US20010004689A1 - Disposable diaper - Google Patents

Abstract

A diaper includes a topsheet, a backsheet and a core disposed therebetween to define a front and rear waist regions and a crotch region, and an elastic member extending to surround a predetermined zone of the core about the vicinity of a longitudinal center line is placed in a rear half of the diaper defined between the vicinity of a transverse center line and the end of the rear waist region and secured under tension to the upper surface of the core so that the zone of the core is depressed downward to form a depression as the elastic member contracts.

Description

BACKGROUND OF THE INVENTION
• This invention relates to a disposable diaper for absorbing and containing body wastes.[0001]
• Japanese Utility Model Application Disclosure No. 1994-5614 describes a disposable diaper having a basis structure comprising a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core disposed between these two sheets wherein the basic structure is formed in a zone adapted to be placed against the wearer's hip with a depression extending from the upper side to the lower side of the core to contain body wastes. The diaper described in the Application is effective to prevent leakage of body wastes by receiving and containing body wastes in the depression formed in the core.[0002]
• Japanese Utility Model Application Disclosure No. 1993-27524 describes a disposable diaper comprising a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core disposed between these two sheets. A pair of flaps extending longitudinally of the diaper across its front waist region and crotch region and wherein a zone of the core lying between the flaps is formed with a protuberance extending upward from the upper surface of the core. The diaper described in the Application enables the wearer's penis to be placed against the protuberance and thereby enables discharged urine to be rapidly absorbed by the core.[0003]
• Certainly it is possible to contemplate from a combination of the inventions disclosed in the Applications a disposable diaper formed in the zone of the core destined to be placed against the wearer's hip with a depression extending from the upper surface to the lower surface of the core to contain the discharged body wastes and in the zone of the core destined to be placed against the wearer's penis with a protuberance extending upward from the upper surface of the core.[0004]
• However, a thickness of the core would inevitably increase by a depth of the depression to form the core with such depression. This would be true in formation of the protuberance. Accordingly, formation of both the depression and the protuberance on the same core would unacceptably increase the thickness of the core as a whole and consequently a bulkiness of the core would give the diaper wearer a feeling of incompatibility. Furthermore, in view of the fact that most of the recent processes for making the core intend to achieve the maximum body wastes absorption with the core as thin as possible, it is difficult to form the core with a depression of a desired depth and a protuberance of a desired height.[0005]
SUMMARY OF THE INVENTION
• An object of this invention is to provide a disposable diaper enabling the core to be formed in its predetermined zones with a depression and a protuberance without previously molding the core to form such depression and protuberance.[0006]
• According to this invention, there is provided a disposable diaper contoured by transversely opposite side edges and longitudinally opposite ends and comprising a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core having first and second surfaces and disposed between the topsheet and the backsheet to configure, longitudinally of the diaper, a front waist region, a rear waist region and a crotch region extending between the front and rear waist regions.[0007]
• This invention further comprises an elastic member being placed on and secured under tension to the first surface of the core to surround a predetermined zone spaced inward from the transversely opposite side edges and the longitudinally opposite side ends so that the predetermined zone of the core is curved toward the second surface of the core as the elastic member contracts against a rigidity of the core.[0008]
• This invention includes the following embodiments.[0009]
• The elastic member surrounds the predetermined zone of the core about the vicinity of a longitudinal center line bisecting a dimension between the transversely opposite side edges of the diaper and such elastic member is placed in at least one of a front half of the diaper extending from the vicinity of a transverse center line bisecting a dimension between the longitudinally opposite ends of the diaper to the end of the front waist region and a rear half of the diaper extending from the vicinity of the transverse center line to the end of the rear waist region.[0010]
• The elastic member is placed in both the front half and rear half of the diaper so that the elastic member surrounds a first predetermined zone on the second surface of the core in the front half and curves the first predetermined zone on the second surface toward the first surface to form a protuberance while the elastic member surrounds a second predetermined zone on the first surface of the core in the rear half and curves the second predetermined zone on the first surface toward the second surface to form a depression.[0011]
• The elastic member is placed in both the front half and rear half of the diaper so that the elastic members surround respective predetermined zones on the first surface of the core and curve the respective predetermined zones in the first half and second half toward the second surface to form depressions, respectively.[0012]
• The core is thinner in the predetermined zones of the core surrounded by the respective elastic members than in the remaining zone of the core not surrounded by the respective elastic members.[0013]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view showing one embodiment of a partially cutaway disposable diaper according to this invention;[0014]
• FIG. 2 is a sectional view taken along line A-A in FIG. 1;[0015]
• FIG. 3 is a sectional view taken along line B-B in FIG. 1;[0016]
• FIG. 4 is a view similar to FIG. 1 showing another embodiment of the diaper;[0017]
• FIG. 5 is a sectional view taken along line C-C in FIG. 4;[0018]
• FIG. 6 is a view similar to FIGS. 1 and 4 showing still another embodiment of the diaper; and[0019]
• FIG. 7 is a sectional view taken along line D-D in FIG.[0020]6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• Details of a disposable diaper according to this invention will be more fully understood from the description given hereunder with reference to the accompanying drawings.[0021]
• FIG. 1 is a perspective view showing one embodiment of a partially cutaway disposable diaper according to this invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1 and[0022]3 is a sectional view taken along line B-B in FIG. 1. The diaper1 basically comprises a liquid-pervious topsheet2, a liquid-impervious backsheet3 and a liquid-absorbent core4 disposed between the top- andbacksheets2,3 and bonded to the inner surface of at least one of the top- andbacksheets2,3. The diaper1 is longitudinally configured by afront waist region20, arear waist region22 and acrotch region21 extending between these front andrear waist regions20,22. The diaper1 is contoured by transverselyopposite side edges1aextending in parallel to each other longitudinally of the diaper1 and, in thecrotch region21, curving inwardly of the diaper1 to describe circular arcs and longitudinallyopposite ends1bextending in parallel to each other transversely of the diaper1. The diaper1 is further provided in the vicinity of transversely opposite side edges4cof thecore4 with a pair ofbarrier cuffs7 extending longitudinally of the diaper1.
• The diaper[0023]1 is further provided in its rear half zone A2 extending from the vicinity of a transverse center line Y bisecting a dimension between the longitudinallyopposite ends1bof the diaper1 to the vicinity of theend1bof therear waist region22 withelastic member5 extending to surround a predetermined zone of thecore4.
• The[0024]elastic member5 extends between the lower surface of thetopsheet2 and the inner surface of thecore4 annularly about the vicinity of a longitudinal center line X bisecting a dimension between the transverselyopposite side edges1aof the diaper1 and secured under tension to the inner surface of thetopsheet2 and the upper surface of thecore4. Theelastic member5 is contractable against a rigidity of thecore4 so that thezone4aof thecore4 surrounded by theelastic member5 may be contracted inwardly of the annulus defined by theelastic member5 as the latter contracts.
• The[0025]zone4aof thecore4 becomes depressed downwardly of the diaper1 to form adepression6 as thezone4ais contracted inwardly of the annulus of theelastic member5. Thedepression6 is formed in the rear half A2 of the diaper1 covering a wearer's hip and able to receive and contain discharged body wastes which are then absorbed by thecore4 through thetopsheet2.
• The[0026]barrier cuffs7 comprisefixed portions7aextending longitudinally of the diaper1 and bonded to transversely oppositeside edge portions2aof thetopsheet2 lying immediately outside transversely opposite side edges4cof thecore4,free side portions7bextending inward transversely of the diaper1 in thecrotch region21 and normally biased to rise on the diaper1 and longitudinallyopposite end portions7ccollapsed inward transversely of the diaper1 and bonded in such collapsed state to thetopsheet2 at the longitudinallyopposite end portions1bof the diaper1, respectively. The respectivefree side portions7bof thecuffs7 are provided along the vicinity of their respective edges withelastic members8 secured under tension thereto and covered with portions of the respectivefree side portions7b.
• Along the opposite[0027]side edge portions1aof the diaper1,elastic members9 associated with leg-holes are disposed between transversely oppositeside edge portions3aof thebacksheet3 and respective outerside edge portions7dextending outward transversely of the diaper1 from the respectivefixed portions7aof thecuffs7 and secured under tension to the inner surfaces of theside edge portions3aof thebacksheet3 and/or of the outerside edge portions7dof thecuffs7.
• Along the longitudinally[0028]opposite end portions1bof the diaper1, film-likeelastic members10 associated with a waist-hole extend between the top- andbacksheets2,3 and secured under tension to the inner surface at least one of these twosheets2,3. In therear waist region22, theside edge portions1aof the diaper1 are provided withtape fasteners11 having their proximal end portions attached to the respectiveside edge portions1aand extending inward transversely of the diaper1. On the other hand, in thefront waist region20 of the diaper1, a strip ofrectangular target tape12 is attached to the outer surface of thebacksheet3 so that thetape fasteners11 may be anchored on the strip oftarget tape12.
• As will be seen in FIG. 2, the transversely opposite[0029]side edge portions2aof thetopsheet2 terminate immediately outside the transversely opposite side edges4cof thecore4 and the transversely oppositeside edge portions3aof thebacksheet3 as well as the outerside edge portions7dof thecuffs7 extend outward beyond theside edge portions2aof thetopsheet2 transversely of the diaper1. In the vicinity of the respectiveside edge portions1aof the diaper1, the respectiveside edge portions2a,3a,7dof the top- andbacksheets2,3 and thecuffs7 are placed upon and bonded to one another.
• Referring to FIG. 1, gathers are formed along the transversely opposite[0030]side edge portions1aas well as the longitudinallyopposite end portions1bof the diaper1 and along thefree side portions7bof thecuffs7 as theelastic members9 associated with the leg-holes, theelastic members10 associated with the waist-hole and theelastic members8 attached to thefree side portions7bof thecuffs7 are relieved of tension. The diaper1 is longitudinally curved thereupon with its inner surface inside and contraction of theelastic members8 attached to the freeside edge portions7bof thecuffs7 causes these freeside edge portions7bto rise on the inner surface of the diaper1. The freeside edge portions7bcooperate with thetopsheet2 to form pockets P opening inward transversely of the diaper1.
• Free end portions of the[0031]respective tape fasteners11 may be anchored on the strip oftarget tape12 by means of pressure-sensitive adhesive (not shown) applied on the inner surfaces of these free end portions to form the pair of leg-holes and the waist-hole (both not shown).
• FIG. 4 is a view similar to FIG. 1 showing another embodiment of the diaper and FIG. 5 is a sectional view taken along line C-C in FIG. 4. The diaper[0032]1 according to this embodiment is similar to that of FIG. 1 in that thecore4 is disposed between the top- andbacksheets2,3 and the diaper1 is longitudinally configured by the front andrear waist regions20,22 and thecrotch region21 extending between these twowaist regions20,22. The diaper1 according to this embodiment also has the transversely oppositeside edge portions1a, the longitudinallyopposite end portions1band the pair ofbarrier cuffs7 normally biased to rise on the inner surface of the diaper1.
• The diaper[0033]1 is further provided in its front and rear half zone A1, A2 extending from the vicinity of a transverse center line Y bisecting a dimension between the longitudinallyopposite ends1bof the diaper1 to the vicinity of therespective ends1bof the diaper1 withelastic members5 extending to surround predetermined zones of thecore4, respectively. The respectiveelastic members5 extend annularly about the vicinity of the longitudinal center line X between thetopsheet2 and thecore4 and secured under tension to said inner surface of thetopsheet2 and the upper surface of thecore4. Theelastic member5 is contractable against a rigidity of thecore4 so that thezones4a,4bof thecore4 surrounded by the respectiveelastic members5 may be contracted inwardly of the annuli defined by theelastic members5 as the latter contract.
• The[0034]zones4a,4bof thecore4 lying in the front and rear halves A1, A2 of the diaper1 become depressed downwardly of the diaper1 to form adepressions6 as thezones4a,4bare contracted inwardly of the annuli defined by theelastic members5. The diaper1 of FIG. 4 is particularly suitable as men's diaper since thedepression6 is formed also in the front half A1 of the diaper1 and wearer's penis can be received in thisdepression6.
• FIG. 6 is a view similar to FIGS. 1 and 4 showing still another embodiment of the diaper and FIG. 7 is a sectional view taken along line D-D in FIG. 6. The diaper[0035]1 according to this embodiment is similar to those shown in FIGS.1-4 in that the diaper1 comprises the top- andbacksheets2,3 and thecore4 disposed between these twosheets2,3 so as to configure, as viewed longitudinally of the diaper1, the front andrear waist regions20,22 and thecrotch region21 extending between these twowaist regions20,22. The diaper1 according to this embodiment also has the transversely oppositeside edge portions1a, the longitudinallyopposite end portions1band the pair ofbarrier cuffs7 normally biased to rise on the inner surface of the diaper1.
• The diaper[0036]1 is provided in its front and rear half zones A1, A2 withelastic members13,5 surrounding predetermined zones of thecore4, respectively. The respectiveelastic members5,13 extend annularly about the vicinity of the longitudinal center line X. Theelastic member13 lying in the front half A1 is disposed between the lower surface of thecore4 and thebacksheet3 and secured under tension to the lower surface of thecore4 and the inner surface of thebacksheet3. Theelastic member5 lying in the rear half A2 disposed between the upper surface of thecore4 and the inner surface of thetopsheet2 and secured under tension to the inner surface of thetopsheet2 and the upper surface of thecore4.
• The[0037]core4 is thinner in thezones4a,4bof thecore4 surrounded by theelastic members5,13, respectively, than in the remaining zone extending outside theseelastic members5,13. Correspondingly, thezones4a,4bare less stiff than the remaining zone extending outside theelastic members5,13. Such local difference in the thickness as well as the rigidity of thecore4 facilitates thezones4a,4bof thecore4 to contract inward from the annuli defined by the respectiveelastic members5,13.
• The[0038]elastic members5,13 are contractable against a rigidity of thecore4 so that thezones4a,4bof thecore4 surrounded by the respectiveelastic members5,13 may be contracted inwardly of the annuli defined by saidelastic members5,13 as the latter contract.
• In the front half A[0039]1 of the diaper1, thezone4bof thecore4 protrudes upwardly of the diaper1 as thezone4bcontracts inward from the annulus defined by theelastic member13 to form aprotuberance14 in thiszone4bof thecore4. In the rear half A2 of the diaper1, on the other hand, thezone4aof thecore4 is depressed downwardly of the diaper1 as thezone4acontracts inward from the annulus defined by theelastic member13 to form thedepression6 in thezone4aof thecore4. The diaper1 of FIG. 6 is particularly suitable as women's diaper since the diaper1 is formed in its front half A1 with theprotuberance14 adapted to be placed against wearer's vulva.
• This embodiment of the diaper[0040]1 may be modified so that a pair ofelastic members13 are provided in the front and rear half zones A1, A2 both annularly extending on the lower surface of thecore4 and secured under tension to the inner surface of thebacksheet3 and the lower surface of thecore4. According to this variant, thezones4a,4bof thecore4 surrounded by the respectiveelastic members13 in the front and rear halves A1, A2 of the diaper1 protrude upwardly of the diaper1 to formrespective protuberances14. Theprotuberance14 formed in the rear half A2 of the diaper1 is adapted to be placed against the wearer's hip and, therefore, the diaper1 according to such variant is particularly suitable for baby's diaper normally discharging loose passage.
• An alternative arrangement is also possible without departing from the scope of this invention such that only the front half A[0041]1 of the diaper1 is formed with thedepression6 or theprotuberance14 or only the rear half A2 of the diaper1 is formed with theprotuberance14. It is also possible without departing from the scope of this invention to form thedepression6 only in the front half A1 of the diaper1 to form theprotuberance14 only in the rear half A2 of the diaper1. It is essential that theelastic member5 is bonded to at least the upper surface of thecore4 and theelastic member13 is bonded at least to the lower surface of thecore4. It is not essential to secure theseelastic members5,13 to both the topsheet and thebacksheet3.
• The[0042]topsheet2 is formed by a liquid-pervious nonwoven fabric or a porous plastic film, preferably by a liquid-pervious hydrophilic sheet. Thebacksheet3 is formed by a hydrophobic nonwoven fabric, a liquid-impervious plastic film, a laminated sheet of these hydrophobic nonwoven fabric and plastic film, preferably by a breathable liquid-impervious sheet. Thecuffs7 are formed by a hydrophobic nonwoven fabric, preferably by a breathable liquid-impervious sheet.
• The nonwoven fabric used for those purposes may be selected from a group including a spun lace nonwoven fabric, a needle punch nonwoven fabric, a melt blown nonwoven fabric, a thermal bond nonwoven fabric, a spun bond nonwoven fabric and a chemical bond nonwoven fabric. The composite nonwoven fabric (SMS nonwoven fabric) consisting of a melt blown nonwoven fabric having a high water-resistance sandwiched between two layers of a spun bond nonwoven fabric being in strength as well as in flexibility may be used. The SMS nonwoven fabric can be made by a process comprising the steps of sandwiching the melt blown nonwoven fabric with the two layers of spun bond nonwoven fabric and then bonding these melt blown nonwoven fabric and the spun bond nonwoven fabric together using a pressing technique. Component fibers of the nonwoven fabric may be selected from a group including polyolefine-, polyester- and polyamide- fibers, and conjugated fiber of polyethylene/polypropylene or polyester and the like.[0043]
• The[0044]core4 is a mixture of fluff pulp and high absorption polymer particles compressed in to a desired thickness and entirely covered with a water-pervious sheet (not shown) such as tissue paper. Bonding of thecore4, theelastic members5,8,9,10,13, thesheets2,3 and thecuffs7 may be carried out using adhesive such as hot melt adhesive or pressure-sensitive adhesive or a heat-sealing technique.
• The disposable diaper according to this invention enables the depression and/or the protuberance to be formed in the core without previously molding the core to form such depression and/or protuberance. More specifically, the core is provided on its upper and/or lower surfaces with the elastic member to surround a predetermined zone of the core and the elastic member is secured under tension to the upper and/lower surfaces of the core so that the zone of the core surrounded by the elastic member may contract inwardly of the elastic member to form the depression extending downwardly and/or the protuberance extending upwardly of the diaper as the elastic member contracts.[0045]
• The diaper formed in its rear half with the depression will be effective to prevent leakage of body wastes from the diaper by reliably containing the discharged body wastes in the depression. The diaper formed in its front half with the depression is particularly suitable as men's diaper since the wearer's penis can be held in this depression. The diaper formed in its front half with the protuberance is particularly suitable as women's diaper since this protuberance is adapted to be placed against the wearer's vulva and thereby facilitates the discharged urine to be absorbed by the core.[0046]

Claims (5)

What is claimed is:

1. A disposable diaper contoured by transversely opposite side edges and longitudinally opposite ends and comprising a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core having first and second surfaces and disposed between said topsheet and said backsheet to configure, longitudinally of said diaper, a front waist region, a rear waist region and a crotch region extending between said front and rear waist regions,

said disposable diaper further comprising an elastic member being placed on secured under tension to said first surface of said core to surround a predetermined zone spaced inward from said transversely opposite side edges and said longitudinally opposite side ends so that said predetermined zone of said core is curved toward said second surface of said core as said elastic member contracts against a rigidity of said core.

2. The diaper according to

claim 1

, wherein said elastic member surrounds said predetermined zone of said core about the vicinity of a longitudinal center line bisecting a dimension between said transversely opposite side edges of said diaper and such elastic member is placed in at least one of a front half of said diaper extending from the vicinity of a transverse center line bisecting a dimension between said longitudinally opposite ends of said diaper to said end of said front waist region and a rear half of said diaper extending from said vicinity of said transverse center line to said end of said rear waist region.

3. The diaper according to

claim 1

, wherein said elastic member is placed in both said front half and rear half of said diaper so that said elastic member surrounds a first predetermined zone on said second surface of said core in said front half and curves said first predetermined zone on said second surface toward said first surface to form a protuberance while said elastic member surrounds a second predetermined zone on said first surface of said core in said rear half and curves said second predetermined zone on said first surface toward said second surface to form a depression.

4. The diaper according to

claim 1

, wherein said elastic member is placed in both said front half and rear half of said diaper so that respective said elastic members surround respective predetermined zones on said first surface of said core and curve said respective predetermined zones in said first half and second half toward said second surface to form depressions, respectively.

5. The diaper according to

claim 1

, wherein said core is thinner in said predetermined zones of said core surrounded by said respective elastic members than in the remaining zone of said core not surrounded by said respective elastic members.

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