those of the top- and backsheets2,3. It should be understood that the waist-surrounding elastic member17as well as the leg-surrounding elastic members18are optionally used to assist the chassis5to be closely placed around the wearer's waist and thighs and the diaper1may be made without one or both of these elastic members17,18.

In the preferred chassis5, the high elasticity segment26has a stretch stress of 0.25 N/15 mm or higher when the segment26is transversely stretched by 15% and a stretch stress of 0.6 N/15 mm when the segment26is transversely stretched by 40%. At these stretch ratios, the high elasticity segment26exhibits the stretch stress corresponding to at least 1.5 times of the stretch stress exhibited by the low elasticity segment27.

The diaper1further comprises fastener means. Specifically, each of the opposite lateral portions13in the rear waist region7is provided with a pair of hook members31a,31battached to the topsheet2each making one cooperating component of the mechanical fastener commonly known in the trade name of MAGIC TAPE, on one hand, and each of the opposite lateral portions13in the front waist region6is provided with a pair of loop members32a,32battached to the backsheet3each making the other cooperating component of the mechanical fastener, on the other hand. Of these mechanical fastener components, at least the hook members31band the loop members32bat least partially overlap the high elasticity segment26.

FIGS. 3 and 4are partially sectional views taken along lines III-III and IV-IV inFIG. 2, respectively. The protrusion21is formed by flexible foamed urethane rubber or the like and bonded to the topsheet2by means of an adhesive33. A bottom of the feces receiving depression22is defined by the topsheet2which covers, in turn, a body fluid absorbent core34underlying the topsheet2. The elastic sheet28and the backsheet3underlie the core34in this order.

The core34is formed by fluff pulp or a mixture of fluff pulp and super-absorbent polymer particles. The topsheet2is liquid-pervious at least in its zone covering the core34and the backsheet3is liquid-impervious at least in its zone underlying the core34.

To put the diaper1formed in the manner as has been described above on the wearer's body, the protrusion21is placed against the wearer's body so that the protrusion21may surround the wearer's anus, then the lateral portions13of the rear waist region7are placed upon the lateral portions13of the front waist region6and finally the lateral portions13of the rear waist region7are pulled in a waist-circumferential direction to engage the hook members31a,31bwith the associated loop members32a,32b. Thereupon the high elasticity segment26extending to the respective lateral portions13of the front and rear waist regions6,7are overlapped with itself in the respective lateral portions13so as to form loops surrounding the wearer's thighs. In this state, the high elasticity segment26having high stretch stress functions to press the protrusion21against the wearer's body. There is no anxiety that the protrusion21might shift off from its desired position and/or might be spaced from the wearer's body, so discharged feces, particularly loose passage can be reliably received by the feces receiving depression22and retained therein without any apprehension that such bodily discharges might leak out beyond the protrusion21. A tensile force of the high elasticity segment26generated when the diaper1is put on the wearer's body principally acts upon a zone defined between the crotch region8and the waist's lateral portions13but substantially not upon the front and rear end portions11,12defining together the waist-hole. Consequently, the diaper1is free from the inconvenience that the diaper1might slip down, particularly in the vicinity of the waist-hole, under the effect of the tensile force of the high elasticity segment26.

FIG. 5is a view similar toFIG. 2showing another embodiment of the invention andFIG. 6is a partially sectional view taken along a line VI-VI inFIG. 5. The diaper1according to this embodiment has a first protrusion21and a feces receiving depression22similar to those in the embodiment shown inFIG. 2and additionally has an annular second protrusion41at a location in the crotch region8put aside toward the front waist region6so as to define a urine receiving depression42inside the second annular protrusion41. A high elasticity segment26comprising top- and backsheets2,3and an elastic sheet28extends so as to pass under the first and second protrusions21,41and to describe X-shape. The feces receiving depression22and the urine receiving depression42have respective bottoms43,44comprising a liquid-pervious sheet46, a liquid-impervious sheet47and a body fluid absorbent core48interposed between these two sheets46,47. These bottoms43,44bulge outwardly of the diaper1in bag-like shape. The diaper1according to this embodiment ensures the first protrusion21to be tightly placed against the wearer's body around the anus and at the same time ensures the second protrusion41to be tightly placed against the wearer's body around the urethral.

It is possible without departing from the scope of the invention to bond the elastic sheet28to the upper surface of the topsheet2or the lower surface of the backsheet3as viewed inFIG. 3instead of interposing the elastic sheet28between the top- and backsheets2,3. It is also possible to implement the present invention in the form of the article having the urine receiving depression42alone but not the feces receiving depression22. The present invention is not limited to the open-type diaper as illustrated but applicable also to a pull-on diaper in which the lateral portions13of the front waist region6as well as the lateral portions13of the rear waist region7are overlaid and joined together. In the course of bonding the lateral portions13, zones of the high elasticity segment26extending in the front and rear waist regions6,7are preferably overlapped each other and substantially contiguous to each other. Between the top- and backsheets2,3, it is possible to interpose a core which is larger than both the core34and the core48in illustrated embodiments. Preferably, the cores34,48are intermittently bonded to only one of the top- and backsheets2,3in order to prevent extensibilities of these top- and backsheets2,3from being deteriorated.

FIG. 7is a view similar toFIG. 2showing still another embodiment of the invention. A wearing article51according to this embodiment has neither the annular protrusion21nor the absorbent core34both seen inFIG. 2and is suitable for use as covering means, for example, diaper cover used to hold a urine-absorbent pad (not shown) in tight contact with the wearer's crotch region. This wearing article51is different from the embodiment shown inFIG. 2in that the elastic sheet28forming the high elasticity segment26comprises a pair of elastically stretchable sheets28a,28bextending substantially parallel to the leg-surrounding lateral portions14from a central zone of the crotch region8to the lateral portions13in the front and rear waist regions6,7and describing substantially circular arcs which are convex inward in a width direction A. These elastic sheets28a,28bare overlapped and joined together by means of an adhesive or welding techniques in the central zone of the crotch region8. As a stock material for these elastic sheets28a,28b, it is possible to use the same sheet material as one of the top- and backsheets2,3or the sheet material having a stretch stress higher than those of the top- and backsheets2,3. In the central zone of the crotch region8, the top- and backsheets2,3may be placed upon and bonded to the elastic sheets28a,28bto maximize a stretch stress in this central zone generated as the wearing article51is stretched in the transverse direction A and in the longitudinal direction B. The wearing article51shown inFIG. 7has a plurality of weld spots53at which the sheets placed one upon another are welded together. Extensibility of the elastic sheets28a,28bcan be controlled by the number of these spots53per unit area or the layout of spot distribution. Referring toFIG. 7, the spots53are distributed most densely in the crotch region8.

In the case of such wearing article51, the high elasticity segment26, particularly the central zone of the crotch region8ensures the disposable diaper or the urine-absorbent pad set on the inner side of the wearing article51to be tightly held in contact with the wearer's crotch region. The wearing article51may be folded in the longitudinal direction B with the topsheet2inside and then the lateral portions13put flat together may be joined together to obtain the pull-on wearing article51. This wearing article51is suitable also as sanitary shorts used to hold a sanitary napkin in close contact with the wearer's body.

With the wearing article according to the present invention, the high elasticity segment extends from the central zone of the crotch region to the lateral portions of the front waist region and to the lateral portions of the rear waist region so as to describe a substantially X-like shape. Under the effect of this high elasticity segment, the central zone of the crotch region reliably holds the annular protrusion defining the feces receiving depression formed in this zone of the wearing article or a disposable diaper, a urine absorbent pad or a sanitary napkin set in this zone of the wearing article in close contact with the wearer's body. In addition, there is no anxiety that the wearing article might slid down along the wearer's waist due to the effect of this high elasticity segment.