Disposable diaper with improved leak prevention properties Number:7,520,874 from the United States Patent and Trademark Office (PTO) owispatent A disposable diaper comprising a fluid-permeable topsheet, a fluid-impermeable backsheet and a fluid-retentive absorbent core interposed between the topsheet and the backsheet, the disposable diaper being formed in a substantially vertically elongated configuration and having a stomach side, a back side and a crotch region positioned between the stomach side and the back side, wherein a second absorbent core is disposed at an outside region of each opposite side edge of the absorbent core at the crotch region along a longitudinal direction of the diaper, and an elastic member is disposed at the region where the second absorbent core is disposed along a longitudinal direction of the diaper.<H properties, prevention, Disposable, diap, 7520874.html, Patent, pto, 7520874

Title: Disposable diaper with improved leak prevention properties

Abstract: A disposable diaper comprising a fluid-permeable topsheet, a fluid-impermeable backsheet and a fluid-retentive absorbent core interposed between the topsheet and the backsheet, the disposable diaper being formed in a substantially vertically elongated configuration and having a stomach side, a back side and a crotch region positioned between the stomach side and the back side, wherein a second absorbent core is disposed at an outside region of each opposite side edge of the absorbent core at the crotch region along a longitudinal direction of the diaper, and an elastic member is disposed at the region where the second absorbent core is disposed along a longitudinal direction of the diaper.

Patent Number: 7,520,874 Issued on 04/21/2009 to Koyama, et al.

Inventors: Koyama; Takao (Tochigi, JP), Ito; Hidekazu (Tochigi, JP), Nemoto; Ken (Tochigi, JP), Ishiguro; Kenji (Tochigi, JP)
Assignee: Kao Corporation (Tokyo, JP)

Appl. No.: 11/561,803

Filed: November 20, 2006

Related U.S. Patent Documents


Application Number	Filing Date	Patent Number	Issue Date
11067249	Feb., 2005	7156830
10005352	Dec., 2001	6878139

Foreign Application Priority Data


Dec 28, 2000 [JP]			2000-402839
Jan 19, 2001 [JP]			2001-11156
Mar 09, 2001 [JP]			2001-66189
Jun 13, 2001 [JP]			2001-178184

Current U.S. Class: 604/385.27 ; 604/385.01; 604/385.101

Current International Class: A61F 13/15 (20060101)

Field of Search: 604/378,379,385.01,385.23,385.24,385.27,385.101,385.201

References Cited [Referenced By]

U.S. Patent Documents


3575174	April 1971	Mogor
4430088	February 1984	Karami
4657539	April 1987	Hasse
4743246	May 1988	Lawson
5366453	November 1994	Zehner et al.
5382246	January 1995	Kawano
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5776122	July 1998	Faulks et al.
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6102892	August 2000	Putzer et al.
6126648	October 2000	Keck et al.
6159190	December 2000	Tanaka et al.
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6635040	October 2003	Kim et al.
6867345	March 2005	Shimoe et al.
2002/0065499	May 2002	Ohashi et al.

Foreign Patent Documents


0880955	Dec., 1998	EP
52-120045	Oct., 1977	JP
58-115105	Jul., 1983	JP
01-119250	May., 1989	JP
01-272802	Oct., 1989	JP
2-10824	Jan., 1990	JP
02-291858	Dec., 1990	JP
03-121069	May., 1991	JP
03-123553	May., 1991	JP
4-67427	Jun., 1992	JP
4-242643	Aug., 1992	JP
5-317362	Dec., 1993	JP
6-17724	Mar., 1994	JP
9-173381	Jul., 1997	JP
10-99372	Apr., 1998	JP
11-99174	Apr., 1999	JP
11-155901	Jun., 1999	JP
2000-15	Feb., 2000	JP
349387	Jan., 1999	TW
376315	Dec., 1999	TW
WO 95/25493	Sep., 1995	WO

Primary Examiner: Zalukaeva; Tatyana
Assistant Examiner: Bogart; Michael G
Attorney, Agent or Firm: Birch, Stewart, Kolasch & Birch, LLP

Parent Case Text

This application is a Divisional of application Ser. No. 11/067,249 filed on Feb. 28, 2005, now U.S. Pat. No. 7,156,830 which is a Divisional of prior application Ser. No. 10/005,352 filed on Dec. 7, 2001, which has now issued as U.S. Pat. No. 6,878,139, and for which priority is claimed under 35 U.S.C. .sctn. 120; and this application claims priority of application Ser. Nos. 2000-402839, 2001-11156, 2001-66189 and 2001-178184 filed in Japan on Dec. 28, 2000, Jan. 19, 2001, Mar. 9, 2001 and Jun. 13, 2001, respectively, under 35 U.S.C. .sctn. 119; the entire contents of all are hereby incorporated by reference.

Claims

What is claimed is:

1. A disposable diaper comprising a fluid-permeable topsheet, a fluid-impermeable backsheet and a fluid-retentive absorbent core interposed between said topsheet and said backsheet, said disposable diaper having a stomach side, a back side and a crotch region positioned between said stomach side and said back side, leg portion elastic members being disposed in their stretched states at a pair of leg portions disposed around the wearer's leg areas, wherein lengthwise opposite end portions of said leg portion elastic members are located at widthwise outside areas of side edges of said absorbent core, respectively and central portions of said leg portion elastic members are curved in such a manner as to pass a widthwise inner direction of the side edges of said absorbent core at a crotch region of the diaper, said absorbent core at said crotch region of said diaper being divided into a pair of lateral absorbent cores located at widthwise outside areas of said leg portion elastic members, respectively, and a central absorbent core located between said pair of lateral absorbent cores by said pair of leg portion elastic members, said lateral absorbent cores are when in wear, being bent towards said backsheet and elastic members disposed below said lateral absorbent cores along the longitudinal direction of said diaper, wherein the elastic members are disposed at the diaper outer surface side or said lateral absorbent cores along a longitudinal direction of said lateral absorbent cores, and said elastic members are lower in elongation stress than said leg portion elastic members.

2. A disposable diaper comprising a fluid-permeable topsheet, a fluid-impermeable backsheet and a fluid-retentive absorbent core interposed between said topsheet and said backsheet, said disposable diaper having a stomach side, a back side and a crotch region positioned between said stomach side and said back side, leg portion elastic members being disposed in their stretched states at a pair of leg portions disposed wound the wearer's leg areas, wherein lengthwise opposite end portions of said leg portion elastic members are located at widthwise outside areas of side edges of said absorbent core, respectively and central portions of said leg portion elastic members are curved in such a manner as to pass a widthwise inner direction of the side edges of said absorbent core at a crotch region of the diaper, said absorbent core at said crotch region of said diaper being divided into a pair of lateral absorbent cores located at widthwise outside areas of said leg portion elastic members, respectively, and a central absorbent core located between said pair of lateral absorbent cores by said pair of leg portion elastic members, said lateral absorbent cores are when in wear, being bent towards said backsheet and elastic members disposed below said lateral absorbent cores along the longitudinal direction of said diaper, wherein leg flap side elastic members are disposed at the opposite side edge portions of said absorbent core at the crotch region of said diaper along the opposite side edges of said absorbent core, and said leg flap side elastic members are lower in elongation stress than said leg portion elastic members.

3. A disposable diaper comprising a fluid-permeable topsheet, a fluid-impermeable backsheet and a fluid-retentive absorbent core interposed between said topsheet and said backsheet, said disposable diaper having a stomach side, a back side and a crotch region positioned between said stomach side and said back side, leg portion elastic members being disposed in their stretched states at a pair of leg portions disposed around the wearer's leg areas, wherein lengthwise opposite end portions of said leg portion elastic members are located at widthwise outside areas of side edges of said absorbent core, respectively and central portions of said leg portion elastic members are curved in such a manner as to pass a widthwise inner direction of the side edges of said absorbent core at a crotch region of the diaper, said absorbent core at said crotch region of said diaper being divided into a pair of lateral absorbent cores located at widthwise outside areas of said leg portion elastic members, respectively, and a central absorbent core located between said pair of lateral absorbent cores by said pair of leg portion elastic members, said lateral absorbent cores are when in wear, being bent towards said backsheet and elastic members disposed below said lateral absorbent cores along the longitudinal direction of said diaper, wherein the opposite side edges of said absorbent core are covered with water-repellent side sheets, respectively, a pair of three-dimensional gathers are formed from a stomach side region to a back side region, each of said three-dimensional gathers being fixedly provided with a water-repellant gather forming sheet having an elastic member, said gather forming sheet and said side sheet being located away from each other, and a side absorption area having a non-water-repellent surface is formed between said gather forming sheet and said side sheet.

4. The disposable diaper according to claim 1, wherein a longitudinal length of said lateral absorbent cores is 1/5 to 2/3 of a longitudinal direction of said diaper.

5. The disposable diaper according to claim 2, wherein a longitudinal length of said lateral absorbent cores is 1/5 to 2/3 of a longitudinal direction of said diaper.

6. The disposable diaper according to claim 3, wherein a longitudinal length of said lateral absorbent cores is 1/5 to 2/3 of a longitudinal direction of said diaper.

7. The disposable diaper according to claim 1, wherein said absorbent core at the crotch region of said diaper includes a pair of lower rigidity regions, lower than the remaining regions, said pair of lower rigidity regions being located away from the opposite side edges of said absorbent core, and said leg portion elastic members are disposed such that their central portions pass said lower rigidity regions, respectively.

8. The disposable diaper according to claim 2, wherein said absorbent core at the crotch region of said diaper includes a pair of lower rigidity regions, lower than the remaining regions, said pair of lower rigidity regions being located away from the opposite side edges of said absorbent core, and said leg portion elastic members are disposed such that their central portions pass said lower rigidity regions, respectively.

9. The disposable diaper according to claim 3, wherein said absorbent core at the crotch region of said diaper includes a pair of lower rigidity regions, lower than the remaining regions, said pair of lower rigidity regions being located away from the opposite side edges of said absorbent core, and said leg portion elastic members are disposed such that their central portions pass said lower rigidity regions, respectively.

Description

BACKGROUND OF THE INVENTION

This invention relates to a disposable diaper excellent in leak-preventive property and capable of preventing leak occurrable particularly around the leg areas. This invention also relates to a disposable diaper excellent in storability/retainability of an auxiliary absorber, wearability (property of feel in wear and easy application to a wearer) and/or fitness at the crotch region and the like, in addition to its excellent leak-preventive property.

Heretofore, it has been an important problem for disposable diapers how to prevent leak occurrable around the leg areas. Japanese Patent Publication No. 05-33630 discloses a disposable diaper in which an absorbent core is comprised of a central absorbent section of a width in conformity with the human body and an outer absorbent section disposed outside thereof, so that close fit to a wearer at the crotch region is enhanced, thereby improving the leak-preventive property. However, this disposable diaper has such a problem that wrinkles are liable to occur to the central absorbent section due to contraction of an expansible part placed between the central absorbent section and the outside absorbent section, and therefore urine and excretions can easily leak from the central absorbent section along the wrinkles. Moreover, since it is designed such that leak is prevented by enhancing the fit at the central absorbent section, those urine and excretions leaked out towards the opposite sides from the central absorbent section can reach the outside absorbent section comparatively easily, and especially, in case the amount of excretions is large, those feces and urine easily leak outside beyond the outside absorbent section.

Moreover, since the outside absorbent section is difficult to deform along the contour of the wearer's body, wearability and fitting property at the crotch region are deteriorated.

Japanese Patent No. 2712044 discloses a disposable diaper in which three-dimensional guards each composed of an absorbent material are disposed at the outside of the an absorbent core in a longitudinal direction thereof. This diaper also has the same problem as the above-mentioned disposable diaper.

Another problem of the disposable diaper of Japanese Patent Publication No. 05-33630 is that it is not easy for a wearer to put it on because this diaper does not deform to the curved configuration of the wearer's body at the time of putting it on.

In the disposable diaper of Japanese Patent Publication No. 05-33630, the outside absorbent section is brought into contact with the inner side of the wearer's upper thigh. However, in this disposable diaper, the outside absorbent section is liable to be turned over at an area in the vicinity of the boundary area between a stomach side region and/or the back side region where the central absorbent section and the outside absorbent section are placed on a same plane and brought into contact with the wearer and the crotch region where the outside absorbent section and the central absorbent section are greatly bent, and leak may occur through a gap formed between the outside absorbent section and the wearer's skin. Moreover, it is difficult for this disposable diaper to sufficiently fit with the outside absorbent section to the inner side of the wearer's upper thigh. In short, in the conventional disposable diapers, sufficient leak-preventive property is not yet realized even for those of the type of which an absorbent core is disposed around the leg area.

Recently, it was attempted in order to reduce the economical/laborious burden in nursing work or the like that an auxiliary absorber is used in combination with a disposable diaper. However, the conventional disposable diaper is deteriorated in storability/retainability of the auxiliary absorber and its improvement is demanded.

Japanese Patent Application Laid-Open No. 01-119250, Japanese Utility Model Application Laid-Open No. 04-67427 and Japanese Utility Model Application Laid-Open No. 02-18824 disclose disposable diapers having a side absorbent core. However, even in those disposable diapers, the side absorbent core cannot fit to the wearer's leg area sufficiently. Furthermore, even in disposable diapers disclosed in Japanese Patent Application Nos. 03-121069 and 03-123553, sufficient leak-preventive property cannot be achieved.

SUMMARY OF THE INVENTION

It is, therefore, a first object of the present invention to provide a disposable diaper excellent in leak-preventive property and capable of surely preventing leak occurrable around the leg areas.

A second object of the present invention is to provide a disposable diaper excellent in leak-preventive property and excellent in storability/retainability of an auxiliary absorber.

A third object of the present invention is to provide a disposable diaper capable of taking such a curved configuration as being able to fit to the wearer's body at the time of putting it on and therefore, capable of being worn very easily.

A fourth object of the present invention is to provide a disposable diaper capable of fitting its second absorbent core disposed portion having a fluid retainability closely to the wearer's skin, excellent in fitness to the inguinal area and capable of surely preventing leak occurrable around the leg areas.

A further object of the present invention is to provide a disposable diaper excellent in storability/retainability of an auxiliary absorber, and excellent in wearability (property of easy application to a wearer) and fitness at the crotch region, in addition to its excellent leak-preventive property.

A still further object of the present invention is to provide a disposable diaper capable of taking the shape of a trunks, excellent in leak-preventive property and designability, and easy to put on or apply to a wearer.

The present invention has achieved the above-mentioned first object by providing a disposable diaper comprising a fluid-permeable topsheet, a fluid-impermeable backsheet and a fluid-retentive absorbent core interposed between the topsheet and the backsheet, the disposable diaper being formed in a substantially vertically elongated configuration and having a stomach side, a back side and a crotch region positioned between the stomach side and the back side, wherein a second absorbent core is disposed at an outside region of each opposite side edge of the absorbent core at the crotch region along a longitudinal direction of the diaper, and an elastic member is disposed at the region where the second absorbent core is disposed along a longitudinal direction of the diaper (the "first invention" used hereinafter refers to this invention).

Also, the present invention has achieved the above-mentioned second and/or third object by providing a disposable diaper comprising a fluid-permeable topsheet, a fluid-impermeable backsheet and a fluid-retentive central absorbent core interposed between the topsheet and the backsheet, the disposable diaper being formed in a substantially vertically elongated configuration and having a stomach side, a back side and a crotch region positioned between the stomach side and the back side, wherein a second absorbent core is disposed at an outside region of each opposite left (or right) side edge of the central absorbent core at the crotch region along a longitudinal direction of the diaper, a basis weight of an absorbent core disposed at an intermediate region between the central absorbent core and each of the second absorbent cores is smaller than a basis weight of any of the absorbent cores located at the region where the central absorbent core is disposed and at the region where each of the second absorbent cores is disposed, and a pair of axes of flexibility are formed on opposite side portions of the central absorbent core along a longitudinal direction (the "second invention" used hereinafter refers to this invention).

The present invention has achieved the above-mentioned fourth object by providing a disposable diaper comprising a fluid-permeable topsheet, a fluid-impermeable backsheet and a fluid-retentive absorbent core interposed between the topsheet and the backsheet, the disposable diaper having a stomach side, a back side and a crotch region positioned between the stomach side and the back side, leg portion elastic members being disposed in their stretched states at a pair of leg portions disposed around the wearer's leg areas, wherein lengthwise opposite end portions of the leg portion elastic members are located at widthwise outside areas of side edges of the absorbent core, respectively and central portions of the leg portion elastic members are curved in such a manner as to pass a widthwise inner direction of the side edges of the absorbent core at a crotch region of the diaper, the absorbent core at the crotch region of the diaper is divided into a pair of second absorbent cores located at widthwise outside areas of the leg portion elastic members, respectively and a central absorbent core located between the pair of second absorbent cores by the pair of leg portion elastic members, and the second absorbent cores are, when in wear, bent towards the backsheet (the "third invention" used hereinafter refers to this invention).

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more particularly described with reference to the accompanying drawings, in which:

FIG. 1 is a plan view showing, partly cut-away, a disposable diaper according to one embodiment of the first invention;

FIG. 2 is a schematic sectional view taken on line X-X of FIG. 1;

FIG. 3 is a schematic sectional view showing a using state of the disposable diaper of FIG. 1;

FIG. 4 is a plan view showing, partly cut-away, a disposable diaper according to another embodiment of the first invention;

FIG. 5 is a schematic sectional view taken on line X-X of FIG. 4;

FIG. 6 is a plan view (bird's eye view) showing a natural state of the disposable diaper of FIG. 4 in which its topsheet side (that surface side facing the wearer's skin) faces upward;

FIG. 7 is a schematic sectional view showing a using state of the disposable diaper of FIG. 4;

FIG. 8 is a plan view showing, partly cut-away, a disposable diaper according to a further embodiment of the first embodiment;

FIG. 9 is a schematic sectional view taken on line X-X of FIG. 8;

FIG. 10 is a schematic sectional view showing a worn state of the disposable diaper of FIG. 8;

FIG. 11 is a schematic view showing a trunks-like worn state of the disposable diaper of FIG. 8;

FIG. 12 is a plan view showing, partly cut-away, a disposable diaper according to one embodiment of the second invention;

FIG. 13 is a schematic sectional view taken on line X-X of FIG. 12;

FIG. 14 is a plan view (bird's eye view) showing a natural state of the disposable diaper of FIG. 12 in which its topsheet side (that surface side facing the wearer's skin) faces upward;

FIG. 15 is a schematic sectional view showing a using state of the disposable diaper of FIG. 12;

FIG. 16 is a perspective view showing a disposable diaper according to one embodiment of the third invention;

FIG. 17 is a partly cut-out plan view showing a developed state of the disposable diaper of FIG. 16;

FIG. 18 is a schematic sectional view taken on line X-X of FIG. 17;

FIG. 19 is a schematic view showing a worn state of the disposable diaper of FIG. 16; and

FIG. 20 is a sectional view of an important portion showing a disposable diaper according to another embodiment of the third invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described hereinafter. A disposable diaper 1 according to a first embodiment of the first invention comprises, as shown in FIGS. 1 to 3, a fluid-permeable topsheet 2, a fluid-impermeable backsheet 3 and a central absorbent core 4 as a fluid-retentive absorbent core interposed between the topsheet 2 and the backsheet 3, the disposable diaper 1 being formed in a substantially vertically elongated configuration.

The topsheet 2 and the backsheet 3 each have an external configuration equal to that of the disposable diaper 1, in which a lengthwise central portion is constricted. The central absorbent core 4 as an absorbent core is interposed between the topsheet 2 and the backsheet 3, and it has a hourglass-like configuration whose lengthwise central portion is constricted. A waist portion elastic member 13 for forming a waist gather is disposed at a back side region A which is located at the back side of the wearer in wear along a back side waist edge portion (that portion forming an opening edge portion on a back side of a waist opening portion which is formed when in wear) 11. Fastening tapes 5, 5 are disposed at opposite side edges of the back side region A, respectively. Landing zones (not shown) for fixing the fastening tapes 5, 5 are disposed at an outer surface of a stomach side region B which is disposed at the wearer's stomach side when in wear.

A crotch region C in the disposable diaper 1 is a portion which is disposed at the wearer's crotch in wear and is located between the back side region A and the stomach side region B. Fluid retentive second absorbent cores 6, 6 are disposed at outside areas of opposite side edges 41, 41 of the central absorbent core 4 in the crotch region C in such a manner as to be spaced apart from the opposite side edges 41, 41, respectively. The second absorbent cores 6, 6 each have a belt-like configuration and are disposed along a longitudinal direction of the diaper 1. More specifically, the second absorbent core 6 is approximately equal in width over its longitudinal direction in the crotch region C and is disposed such that its longitudinal direction is aligned with a longitudinal direction of the diaper 1. The second absorbent cores 6, 6 are disposed between the back side region A and the stomach side region B and are integrally connected to the central absorbent core 4 at opposite end portions 6a, 6b thereof, respectively.

As the second absorbent core 6, those conventional ones having various constitutions and used as an absorbent core in an absorbent article such as disposable diaper or the like can be used without any particular limitation. For example, there can be used an aggregate of hydrophilic fibers composed of a natural material such as, rayon, cellulose or the like, an aggregate obtained by surface treating synthetic fibers such as polyethylene, polypropylene or the like, any of those aggregates with a water absorption polymer retained thereby, and the like.

In the disposable diaper of the first invention, an elastic member 8 is disposed at each region D (see FIGS. 2 and 3) where the second absorbent core 6 is disposed, along a longitudinal direction of the diaper 1. The "region D" where the second absorbent core 6 is disposed refers to a region, at the inside of which the second absorbent core 6 is arranged when the disposable diaper is developed and plan viewed as shown in FIG. 1. In the disposable diaper 1 of this embodiment, as shown in FIG. 2, plural pieces of elastic members 8 are disposed between the second absorbent core 6 and the backsheet 3 in the region D where the second absorbent core 6 is disposed. Each elastic member 8 is fixedly sandwichingly held between the backsheet 3 and a fixing sheet 82 disposed on the backsheet 3 in an stretched state thereof.

The second elastic member 81 is disposed at an outside area of the region D where the second absorbent core 6 is disposed in a widthwise direction of the disposable diaper 1, i.e., in an outside area of the region D where the second absorbent core 6 is disposed, in a widthwise direction of the diaper 1 when plan viewed in a developed state of the diaper 1 as shown in FIG. 1, along a longitudinal direction of the diaper 1. One piece each of the second elastic member 81 is disposed at an edge portion of each opposite left (or right) side and is fixedly sandwichingly held, as shown in FIG. 2, between the topsheet 2 and the backsheet 3 in its stretched state.

The elastic members 8 disposed at the region D and the second elastic member 81 disposed at the outside region are each arranged over the length between the back side region A and the stomach side B and in parallel with each other.

The material for forming the various members of the disposable diaper 1 of this embodiment will now be described. As the material for forming the topsheet 2, the backsheet 3, the central absorbent core 4, the fastening tape 5, the waist elastic member 13 and the landing zone (not shown), various kinds of those which have heretofore been used for disposable diapers can be used without any particular limitation. As the raw material for forming the elastic members 8 and the second elastic member 81, those of various kinds such as natural rubber, synthetic rubber, spandex and the like can be used. Their shapes may be in the form of thread, belt, film or the like.

The disposable diaper 1 of this embodiment is applied to the wearer for use in the same manner as the normal disposable diapers. According to the disposable diaper 1 of this embodiment, since the elastic members 8 are disposed at the regions D where the second absorbent cores 6 are disposed, the skin side surfaces of the regions D where the second absorbent cores 6 are disposed nicely fit around the leg areas of the wearer M, as shown in FIG. 3. For this reason, even if urine, etc. should leak out to the side of the central absorbent core 4, they would surely be absorbed by the second absorbent cores 6 without allowing them to reach the side edge portion of the diaper 1. Consequently, leak of the excretions, particularly leak of urine around the leg areas, can surely be prevented.

Moreover, since the central absorbent core 4 and the second absorbent cores 6, 6 are divided from one another at the crotch region C, wrinkles hardly occur to the central absorbent core 4 even if the elastic members 8 are contracted. This makes it possible to prevent urine, etc. from migrating in a lateral direction along the wrinkles which would otherwise be formed on the central absorbent core 4. In addition, the above makes it possible to fully exhibit the absorption capability of the central absorptive core 4. Accordingly, leak of urine, etc. can be prevented more effectively.

In the disposable diaper 1 of this embodiment, since the second elastic members 81 are disposed at the outside areas of the regions D where the second absorbent cores 6, 6 are disposed, the urine absorbed by the second absorbent cores 6, 6 can be prevented from leaking from the side edges.

In the disposable diaper 1 of this embodiment, since the central absorbent core 4 and the second absorbent cores 6, 6 are individually spaced apart from one another, those regions F, F, which are, when in wear, located between the central absorbent core 4 and the second absorbent cores 6 of the diaper 1 are, as shown in FIG. 3, angularly stood up with respect to the wearer's skin surface and are functioned as three-dimensional barriers for the prevention of leak from those areas. Accordingly, the leak-preventive property, particularly leak-preventive property around the leg areas is further enhanced. Moreover, since the regions F, F located between the absorbent core 4 and the second absorbent cores are stood up, a receiving space S having a shape capable of retaining an auxiliary absorber 20 can easily be formed on an inner surface of the disposable diaper 1. Accordingly, the displacement occurrable to the auxiliary absorber 20 when the auxiliary absorber 20 is disposed on the inner surface of the disposable diaper 1, can be prevented effectively. Moreover, the arrangement or replacement of the auxiliary absorber 20 can be carried out very easily and rapidly.

The absorbent core may be disposed at the region F located between the central absorbent core 4 and each second absorbent core 6. From the view point of enhancing the standing propensity of the region F, however, the weight per unit area of the region F is preferably 2/3 or smaller than the weight per unit area of the region D where the second absorbent core 6 is disposed. The weight per unit area of the region F located between the central absorbent core 4 and each second absorbent core 6 and the weight per unit of the region D where the second absorbent core 6 is disposed can be obtained as follows, respectively. Test pieces of 1 cm.times.1 cm cut out from the region F and the region D in the disposable diaper, respectively. Then, the weights of the test pieces are measured.

The auxiliary absorber 20 of FIGS. 3 and 7 is a substantially vertically elongated absorptive pad (auxiliary pad) comprising a fluid-permeable topsheet 22, a fluid-impermeable backsheet 23 and a fluid-retentive absorbent core 24 interposed between the topsheet 22 and the backsheet 23. This auxiliary absorber 20 is disposed on an inner surface of the diaper such that its longitudinal direction is aligned with a longitudinal direction of the disposable diaper.

From the view point of exhibiting at least one of the above-mentioned effects efficiently, the width L (see FIG. 2) of the central absorbent core 4 is preferably from 5 to 25 cm, the distance L2 between the central absorbent core 4 and each second absorbent core 6 is preferably from 0.5 to 10 cm and the width L3 of the second abosrbent core 6 is preferably from 1 to 10 cm, all at the crotch region C of the disposable diaper 1. Also, from the same view point, the ratio (L1/L) of the width L1 of the central absorbent core 4 with respect to the smallest width L of the disposable diaper 1 at the crotch region C is preferably from 0.1 to 0.8, the ration (L2/L) of the distance L2 between the central absorbent core 4 and each second absorbent core 6 with respect to the smallest width L of the disposable diaper 1 is preferably from 0.01 to 0.3 and the ratio (L3/L) of the width L3 of the second absorbent core 6 with respect to the smallest width L of the disposable diaper 1 at the crotch region C is preferably from 0.02 to 0.3. The dimensions of the various portions and the ratios are dimensions obtained by measurement carried out in a state in which the diaper is developed and planarly spread as shown in FIG. 1 and the ratios based thereon.

The present invention is not limited to the above-mentioned embodiment and it can be changed or modified in accordance with necessity and without departing from the gist of the invention. For example, it is accepted that the central absorbent core 4 and the second absorbent cores 6 are not spaced apart form each other and that they are adjacent to each other through a slit. Moreover, the second absorbent cores 6, 6 may be formed as completely separate bodies from the central absorbent core 4. In other words, the second absorbent cores 6, 6 and the central absorbent core 4 may be divided over the lengthwise entire area of the central absorbent core 4.

It is also accepted that an absorptive material having a smaller weight per unit area than the central absorbent core 4 and the second absorbent cores 6 is disposed at the region F between the central absorbent core 4 and each second absorbent core 6. For example, it is accepted that an absorbent core having a small width is laminated on an absorbent core having a large width at a widthwise center thereof and opposite side edge portions of the large width absorbent core are folded back towards the surface of the large width absorbent core on which the small width absorbent core is laminated, so that a predetermined gap is formed between the opposite side edge portions of the small width absorbent core and the opposite side edge portions of the large width absorbent core.

The elastic member 8 at the region D where the second absorbent core 6 is disposed may be disposed at any part in a thickness direction of the region D. For example, the elastic member 8 may be disposed between the topsheet 2 and the second absorbent core 6, or within the second absorbent core 6, or at the outer surface of the backsheet 3. The elastic member 8 is preferable disposed at a location on the more outer surface side of the diaper than the second absorbent core 6. The number of the elastic members 8 and the second absorbent cores 81 is not particularly limited. The number may be only one or plural. The configuration, dimension, forming material, etc. of each part of the disposable diaper can be changed in accordance with necessity. The disposable diaper of the present invention is especially suited to be used as a diaper for an adult person. The same effect can be obtained when the present invention is applied to a case where no auxiliary absorber is employed.

The disposable diaper of the first invention is excellent in leak-preventive property and is capable of surely preventing the leak (side leak) particularly around the leg areas.

A second embodiment of the first invention will be described with reference to FIGS. 4 to 7. The same explanation as in the first embodiment will be omitted.

In the disposable diaper 1A according to this embodiment, the second absorbent cores 6, 6 are integral with the central absorbent core 4 through the absorbent core (the absorbent core disposed at the intermediate region F) having a lower basis weight than the second absorbent cores 6, 6. In more detail, the central absorbent core 4 and the leg absorbent cores 6, 6 are segmented by intermediate regions F, F provided with the absorbent cores whose basis weights are lower than the basis weights of the central and leg absorbent cores 6, 6 and 4 (see FIG. 5). The regions D where the second absorbent cores 6 are disposed are referred to as the leg absorbent portions D hereinafter.

The topsheet 2 and the backsheet 3 in the disposable diaper 1A according to this embodiment are further extended outwardly in the widthwise direction from the position where the outer edge 61 of the second absorbent core 6 is located, and edge flap portions E, E are formed at opposite side edge portions of the diaper 1A by the extended parts of the topsheet 2 and the backsheet 3. In the disposable diaper 1A according to this embodiment, a plurality of elastic members 7a to 7d are disposed at the edge flap portions E and the leg absorbent portions D on opposite left and right sides of the diaper 1A along a longitudinal direction of the diaper. Specifically, two elastic members 7a, 7b are disposed at each edge flap portion E, and two elastic members 7c, 7d are disposed at each leg absorbent portion D. The elastic members 7a, 7b are fixedly sandwichingly held between the topsheet 2 and the backsheet 3 which constitute the edge flap portion E, and the elastic members 7c, 7d are fixedly sandwichingly held between the second absorbent core 6 and the backsheet 3.

In the disposable diaper according to the second embodiment, the lengthwise shrinkage of the edge flap portion E in the crotch region C on the opposite left and right sides in the longitudinal direction is larger than the lengthwise shrinkage of the leg absorbent portion D. The shrinkage of the edge flap portion and the shrinkage of the leg absorbent portion D in the longitudinal direction are measured as follows, respectively.

<Method for Measuring Shrinkage>

The disposable diaper is held in a tensioned state (the state in which the elastic members at various portions are stretched and planarly spread) as shown in FIG. 4. In that state, two points are defined on an outer edge E1 of the edge flap portion E and on an inner side edge D2 (the same as on the inner side edge 62 of the second absorbent core 6) of the leg absorbent portion D in the crotch region C, respectively. Then, a shortest distance in a longitudinal direction between the two points is represented by a.

Then, the tensioned state is released, and a shortest distance between the two points in a state (natural state) in which no external force is exerted thereto is represented by b.

The shrinkage can be obtained by using the following equation. shrinkage (%)={(a-b)/a}.times.100

The shrinkage at the outer edge of the edge flap portion is regarded as the "shrinkage at the edge flap portion E" and the shrinkage at the inner side edge of the leg absorbent portion D is regarded as the "shrinkage at the leg absorbent portion".

The two points taken on the side edge of the edge flap portion E and on the inner side edge of the leg absorbent portion D are, in principle, decided by taking one point on a border line between the crotch region C and the back side region A and another one point on a border line between the crotch region C and the stomach side region B. The crotch region C in the disposable diaper according to this second embodiment refers to the "two inside regions" of all four regions which are obtained by dividing the disposable diaper into four equal parts in a longitudinal direction of the diaper.

From the view point of enhancing the leak-preventive property, feel during wear, storability/retainability of the auxiliary absorber, fitness at the crotch region attributable to the enhancement and effect of formability of the leak-preventive barrier formed by bending the leg absorbent portion D, the ration (P/Q) of the shrinkage P of the edge flap portion E with respect to the shrinkage Q at the leg absorbent portion D is preferably from 1.1 to 3.0, and particularly preferably from 1.3 to 2.0. Also, from the same view point, the shrinkage at the edge flap portion E is preferably from 20 to 70%, and particularly preferably from 30 to 60%, and the shrinkage at the edge flap portion E is preferably from 5 to 55%, and particularly preferably from 15 to 45%.

In the disposable diaper 1A, the leg absorbent portion D takes a curved form, as later described, in its natural state owing to the feature that the shrinkage at the edge flap portion E in the longitudinal direction is larger than the shrinkage at the leg absorbent portion D in the longitudinal direction. Even in a case where no elastic member is disposed at the edge flap portion E, the leg absorbent portion D can be protuberatingly curved inward, for example, by applying a high elasticity to the leg absorbent portion D at the area offset to the outer edge thereof and by extremely reducing the rigidity of the edge flap portion compared with the rigidity of the leg absorbent portion D. However, it is preferred that the elastic member is disposed at the edge flap portion E from the view point of surely obtaining the above-mentioned curve, surely exhibiting the enhancement and effect of the formability of the leak-preventive barrier, storability/retainability of the auxiliary absorber, etc., fitness around the leg areas, and the like, and further enhancing the above-mentioned effect. In the case where the elastic member is disposed at the edge flap portion E, the shrinking force of the elastic member is never lost by the shrinkage of the leg absorbent portion D.

In a natural state of the disposable diaper 1A as shown in FIG. 6, the leg absorbent portions D, D are protuberatingly curved inward in a widthwise direction of the diaper. The natural state used herein refers to a state in which the disposable diaper is placed on a horizontal plane and left as it is (the state in which the stretched state of each elastic member is released) with its topsheet side (that surface side facing the wearer's skin) faced upward. In the disposable diaper 1A according to this embodiment, the leg absorbent portions D, D are curved in such a manner as to form an arc as a whole.

In the disposable diaper 1A according to this embodiment, a shrinking force damping region having a predetermined width is formed between the central absorbent portion (referred to as the region provided with the central absorbent core 4) G and each of the leg absorbent portions D, D at least in the crotch region. In this embodiment, the intermediate regions F, F are the shrinking force damping regions. The shrinking force damping region used herein refers to a region where its lengthwise inner side edge is small in shrinkage and its lengthwise outer edge is large when compared with a case in which the region is composed of the leg absorbent portion D. By providing such a shrinking force damping region, twisting which would otherwise occur to the central absorbent portion G can be prevented by buffering the shrinking force conveyed from the leg flap portion (the region formed by a combination of the leg absorbent portion D with the edge flap portion E). Moreover, by sandwiching the leg absorbent portion D between the edge flap portion E having a large shrinkage and the shrinking force damping region having a small shrinkage, the curve of the leg absorbent portion D in the crotch region C can surely be achieved. That is, the leg absorbent portions D, D can surely be curved in such a manner as to be constricted inward at the nearby area of the shrinking force damping region in the crotch region C, thereby further enhancing the formability of the leak-preventive barrier and the storability/retainability of the auxiliary absorber, etc. As a method (means) for forming the shrinking force damping region, the area between the central absorbent portion G and each leg absorbent portion D may be composed of (a) a material (plural members are also accepted) having a lower rigidity than the leg absorbent portion D (for example, a absorbent core having a lower basis weight than the second absorbent core 6 is disposed between the topsheet and the backsheet, or not absorbent core is disposed therebetween), or (b) a cushion material such as urethane capable of absorbing the shrinking force (a cushion material may also be disposed between the topsheet and the backsheet). In this embodiment, an absorbent core having a lower basis weight than the central absorbent core 4 and the second absorbent core 6 is disposed between the topsheet 2 and the backsheet 3. The shrinkage at the shrinking force damping region in its longitudinal direction is obtained by the measuring the shrinkage at the inner side edge of the shrinking force damping region (same as the outer edge G1 of the central absorbent portion G) in the same manner as the above-mentioned method for measuring the shrinking force at the leg absorbent portion D, etc.

In the case where the shrinking force damping region is provided, an elastic member may be disposed at the shrinking force damping region inasmuch as the shrinkage of the elastic member is smaller than the shrinkage of the leg absorbent portion D. However, from the view point of preventing the twisting occurrable to the central absorbent portion G, it is preferred that no elastic member is disposed at the shrinking force damping region.

The material of the elastic members 7a to 7d are preferably thread rubber, or flat rubber and particularly preferably flat rubber from the view point of shrinkability around the leg areas, machinability and cost.

The disposable diaper 1A according to the second embodiment is applied to the wearer in the same manner as the normal flat type disposable diapers. According to the disposable diaper 1A of this second embodiment, since the leg absorbent portions D, D are protuberatingly curved inward in a widthwise direction of the diaper, the intermediate portions F, F, which are, when in wear, located between the central absorbent portion G and the leg absorbent portions D, are, as shown in FIG. 7, angularly stood up with respect to the wearer's skin surface and are functioned as leak-preventive barrier (three-dimensional barriers). Accordingly, this disposable diaper 1A is excellent in leak-preventive property, particularly leak-preventive property around the leg areas.

Moreover, since the intermediate portions F, F located between the central absorbent portion G and the leg absorbent portions D are stood up, pockets S having a recessed form and capable of stably retaining the auxiliary absorber 20 are formed in an inner surface of the disposable diaper 1A. Accordingly, the storability/retainability of the auxiliary absorber 20 obtainable when the auxiliary absorber 20 is disposed on the inner surface of the disposable diaper 1 for use in combination, is enhanced. For example, even in case the auxiliary absorber 20 has no fixing means, displacement hardly occurs when in wear. Moreover, the arrangement or replacement of the auxiliary absorber 20 can be carried out very easily and rapidly.

Moreover, since the leg absorbent portions D, D are fit around the leg areas in such a manner as to be protuberatingly curved inward in a widthwise direction of the diaper, the diaper is easy to put on or apply and is excellent in fitness at the crotch region.

In the disposable diaper 1A according to this embodiment, since the elastic members 7c, 7c are also disposed at the leg absorbent portions D along a longitudinal direction of the diaper, the skin side surfaces of the leg absorbent portions D nicely fit around the leg areas of the wearer M, as shown in FIG. 7. For this reason, even if the urine, etc. should leak out to the side of the central absorbent portion, they would surely be absorbed by the leg absorbent portion D without allowing them to reach the side edge portion of the diaper 1. Moreover, since the elastic members 7a, 7b are also disposed at the edge flap portion E located at an outside area of the leg absorbent portion D, duplex leak preventing means is formed at the crotch region. Thus, leak of the excretions from the crotch region can more surely be prevented. Owing to the feature that the elastic members 7c, 7d are disposed at the leg absorbent portion D and the shrinking force damping region (intermediate region F) is formed between the leg absorbent portion D and the central absorbent portion G, the leg absorbent portion D is more surely curved inward at a peripheral area of the shrinking force damping region in the crotch region and the formability of the leak-preventive barrier and retainability of the auxiliary absorber such as auxiliary pad are extensively enhanced.

In the case where the elastic members are disposed at the leg absorbent portion D, the elastic members may be disposed at any part in the thickness direction at the regions. From the view point of surely fitting the specific region to the thigh portion or from the view point of preventing the leg absorbent portion D from falling towards the inner surface side of the diaper, the elastic members are preferably disposed more on the outer surface side than the second absorbent core 6 in the thickness direction. At that time, from the view point of preventing the deterioration of the shrinking force due to detachment of the elastic members, it is preferred that a fixing sheet (not shown) is disposed at the reverse surface side of the second absorbent core in such a manner as to be in abutment with the second absorbent core and the elastic members are fixedly sandwichingly held between the fixing sheet and the reverse surface sheet.

In the disposable diaper 1A according to this embodiment, since at least one pair of fastening tapes as fixing means are disposed at the opposite left and right side edge portions of the back side region A and the waist portion elastic member 13 for forming a waist gather is disposed at an area in the vicinity of the waist opening edge portion 11 in the back side region A, the disposable diaper 1A is very easy to put on or apply. That is, although there is such a fear that when the leg absorbent portion D is curved, the back side flaps forming the opposite side edge portions in the back side region where the fixing mean is disposed are slanted towards the crotch region depending on the degree of the curve, with the result that wearability is lowered, the back side flaps can be prevented from slanting towards the crotch region C by forming a waist gather at an area in the vicinity of the waist opening edge portion 11 so as to provide expanding/contracting property. Moreover, by disposing the waist gather, it becomes possible not only that the effect of leak prevention around the leg areas is enhanced but also that leak from the waist opening portion is more surely prevented. From the view point of enhancing the effect of leak prevention, the waist elastic member is preferably disposed at the stomach side region B, too, as in the back side region A.

From the view point of exhibiting at least one of the above-mentioned various effects effectively, the preferable ranges of the width of the various portions and the ratio of the width of the various portions in the crotch region of the disposable diaper 1A, are preferably the same as those of the disposable diaper 1 according to the first embodiment.

The disposable diaper according to this second embodiment is excellent in storability/retainability of the auxiliary absorber in case the leak preventability and the auxiliary absorber are employed in combination. Also, the diaper according to the second embodiment is excellent wearability and fitness at the crotch region.

A third embodiment of the first invention will be described hereinafter with reference to FIGS. 8 to 11. A disposable diaper 1B according to this third embodiment is designed such that it takes, especially, the shape of trunks when in wear. About those points which are not particularly described or shown with respect to the third embodiment, the description made with respect to the first or second embodiment is applied, where appropriate.

The topsheet 2 and the backsheet 3 is the disposable diaper 1B according to this third embodiment are extended widthwise outward from longitudinal opposite side edges 41, 41 of the central absorbent core 4, and those extended portions form leg flap portions LF, LF at longitudinal opposite side portions of the diaper. A landing zone 9 for fixing the fastening tapes 5, 5 is disposed at the outer surface of the stomach side region B.

In the disposable diaper 1B according to this third embodiment, a ration (L4/L5) between a smallest width L4 of a crotch region which occupies two inside regions of all four regions which are obtained by dividing the disposable diaper 1B into four equal parts in a longitudinal direction of the diaper and a largest width L5 of the disposable diaper is from 0.4 to 0.8 and more preferably from 0.55 to 0.75. If the ratio (L4/L5) is smaller than 0.4, there occur such inconveniences that (a) the region where the absorbent core is disposed is too small to obtain a sufficient absorption performance and especially when it is tried to form the diaper into the shape of trunks, it becomes difficult to substantially obtain the region where the absorbent core is disposed, and that (b) the lug portion of the side flap is likely to open and flap during conveyance in machining process (deterioration in machining). In contrast, if the ratio is larger than 0.8, deterioration in wearability is unavoidable.

In FIG. 8, one dot chain lines Q1, Q and Q2 denote lines for longitudinally dividing the disposable diaper 1B into four equal parts. R1 to R4 denote the respective regions obtained by equally dividing the disposable diaper into four parts in a longitudinal direction. The crotch region C is a combination of the region R2 and the region R3. The dimensions of the various portions and the ratios described in this specification are dimensions obtained by measurements carried out in a state (tensioned state) in which the diaper is planarly spread as shown in FIG. 8 and the ratios based thereon unless described otherwise specifically.

In the disposable diaper 1B according to this embodiment, the largest width L5 at the back side region A is preferably larger than the