Note: Descriptions are shown in the official language in which they were submitted.
CA 02213802 1997-08-22
WO 96/29038 PCT/I1S96102922
DISPOSABLE DIAPER
Field of the Invention
The present invention relates to a disposable diaper having an
absorbent part, a pair of ear parts projecting in opposite directions from the
side edges of one longitudinal end portion of the absorbent part, and one
fastening means provided on the oblique side edges of the ear parts,
respectively, and capable of effectively distributing tensile forces applied
to
the absorbent part by the fastening means around the waist and around the
legs to prevent the leakage of liquid excrements through spaces between
the edges of the disposable diaper and the wearer's waist and legs and of
giving-comfort to the wearer.
Back4round of the Invention
A generally known disposable diaper comprises an absorbent part for
covering the wearer's crotch, formed by sandwiching an absorbent core
between a top sheet and a back sheet, a pair of ear parts projecting in
opposite directions from the side edges of one longitudinal end portion of
the absorbent part so as to fap around the wearer's waist, and two fastening
means provided on the side edges of the ear parts, respectively. When
using this disposable diaper, the disposable diaper is put on the wearer in
an ordinary manner, and then the fastening means are attached to portions
of the absorbent part lapping around the waist, on the opposite sides of the
fastening means, respectively, to hold the disposable diaper on the wearer.
When thus put on the wearer, the disposable diaper must fit to the wearer's
waist and legs so that any spaces through which liquid excrements will leak
may not be formed between the disposable diaper and the wearer's waist
and legs. When putting the disposable diaper provided with the fastening
means provided on the side edges of the ear parts, respectively, on the
wearer, it is difficult to concentrate the tensile forces applied to the
absorbent part by the fastening means effectively on portions of the
absorbent part lapped around the wearer's waist and legs; that is, spaces
are formed around the wearer's legs if the disposable diaper is fitted to the
wearer's waist, or spaces are formed around the wearer's waist and the
disposable diaper cannot lap fitly around the wearer's waist if the
disposable diaper is fitted to the wearer's legs.
CA 02213802 2000-04-25 - . ,
wo ~o3s pcrws~oz9u
Various improvements have been proposed to solve such problems
and to improve the fit of a disposable diaper to the wearer's waist and legs.
Techniques for improving the fit of a disposable diaper to both the waist and
the legs are disclosed in U.S. Pat. No. 4,680,030 to Aled, et al., U.S. Pat.
No. 4,826,499 to Ahr and U.S. Pat. No. 4,937,887 to Schreiner, which use
two pairs of fastening means attached to a pair of ear parts projecting in
opposite directions from a portion of the disposable diaper to be lapped
around the waist, respectively. These prior art disposable diapers,
however, require troublesome work for handling the two pairs of fastening
means and there is room for improvement in those prior art disposable
diapers.
Techniques eliminated such a disadvantage are disclosed
in U.S. Pat. No. 4,911,702 to 0'Leary and U.S. Pat. No. 4,857067 to Wood,
which use two fastening means attached to two ear parts, respectively, and
capable of effectively concentrating the tensile forces applied thereto on
portions of the absorbent part lapped around the waist and the legs.
However, these techniques mention nothing about the positions of the two
fastening means to distribute the tensile forces applied to the two fastening
means
effectively and directly around the waist and the legs and about the
positions of the two fastening means to distribute the tensile forces applied
to the two fastening means around the waist and the legs at an intentionally
determined distribution ratio.
A disposable diaper disclosed in, for example, Japanese Utility Model
Laid-open (Kokai) No. 59-73305 has a main part, ear parts projecting in
opposite directions from the side edges of the main part, respectively, and
two fastening means attached to the side edges of the ear parts parallel to
the longitudinal axis of the main part respectively, so as to extend obliquely
to the transverse edge of the longitudinal end of a portion of the main part
on the back side to distribute the tensile forces applied to the main part by
the two fastening means effectively around the waist and the legs. Although
the two fastening means are attached to the ear parts, respectively, so as to
extend obliquely to the transverse edge of the longitudinal end of a portion
of the main part on the back side. the fastening means are pulled
involuntarily in a direction perpendicular to the side edges of the ear parts
because the fastening means are attached to the side edges of the ear
parts parallel to the longitudinal axis of the main part, respectively, and,
CA 02213802 2000-04-25
3
consequently, the tensile forces applied to the main part by the two fastening
means cannot be properly distributed around the waist and the legs at an
intended distribution ratio.
Summary of the Invention
Accordingly, it is a first object of an aspect of the present invention to
provide a disposable diaper having an absorbent part provided with fastening
means disposed so as to be pulled necessarily obliquely to the axis of the
disposable diaper and capable of effectively and directly concentrating
tensile
forces applied thereto on portions of the absorbent part lapped around the
waist and the legs, respectively.
A second object of an aspect of the present invention is to provide a
disposable diaper having an absorbent part provided with fastening means
disposed so that tensile forces applied thereto are distributed around the
waist and the legs at a desired distribution ratio, respectively.
A third object of an aspect of the present invention is to provide a
disposable diaper having an absorbent part having leg lapping sections to be
lapped around the legs, provided with elastic fitting members, respectively,
and fastening means disposed so that the tensile forces applied thereto are
concentrated effectively and directly on a portion of the absorbent part to be
lapped around the waist and on the elastic fitting members.
A fourth object of an aspect of the present invention is to provide
a disposable diaper having an absorbent part having a waist tapping section
and leg lapping sections to be lapped around the waist and the legs provided
with elastic fitting members, respectively, and fastening means disposed so
that the tensile forces applied thereto are concentrated effectively and
directly
on the elastic fitting members.
In a first aspect of the present invention, a disposable diaper
comprises: an absorbent part formed by sandwiching an absorbent core
between a top sheet and a back sheet so that the absorbent core may
correspond to a wearer's crotch when the disposable diaper is put on a
wearer, and having a first longitudinal end edge and a second longitudinal
end edge; a pair of ear parts projecting in opposite directions from opposite
CA 02213802 2000-04-25
4
side edges of one longitudinal end portion of the absorbent part on the side
of
the first longitudinal end edge, respectively; and one fastening means
attached to oblique side edges of the ear parts, respectively;
the oblique side edges of the ear parts to which the fastening means
are attached, respectively, being inclined so as to extend at a predetermined
angle to a longitudinal center axis of the absorbent part the fastening means
being attached to the oblique side edges of the ear parts so as to extend
perpendicularly to the corresponding oblique side edges, respectively, each
ear part having a stress relaxing structure, in which a tensile stress smaller
than that which is induced in a peripheral portion of the ear part is induced,
in
a portion thereof other than the peripheral portion, and each fastening means
being attached to the ear part in a pulling section of the oblique side edge
of
the ear part, overlapping at least part of a first side edge section on the
oblique side edge of the ear part, extending on the side of the first
longitudinal end edge of the absorbent part from an intersection point of the
oblique side edge and a first boundary line extending from a point on the
first
longitudinal end edge so as to be tangent to a point on the stress relaxing
structure on the side of the first longitudinal end edge, and part of a second
side edge section extending on the side of a lateral center axis of the
absorbent part perpendicular to the longitudinal center axis of the absorbent
part from the intersection point of the oblique side edge and a second
boundary line extending from a point on the side edge of the absorbent part
at which the lower end of the ear part joins to the absorbent part so as to be
tangent to a point on the stress relaxing structure on the side of the
transverse center line.
In a second aspect of the present invention, a disposable diaper
comprises: an absorbent part formed by sandwiching an absorbent core
between a top sheet and aback sheet so that the absorbent core may
correspond to a wearer's crotch when the disposable diaper is put on a
wearer, and having a first longitudinal end edge, a second longitudinal end
edge, a first waist lapping section contiguous with the first longitudinal end
edge, a second waist lapping section contiguous with the second longitudinal
CA 02213802 2000-04-25
end edge, and a crotch lapping section extending between the first and the
second waist lapping section; a pair of ear parts projecting from the opposite
side edges of the first waist lapping section of the absorbent part; and one
fastening means attached to oblique side edges of the ear parts, respectively;
the oblique side edges of the ear parts to which the fastening means
are attached, respectively, being inclined at a predetermined inclination to a
longitudinal center axis of the absorbent part, the fastening means being
attached to the oblique side edges of the ear parts so as to extend
perpendicularly to the corresponding oblique side edges, respectively, each
ear part having a stress relaxing structure, in which a tensile stress smaller
than that which is induced in a peripheral portion of the ear part is induced,
in
a portion other than the peripheral portion thereof, a portion of the first
waist
lapping section, extending on the side of the first longitudinal end edge from
a
first boundary line extending from a point on the first longitudinal end edge
so
as to be tangent to a point on the stress relaxing structure on the side of
the
first longitudinal end edge being a waist lapping component force distributing
region to which a component tensile force of a tensile force applied to the
fastening means acts directly, a section of the oblique side edge of the ear
part corresponding to the waist lapping component force distributing region
being a first oblique side edge section a portion of the first waist portion,
extending on the side of a crotch lapping section from a second boundary line
extending from a point on the side edge of the absorbent part at which the
lower end of the ear part joins to the absorbent part so as to be tangent to a
point on the stress relaxing structure on the side of the crotch lapping
section
being a leg lapping component force distributing region to which a component
tensile force of a tensile force applied to the fastening means acts directly,
a
section of the oblique side edge of the ear part corresponding to the leg
lapping component force distributing region being a second oblique side edge
section, and each fastening means being attached to the ear part in a pulling
section of the oblique side edge of the ear part, overlapping at least part of
the first side edge section and part of the second side edge section.
CA 02213802 2000-04-25
6
In a third aspect of the present invention, a disposable diaper
comprises; an absorbent part formed by sandwiching an absorbent core
between a top sheet and a back sheet so that the absorbent core may
correspond to a wearer's crotch when the disposable diaper is put on a
wearer, and having a first longitudinal end edge, a second longitudinal end
edge, a first waist lapping section contiguous with the first longitudinal end
edge, a second waist lapping section contiguous with the second longitudinal
end edge, and a crotch lapping section extending between the first and the
second waist lapping section; elastic leg fastening means extended along the
opposite side edges of the crotch lapping section of the absorbent part,
respectively; a pair of ear parts projecting from opposite side edges of the
first waist lapping section of the absorbent part; and one fastening means
attached to oblique side edges of the ear parts, respectively;
the oblique side edges of the ear parts to which the fastening means
are attached, respectively, being inclined at a predetermined inclination to
a longitudinal center axis of the absorbent part, the fastening means being
attached to the oblique side edges of the ear parts so as to extend
perpendicularly to the corresponding oblique side edges, respectively, each
ear part having a stress relaxing structure, in which a tensile stress smaller
than that which is induced in a peripheral portion of the ear part is induced,
in
a portion other than the peripheral portion thereof, a portion of the first
waist
lapping section, extending on the side of the first longitudinal end edge from
a
first boundary line extending from a point on the first longitudinal end edge
so
as to be tangent to a point on the stress relaxing structure on the side of
the
first longitudinal end edge being a waist lapping component force distributing
region to which a component tensile force of a tensile force applied to the
fastening means acts directly, a section of the oblique side edge of the ear
part corresponding to the waist lapping component force distributing region
being a first oblique side edge section, a portion of the first waist portion,
extending on the side of the crotch lapping section from a second boundary
line extending from one end of the leg fastening means on the side of the
first
longitudinal side edge so as to be tangent to a point on the stress relaxing
CA 02213802 2000-04-25
structure on the side of the crotch lapping section being a leg lapping
component force distributing region to which a component tensile force of a
tensile force applied to the fastening means acts directly, a section of the
oblique side edge of the ear part corresponding to the leg lapping component
force distributing region being a second oblique side edge section, and each
fastening means being attached to the ear part in a pulling section of the
oblique side edge of the ear part, overlapping at least part of the first side
edge section and part of the second side edge section.
In a fourth aspect of the present invention, a disposable diaper
comprises; an absorbent part formed by sandwiching an absorbent core
between a top sheet and a back sheet so that the absorbent core may
correspond to a wearer's crotch when the disposable diaper is put on a
wearer, and having a first longitudinal end edge, a second longitudinal end
edge, a first waist lapping section contiguous with the first longitudinal end
edge, a second waist lapping section contiguous with the second longitudinal
end edge, and a crotch lapping section extending between the first and the
second waist lapping section; elastic waist fastening means extended along
the first longitudinal end edge in the first waist lapping section; a pair of
ear
parts projecting from opposite side edges of the first waist lapping section
of
the absorbent part; and one fastening means attached to oblique side edges
of the ear parts, respectively;
the oblique side edges of the ear parts to which the fastening means
are attached, respectively, being inclined at a predetermined inclination to a
longitudinal center axis of the absorbent part, the fastening means being
attached to the oblique side edges of the ear parts so as to extend
perpendicularly to the corresponding oblique side edges, respectively, each
ear part having a stress relaxing structure, in which a tensile stress smaller
than that which is induced in a peripheral portion of the ear part is induced
in
a portion other than the peripheral portion thereof, a portion of the first
waist
lapping section, extending on the side of the first longitudinal end edge from
a
first boundary line extending from one end of the elastic waist fastening
means on the side of the ear part so as to be tangent to a point on the stress
CA 02213802 2000-04-25
g
relaxing structure on the side of the first longitudinal end edge being a
waist
lapping component force distributing region for directly applying a component
tensile force of a tensile force applied to the fastening means to the one end
of the elastic waist fastening means, a section of the oblique side edge of
the
ear part corresponding to the waist lapping component force distributing
region being a first oblique side edge section, a portion of the first waist
lapping portion, extending on the side of the crotch lapping section from a
second boundary line extending from a point on a side edge of the ear part
on the side of the crotch lapping section so as to be tangent to a point on
the
stress relaxing structure on the side of the crotch lapping section being a
leg
lapping component force distributing region for directly applying a component
tensile force of a tensile force applied to the fastening means to the point
on
the side edge of the ear part on the side of the crotch lapping section, a
section of the oblique side edge of the ear part corresponding to the leg
lapping component force distributing region being a second oblique side edge
section, and each fastening means being attached to the ear part in a pulling
section of the oblique side edge of the ear part, overlapping at least part of
the first side edge section and part of the second side edge section.
In a fifth aspect of the present invention, a disposable diaper
comprises an absorbent part formed by sandwiching an absorbent core
between a top sheet and a back sheet so that the absorbent core may
correspond to a wearer's crotch when the disposable diaper is put on a
wearer, and having a first longitudinal end edge, a second longitudinal end
edge, a first waist lapping section contiguous with the first longitudinal end
edge, a second waist lapping section contiguous with the second longitudinal
end edge, a crotch lapping section extending between the first and the
second waist tapping section; elastic leg fastening means extended along
opposite longitudinal side edges of the crotch lapping section; elastic waist
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8a
fastening means extended along the first longitudinal end edge of the
absorbent part in the first waist lapping section; a pair of ear parts
attached
the first waist lapping section of the absorbent part; and one fastening means
attached to oblique side edges of the ear parts, respectively;
the oblique side edges of the ear parts to which the fastening means
are attached, respectively, being inclined at a predetermined inclination to a
longitudinal center axis of the absorbent part, the fastening means being
attached to the ear parts so as to extend perpendicularly to the corresponding
oblique side edges, respectively, each ear part having a stress relaxing
structure, in which a tensile stress smaller than that which is induced in a
peripheral portion of the ear part is induced, in a portion thereof other than
the peripheral portion, a portion of the first waist lapping section,
extending on
the side of the first longitudinal end edge from a first boundary line
extending
from one end of the elastic waist fastening means on the side of the ear part
so as to be tangent to a point on the stress relaxing structure on the side of
the first longitudinal end edge being a waist lapping component force
distributing region for directly applying a component tensile force of a
tensile
force applied to the fastening means to the one end of the elastic waist
fastening means, a section of the oblique side edge of the ear part
corresponding to the waist lapping component force distributing region being
a first oblique side edge section, a portion of the first waist portion,
extending
on the side of the crotch lapping section from a second boundary line
extending from one end of the elastic leg fastening means on the side of the
first longitudinal side edge so as to be tangent to a point on the stress
relaxing structure on the side of the crotch lapping section being a leg
lapping
component force distributing region for directly applying a component tensile
force of a tensile force applied to the fastening means to the one end of the
elastic leg fastening means, a section of the oblique side edge of the ear
part
corresponding to the leg lapping component force distributing region being a
second oblique side edge section, and each fastening means being attached
CA 02213802 2000-04-25
8b
to the ear part in a pulling section of the oblique side edge of the ear part,
overlapping at least part of the first side edge section and part of the
second
side edge section.
The oblique side edges of the ear parts of the disposable diaper in
accordance with the present invention are inclined at the predetermined
angle to the longitudinal center axis of the disposable diaper, and the
fastening means are disposed on the oblique side edges so as to extend
substantially perpendicular to the oblique side edges, respectively:
consequently, each fastening means is pulled invariably in a fixed direction
relative to the corresponding oblique side edge of the ear part and
appropriate tensile force is distributed to the portions of the absorbent part
lapped around the legs.
When the inclination of the oblique side edge of the ear part, i.e., the
angle as measured counterclockwise from a line parallel to the longitudinal
center axis of the disposable diaper to the oblique side edge is in a range
defined by: 0 < angle < 45, a major part of a tensile force applied to the
fastening means can be distributed to the leg lapping section and a minor
part of the same can be distributed to the waist lapping section, and a major
part of a tensile force applied to the fastening means can be distributed to
the
waist lapping section and a minor portion of the same can
CA 02213802 1997-08-22
WO 96!29038 PCT/US96/02922
9
be distributed to the leg lapping section when 45 .
The stress relaxing structure of the ear part absorbs the tensile force
applied thereto, and the peripheral portion of the ear part transmits the
tensile force directly to the absorbent part, so that the tensile force
applied
to the fastening means can be effectively and directly applied to the waist
lapping section and the leg lapping section of the absorbent part.
Attachment of the fastening means to the oblique side edge of the
ear part in the pulling section overlapping at least part of the first oblique
side edge section and the second oblique side edge section defined in
positional connection with the absorbent part and the stress relaxing
structure of the ear part ensures the application of the tensile force applied
to the fastening means to part of the longitudinal end edge of the absorbent
part on the side of the first waist lapping section or to part of the edge of
the
ear part on the side of the transverse center axis of the disposable diaper.
The tensile force that acts on part of the longitudinal end edge of the
absorbent part on the side of the first waist lapping section or on part of
the
edge of the ear part on the side of the transverse center axis of the
disposable diaper can be adjusted by adjusting the degree of overlap of the
pulling section in which the fastening means is attached to the ear part with
the first oblique side edge section or the second oblique side edge section.
A major part of the tensile force applied to the fastening means is applied to
the first waist lapping section when the degree of overlap of the pulling
section with the first oblique side edge section is greater than that with the
second oblique side edge section, and to a portion of the end edge of the
ear part on the side of the transverse center axis of the disposable diaper
when degree of overlap of the pulling section with the first oblique side edge
section is smaller than that with the second oblique side edge section.
When the first oblique side edge section or the second oblique side
edge section is defined in positional connection with the point where the line
extending from the end of the elastic waist fastening means or the elastic
leg fastening means so as to be tangent to the stress relaxing structure
intersects the oblique side edge of the ear part, the application of the
tensile
force applied to the fastening means to the elastic waist fastening means
and the elastic leg fastening means is ensured.
The above and other objects, features and advantages of the present
invention will become more apparent from the following description taken in
connection with the accompanying drawings.
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WO 96/29038 PCTfUS96/02922
Brief description of the Drawings
Fig. 1 is a development of a disposable diaper in accordance with the
present invention;
Fig. 2 is a fragmentary sectional view of a absorbent part of a
disposable diaper in accordance with the present invention;
Fig. 3 is a fragmentary sectional view of a ear part;
Fig. 4 is a plan view of a stress relaxing structure in a first example
included in a disposable diaper in accordance with the present invention;
Fig. 5 is a stress relaxing structure in a second example included in a
disposable diaper in accordance with the present invention;
Fig. 6 is a stress relaxing structure in a third example included in a
disposable diaper in accordance with the present invention;
Fig. 7 is a stress relaxing structure in a fourthexample included in a
disposable diaper in accordance with the present invention;
Fig. 8 is a typical side view of assistance in explaining a stress
relaxing structure forming device;
Fig. 9 is a plan view of a forming plate of the stress relaxing structure
forming device;
Fig. 10 is a fragmentary perspective view of a stress relaxing
structure formed by the stress relaxing structure forming device of Fig. 8;
Fig. 11 is a fragmentary perspective view of a formed intermediate
film shown in Fig. 10, in a half stretched state;
Fig. 12 is a fragmentary perspective view of the formed intermediate
film shown in Fig. 10 in a fully stretched state;
Fig. 13 is a fragmentary development of a disposable diaper in
accordance with the present invention, for assistance in explaining the
distribution of a tensile force applied to a fastener at a predetermined
distribution ratio;
Fig. 14 is a fragmentary development of a disposable diaper in
accordance with the present invention, for assistance in explaining the
distribution of a major part and a minor part of a tensile force applied to a
fastener to a waist lapping section and a leg lapping section, respectively,
of the disposable diaper;
Fig. 15 is a fragmentary development of a disposable diaper in
accordance with the present invention, for assistance in explaining the
distribution of a minor part and a major part of a tensile force applied to a
fastener to a waist lapping section and a leg lapping section, respectively,
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WO 96/29038 PCT/US96/02922
11
of the disposable diaper;
Fig. 16 is a fragmentary development of assistance in explaining a
first oblique side edge section a and a second oblique side edge section b;
Fig. 17 is a fragmentary development of assistance in explaining the
dependence of the distribution of a tensile force on the position of a
fastener on an ear part;
Fig. 18 is a fragmentary development of assistance in
explaining the distribution of a tensile force applied to a fastener;
Fig. 19 is a fragmentary development of assistance in explaining a
method of determining a first oblique side edge section;
Fig. 20 is a fragmentary development of assistance in explaining
another method of determining a first oblique side edge section;
Fig. 21 is a fragmentary development of assistance in explaining the
positional relation of a first oblique side edge section a and a second
oblique side edge section b with a stress relaxing structure formed in a
disposable diaper in accordance with the present invention;
Fig. 22 is a fragmentary development of assistance in explaining the
positional relation of a first oblique side edge section a and a second
oblique side edge section b with a stress relaxing structure formed in a
disposable diaper in accordance with the present invention;
Fig. 23 is a fragmentary development of assistance in
explaining a first oblique side edge section a and a second oblique side
edge section b of an oblique side edge of an ear part of a disposable diaper
in accordance with the present invention; and
Fig. 24 is a fragmentary development of an ear part in another
example.
Description of the Preferred Embodiments
In the following description, terms expressing positions, directions
and the like indicate those as viewed in the drawings.
Referring to Fig. 1 a disposable diaper 1 in a first embodiment
according to the present invention has a first waist lapping section 2a, a
crotch lapping section 2b and a second waist lapping section 2c, and
comprises an absorbent part formed substantially .in a rectangular shape an
hourglass shape, a T-shape, an asymmetric shape or such, side flaps 4
formed in the opposite side portions of the absorbent part 3, respectively,
elastic members 5 longitudinally extended in the flaps 4 to provide the flaps
4 with elasticity, a pair of ear parts 6 projecting in opposite directions
from
CA 02213802 2000-04-25
WO 96~I9038 PCT/OS96/02922
1?
the opposite side edges of the upper end partion of the first waist lapping
section 2a of the absorbing part 3, respectively, and two fasteners 7
attached to the oblique side edges 6a of the ear parts 6, respectively.
Each ear part 6 has a slightly oblique upper edge 6b declining at a
predetermined angle to the upper edge 1 a parallel to the transverse center
axis of the disposable diaper 1, an oblique side edge 6a extending obliquely
downward from the outer end of the upper edge 6b, and an oblique lower
edge 6c extending from the outer end of the oblique side edge 6a to the
side edge of the absorbent part 3. The fastener 7 is attached to the ear part
6 so as to extend substantially perpendicularly to the oblique side edge 6a
from the oblique side edge fia. The inclination , i.e., the angle, as
measured in a counterclockwise direction, between the oblique side edge
fia and a vertical line passing the intersection point of the upper side edge
6b and the oblique side edge 6a and parallel to the longitudinal center axis
L-L' of the disposable diaper 1 meets an inequality: 0 < angle < 45. The
tensile
force distribution ratio, i.e., the ratio between a component of a tensile
force
applied to the fastener 7 distributed to a portion of the absorbent part 3
lapped around the waist and the waist lapping section and a component of
the tension force distributed to a portion of the absorbent part 3 lapped
around the leg, is dependent on the inclination . For example, it is possible
to distribute a major component of the tensile force to the portion of the
absorbent part 3 lapped around the leg and a minor component of the same
to a portion of the absorbent part 3 lapped around the waist by properly
determining the inclination .
Referring to Fig. 2 showing a sectional view taken on line A-A in Fig
1, .the absorbent part 3 is formed by sandwiching an absorbent core 9
between a liquid-permeable top sheet 8 and a liquid-impermeable back
sheet 10. The top sheet 8 and the back sheet 10 have a length and a width
greater than those of the absorbent core 9. At least portions of the top
sheet 8 and the back sheet 10. corresponding to the crotch lapping section
2b and extending outward beyond each longitudinal side edge of the
absorbent core 9 form a side flap 4, and elastic members 5 are extended
longitudinally in the side flap 4 to provide the side flap with elasticity.
The
absorbent core 9 is unirritative to the skin and capable of absorbing and
holding liquid excrements including urine. Generally, the absorbent core 9
is formed of crushed wood pulp generally cold cotton pulp. The absorbent
core 9 may be formed in any suitable shape and construction as occasion
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WO 96!29038 PCTlUS96/02922
13
demands. The total absorption of the absorbent core 9 must correspond to a
design charge and a desired use. The size and the absorbing ability of the
absorbent core 9 are dependent on the wearer's age.
The back sheet 10 prevents wetting an article, such as a bed sheet
or underwear, that comes into contact with the disposable diaper 1 with
excrements absorbed and held by the absorbent core 9. The back sheet 10
is a film of a thermoplastic polymer, such as a polyethylene film, a
polypropylene film or the like, or a film of a composite material, such as
film-
coated nonwoven fabric. Preferably, the back sheet 10 is an embossed
thermoplastic film simulating fabric. The top sheet 8 is is a porous foam
sheet, a meshed foam sheet, a perforated plastic film or a woven or
nonwoven fabric of a natural textile material, such as wood fibers or cotton
fibers, a synthetic textile material, such as polyester fibers or
polypropylene
fibers, or a blended textile material, such as a blend of a natural textile
material (or natural textile materials) and a synthetic textile material (or
synthetic textile materials). Preferably, the top sheet 8 is formed of a
hydrophobic material to separate the liquid absorbed by the absorbent core
9 from the wearer's skin.
The ear parts 6 having a substantially trapezoidal shape are joined to
the opposite side edges of the first waist lapping section 2a of the
rectangular absorbent part 3, respectively, by a known method, such as
heat-sealing or adhesive bonding. The ear parts 6 may be formed integrally
with the absorbent part 3 by projecting the respective upper side portions of
the top sheet 8 and the back sheet 10 outward in lugs having the shape of
the ear parts 6, and directly joining together the projecting lugs of the top
sheet 8 and the back sheet 10. The absorbent part 3 and the ear parts 6
may be formed in an integral structure by cutting a laminated sheet formed
by sandwiching a sheet between the top sheet 8 and the back sheet 10 in
desired dimensions. Preferably, the ear parts 6 are formed by laminating a
nonwoven fabric 11 of natural fibers; synthetic fibers or a blend of natural
fibers and synthetic fibers, a thermoplastic film 13 of polyethylene or
polypropylene, and a porous film 12 formed by a known process and
sandwiched between the nonwoven fabric 11 and the thermoplastic film 13
by adhesive layers 14 and 15 as shown in Fig. 3. When each of the ear
parts 6 is formed of an extension of the top sheet 8 and an extension of the
back sheet 10, the nonwoven fabric 11 and the thermoplastic film 13
correspond to the extension of the top sheet 8 and the extension of the back
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14
sheet 10, respectively. The porous film 12 sandwiched between the
nonwoven fabric 11 and the thermoplastic film 13 provides the ear parts 6
with firmness, which facilitates handling the ear parts 6 when putting the
disposable diaper 1 on the wearer.
As shown in Fig. 6, the ear parts 6 have each a substantially
trapezoidal stress relaxing structure 20 in their inner portions excluding the
.
peripheral portions. The stress relaxing structure 20 may be formed in a
substantially trapezoidal shape having longitudinal gaps 20a as shown in
Fig. 4 or in a substantially trapezoidal shape having transverse gaps 20b as
shown in Fig. 5. The stress relaxing structure 20 may be formed in any
suitable shape other than a trapezoidal shape, such as a triangular shape, a
rectangular shape, a shape of a part of an ellipse or a shape of a part of a
circle, provided that the stress relaxing structure 20 has a function to relax
stress. The stress relaxing structure 20 of the ear part 6 may be ari
aggregate of a plurality of longitudinal slits 21 a formed in the laminated
sheet forming the ear part 6 as shown in Fig. 6. The stress relaxing
structure 20 may be a single slit 21 a provided that the single slit 21 a is
capable of intercepting the transmission of a tensile force applied to the ear
part 6 to the absorbent part 3. As shown in Fig. 7, the ear part 6 may be
formed in an elastic structure, and a strip of an unstretchable film or an
unstretchable strand 30 may be attached to a peripheral portion of the
elastic structure excluding an inner trapezoidal elastic portion
corresponding to the stress relaxing structure 20 to use the inner
trapezoidal elastic portion as the stress relaxing structure 20.
When a tensile force is applied to the ear part 6, a tensile stress
induced in the stress relaxing structure 20 is smaller than that which is
induced in the peripheral portion of the ear part 6 surrounding the stress
relaxing structure 20. Tensile stress is a resistive force developed by a
material bearing a tensile load. Therefore, "a structure having a small
tensile stress" is a structure yielding to and easily stretchable by a
comparatively small tensile force. Structures expressed by the term "stress
relaxing structure" include a vacancy formed in the ear part 6 and virtually
serving as a stress relaxing structure 20. '
Preferably, the stress relaxing structure 20 is formed by the following
method. As shown in Fig. 8, a sheet 21 to form the ear part 6 is
compressed between a plate 22 provided with a plurality of ridges 22a in an
area of the inner surface thereof corresponding to the stress relaxing
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structure 20, and a plate 23 provided with a plurality of ridges 23a in an
area of the inner surtace thereof corresponding to the stress relaxing
structure 20. As shown in Fig. 9, narrow grooves 25a are formed across the
plurality of ridges 23a of the plate 23. The plurality of ridges 22a of the
plate 22 are continuous and not interrupted. As shown in Fig. 10, the stress
relaxing structure 20 formed by thus compressing the sheet 21 between the
plates 22 and 23 has a plurality of undeformed sections 25, a plurality of
permanently deformed sections 26, and transitional sections 27 between the
undeformed sections 25 and the permanently deformed sections 26. Ridges
28 are formed in the permanently deformed sections 26. The undeformed
sections 25 are defined by the narrow grooves 25a of the plate 23 and the
corresponding portions of the ridges 22a of the plate 22, and the
permanently deformed sections 26 are defined by the respective ridges 22a
and 23a of the plate 22 and the plate 23.
When the ear part 6 is tensioned by forces acting in the directions
of the arrows E as shown in Fig. 10, the undeformed sections 25 are
plastically stretched to some extent as shown in Fig. 11 and, as the
undeformed sections 25 are further stretched, the ridges 28 of the
permanently deformed sections 26 are flattened as shown in Fig. 12 and
the ear part 6 cannot be stretched any further. When the sheet 21 having
such characteristics is a laminated sheet, at least one of the component
layer of the sheet 21 is formed of a stretchable film, such as a polyolefin
film, a low-density linear polyethylene film, a fow-density polyethylene film.
a high-density polyethylene film or a polypropylene film.
The stress relaxing structure 20 that can be stretched by a small
tensile force is thus formed in the sheet 21 forming the ear part 6. Since the
periphery of the sheet 21 surrounding the stress relaxing structure 20 is
unprocessed, the periphery of the sheet 21 does not yield to tension when
the sheet 21 is tensioned or the periphery is harder to stretch than the
stress
relaxing structure 20. When tensioned, the stress relaxing structure 20 yields
to the tensile force to absorb the tensile force and does not cause the
peripheral portion of the ear part 6 to shrink.
The sheet 21 forming the ear part 6 may be formed of a somewhat
stretchable material. When formed of such a somewhat stretchable material,
the stress relaxing structure 20 can be formed in the sheet 21 by the
aforesaid process. In either case, the stress relaxing structure 20 can be
stretched by a tensile force smaller than that necessary for stretching the
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16
peripheral portion of the ear part 6.
As shown in Fig. 13, when a tensile force D is applied to the fastener
7 in a direction perpendicular to the oblique side edge 6a of the ear part fi,
the stress relaxing structure 20 of the ear part 6 serves to divide the
tensile
force D into a component tensile force D1 acting on the waist lapping
portion and a component tensile force D2 acting on the leg lapping portion.
That is, since a tensile force greater than that necessary for stretching the
stress relaxing structure 20 must be applied to the peripheral portions of the
ear part 6 to stretch the peripheral portion, most part of the tensile force
applied to the fastener 7 is divided into the component tensile forces D1 and
D2, and the component tensile forces D1 and D2 act directly on regions X
and Z of the absorbent part 3, respectively. Even if part of the tensile force
D acts on the stress relaxing structure 20, the stress relaxing structure 20
is
not stretched in a extreme state as shown in Fig. 12 because the stress
. . relaxing structure 20 can be stretched by a comparatively small tensile
force
and the peripheral portion surrounding the stress relaxing structure 20
cannot be virtually stretched. Thus, the stretchable stress relaxing structure
'. 20 absorbs the tensile force that acts thereon and, consequently, any
. tensile force is not transmitted directly to a region Y of the absorbent
part 3.
~ Thus the tensile force D applied to the fastener 7 is divided into the
component tensile force D1 acting on the waist lapping portion of the
absorbent part 3 and the component tensile force D2 acting on the leg
lapping portion of the absorbent part 3 to fasten the absorbent part 3 around
the waist and the leg.
The fastener 7 is attached to the oblique side edge 6a of the ear part
6 so as to extend perpendicularly to the oblique side edge 6a. and the
fastener 7 is pulled in a direction perpendicular to the oblique side edge 6a.
Since the fastener 7 is pulled necessarily in a direction perpendicular to the
oblique side edge 6a of the ear part 6, the direction in which the fastener 7
is pulled with respect to the absorbent part 3 is dependent on the inclination
- of the oblique side edge 6a, which may be varied in the range of p < angle <
45.
That is, since the fastener 7 is pulled in a fixed direction with respect to
the
oblique side edge 6a, the difference between the component tensile forces
D1 and D2 is not very large when the inclination of the oblique side edge
fia is small, and the ratio of the component tensile force D2 to the
component tensile force D1 increases with the increase of the inclination
of the oblique side edge fia. The division of the tensile force D applied to
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17
the fastener 7 into the component tensile forces D1 and D2 cam be adjusted
by adjusting the position of a pulling section R where the fastener 7 is
attached to the oblique side edge 6a of the ear part 6. When the pulling
section R corresponds substantially to the middle of the side edge of the
stress relaxing structure 20 as shown in Fig. 13, the tensile force D applied
to the fastener 7 in the direction of the arrow is divided into the component
tensile forces D1 and D2, and the component tensile force D2 that acts
around the leg is greater than the component tensile force D1 that acts
around the waist by a predetermined value. When the pulling section R is
at a position shown in Fig. 14 below the position of the pulling section R
shown in Fig. 13, the tensile force D applied to the fastener 7 in the
direction of the arrow is divided into the component tensile forcesD1 and
D2, the component tensile force D1 that acts around the waist is
comparatively large and the component tensile force D2 that acts around
the leg is comparatively small.
The position of the pulling section R and the positional relation
between the same and other parts to distribute the tensile force applied to
the fastener 7 surely to desired portions of the absorbent part 3 will be
described below. The position of the pulling section R for the fastener 7 on
the oblique side edge 6a is determined by construction shown in Fig. 16
The position of the pulling section R is important for effectively and
directly
distributing a tensile force applied to the fastener 7 to a desired waist
lapping portion and a desired leg lapping portion of the disposable diaper 1
Referring to Fig. 16, a line L-L' indicates the longitudinal center axis of
the
disposable diaper 1 and a line H-H' indicates the transverse center axis of
the disposable diaper 1 perpendicular to the longitudinal center axis L-L'
Indicated at P is the intersection point of the longitudinal center axis L-L'
and the upper edge 1 a of the first waist lapping section 2a, at Q is the
intersection point of the lower side edge 6c of the ear part 6 on the side of
the transverse center line H-H' and the side flap 4, at L1 is a line extending
from the intersection point P so as to be tangent to a point on the stress
relaxing structure 20 on the side of the upper edge 1 a, at L2 is a line
extending from the intersection point Q so as to be tangent to a point on the
stress relaxing structure 20 on the side of the transverse center axis H-H',
at
A is the intersection point of the line L1 and the oblique side edge 6a, and
at B is the intersection point of the line L2 and the oblique side edge 6a. A
first oblique side edge section a extends on the side of the upper edge 1 a
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18
from the intersection point A, and a second oblique side edge section b
extends on the side of the transverse center axis H-H' from the intersection
point B.
A tensile force D applied to the oblique side edge 6a by the fastener
7 is distributed in the ear part 6 as shown in Fig. 17. In Fig. 17, a point M
of
action of the tensile force applied to the fastener 7 is in the pulling
section R .
in which the fastener 7 is attached to the oblique side edge 6a and
coincides with the intersection point A in this example. When part of a
tensile force applied to the fastener 7 acts on the oblique side edge 6a at
the point M of action, the part of the tensile force is decomposed into
representative component forces F1, F2, F3 and F4 as shown in Fig. 18.
The component force F1 is directed toward the upper edge 1 a and not
directly toward the intersection point P. Therefore, the component force F1
does not act directly on the intersection point P. The direction of the
component force F2 is aligned with the line L1 and hence the component
force F2 acts directly on the intersection point P. The component force F3
is directed toward the stress relaxing structure 20 and tends to stretch the
stress relaxing construction 20. However, since the stress relaxing
structure 20 absorbs the force applied thereto, the component force F3 is
not transmitted to the region Y of the absorbent part 3 shown in Fig. 13.
The component force F4 is directed toward the intersection point Q and acts
directly on the absorbent part 3 at the intersection point Q.
If the point M of action in the pulling section R in which the fastener 7
is attached to the oblique side edge 6a is on the side of the transverse
center axis H-H' with respect to the intersection point A, i.e., at a point M'
outside the first oblique side edge section a (Fig. 16), the component force
F2 directed from the point M' toward the intersection point P is absorbed by
the stress relaxing structure 20 and is ineffective. Therefore, no component
force acts directly on the intersection point P if the point M of action of
the
tensile force applied to the fastener 7 on the oblique side edge 6a is at the
point M'. If the point M action is shifted to a point M" on the side of the
upper
edge 1 a with respect to the intersection point A shown in Fig. 17, i.e., if
the _
point M of action is in the first oblique side edge section a, some component
force acts directly on the intersection point P.
As is obvious from the foregoing explanation, the line L1 is a boundary
line between positions for the point M of action that enables the direct
action
of a component force of the tensile force applied to the fastener 7 on the
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19
intersection point P and those for the point M of action that disables the
direct
action of the component force on the intersection point P. When the point M
of action at which the tensile force applied to the fastener 7 acts on the ear
part 6 is in the first oblique side edge section a, at least part of the
tensile
force applied to the point M of action is able to act directly on the
intersection
point P. The line L2 drawn in connection with the intersection point Q is a
boundary line between positions for the point M of action that enables the
direct action of a component force of the tensile force applied to the
fastener
7 on the intersection point Q. When the point M of action at which the tensile
force applied to the fastener 7 acts on the ear part 6 is in the second
oblique
side edge section b, at least part of the tensile force applied to the point M
of
action is able to act directly on the intersection point Q. Accordingly, part
of
the tensile force applied to the fastener 7 can be applied directly on the
desired points P and Q on the absorbent part 3 when the pulling section R in
which the fastener 7 is attached to the oblique side edge 6a of the ear part 6
overlaps part of the first oblique side edge section a defined by the line L1
and part of the second oblique side edge section b defined by the line L2.
Since the intersection point P is on the longitudinal center line L-L' of the
disposable diaper 1, the waist lapping portion of the disposable diaper 1 can
be firmly fastened around the waist by applying tensile forces to the two ear
parts 6, when part of each of the tensile forces can be applied directly to
the
intersection point P. When part of the tensile force applied to each fastener
7 can be directly applied to the intersection point Q, the leg lapping portion
of
the absorbent part 3 can be firmly fastened around the leg. Since the
fastener 7 is attached to the oblique side edge 6a of the ear part 6 in the
pulling section R so as to extend perpendicularly to the oblique side edge 6a,
the direction in which a tensile force is applied to the fastener 7 with
respect
to the absorbent part 3 is dependent on the inclination of the oblique side
edge 6a and the tensile force applied to each fastener 7 can be distributed in
directions toward the waist lapping portion and the leg lapping portion at a
predetermined distribution ratio.
As shown in Fig. 19, in a disposable diaper 1 in a second
embodiment according to the present invention, a line L1 is extended from
the intersection point P', which corresponds to the intersection point P in
the
first embodiment, of the upper edge 1 a of an absorbent part 3 and the side
edge 31 of the absorbent part 3 parallel to the longitudinal center axis L-L'
of the disposable diaper 1 so as to be tangent to a stress relaxing structure
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20, a line L2 is extended from the intersection point Q of the lower end of an
ear part 6 and a flap 4 extended along the side edge 31 of the absorbent
part 3, the line L1 intersects the oblique side edge 6a of the ear part 6 at
an
intersection point A, which corresponds to the intersection point A in the
first
embodiment, and the line L2 intersects the oblique side edge 6a at an
intersection point B, which corresponds to the intersection point B in the
first
embodiment.
The respective magnitudes of a component tensile force D1 for
fastening the waist lapping portion of the absorbent part 3 around the waist
and a component tensile force D2 for fastening the leg lapping portion of the
absorbent part 3 around the leg are determined by adjusting the ratio of the
size of a portion of the pulling section R, in which a fastener 7 is attached
to
the oblique side edge 6a, overlapping the first oblique side edge section a
to the size of the pulling section R, and the ratio of the size of a portion
of
the pulling section R overlapping the second oblique side edge section b to
the size of the pulling section R. The greater the portion of the pulling
section R, overlapping the first oblique side edge section a, the greater is
the ratio of the component tensile force D1 that acts on the intersection
point P' to the tensile force applied to the fastener 7. An area defined by
the line L1, the upper side edge 6b of the ear part 6 and the oblique side
edge 6a of the ear part 6 is a waist lapping portion fastening component
force distributing area 40, and a portion of the oblique side edge 6a
associated with the waist lapping portion fastening component force
distributing area 40 is a first oblique side edge section a. As long as part
of
the pulling section R in which the fastener 7 is attached to the oblique side
edge 6a overlaps the first oblique side edge section a, a component tensile
force of the tensile force applied to the fastener 7 acts directly on the
intersection point P'. The greater the portion of the pulling section R,
overlapping the first oblique side edge section a, the greater is the
component tensile force D1 distributed to the waist lapping portion fastening
component force distributing area 40.
On the other hand, the greater the portion of the pulling section R,
overlapping the second oblique side edge section b, the greater is the
component tensile force D2 that acts directly on the intersection point Q. An
area defined by the line L2, the lower side edge 6c of the ear part 6 and the
oblique side edge 6a of the ear part 6 is a leg lapping portion fastening
component force distributing area 41, and a portion of the oblique side edge
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21
6a associated with the leg lapping portion fastening component force
distributing area 41 is a second oblique side edge section b. As long as
part of the pulling section R overlaps the second oblique side edge section
b. a component tensile force of the tensile force applied to the fastener 7
acts directly on the intersection point Q. The greater the portion of the
_pulling section R, overlapping the second oblique side edge section b, the
greater is the component tensile force D2 distributed to the leg lapping
portion fastening component force distributing area 41.
The ratio between the component tensile force D1 distributed to the
waist lapping portion fastening component force distributing area 40 and
the component tensile force D2 distributed to the leg lapping portion
fastening component force distributing area 41 can be adjusted by
adjusting the the ratio of the size of a portion of the pulling section R, in
which a fastener 7 is attached to the oblique side edge 6a, overlapping the
first oblique side edge section a to the size of the pulling section R, and
the ratio of the size of a portion of the pulling section R overlapping the
second oblique side edge section b to the size of the pulling section R.
When the pulling section R, in which the fastener 7 is attached to the
oblique side edge 6a, overlaps the first oblique side edge section a
entirely and overlaps the second oblique side edge section b partly, a
major part of the tensile force applied to the fastener 7 is distributed to
the
waist lapping portion fastening component force distributing area 40.
When the pulling section R overlaps the second oblique side edge section
b entirely and overlaps the first oblique side edge section a partly, a major
part of the tensile force applied to the fastener 7 is distributed to the leg
lapping portion fastening component force distributing area 41. The
pulling ,section R in which the fastener 7 is attached to the oblique side
edge 6a need not necessarily be included in either the first oblique side
edge section a or the second oblique side edge section b, provided that
pulling section R overlaps the first oblique side edge section a and the
second oblique side edge section b at different overlapping ratios,
respectively.
The fastener 7 is attached to the oblique side edge 6a in the pulling
section R so as to extend perpendicularly to the oblique side edge 6a, so
that the tensile force applied to the fastener 7 acts in a direction oblique
to
the longitudinal center axis L-L' of the disposable diaper 1, and the tensile
forces applied to the two fasteners 7 attached to the ear parts 6 can be
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distributed to the waist lapping portion and the leg lapping portions at a
predetermined distribution ratio.
Figs. 21 and 22 show the dependence of the relation between the
first oblique side edge section a and the second oblique side edge section b
on the position of a stress relaxing structure 20 in an ear part 6 in a
disposable diaper 1 in a third embodiment according to the present
invention. Referring to Fig. 21, the stress relaxing structure 20 has a shape
resembling a rectangle, which is different from the shape of the stress
relaxing structure 20 shown in Fig. 16. In the third embodiment, the line L1
extending from the intersection point P so as to be tangent to the stress
relaxing structure 20 and the fine L2 extending from the intersection point Q
so as to be tangent to the stress relaxing structure 20 do not intersect each
other within the ear part 6. The lines L1 and L2 intersect the oblique side
edge 6a at intersection points A and B, respectively. A first oblique side
edge section a extends on the side of the upper edge 1 a of an absorbent
part 3 from the intersection point A, a second oblique side edge section b
extends on the side of the transverse center axis H-H' of the absorbent part
3 from the intersection point B, and a neutral section 33 connected with
neither the waist lapping portion fastening component force distributing area
40 nor the leg portion fastening component force distributing area 41 is
formed between the first oblique side edge section a and the second
oblique side edge section b. The pulling section R in which a fastener 7 is
attached to the oblique side edge 6a must extend across the neutral section
33 and overlap the oblique side edge sections a and b partly to concentrate
the component forces of the tensile force applied to the fastener 7 directly
on_ the waist lapping portion and the leg lapping portion; that is, the
component forces of the tensile force applied to the fastener 7 can be
directly concentrated on desired portions by determining the position of the
pulling section R so that the pulling section R overlap the oblique side edge
sections a and b partly.
In a disposable diaper 1 in a fourth embodiment according to the
present invention shown in Fig. 22, a line L1 is extended from the _
intersection point P so as to be tangent to a stress relaxing structure 20 and
intersects the oblique side edge 6a of an ear part 6 at an intersection point
A, and a line L2 is extended from the intersection point Q so as to be
tangent to the stress relaxing structure 20 and intersects an extension of the
oblique side edge 6a at an intersection point B. Since the intersection point
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23
B is a virtual point apart from the ear part 6, an actual second oblique side
edge section b' is a portion of a second oblique side edge section b, on the
oblique side edge 6a. A fastener 7 is attached to the
oblique side edge 6a in a pulling section R partially overlapping the first
oblique side edge section a and the actual second oblique side edge
section b'. Thus the oblique side edge sections a and b can be defined
even if the lines L1 and L2 do not intersect the oblique side edge 6a. In
this specification, an expression, "a point where the line L1 (L2) intersects
the oblique side edge 6a" has an implication that "a point where the line L1
(L2) intersects an extension of the oblique side edge 6a".
A disposable diaper 1 in a fifth embodiment according to the present
invention is provided with ear parts 6 each having a lower side edge 6c
having a lower curved portion S curved in the shape of a circular arc as
shown in Fig. 23. A line L2 is tangent to the lower curved portion S of the
lower side edge 6c and a stress relaxing structure 20 and intersects the
oblique side edge 6a of the ear part 6 at an intersection point B. Therefore,
a component tensile force of a tensile force applied to the ear part 6 at the
intersection point B can be transmitted, acting along the line L2 can be
transmitted to an absorbent part 3. A line 34 extended from the the
intersection point of the lower side edge 6c of the ear part 6 and a side flap
4 extended along the side edge of an absorbent part 3 so as to be tangent
to the stress relaxing structure 20 intersects the oblique side edge 64 at an
intersection point B'. The transmission of a component tensile force of a
tensile force applied to the ear part 6 at the intersection point B' and
transmitted along the line 34 is intercepted at the intersection point of the
line 34 and the lower side edge 6c. In this embodiment, a first oblique side
edge section a extends upward from the intersection point A, and a second
oblique side edge section b extends downward from the intersection point B.
A pulling section R in which a fastener 7 is attached to the oblique side
edge 6a must overlap at least a section c between the intersection points A
and B in which the first oblique side edge section a and the second oblique
side edge section b overlap each other.
The line L2 may be extended from the upper end of one of elastic
. members 5, i.e., the outermost, the middle or the innermost elastic member
5, instead of from a point on the lower portion of the lower side edge 6c, so
as to be tangent to the stress relaxing structure 20. In this case, a
component tensile force of a tensile force applied to the ear part 6 at the
w0 96fI9038 CA 0 2 213 8 0 2 2 0 0 0 - 0 4 - 2 5 p~/Ugg6ro2922
74
intersection point B acts directly on the elastic members 5. The line L2
defines a second oblique side edge section b for directly applying a tensile
force to the elastic members 5. Although the line L1 for determining the first
oblique side edge section a is extended from the intersection point P of the
longitudinal center axis L-L' of the absorbent part 3 and the upper edge 1 a
of the absorbent part 3 in this embodiment, the line L1 may be extended
from the right end, as viewed in Fig. 23, of one of elastic members, not
shown, i.e., the outermost, the middle or the innermost elastic member,
attached to the upper waist lapping portion of the absorbent part 3 so as to
be tangent to the stress relaxing structure 20. In this case, a component
tensile force of a tensile force applied to the oblique side edge 6a at the
intersection point A acts directly on the right ends of the elastic members.
Thus, the line L1 defines the first oblique side edge section a for directly
applying a component tensile force of a tensile force applied to a fastener 7
to the elastic members.
In a disposable diaper 1 in a sixth embodiment according to the
present invention shown in Fig. 24, the oblique side edge 6a' of an ear part
6 extends obliquely downward and toward the longitudinal center axis L-L'
of an absorbent part 3 from the outer extremity of the upper side edge 6b of
the ear part 6. The inclination , i.e., the angle between the oblique side
edge 6a' and a line passing the outer extremity of the upper side edge 6b
and parallel to the longitudinal center axis L-L' of the absorbent part 3.
meets an inequality: 0 < angle < 45. A fastener 7 is attached to the oblique
side
edge 6a' of the ear part 6 so as to extend perpendicularly to the oblique
side edge fia'.
Supposing the longitudinal center axis L-L' of the absorbent part 3
intersects the upper edge 1 a of the absorbent part 3 at an intersection point
P, the lower side edge 6c of the ear part 6 intersects a side flap 4 attached
to the side edge of the absorbent part 3 at an intersection point Q, a line L1
extends from the intersection point P in tangent to an upper point of a stress
relaxing structure 20 on the side of the upper edge 1 a and intersects the
oblique side edge 6a' at an intersection point A, and a line L2 extends from
the intersection point Q in tangent to a lower point of the stress relaxing
structure 20 on the side of the transverse center axis H-H' of the absorbent
part 3 and intersects the oblique side edge 6a' at an intersection point B, a
first oblique side edge section a extends obliquely upward from the
intersection point A, and a second oblique side edge section b extends
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WO 96/29038 PC"T/US96/02922
obliquely downward from the intersection point B.
A fastener 7 is attached to the oblique side edge 1 a' of the ear part 6
so as to extend perpendicularly to the oblique side edge 6a'. Since the
fastener 7 is pulled in a direction perpendicular to the oblique side edge 6a'
of the ear part 6, the direction with respect to the longitudinal center axis
L-
L' of the absorbent part 3 in which the fastener 7 is pulled is dependent on
the inclination of the oblique side edge 6a' meeting an inequality: 0 < <
45 . The fastener 7 is pulled perpendicularly to the oblique side edge 6a'
regardless of the inclination of the oblique side edge 6a' of the ear part 6.
Thus the direction with respect to the longitudinal center line L-L' in which
the fastener 7 is pulled is dependent on the inclination of the oblique side
edge 6a', the difference between a component tensile force D1 of a tensile
force applied to the fastener 7, distributed to a waist lapping portion, and a
component tensile force D2 of the same, distributed to a leg lapping portion
is small when the inclination of the oblique side edge 6a' is comparatively
small, the component tensile force D1 is greater than the component tensile
force D2 when the inclination of the oblique side edge 6a' is comparatively
large. The fastener 7 is attached to the oblique side edge 6a' of the ear
part 6 in a pulling section R. The ratio between the component tensile
forces D1 and D2 is dependent on the position of the pulling section R on
the oblique side edge 6a'.
As shown in Fig. 1, the fastener 7 of the disposable diaper 1 as
packaged is folded back at its middle, and projects from the ear part 6 when
the disposable diaper 1 is unfolded for use. The fastener 7 may be formed
in the shape of a fork. When thus folded back at the middle, no portion of
the fastener 7 projects outward from the ear part 6. When the fastener 7 is
formed in the shape of a fork, the tensile force applied to the fastener 7 can
be further surely distributed to the waist lapping portion and the leg tapping
portion. Since the stress relaxing structure 20 is elastic, the stress
relaxing
structure 20 conforms easily to the shape of the hipbone and the like, which
improves the wearing comfort of the wearer. Although the invention has
been described in its preferred forms with a certain degree of particularity,
obviously many changes and variations are possible therein. It is therefore
to be understood that the present invention may be practiced otherwise than
as specifically described herein without departing from the scope and spirit
thereof.
