Note: Descriptions are shown in the official language in which they were submitted.
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2096672
DISPOSABLE DIAPERS
BACKGROUND OF THE INVENTION
This invention generally relates to a disposable
diaper and, more particularly, to such a diaper adapted to
be selectively usable either as so-called pants type diaper
having front and rear bodies which have been connected with
each other already on a step of manufacturing so as to form
a closed loop around the waist or as so-called open type
diaper having front and rear bodies to be connected with
each other so as to form a closed loop around the waist by
means of fastening flaps just when the diaper is actually
put on a wearer.
Japanese Utility Model Application Disclosure Gazette
No. 1992-5826 discloses a disposable diaper comprising
front and rear bodies which have been previously bonded
together along one of the waist zone's laterally opposite
side portlons but can be releasably bonded together by a
tape-like fastener along the other side portion. On the
other hand, Japanese Patent Application Disclosure Gazette
No. 1992-89050 discloses a disposable diaper comprlsing
front and rear bodies adapted to be releasably bonded
together by adhesive tape along at least one of the waist
zone's laterally opposite side portions.
The diaper disclosed in the above-identified Japanese
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Utility Model Application Disclosure Gazette No. 1992-5826
is inconvenient to put it on a wearer no matter whether the
wearer is in standing-up posture or lying posture, because
one of said laterally opposite side portions is permanently
closed. The diaper disclosed in the above-identified
Japanese Patent Application Disclosure Gazette No. 1992-
89050 is disadvantageous in that, when the waist-opening is
widened in order to put such diaper on a wearer as it is
usually done for normal pants having the waist line closed
in a loop, one or both of the waist zone's laterally
opposite side portions previously closed as in the case of
said normal pants can be unintentionally opened and an
expected effect of previously closing the waist line can be
decreased to half, because such closure is made merely by
adhesive tape (in the course of manufacturing).
Accordingly, it is a principal object of the invention
to provide an improved disposable diaper having front and
rear bodies which have been previously bonded together
along the waist zone's laterally opposite side portions in
the course of manufacturing but, if desired, can be
separated from each other and bonded together again so that
the opposite side portions thus bonded together again can
never be unintentionally opened even if the waist-opening
is widened in order to put the diaper on a wearer.
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SUMMARY OF THE INVENT I ON
The object set forth above is achieved, in accordance
with the invention, by a disposable diaper generally
comprising longitudinally continuous front and rear bodies
and a pair of fastening flaps extending outward from waist
zone's laterally opposite side portions of said front or
rear body, characterized by said longitudinally continuous
front and rear bodies being folded so that laterally
opposite side portions of said front body are accurately
laid upon those of said rear body; said fastening flaps
carrying on respective inner surface adjacent respective
front ends thereof fastening spots and having respective
base ends laid upon the waist zone's laterally opposite
side portions of said front body; bond lines along which
said waist zone's laterally opposite side portions of said
front and rear bodies and said base ends of respective said
fastening flaps are bonded together; cutting lines provided
inside and adjacent respective said bond lines so that said
front body may be torn off along these cutting lines from
said rear body; and each of said bond lines having a
resistance of 1000 g/inch or higher to separation occurring
between said front and rear bodies.
Preferably, said bond lines are formed by welding and
said cutting lines are formed by intermittent cuts or
perforations.
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According to a further broad aspect of the present
invention there is provided a disposable diaper which
comprises a front body and rear body. The front body is
longitudinally continuous with the rear body and folded
over with respect to the rear body so as to produce a
completely formed waist opening, two completely formed leg
openings and opposed side portions extending between each
completely formed leg opening and said completely formed
waist opening. The side portions are formed by permanently
bonding the front body and the rear body together along
permanent bonding lines having a separation resistance of
at least lOOOg/inch. Two fastening flaps are also provided
and each has a base end bonded to a respective one of the
side portions and an outer end that can be extended
laterally with respect to the side portion to which it is
attached. Fastening means is provided on each of the
fastening flaps and adapted to engage the front body. Two
lines of perforations are also provided in the front body
and are each disposed adjacent one of the side portions and
extend generally parallel to and inwardly of the permanent
bonding lines. The two lines of perforations each extend
between one of the leg openings and the waist opening, and
each located inwardly of the base end of an associated one
of the fastening flaps. This diaper construction permits
the diaper to be put on a baby that is able to stand
without the need to tear the front body along the
perforation lines, or can be put on a baby that is not able
or willing to stand by separating the front body along the
perforation lines without separating the permanent bonding
lines and thus fitting the separated front body and back
body around the baby, and then, after fitting the diaper on
the baby, engaging the fastening means of the fastening
flaps to a portion of the separated front body.
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BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described more in details by way
of example in reference with the accompanying drawings, in
which:
Fig. 1 is a front view of a diaper erected with one of
fastening flaps being fastened to a front body;
Fig. 2 is a rear view of the diaper completely
erected;
Fig. 3 is a fragmentary sectional view showing, in an
enlarged scale, a line along which the front body, the rear
body and the fastening flaps are bonded together in the
proximities of their laterally opposite side edges and base
ends, respectively;
Fig. 4 is an upper end view of the erected diaper;
Fig. 5 is a view similar to Fig. 4 but showing the
erected diaper with laterally opposite side portions of the
front body being cut apart from those of the rear body;
Fig. 6 is a plan view showing the inner side of the
unfolded diaper;
Fig. 7 is an enlarged sectional view taken along a
line X-X in Fig. 6; and
Fig. 8 is a perspective view illustrating a measuring
method for separation-resistance of the bond line conducted
using a test piece.
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PREFERRED EMBODIMENT OF THE INVENTION
Referring to Figs. 1 through 5, front and rear bodies
1, 2 of a diaper are longitudinally continuous. The front
and rear bodies 1, 2 is folded back one on the other with
laterally opposite side portions 3, 3 of the front body
at the level of waist zone being accurately laid upon the
corresponding opposite side portions 4, 4 of the rear body
2, then a pair of fastening flaps 6 carrying on inner
surfaces adjacent front ends thereof fastening spots 5
serving as fastening means are laid at base ends 7 thereof
upon said laterally opposite side portions 3, 3 and 4, 4 of
the front and rear bodies 1, 2 which have already been laid
one upon the other, and these components 1, 2, 6 thus laid
one upon another are intermittently bonded together under
effect of heat or supersonic wave along lines 8 extending
in parallel to and adjacent said side portions 3, 4 as well
as said base ends 7 so as to leave respective outer edges
of these components not bonded. The front body 1 is
provided at locations 9a adjacent the respective bond lines
8 with cutting lines 9b extending in parallel to the
respective bond lines 8 in the form of intermittent cuts or
holes (i.e., so-called perforations) so that the front body
1 can be torn off along these cutting lines 9b from the
rear body 2.
Bond strength (or separation-resistance) of each bond
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line 8 along which the front and rear bodies 1, 2 have been
bonded together preferably should be 1000 g/inch or higher
so that the laterally opposite side portions 3, 3, and 4, 4
of the respective bodies 1, 2 bonded together along said
bond lines 8 may be reliably prevented from being separated
from each other even if each bond line 8 is subjected to a
tearing force possibly tending to separate off said
laterally opposite side portions 3, 3 and 4, 4 from each
other, for example, when it is desired to widen the waist-
opening formed by bonding the laterally opposite side
portions 3, 3 and 4, 4 at the level of waist zone of the
front and rear bodies 1, 2 in the manner as has previously
been mentioned in order to put the diaper on a wearer or
when the front body 1 is pulled, with the diaper put on a
wearer, to cut the front body 1 off from the rear body 2
along each cutting line 9b. It should be understood that
the separation-resistance is measured using a test piece
including a partial length of the bond line 8, which was
sampled from the diaper by cutting off a portion surrounded
by broken lines in Fig. 8. As shown, the test piece is a
rectangular strip having a width of 1 inch and
longitudinally extending from the bond line 8 over length
larger than 10 mm in opposite directions, respectively.
The test piece is held at longitudinally opposite ends
thereof by a pair of chucks, respectively, so that
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initially the test piece linearly extends between said pair
of chucks accurately over a distance of 20 mm with the bond
line 8 lying in the middle. Then, the test piece is
longitudinally tensioned at a rate of 100 mm/min and
thereby a value (g) at a moment of separation occurring
along the bond line 8 is determined as the separation-
resistance value.
Referring to Figs. 1, 2 and 6, each blank of the
diaper comprising longitudinally continuous front and rear
bodies 1, 2 is then formed with laterally opposite concave
edges 10 extending between the respective waist zones of
the front and rear bodies 1, 2 so as to define respective
leg-openings. This blank is composed, as best seen in Fig.
7, of a liquid-permeable topsheet 11, a liquid-impermeable
backsheet 12 and an hourglass-shaped liquid-absorbent panel
13 sandwiched between said top- and backsheets 11, 12. The
blank is further provided along the respective waist zones
of the front and rear bodies 1, 2 as well as along the
above-mentioned concave edges 10 destined to form the
respective leg-openings with a plurality of parallelly
extending thread-like elastic members 14, 15, respectively,
which are attached under their longitudinally stretched
condition between the top- and backsheets 11, 12 utilizing
hot melt type adhesive. The elastic members 14 associated
with the waist zone of the rear body 2 are arranged to
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occupy substantially all over this zone in parallel to one
another with their spacings increasing from the outermost
edge toward the inside of the waist zone so that a total
elasticity of these elastic members 14 is higher than that
of the elastic members 14 associated with the waist zone of
the front body 1. It should be understood that, though not
shown, the waist zone of the rear body 2 may be partially
made from pieces of elastic fabric without providing both
front and rear bodies 1, 2 with the respective elastic
members 14 as in the illustrated embodiment. For example,
such pieces of elastic fabric may be connected to the waist
zone of the rear body 2 at laterally opposite side edges
thereof by means of welding or the like. While not shown,
it is also possible to form the fastening flaps 6 wholly or
partially from elastic material without departure from the
scope of the invention.
The waist zone of the front body 1 has a scaled narrow
sheet 16 sticked on outer surface thereof in order to
protect this surface which otherwise would be directly and
repeatedly engaged by the fastening spots 5 of the
respective fastening flaps 6. The scaled narrow sheet 16
functions also as an indicator adapted to conveniently
indicate locations at which the respective fastening spots
5 are laid upon said outer surface. The fastening spots 5
may be formed by application of the adhesive conventionally
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209667~
used for such purpose or may be a piece of tape having
thereon a plurality of hooks such as Velcro (trademark) or
Magic Tape (trademark) both of which are well known to
those skilled in the art. To use such piece of tape as the
fastening spot 5, the scaled narrow sheet 16 must have a
piled surface with which the hooks of the fastening spot 5
is effectively engageable.
The fastening flap 6 may be made from nonwoven fabric
or laminate sheet consisting of such nonwoven fabric and
plastic film or paper of fine quality. The topsheet 11 may
be made of nonwoven fabric or porous plastic film. The
backsheet 12 may be made of plastic film or laminate sheet
consisting of such plastic film and nonwoven fabric. The
scaled narrow sheet 16 may be made of plastic film or
nonwoven fabric or felt, depending on a desired nature of
the fastening spot 5.
The diaper constructed according to the teachings of
this invention as has been described hereinabove can be put
on a wearer as a pants type diaper, i.e., in its original
configuration, for example, when it is desired to put the
diaper on a wearer who is in standing up posture. While
the fastening flaps 6 are principally unnecessary in this
case, it is preferred that the fastening spots 5 are firmly
engaged with the narrow sheet 16 at appropriate locations
thereof to avoid undesirable movement of the diaper with
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respect to a wearer's body during use of the diaper (Fig.
4). When it is desired to put the diaper on a wearer who
is in lying posture, the laterally opposite side portions
of the front body 1 is torn off from those of the rear body
2 along the cutting lines 9b by pulling the front body 1 or
the fastening flaps 6 so as to obtain the diaper of open
type (Fig. 6) and, after having put it on a wearer, the
fastening flaps 6 are folded inward onto the narrow sheet
16 so that the respective fastening spots 5 may be firmly
engaged with said sheet 16 at desired locations thereof
(Fig. 5).
The invention allows the diaper to be put on a wearer
selectively either as the pants type diaper or as the open
type diaper. The diaper of this invention is advantageous
particularly in that, even if the bond lines extending
along the laterally opposite side portions are subjected to
a tearing force usually exerted thereon when the diaper is
used as the pants type diaper, no separation occurs along
the laterally opposite side portions of the front and rear
bodies, because each of the bond lines has a separation-
resistance as high as 1000 g/inch or higher.
After solid excretion has been discharged on the
diaper, the front body may torn off from the rear body
along the cutting lines provided along the laterally
opposite side potions and thereby the diaper may be easily
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removed from a wearer without undesirably smearing the
wearer's skin with solid excretion.
