Note: Descriptions are shown in the official language in which they were submitted.
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DISPOSABLE DIAPERS
BACKGROUND OF THE INVENTION
This invention relates to disposable diapers.
It is well known to provide disposable diapers with side
flaps extending between longitudinally opposite ends of such
diapers and adapted to rise on the topside of such diapers as
they are put on a wearer so that a quantity of body fluids may
beeffectivelyprevented fromleaking throughlegopenings of
such diapers. Such technique is disclosed, for example, by
the specification of US Patent No. 4,704,116, according to
which a liquid-permeable topsheet is partially folded so as
to form sleeve-like flaps extending between the
longitudinally opposite ends of a diaper and elastic members
are bonded under tension longitudinally to these sleeve-like
flaps so that these sleeve-like flaps may rise on the topside
of the diaper as it is put on a wearer. Such a kind of
techniqueiswell knownalso from JapanesePatent Application
Disclosure Gazettes Nos. 1988-105102 and 1988-112703, in
accordance with which there are separately prepared a pair of
sleeve-likemembers eachhavinga lengthcorrespondingto the
longitudinal dimension of a diaper and flaps are formed by
bonding these sleeve-like members to the topsheet of the
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diaper. When the sleeve-like flaps or members are formed
from a liquid-permeable sheet such as the topsheet, they are
sometimes treated to obtain desired water-repellency to
prevent body fluids from permeating therethrough.
Said flaps adapted to rise on the topside of the diaper
as it is put on a wearer will be able to function in an
expected manner so far as said flaps extend at least along the
longitudinal dimension of a crotch zone. Nevertheless, the
sleeve-likeflapsormembersaccordingtotheabove-mentioned
prior arts fully extend between the longitudinally opposite
ends, i.e., the opposite waist lines of the diaper and
portionsof thesesleeve-like flapsormembers lying adjacent
said opposite waist lines are collapsed and bonded to the
topsheet. Such an arrangement is obviously disadvantageous
in that the zones adjacent the front and rear waist lines
become bulky and stiffy, causing the wearer to feel
uncomfortable.
Accordingly, it is a principal object of the invention to
solve the problem as has been mentioned above without a loss
of a body fluid damming effect of flaps by folding portions
oftop-and/orbacksheetsextendingoutwardfromtransversely
opposite sides of an absorbent core of a diaper to form the
flaps adapted to rise on the topside of the diaper as it is
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put on a wearer so that said flaps should not be beyond a
necessary extent substantially corresponding to the
longitudinal dimension of the crotch zone.
SUMMARY OF THE INVENTION
The object set forth above is achieved, according to
a broad aspect of the present invention, by a disposable
diaper which comprises a liquid-permeable topsheet having
two spaced apart end portions and two spaced apart
lateral sides. A liquid-impermeable backsheet is
provided and has two spaced apart end portions and two
spaced apart lateral sides. An absorbent core is
sandwiched between the topsheet and the backsheet. The
absorbent core has two spaced apart sides that are
generally parallel the lateral sides of the topsheet and
the lateral side of the backsheet, at a spaced distance
inwardly from the lateral sides of the topsheet and the
backsheet. A front body portion, a rear body portion,
and a crotch zone intermediate the front body portion and
the rear body portion is also provided. Two spaced apart
laterally extending first flaps are formed from the
topsheet and the backsheet. The first flaps extend along
the crotch zone and are located laterally outwardly with
respect to each the side of the absorbent core and
located generally parallel to the sides of the absorbent
core. Elastic members are mounted under tension in each
of the first flaps between the topsheet and the
backsheet. Two spaced apart second flaps are also
provided. Each second flap is located intermediate one
of the sides of the absorbent core and the adjacent first
flap. The second flap also extends upwardly in a
generally upstanding position which is generally at a
right angle to a horizontal plane of said absorbent core.
The second flap also extends along a length of the crotch
zone and has spaced apart ends that terminate at spaced
apart locations of the crotch zone. The second flap also
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has an elongated bottom in the general shape of a bow and
an elongated top edge that is substantially in a straight
line. The second flap also has a height (H) which is
greatest at its midpoint and which progressively and
gradually decreases in height in both directions from the
midpoint towards its spaced apart ends. Still further,
the second flap has a second elastic member in a
stretched condition extending along the elongated top
edge, wherein the length of each second flap corresponds
to the length of the crotch zone and wherein each second
flap is composed of portions of the topsheet and
backsheet that have been folded upwardly in a general
closed U-shaped configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
The disposable diaper according to the invention
will be readily understood more in details from the
following description made by way of example in reference
with the accompanying drawings, in which:
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Fig. 1 is a perspective view of a disposable diaper
constructed according to the invention;
Fig. 2 is a sectional view taken along a line A-A in Fig.
l; and
Figs, 3A and 3B are views similar to Fig. 2 showing
alternative embodiments of second flaps.
PREFERRED EMBODIMENTS OF THE INVENTION
Figs. 1 and 2 illustrate a disposable diaper 1 in a
perspective view and in a sectional view taken along a line
A-A in Fig. 1, and Fig. 1 particularly illustrates a state in
which the diaper 1 is curved toward the topside due to
contraction of elastic members 13, 18 as will be described
later. The diaper 1 basically comprises a liquid-permeable
topsheet 2, a liquid-impermeable backsheet 3, and an
absorbent core 4 sandwiched between these sheets 2, 3. The
portions of said top- and backsheets 2, 3 extending beyond
transversely opposite side edges 5 of the absorbent core 4
form first flaps 6 horizontally extending around respective
leg-openings and second flaps 7 lying inside the respective
first flaps 6 and adapted to rise on the topside of the diaper
1. The diaper 1 is longitudinally composed of front and back
bodies 10, 11, and a crotch zone 12 extending between these
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front and rear bodies 10, 11. The first flaps 6 respectively
contain said elastic members 13 having their intermediate
sections extending along the longitudinal dimension for the
crotch zone 12. The front and rear bodies 10, 11 are provided
along their longitudinally opposite ends 15, 16 with elastic
members 15A, 16A, respectively. These elastic members 13,
15A, 16A are interposed between the top- and backsheets 2,
3 and intermittently bonded under tension to one of these
sheets. The second flaps 7 contain in their top edges 17 said
elasticmembers18 intermittentlybondedunder tensionto the
backside of the backsheet 3. The rear body 11 is provided on
transversely opposite side edges with tape fasteners 20,
respectively, each being bonded at one end thereof to the
respective side edges.
In such an arrangement, the second flaps 7 are provided
within a necessary extent defined 30mm or more inside the
longitudinally opposite ends 15, 16 of the front and rear
bodieslO, 11, andhavetheir intermediatesections extending
along the longitudinal dimension of the crotch zone 12. Each
of the second flaps 7 is defined by a top edge 17 linearly
connecting longitudinally opposite ends 21, 22 thereof under
contraction of the elastic member 18 and a bottom edge 19
connecting said ends 21, 22 in a curved line. Said ends 21,
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22 substantially correspond to the points at which the ends
18A, 18B of the elastic member 18 are bonded to the backsheet
3. The top- and backsheets 2, 3 are folded along the elastic
member 18 toward the backside so as to form a fold having said
top edge 17, and inner surfaces of this fold, i.e., areas of
the backsheet 3 opposed to each other are intermittently
bonded together. The second flap 7 rises along said bottom
edge 19 on the topside of the diaper as the elastic member 18
contracts and a distance between the top and bottom edges 17,
19 is a projecting height H of the second flap 7 in such a
rising state.
To obtain these second flaps 7, the elastic members 18
are bonded under tension to the backside of the backsheet 3
having no slack and then the elastic members 18 are
contracted by an appropriate amount so that the diaper 1 is
slackened like a bow with the elastic members 18 forming
strings. After such a slackening, the top- and backsheets 2,
3 are folded along the full lengths of the respective elastic
members 18 extending between the opposite ends 18A, 18B
toward the backside by a width h (not shown) with the top
edges defined by the respective elastic members 18 and the
areas of the backsheet 3 opposed to each other are bonded
together. Bonding the elastic members 18 to the backsheet 3
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and bonding the areas of the backsheet 3 to each other are
preferably made in an intermittent fashion in order to
facilitate the elastic members 18 to contract easily. The
width h of each fold corresponds to the height H of each
second flap 7 and a location of the bottom edge 19 relative to
the top edge 17 is determined in such a manner that the
dimension h progressively increases from the minimum at the
opposite ends 18A, 18B to the maximum at the middle of the
crotch zone 12. In this way, the second flaps 7 can rise on
the topside of the diaper 1 as the diaper 1 is slackened in a
bow-shape and have their projecting heights gradually
decreasing from the maximum at the middle of the crotch zone
12 longitudinally toward the front and rear bodies 10, 11,
respectively.
Referring to (A) and (B) of Fig. 3, alternative
embodiments of the second flaps 7 which are distinguished
from that of Fig. 2 are illustrated in views similar to Fig.
2. Referring to (A), the elastic members 18 are interposed
between the top- and backsheets 2, 3 and intermittently
bonded to at least one of these sheets 2, 3. Referring to
(B), on the other hand, the topsheet 2 is relatively narrow
and terminates inside the respective second flaps 7, i.e.,
the second flaps 7 are formed only by the backsheet 3.
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Besides the second flaps 7 may be formed by any one of the
top- and backsheets 2, 3. While the opposed areas of the
backsheet3 areillustrated ascloselycontactingeachother,
these opposed areas may be gradually spaced from each other
toward the bottom edges 19 due to the intermittent bonding.
Referring to Fig. 1, portions of the top- and backsheets
2, 3 which extend outward beyond the periphery of the
absorbent core 4 are water-tightly bonded to each other
around the absorbent core 4. The topsheet 3 may be made of
nonwoven fabric or porous plastic film, the backsheet 3 may
be made of plastic film and the absorbent core 4 may be of
fluff pulp, a mixture of fluff pulp and superabsorbant
polymer, or the like. Attaching and bonding in making the
diaper 1 may be achieved by utilizing adhesive such as hot
melt type adhesive, sticky glue, heat sealing technique, or
the like.
According to the invention, a diaper is provided with
flaps longitudinally limited within a necessary extent so
that theirintermediatesections extendalong the crotchzone
and adapted to rise on the topside of the diaper as it is put
on a wearer so that these flaps have the maximum heights at
the middle of the crotch zone in which a quantity of excreted
body fluids is apt to gather. Such an arrangement solves the
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problem that the portions of the diaper lying adjacent the
waist line become bulky and stiffy, causing a wearer to feel
uncomfortable, without loss of a body fluids damming effect.
