U.S. patent application number 12/893973 was filed with the patent office on 2011-01-27 for absorbent article.
This patent application is currently assigned to Uni-Charm Corporation. Invention is credited to Tatsuya Hashimoto, Hirotomo Mukai, Kenichi Sasayama, Tomoko Tsuji, Kei Wakasugi.
Application Number | 20110022020 12/893973 |
Document ID | / |
Family ID | 39464607 |
Filed Date | 2011-01-27 |
United States Patent
Application |
20110022020 |
Kind Code |
A1 |
Wakasugi; Kei ; et
al. |
January 27, 2011 |
ABSORBENT ARTICLE
Abstract
The present invention provides an absorbent article 1 that does
not easily warp in a leg-surrounding portion. The absorbent article
1 includes an absorbing member 2 in an elongated shape arranged
along a longitudinal direction of the absorbent article, and a
stretchable chassis 3 having a leg-surrounding portion 3a recessed
inward in a width direction. At least a part of the chassis 3 is
composed of a composite sheet 13 obtained by affixing a stretchable
sheet 15 and a non-stretchable sheet 16 to each other by a
plurality of adhesive portions 18. The leg-surrounding portion 3a
has an intersection crossing an expansion and contraction direction
of the chassis 3 at a predetermined angle. The plurality of
adhesive portions 18 extend in a direction substantially
perpendicular to the expansion and contraction direction.
Inventors: |
Wakasugi; Kei; (Kagawa,
JP) ; Mukai; Hirotomo; (Kagawa, JP) ; Tsuji;
Tomoko; (Kagawa, JP) ; Sasayama; Kenichi;
(Kagawa, JP) ; Hashimoto; Tatsuya; (Kagawa,
JP) |
Correspondence
Address: |
MORRISON & FOERSTER LLP
1650 TYSONS BOULEVARD, SUITE 400
MCLEAN
VA
22102
US
|
Assignee: |
Uni-Charm Corporation
Shikokuchuo-shi
JP
|
Family ID: |
39464607 |
Appl. No.: |
12/893973 |
Filed: |
September 29, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11945404 |
Nov 27, 2007 |
|
|
|
12893973 |
|
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Current U.S.
Class: |
604/385.29 |
Current CPC
Class: |
A61F 13/49009 20130101;
A61F 13/51464 20130101 |
Class at
Publication: |
604/385.29 |
International
Class: |
A61F 13/15 20060101
A61F013/15 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 27, 2006 |
JP |
2006-319392 |
Claims
1. An absorbent article having a width direction and a longitudinal
direction perpendicular to the width direction, comprising: an
absorbing member in an elongated shape disposed along the
longitudinal direction of the absorbent article; and a stretchable
chassis having a leg-surrounding portion recessed inward in the
width direction of the absorbent article on both sides in the width
direction formed therein, and an abdominal region provided in a
front and back region of the chassis, wherein at least the
abdominal region and a portion of the leg surrounding portion of
the chassis is composed of a stretchable composite sheet obtained
by affixing, by way of a plurality of adhesive portions, a first
sheet and a second sheet having a ratio of expansion and
contraction that is different from that of the first sheet, the
leg-surrounding portion has an intersection crossing an expansion
and contraction direction of the chassis at a predetermined angle,
the plurality of adhesive portions are provided with predetermined
spacing in the expansion and contraction direction at the
intersection and extend in a direction substantially perpendicular
to the expansion and contraction direction in the entire
stretchable composite sheet.
2. The absorbent article according to claim 1, wherein the
predetermined angle at the intersection is in the range of 20
degrees to 90 degrees.
3. The absorbent article according to claim 1, wherein the
difference in ratios of expansion and contraction in the composite
sheet between the first sheet and the second sheet is at least
20%.
4. The absorbent article according to claim 1, wherein a size in
the expansion and contraction direction of the plurality of
adhesive portions is in the range of 0.1 mm to 20 mm.
5. The absorbent article according to claim 1, wherein among the
plurality of adhesive portions, the spacing between the adhesive
portions adjacent to each other at the intersection of the
leg-surrounding portion is in the range of 4 mm to 25 mm.
6. The absorbent article according to claim 1, wherein the
expansion and contraction direction is the width direction, and
each of the plurality of adhesive portions is formed in a linear
shape extending in a direction substantially perpendicular to the
expansion and contraction direction.
7. The absorbent article according to claim 1, wherein the ratio of
the dimensions of the plurality of adhesive portions in the
vicinity of the intersection is in the range of 0.4% to 83%.
8. The absorbent article according to claim 1, wherein the
absorbent article is a diaper in the shape of pants.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S. Ser.
No. 11/945,404, filed Nov. 27, 2007, which claims the benefit of
priority from Japanese Patent Application No. 2006-319392, filed on
Nov. 27, 2006, the entire contents of which are incorporated herein
by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an absorbent article
including a composite sheet obtained by affixing two types of
sheets having different ratios of expansion and contraction.
BACKGROUND OF THE INVENTION
[0003] Conventionally, disposable diapers, for example, have been
known as absorbent articles. The disposable diapers widely employed
for babies and children to the elderly persons and
physically-handicapped persons have been replaced with reusable
absorbent articles made of cloth. Such a disposable diaper
generally includes an absorbing member in an elongated shape
arranged along a longitudinal direction and a chassis having a
leg-surrounding portion recessed inward in a width direction on
both sides in the width direction formed therein, and composed of a
composite sheet obtained by affixing two sheets. According to
Japanese Unexamined Patent Application, First Publication No.
2004-136068 (hereinafter referred to as "patent publication 1"),
some composite sheets have been manufactured by a method of coating
the whole surface of one of the two sheets with adhesives, finely
arranging a thread-shaped stretchable member between the two
sheets, and bonding the other sheet thereto.
[0004] Additionally, as disclosed in Japanese Unexamined Patent
Application, First Publication No. 2002-143218 (hereinafter
referred to as "patent publication 2"), there is also a technique
for affixing a sheet-shaped stretchable sheet to a non-stretchable
sheet to manufacture a composite sheet in order to enhance the
appearance and the fitting properties of a diaper in the shape of
pants. FIG. 6 is a front view of a diaper in the shape of pants 201
using a composite sheet 213 obtained by affixing such stretchable
and non-stretchable sheets 215 and 216, respectively, to each other
for portions including a trunk-surrounding portion and a
leg-surrounding portion of the diaper. The composite sheet 213 is
formed of two sheets, i.e., the non-stretchable sheet 216 on the
side of a skin contacting surface directed toward the body of a
wearer and the stretchable sheet 215 on the side of a non-skin
contacting surface that is the opposite side of the skin contacting
surface and affixed to each other with adhesives applied to the
entire surfaces of the sheets.
[0005] When the non-stretchable sheet 216 and the stretchable sheet
215 are thus affixed to each other with the adhesives applied to
the entire surfaces of the sheets, a warping portion 225 that warps
toward the non-skin contacting surface, i.e., a portion having a
height no less than two times that of the other portions in a
stationary state or a portion with a front surface appearing to be
turned toward the reverse surface or reverse surface appearing to
be turned toward the front surface in a stationary state occurs at
a cut edge 204 of a leg-surrounding portion 203a. FIG. 7 is an
enlarged view of the region A of FIG. 6, showing a cross-sectional
view of a portion where such a warping portion 225 occurs. The
arrows show an expansion and contraction direction (ECD) at the
portion. The non-stretchable sheet 216 on the side of the skin
contacting surface is pulled with a contractive force of the
stretchable sheet 215 on the side of the non-skin contacting
surface so that the warping portion 225 occurs. When the warping
portion 225 is thus provided in the chassis 203, adhesion between
the skin and the composite sheet 213 is degraded, so that a gap
occurs between the skin and the composite sheet 213. Therefore,
urine is likely to leak out of the gap.
[0006] An objective of the present invention is to provide an
absorbent article that does not easily warp in a leg-surrounding
portion.
[0007] The inventors of the present invention have performed
thorough examination in order to attain the abovementioned
objective. As a result, they have found that when a stretchable
sheet and a non-stretchable sheet are bonded to each other, and
adhesive portions are provided to extend in a direction
substantially perpendicular to an expansion and contraction
direction between the sheets at a cut edge of both the sheets to
prevent a warping portion from occurring at the cut edge, the
present invention is achieved. Specifically, an objective is to
provide the absorbent article described below.
SUMMARY OF THE INVENTION
[0008] In a first aspect of the present invention, an absorbent
article has a width direction and a longitudinal direction
perpendicular to the width direction, and includes an absorbing
member in an elongated shape disposed along an longitudinal
direction of the absorbent article; and a stretchable chassis
having a leg-surrounding portion recessed inward in a width
direction of the absorbent article on both sides in the width
direction formed therein, in which at least a portion of the
chassis is composed of a stretchable composite sheet obtained by
affixing, by way of a plurality of adhesive portions, a first sheet
and a second sheet having a ratio of expansion and contraction that
is different from that of the first sheet, the leg-surrounding
portion having an intersection crossing an expansion and
contraction direction of the chassis at a predetermined angle, and
the plurality of adhesive portions extend with predetermined
spacing in the expansion and contraction direction at the
intersection and in a direction substantially perpendicular to the
expansion and contraction direction.
[0009] In a second aspect of the absorbent article as described in
the first aspect of the present invention, the predetermined angle
is in the range of 20 degrees to 90 degrees.
[0010] In a third aspect of the absorbent article described in the
first or second aspect of the present invention, the difference in
ratios of expansion and contraction in the composite sheet between
the first sheet and the second sheet, respectively, is at least
20%.
[0011] In a fourth aspect of the absorbent article as described in
any one of the first to third aspects of the present invention, a
size in the expansion and contraction direction of the plurality of
adhesive portions is in the range of 0.1 mm to 20 mm.
[0012] In a fifth aspect of the absorbent article as described in
any one of the first to fourth aspects of the present invention,
among the plurality of adhesive portions, the spacing between the
adhesive portions adjacent to each other at the intersection of the
leg-surrounding portion is in the range of 4 mm to 25 mm.
[0013] In a sixth aspect of the absorbent article as described in
any one of the first to fifth aspects of the present invention, the
expansion and contraction direction is the width direction, and
each of the plurality of adhesive portions is formed in a linear
shape extending in a direction substantially perpendicular to the
expansion and contraction direction.
[0014] In a seventh aspect of the absorbent article as described in
any one of the first to sixth aspects of the present invention, the
ratio of the dimensions of the plurality of adhesive portions in
the vicinity of the intersection is in the range of 0.4% to
83%.
[0015] In an eighth aspect of the absorbent article as described in
any one of the first to seventh aspects of the present invention,
the adsorbent article is a diaper in the shape of pants.
[0016] The present invention provides an absorbent article that
does not easily warp in a leg-surrounding portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is an exploded view of a disposable diaper according
to a first embodiment of the present invention;
[0018] FIG. 2 is a front view of the disposable diaper, formed in
the shape of pants, according to the first embodiment of the
present invention;
[0019] FIG. 3 is a cross-sectional view showing a state where a
stretchable sheet and a non-stretchable sheet are affixed to each
other;
[0020] FIG. 4 is an exploded view of a disposable diaper according
to a second embodiment of the present invention;
[0021] FIG. 5 is a front view of the disposable diaper, formed in
the shape of pants, according to the second embodiment of the
present invention;
[0022] FIG. 6 is an exploded view of a conventional disposable
diaper; and
[0023] FIG. 7 is an enlarged view of the region A of FIG. 6,
showing a warping portion occurring at a cut edge of the
conventional disposable diaper.
DETAILED DESCRIPTION OF THE INVENTION
[0024] A disposable diaper 1 serving as an absorbent article
according to a first embodiment of the present invention is now
described while referring to the drawings. In the following
description, a surface directed toward the body of a wearer of the
disposable diaper is considered as a skin contacting surface, and a
surface on the opposite side of the skin contacting surface is
considered as a non-skin contacting surface.
[0025] FIG. 1 is an exploded view of the disposable diaper 1
according to the first embodiment. FIG. 2 is a front view of the
disposable diaper 1, formed in the shape of pants shown in an
unfolded state in FIG. 1. As shown in FIG. 1, the disposable diaper
1 includes an absorbing member 2 in an elongated shape arranged
along a longitudinal direction (LD) and a stretchable chassis 3
having a leg-surrounding portion 3a recessed in a U-shape inward on
both sides in a width direction (WD) formed therein.
[0026] First, the chassis 3 is described. As shown in FIG. 1, the
chassis 3 has the U-shaped leg-surrounding portion 3a recessed
inward in the width direction on both sides in the width direction
formed therein, as described above. The chassis 3 is divided into
two portions, i.e., a front body portion 10 and a rear body portion
11, by a line C passing through a portion, which becomes the
narrowest by U-shaped cuts of the leg-surrounding portion 3a of the
chassis 3 and extending in the width direction. If we let .alpha.
be an angle of a cut edge 4 of the leg-surrounding portion 3a to an
expansion and contraction direction of the chassis 3 (the width
direction) at the cut edge 4, as illustrated, at an end in the
width direction of the front body portion 10, the angle .alpha. is
0 degrees, that is, the cut edge 4 is parallel to the expansion and
contraction direction of the chassis 3. The angle .alpha. gradually
increases from the position of the end toward the center in the
width direction of the chassis 3 to a position where the chassis 3
and the absorbing member 2 overlap with each other, to form an
intersection crossing the expansion and contraction direction of
the chassis 3. At the position where the chassis 3 and the
absorbing member 2 overlap with each other, the angle .alpha. is
approximately 90 degrees.
[0027] FIG. 3 is a cross-sectional view of the chassis 3 from the
width direction. A sheet composing the chassis 3 is a composite
sheet 13 obtained by affixing a stretchable sheet 15 and a
non-stretchable sheet 16 to each other in adhesive portions 18 with
an adhesive 19 such as a hot melt adhesive, as illustrated. This
composite sheet 13, produced by affixing the stretchable sheet 15
in its expanded state to the non-stretchable sheet 16, can expand
and contract in the width direction and is placed on the chassis 3
so as to expand and contract in the width direction. With the
stretchable sheet 15 relaxed, a plurality of pleats 17 are formed
in a direction perpendicular to the expansion and contraction
direction in non-adhesive portions, which are not joined to the
stretchable sheet 15, of the non-stretchable sheet 16.
[0028] A material for the stretchable sheet 15 can be changed as
required, in accordance with the intended use or the like of the
absorbent article. For example, various types of known stretchable
sheets 15 such as a spunbonded sheet and a meltblown sheet can be
selected. Usable as fibers constituting the stretchable sheets 15
are polyolefin-, polyester-, or polyamide-based fibers, or
core-sheath type conjugate fibers or side-by-side type conjugate
fibers formed of polyethylene/polypropylene or
polyethylene/polyester. Furthermore, a stretchable sheet 15
obtained by melting and spinning urethane-based thermoplastic
synthetic resin to produce a spunbonded sheet and stretching the
spunbonded sheet in at least one direction to develop stretchable
elasticity may be used.
[0029] Although the basis weight of the stretchable sheet 15 can be
changed as required, in accordance with the intended use or the
like, it is preferably 20 to 80 g/m.sup.2 before the stretchable
sheet 5 is affixed to the non-stretchable sheet 16. When the basis
weight of the stretchable sheet 15 is less than 20 g/m.sup.2, the
strength thereof may, in some cases, decrease. On the other hand,
when the basis weight of the stretchable sheet 15 exceeds 80
g/m.sup.2, the thickness thereof may, in some cases, increase.
[0030] The strength at the time of 100 percent expansion of the
stretchable sheet 15 is preferably not more than 10 N/50 mm and
more preferably in the range of 1 to 7 N/50 mm.
[0031] Furthermore, the strain of the stretchable sheet 15 after
100 percent expansion is preferably not more than 15%, and more
preferably not more than 10%.
[0032] A material for the non-stretchable sheet 16 can be changed
as required, in accordance with the intended use or the like of the
absorbent article. For example, various types of known
non-stretchable sheets 16 such as a spunbonded sheet, an SMS
(spunbond/meltblown/spunbond) sheet, a point-bonded sheet, a
through-air sheet, a spun lace sheet, and a needle punch sheet can
be selected. They may be used alone or in combination. Usable as
fibers composing the non-stretchable sheets 16 are polypropylene-,
polyolefin-, polyester-, or polyamide-based fibers, or core-sheath
type conjugate fibers or side-by-side type conjugate fibers formed
of polyethylene/polypropylene or polyethylene/polyester.
[0033] Although the basis weight of the non-stretchable sheet 16
can be changed as required, in accordance with the intended use or
the like, it is preferably in the range of 10 to 50 g/m.sup.2. When
the basis weight of the stretchable sheet 16 is less than 10
g/m.sup.2, the strength thereof may in some cases decrease. On the
other hand, when the basis weight of the non-stretchable sheet 16
exceeds 50 g/m.sup.2, the thickness thereof may in some cases
increase. When the thickness of the non-stretchable sheet 16
increases, the rigidity thereof increases, thereby inhibiting the
stretchability. This causes the flexibility of the composite sheet
13 to be reduced.
[0034] Examples of a coating method of adhesives for bonding the
stretchable sheet 15 and the non-stretchable sheet 16 to each other
include control seam coating, coater coating, curtain coater
coating, and summit gun coating. The basis weight of adhesives in
hot melt adhesion is preferably in the range of 1 to 30 g/m.sup.2
and more preferably in the range of 3 to 10 g/m.sup.2.
[0035] The absorbing member 2 is next described. The absorbing
member 2 has a liquid-permeable top sheet 6 in a substantially
longitudinal shape composing a front surface layer, a
liquid-impermeable back sheet 7 in a substantially vertically-long
shape constituting a reverse surface layer, and an absorbent body 8
in a substantially rectangular shape having liquid holding
properties and constituting an absorbing layer arranged between the
liquid-permeable top sheet 6 and the liquid-impermeable back sheet
7. The absorbing member 2 is affixed to a surface, on the side of
the skin contacting surface, at the center of the chassis 3 such
that the liquid-impermeable back sheet 7 and the chassis 3 are
opposed to each other.
[0036] It should be noted that "substantially longitudinal shape"
indicates a substantially rectangular or elliptical shape having a
longer-side direction (longitudinal direction) and a shorter-side
direction, and further includes such a shape in which parts of both
the sides in the longitudinal direction are recessed in a direction
toward the center in the longitudinal direction or projected in the
opposite direction to the direction toward the center. More
specifically, the absorbent body 8 in a substantially longitudinal
shape includes one having portions that differ in width along the
longitudinal direction. Although the absorbent body 8 extends in
the longitudinal direction in the present embodiment, the present
invention is not limited to the same. The absorbent body 8 may
extend in the width direction.
[0037] Furthermore, the absorbent body 8 may be arranged in a state
in which it is wrapped in a tissue (not shown) or a hydrophilic
sheet (not shown). When wrapped in the hydrophilic sheet, the
absorbent body 8 may not use the liquid-permeable top sheet 6 or
may only partially use the liquid-permeable top sheet 6. This
allows the production cost to be reduced, for example. Furthermore,
a sheet such as a nonwoven fabric may be joined to a surface on the
side of the non-skin contacting surface of the liquid-impermeable
back sheet 7, which is preferable because the feel against the skin
of a wearer at the time of wearing, for example, is improved.
Alternatively, when a film is used for the liquid-impermeable back
sheet 7, a sheet or the like may be joined to the film, which is
preferable because an undesired sound can be prevented from being
produced by friction of the film, for example.
[0038] The absorbent body 8 is for absorbing and holding a
discharged body fluid such as urine, and may be formed by mixing
and laminating a highly absorbent polymer and hydrophilic fibers,
or formed by fixing a highly absorbent polymer to a hydrophilic
sheet with a hot melt adhesive or the like.
[0039] The liquid-permeable top sheet 6 is arranged on the side of
the body and is brought into contact with an excretory portion when
it is employed. Examples of the liquid-permeable top sheet 6
include not only one having an entire surface liquid-permeable, but
also one that is partially liquid-permeable. Furthermore, the
liquid-permeable top sheet 6 may be composed of one sheet-shaped
member or may be formed by bonding a plurality of sheet-shaped
members to one another.
[0040] Preferable as the liquid-permeable top sheet 6 is a material
that has enough strength so as not to be damaged, even if a load is
applied thereto due to compression, torsion, friction or the like
during wearing, and does not irritate the skin. Usable as the
material is a sheet-shaped material having liquid permeability such
as a woven fabric, a nonwoven fabric, or a porous plastic
sheet.
[0041] Although the liquid-impermeable back sheet 7 is arranged on
the side of the non-skin contacting surface so as to be opposed to
the chassis 3, as described above, the present invention is not
limited to the same. For example, it may be provided among a
plurality of sheets constituting the chassis 3.
[0042] A coating pattern of the adhesive portions 18 in the chassis
3 is described next. As indicated by dotted lines in FIGS. 1 and 2,
in a trunk-surrounding portion 5 in the chassis 3, the adhesive
portions 18 inconsistently extend, respectively, with predetermined
lengths along a plurality of straight lines extending with
predetermined spacing in the longitudinal direction. The adhesive
portions 18 on the adjacent straight lines are alternate. That is,
the adhesive portions 18 extend in a direction substantially
perpendicular to the expansion and contraction direction of the
chassis 3. A cut portion 18a of the adhesive portion 18 on the one
straight line is not present at the same position in the
longitudinal direction as a cut portion 18a of the adhesive portion
18 on the adjacent straight line. It should be noted that the size
(width) in the expansion and contraction direction of the adhesive
portions 18 is preferably in the range of 0.1 mm to 20 mm, and is
2.5 mm in the present embodiment.
[0043] Furthermore, at the cut edge 4 of the leg-surrounding
portion 3a, the adhesive portions 18 extend in the longitudinal
direction, similarly to those in the trunk-surrounding portion 5.
That is, the adhesive portions 18 extend in a direction
substantially perpendicular to the expansion and contraction
direction of the chassis 3 in all regions of the leg-surrounding
portion 3a, irrespective of an angle of the cut edge 4 to the
expansion and contraction direction of the chassis 3. In this
embodiment, the spacing in the width direction of the adhesive
portions 18 at the cut edge 4 of the leg-surrounding portion 3a is
denser than that in the trunk-surrounding portion 5, and is
approximately one-half that in the trunk-surrounding portion 5.
Specifically, the spacing between the adhesive portions 18 in the
leg-surrounding portion 3a is preferably at least 4 mm. If the
spacing between the adhesive portions 18 is too great, however, a
space is noticeable at an end of the leg-surrounding portion 3a.
Therefore, the spacing is appropriately not more than 25 mm,
although it varies depending on a ratio of expansion and
contraction. Therefore, by making the spacing between the adhesive
portions 18 at the cut edge 4 of the leg-surrounding portion 3a
narrower than that in the trunk-surrounding portion 5, integration
between the stretchable sheet 15 and the non-stretchable sheet 16
in the composite sheet 13 is improved to improve fitting properties
to the body, which can inhibit urine leakage or the like. The
minimum area ratio of the adhesive portions 18 to the composite
sheet 13 in the vicinity of an intersection at which the cut edge 4
crosses the expansion and contraction direction of the chassis 3 is
0.1/(0.1+24).times.100=0.4%, because the width of the adhesive
portions 18 is in the range of 0.1 mm to 20 mm and the spacing
between the adjacent adhesive portions 18 is in the range of 4 mm
to 25 mm. On the other hand, the maximum area ratio is
20/(20+4).times.100=83%. Consequently, the area ratio is preferably
in a range of 0.4% to 83%. Here, "vicinity" indicates a
predetermined region between the cut edge 4 and a curve separated
from the cut edge 4 by a length that is not more than the
respective lengths of the adhesive portions 18.
[0044] The disposable diaper 1 having the above-mentioned
configuration is folded from the unfolded state shown in FIG. 1,
and is formed in the shape of pants as shown in FIG. 2 by
intermittently joining the front body portion 10 and the rear body
portion 11 at joining portions 20 provided on both sides in the
width direction using ultrasonic sealing, heat sealing, or the
like.
[0045] The disposable diaper 1 formed in the shape of pants is
generally in the state shown in FIG. 3, where the stretchable sheet
15 does not expand so that the plurality of pleats 17 are formed in
the non-stretchable sheet 16. When the chassis 3 is extended in the
width direction at the time of wearing, for example, the
stretchable sheet 15 expands so that the pleats in the
non-stretchable sheet 16 become smooth.
[0046] As described above, according to the present embodiment, the
adhesive portions 18 extend in the direction substantially
perpendicular to the expansion and contraction direction of the
chassis 3 in all of the regions of the leg-surrounding portion 3a,
i.e., the intersection at which the cut edge 4 of the
leg-surrounding portion 3a crosses the expansion and contraction
direction of the chassis 3 at a large angle. Therefore, even if at
the cut edge 4 of the leg-surrounding portion 3a, the stretchable
sheet 15 on the side of the non-skin contacting surface contracts,
the non-stretchable sheet 16 on the side of the skin contacting
surface is pulled toward the stretchable sheet 15 due to the
presence of the adhesive portions 18, thereby inhibiting the
disposable diaper 1 from warping outward. The warping is thus
inhibited, which prevents urine leakage or the like.
[0047] A disposable diaper 101 serving as an absorbent article
according to a second embodiment of the present invention is now
described while referring to the drawings. In the second
embodiment, the same descriptions as those in the first embodiment
are not repeated. FIG. 4 is an exploded view of the disposable
diaper 101 according to the second embodiment. The present
embodiment differs from the first embodiment in that a chassis 103
is not formed as an integral member and, in addition to a front
body portion 110 and a rear body portion 111 that expand and
contract in a width direction (WD), has an intermediate body
portion 112 that is arranged between the front body portion 110 and
the rear body portion 111, which expands and contracts in a
longitudinal direction (LD).
[0048] The front body portion 110 is a substantially rectangular
member in a horizontally-long shape extending in the width
direction. The front body portion 110 is composed of a composite
sheet 113 including a stretchable sheet (not shown in FIG. 4) and a
non-stretchable sheet 116, and expands and contracts in the width
direction, as in the first embodiment.
[0049] Although the rear body portion 111 is also a substantially
rectangular member in a horizontally-long shape extending in the
width direction, it is slightly curved in order to fit the body
better at a cut edge 104 of a leg-surrounding portion 103a. The
rear body portion 111 is composed of a composite sheet 113
including a stretchable sheet and a non-stretchable sheet 116, and
expands and contracts in the width direction, similarly to the
front body portion 110.
[0050] The intermediate body portion 112 positioned between the
front body portion 110 and the rear body portion 111 is a
substantially longitudinal member extending in the longitudinal
direction. The cut edge 104 is curved in a U shape so as to be
smoothly continuous from respective cut edges of the front body
portion 110, the intermediate body portion 112, and the rear body
portion 111. Although the intermediate body portion 112 is composed
of a composite sheet 113 including a stretchable sheet and a
non-stretchable sheet 116, similarly to the front body portion 110,
it expands and contracts in the longitudinal direction.
[0051] An absorbing member 102 formed in the same manner as that in
the first embodiment is made to adhere over a range from the front
body portion 110 to the rear body portion 111 centered at the
intermediate body portion 112.
[0052] The chassis 103 composed of the composite sheet 113 and in
an unfolded state, as shown in FIG. 4, where the absorbing member
102 affixed to its center is folded, is formed in the shape of
pants, as shown in FIG. 5, by intermittently joining the front body
portion 110 and the rear body portion 111, respectively, to joining
portions 120 provided on both sides in the width direction using
ultrasonic sealing, heat sealing, or the like, as in the first
embodiment.
[0053] A coating pattern of adhesive portions 118 in the front body
portion 110 and the rear body portion 111 that expand and contract
in the width direction are described. As indicated by dotted lines
in FIGS. 4 and 5, the adhesive portions 118 intermittently extend,
respectively, with predetermined lengths along a plurality of
straight lines extending with predetermined spacing in the
longitudinal direction, as in the first embodiment. The adhesive
portions 118 on the adjacent straight lines extend so as to
alternate. That is, the adhesive portions 118 extend in a direction
substantially perpendicular to an expansion and contraction
direction of the chassis 103.
[0054] In the leg-surrounding portion 103a in the front body
portion 110 and the rear body portion 111, the direction in which
the adhesive portions 118 extend is the longitudinal direction, as
in the other portions, i.e., the direction substantially
perpendicular to the expansion and contraction direction of the
chassis 103. In this embodiment, the spacing in the width direction
between the adhesive portions 118 in the leg-surrounding portion
103a is approximately one-half that in the width direction in a
trunk-surrounding portion 105.
[0055] As stated above, the present embodiment is a case in which
the expansion and contraction direction of the chassis and that of
the intermediate body portion 112, the front body portion 110, and
the rear body portion 111 are different. In this respect, the
adhesive portions 118 in the intermediate body portion 112 extend
in a direction parallel to the expansion and contraction direction
of the chassis 103 (width direction), and are applied along a
plurality of straight lines arranged with predetermined spacing in
the longitudinal direction. In this manner, although an expansion
and contraction direction of the intermediate body portion 112
differs from that of the front body portion 110 and the rear body
portion 111, the adhesive portions 118 extend in a direction
substantially perpendicular to the expansion and contraction
direction in the leg-surrounding portion 103a.
[0056] As described above, according to the present embodiment, the
adhesive portions 118 extend in a direction substantially
perpendicular to the expansion and contraction direction of the
chassis 103 in all regions of the leg-surrounding portion 103a.
That is, the adhesive portions 118 extend so as to be substantially
perpendicular to the expansion and contraction direction of the
front body portion 110 and the rear body portion 111, and so as to
be substantially perpendicular to the expansion and contraction
direction of the intermediate body portion 112. Consequently, the
same effect as that of the first embodiment is provided.
[0057] Although a description is provided of the suitable
embodiments of the present invention, the present invention is not
limited to the same. Although in the present embodiment, a
description is provided of the disposable diaper in the shape of
pants having a trunk opening and a pair of leg openings by joining
the front body portion and the rear body portion in predetermined
adhesive portions, the present invention is not limited to the
same. For example, the present invention may be applied to an
unfolded-type disposable diaper that can be worn by locking a front
body portion and a rear body portion using a locking member or the
like.
[0058] Alternatively, the present invention may be used for a
disposable diaper formed in the shape of pants, which are locked by
a locking member such as a re-lockable hook-and-loop fastener, as
used for an unfolded-type disposable diaper, is easily unlocked in
adhesive portions in a front body portion and a rear body portion,
and can be unfolded and relocked.
[0059] Furthermore, although in the present embodiment, a
description is provided of a disposable diaper for adults, the
present invention is not limited to the same. For example, it may
be a disposable diaper for children.
Examples
[0060] A description is now provided of an experiment conducted in
order to check for appropriate conditions in a coating pattern of
adhesives.
[0061] 1) A cut edge of a composite sheet in which a ratio of
expansion and contraction of a stretchable sheet was 1.8 at the
time of affixing the stretchable sheet and a non-stretchable sheet
was set to 10 degrees, 30 degrees, 45 degrees, 60 degrees, and 80
degrees to an expansion and contraction direction, the width along
the expansion and contraction direction of adhesive portions was a
constant value of 2.5 mm, and the spacing between the adhesive
portions was changed to (d) 1 mm, (e) 2.5 mm, (f) 4 mm, and (g) 7.5
mm, to examine the degree of warping occurring. For reference, the
same experiment was also conducted with respect to a case (a) where
adhesives were applied to the entire surface, a case (b) where the
spacing between lines adjacent in a spiral shape was not more than
3 mm (a fine mesh shape), and a case (c) where the spacing between
adjacent lines in a spiral shape was approximately 4 mm and was not
less than 3 mm (a coarse mesh shape).
[0062] Here, the non-stretchable sheet was a 19 g/m.sup.2
spunbonded sheet, and the stretchable sheet was a 35 g/m.sup.2
stretchable spunbonded sheet (urethane/PP). The results are shown
in Table 1, described below. Here, .smallcircle. indicates a good
state, .DELTA. indicates a slightly warped state, x indicates a
significantly warped state, and xx indicates a state where the
degree of warping is worse. Here, x and xx indicate that the
disposable diaper is defective.
TABLE-US-00001 TABLE 1 Cut angle of end of composite sheet to
expansion and contraction direction 10.degree. 30.degree.
45.degree. 60.degree. 80.degree. a. Coat whole surface
.smallcircle. .DELTA.~x x xx xx b. Spiral (fine mesh shape)
.smallcircle. x xx xx xx c. Spiral (coarse mesh .smallcircle.
.smallcircle. .DELTA. x x shape) d. Spacing between adhesive
.smallcircle. .DELTA. x xx xx portions; 1 mm e. Spacing between
adhesive .smallcircle. .smallcircle. .DELTA. x xx portions; 2.5 mm
f. Spacing between adhesive .smallcircle. .smallcircle.
.smallcircle. .DELTA. x portions; 4 mm g. Spacing between adhesive
.smallcircle. .smallcircle. .smallcircle. .smallcircle. .DELTA.
portions; 7.5 mm
[0063] Table 1 shows that warping hardly occurred in a case where
the adhesives were applied in a linear shape, as compared with that
of a case where the adhesives were applied to the entire surface.
It was found that the greater the spacing between the adhesive
portions, the less warping occurred. Furthermore, it was found that
even in a case where the adhesives were applied in a spiral shape
continuous in a plane shape, warping did not easily occur when the
spacing between the lines was coarse.
[0064] 2) The results of the same experiment conducted by changing
only the ratio of expansion and contraction to 1. 3 in 1) are shown
in Table 2.
TABLE-US-00002 TABLE 2 Cut angle of end of composite sheet to
expansion and contraction direction 10.degree. 30.degree.
45.degree. 60.degree. 80.degree. a. Coat whole surface
.smallcircle. .DELTA. x xx xx b. Spiral (fine mesh shape)
.smallcircle. .DELTA. x xx xx c. Spiral (coarse mesh .smallcircle.
.smallcircle. .DELTA. x x shape) d. Spacing between adhesive
.smallcircle. .DELTA.~.smallcircle. x xx xx portions; 1 mm e.
Spacing between adhesive .smallcircle. .smallcircle. .DELTA. x xx
portions; 2.5 mm f. Spacing between adhesive .smallcircle.
.smallcircle. .smallcircle. .DELTA. x portions; 4 mm g. Spacing
between adhesive .smallcircle. .smallcircle. .smallcircle.
.smallcircle. .DELTA. portions; 7.5 mm
[0065] Similarly to Table 1, Table 2 shows that warping hardly
occurred in a case where the adhesives were applied in a linear
shape, as compared with that of a case where the adhesives were
applied to the entire surface. It was found that the greater the
spacing between the adhesive portions, the less warping occurred.
It was found that in a case where the adhesives were applied in a
spiral shape continuous in a plane shape, warping did not easily
occur when the spacing between the lines was large. Furthermore, it
was found that the degree of warping was low until the cut angle
reached 30 degrees, although the warping had already occurred when
the cut angle was 30 degrees in the case where the ratio of
expansion and contraction was 1.8.
[0066] 3) The results of examination of the degree of occurrence of
warping by setting the spacing between the adhesive portions to a
constant value of 1 mm and changing the width of the adhesive
portions to (a) 2.5 mm, (b) 5.0 mm, (c) 1.0 mm, and (d) 20 mm are
shown in Table 3. It should be noted that no experiment was
conducted with respect to cases where the width of the adhesive
portions was 5.0 mm, 10 mm, and 20 mm when the cut angle was 10
degrees.
TABLE-US-00003 TABLE 3 Cut angle of end of composite sheet to
expansion and contraction direction 10.degree. 30.degree.
45.degree. 60.degree. 80.degree. a. Width of adhesive .smallcircle.
.smallcircle. .DELTA. x xx portions; 2.5 mm b. Width of adhesive --
x x xx xx portions; 5.0 mm c. Width of adhesive -- x xx xx xx
portions; 10 mm d. Width of adhesive -- x xx xx xx portions; 20
mm
[0067] Table 3 shows that less warping occurred when the width of
the adhesive portions was decreased.
[0068] 4) The results of examination of the degree of occurrence of
warping by setting the spacing between the adhesive portions to a
constant value of 4 mm and changing the width of the adhesive
portions to 2.5 mm, 5.0 mm, 1.0 mm, and 20 mm are shown in Table
4.
TABLE-US-00004 TABLE 4 Cut angle of end of composite sheet to
expansion and contraction direction 10.degree. 30.degree.
45.degree. 60.degree. 80.degree. a. Width of adhesive .smallcircle.
.smallcircle. .smallcircle. .smallcircle. portions; 2.5 mm b. Width
of adhesive .smallcircle. .smallcircle. .DELTA.~.smallcircle. x
portions; 5.0 mm c. Width of adhesive .smallcircle. .smallcircle. x
xx portions; 10 mm d. Width of adhesive .smallcircle. .smallcircle.
xx xx portions; 20 mm
[0069] Table 4 shows that less warping occurred when the width of
the adhesive portions was decreased. The spacing between the
adhesive portions was greater, so that the degree of warping was
lower overall when compared with the results shown in Table 3.
[0070] 5) The results of measurement of the degree of warping by
setting the spacing between adhesive portions to a constant value
of 7.5 mm and changing the width of the adhesive portions to 2.5
mm, 5.0 mm, 10 mm, and 20 mm are shown in Table 5.
TABLE-US-00005 TABLE 5 Cut angle of end of composite sheet to
expansion and contraction direction 10.degree. 30.degree.
45.degree. 60.degree. 80.degree. a. Width of adhesive .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .DELTA. portions; 2.5 mm
b. Width of adhesive .smallcircle. .smallcircle. .smallcircle.
.DELTA. x portions; 5.0 mm c. Width of adhesive .smallcircle.
.smallcircle. .DELTA.~.smallcircle. x xx portions; 10 mm d. Width
of adhesive .smallcircle. .smallcircle. x xx xx portions; 20 mm
[0071] Table 5 shows that warping less easily occurred when the
width of the adhesive portions was decreased. The spacing between
the adhesive portions was as great as 7.5 mm, so that the degree of
warping was lower overall when compared with the results shown in
Table 3 and Table 4.
[0072] From the foregoing results in 1) to 5), it was found that
the greater the spacing between the adhesive portions, the less
warping occurred. The spacing between the adhesive portions was
preferably not less than 4 mm. If the spacing was too great,
however, a space was noticeable at an end of the composite sheet.
Therefore, the spacing was preferably not more than 25 mm, although
it varied depending on a ratio of expansion and contraction.
Furthermore, it was found that the width of the adhesive portions
was preferably narrow.
[0073] While preferred embodiments of the present invention have
been described and illustrated above, it is to be understood that
they are exemplary of the invention and are not to be considered to
be limiting. Additions, omissions, substitutions, and other
modifications can be made thereto without departing from the spirit
or scope of the present invention. Accordingly, the invention is
not to be considered to be limited by the foregoing description and
is only limited by the scope of the appended claims.
* * * * *