Note: Descriptions are shown in the official language in which they were submitted.
WO95/13771 2 1 7 5 q 2 5 PCT/SE94/0106~
TITLE: Disposable absorbent article
TECHNICAL FIELD:
The present invention relates to a disposable absorbent
article such as a disposable diaper according to the
preamble of claim l.
BACKGROUND OF THE INVENTION:
Disposable absorbent articles are commonplace and have many
uses. As examples of such articles can be named disposable
diapers, bandages and sanitary napkins. The purpose of
these articles is to absorb and retain discharged liquids,
thereby preventing such liquids from soiIing for example
the clothing of the wearer of such articles.
In order to promote the retention of liquids in diapers, it
is known from, for example, US-A-4 486 192 to provide an
elastic member in the diaper. The elastic member is
positioned so that when the diaper is worn, the elastic
causes the diaper to form a seal around the legs of the
wearer. In said document, the elastic member is sandwiched
between a liquid permeable facing sheet and a liquid
impermeable backing sheet along opposed longitudinal free
edges of the diaper. The elastic member thus occupies a
"tunnel" and is adhered to the sheets at regions in which
gathering of the diaper is desired. This implies that at
non-adhered regions there is a risk that liquid absorbed by
the diaper may escape to the exterior through the tunnel
between the permeable and impermeable sheets.
This problem is addressed in US-A-4 850 989 in which
longitudinal elastic members are adhesively bonded under
tension onto the outside surface of the backing sheet,
thereby overcoming the need for a tunnel between the facing
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sheet and the backing sheet. A disadvantage with this
arrangement is that each longitudinal edge face of the
diaper consists of the edge face of the facing sheet and
the edge face of the backing sheet. This implies that the
longitudinal edge faces of the diaper are not particularly
smooth, which can lead to irritation of the skin of the
wearer.
In US-A-4 808 178, a smooth longitudinal edge is obtained
by enclosing the elastic member in a flap which is an
extension of the backing sheet. It is stated in said patent
that the backing sheet is impervious to liquids and is
preferably manufactured from a thin plastic film. Whilst
the construction according to US-A-4 808 178 provides a
smooth longitudinal edge, the fact that the flap material
is impervious to liquids implies that the wearer can
-experience discomfort due to a build up of perspiration in
the area at which the flap contacts the wearer's skin.
SUMMARY OF THE INVENTION:
It is therefore an object of the present invention to
provide an absorbent article such as a disposable diaper
which overcomes the disadvantages mentioned above and which
provides increased comfort for the wearer.
This object is achieved in accordance with the present
invention by a disposable diaper according to claim l.
Preferred embodiments of the present invention are detailed
in the dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS:
The invention will be described in greater detail in the
following by way of example only and with reference to the
attached drawings, in which:
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Fig.l is a plan view of an absorbent article in
accordance with the present invention having
elasticized leg cuffs, the article being
illustrated during a stage of the manufacturing
process;
Fig. 2 is a partial sectional perspective view taken
substantially~ along the line II-II of Fig. l,
though with the article in a finished condition.
Fig. 3 is a sectional view along the same line as in Fig.
2, though showing one embodiment according to the
invention of the edge portion of the absorbent
article;
Fig. 4 is a sectional view corresponding essentially to
that of Fig. 3, though illustrating a second
embodiment of the edge portion of the absorbent
article according to the invention;
Fig. 5 is a sectional view corresponding essentially to
that of Fig. 3, though illustrating a third
embodiment of the edge portion of the absorbent
article according to the invention, and
Fig. 6 is a sectional view corresponding essentially to
that of Fig. 3, though illustrating a fourth
embodiment of the edge portion of the absorbent
article according to the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS:
In the drawings, an absorbent article in the form of a
disposable diaper is generally denoted by reference numeral
l0. For reasons of clarity, the diaper lO is shown in Fig.
l in a stage occupied by the diaper during its manufacture.
Accordingly, reference numeral 12 denotes joining lines,
WO95/13771 PCT/SE94/01065
for example glue lines or heat bonding lines, about which
the diaper is gathered in a manner known per se to form a
pair of inner cuffs 14 (Fig. 2) through which an elastic
chord 16 runs. Due to the gathering of the diaper about the
joining lines 12, the diapér adopts a generally hour glass
shape with a narrow centrally disposed crotch portion 18
and wider waist portions 20, 22 at transverse end regions
of the crotch portion.
In accordance with the invention, the diaper lo is provided
with prestretched elastic means 24 disposed along edge
portions, preferably longitudinal edge portions 25, of the
diaper. Advantageously, the waist portions 20, 22 may be
provided with transversely extending elastic means 26, 28
respectively.
To permit the diaper to be fastened around a wearer,
fastening means are provided at the waist portions. As
illustrated in Fig. 1, the waist portion 20 which would
normally be disposed at the front of the wearer may be
provided with a pair of fastening means such as hook
members 30, with each hook member 30 extending from the
longitudinal edge portion 25 of the diaper. The fastening
means may further comprise a belt 32 extending from the
waist portion 22 which, during use, is normally disposed at
the back of the wearer. As illustrated in Fig. 1, the belt
may be in two halves, with each half extending from the
opposed longitudinal edge portions 25 of the diaper.
Preferably, the belt is made from a nonwoven material which
acts as a loop fastener for the hook members 30.
The structure of the diaper of Fig. 1 will be more easily
understood from the partial sectional view through the
crotch portion 18, as illustrated in Fig. 2. The diaper 10
has a generally hour glass shape and includes a facing
sheet 34, a backing sheet 36 and an absorbent core 38
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WO95/13771 PCT/SE94/01065
sandwiched between the facing and backing sheets 34, 36
respectively. The specific components used to form the
illustrated diaper may be any of the types commonly used
for such purposes. For example, the facing sheet 34 may be
any soft flexible liquid permeable material such as a
nonwoven fibrous web having a basis weight of around 20
g/m2. The backing sheet 36 is made from a liquid
impermeable material~ such as a thin (for example 20~)
plastic film of polyethylene, polypropylene,
polyvinylchloride or the like. The absorbent core 38 may
comprise wood pulp fibres, air-laid tissue, various
superabsorbent materials, etc.
As mentioned above with reference to Fig. l, prestretched
elastic means 24 are disposed along the longitudinal edge
portions 25 of the diaper. As clearly shown in Fig. 2, the
elastic means 24 may be in the form of an elongate elastic
band. Advantageously, the elastic band is relatively wide,
for example between about l and 2 cm, preferably about l.5
cm, so as to reduce the tendency for the leg cuff to mark
the wearer.
The arrangement of the elastic means 24 along the
longitudinal edge portions 25 of the diaper will now be
described with particular reference to Figs. 3 to 6. In
accordance with the present invention, the elastic means 24
is surrounded by a pocket of nonwoven material, i.e. a
nonwoven fibrous web, advantageously along each of the
longitudinal edge portions 25 of the diaper. In the
embodiments illustrated in Figs. 3, 4 and 5, the pocket is
formed by the facing sheet 34. More particularly, in Figs.
3 and 5 the facing sheet 34 presents a longitudinal free
edge portion 40 which is folded under and adhered to the
underside of the facing sheet to thereby form a pocket
within which the elastic means 24 is accommodated, whilst
in Fig. 4 the longitudinal free edge portion 40 of the
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facing sheet 34 is folded under and adhered to the backing
sheet 36. The pocket advantageously extends along the
entire longitudinal edge portion 25 of the diaper and the
elastic band 24 is adhered to the material forming the
pocket at those regions along the longitudinal edge portion
25 at which gathering of the facing sheet is desired, for
example in the crotch portion 18 where the longitudinal
edge portions 25 form leg cuffs (see for example Fig. 2).
Where no gathering is desired, for example in the waist
portions 20, 22, the elastic band remains unadhered to the
pocket.
The backing sheet 36 presents a longitudinal free edge
portion 42 which terminates short of the longitudinal edge
15 portion of the diaper. In this manner, the longitudinal
edge portion 25 of the diaper consists essentially of
nonwoven material which is soft on the skin and which has
a tendency to absorb any perspiration which may form.
In order to hinder leakage of liquid from the absorbent
core 38, it is advantageous if the facing sheet 34 and the
backing sheet 36 are adhered together at the longitudinal
edges of the absorbent core, as denoted by reference
numeral 44 in Figs. 3 to 6.
In the embodiment shown in Fig. 3, the longitudinal free
edge portion 42 of the backing sheet 36 overlaps the
longitudinal free edge portion 40 of the facing sheet,
whilst in Fig. 4, the longitudinal free edge portion 40 of
the facing sheet overlaps the longitudinal free edge
portion 42 of the backing sheet 36. In both embodiments,
the longitudinal free edge portion 42 of the backing sheet
terminates in the vicinity of the elastic band 24. In the
embodiment illustrated in Fig. 5, however, the longitudinal
free edge portion 42 of the backing sheet 36 terminates in
the vicinity of the longitudinal edge of the absorbent core
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WO95/13771 PCT/SE94/01065
38, i.e. in the shown example in the vicinity of the
elastic chord 16 of the inner cuff 14. At the same time,
the facing sheet 34 extends around the elastic band 24,
with the longitudinal free edge portion 40 of the facing
sheet 34 terminating in the vicinity of the longitudinal
free edge portion 42 of the backing sheet 36. A particular
advantage with this embodiment is that the leg cuff, i.e.
the region which extends from the longitudinal edge portion
25 of the diaper to the inner cuff 14, consists essentially
of nonwoven material. This implies that the entire leg cuff
is "breathable", thereby providing more comfort to the
wearer.
In Fig. 6, an alternative embodiment of a breathable leg
cuff is illustrated. In said figure, both the facing sheet
34 and the backing sheet 36 terminate in the vicinity of
the absorbent core 38. The leg cuff is formed in this case
by an additional sheet 46 of nonwoven material. One lateral
edge portion of the additional sheet 46 is inserted between
the longitudinal free end portions 40, 42 of the facing
sheet and backing sheet respectively. The remaining
longitudinal free edge portion of the additional sheet 46
is folded under and adhered to the underside of the
additional sheet to thereby form the pocket for the elastic
band 24. Preferably, the material of the additional sheet
46 has a basis weight greater than that of the facing sheet
34, for example in the order of 25 to 40 g/m2, preferably
about 35 g/m2.
The present invention is not restricted to the embodiments
described above and illustrated by way of example in the
drawings, but may be varied within the scope of the
appended claims. For example, more than one elastic band 24
may be provided in each pocket. In the embodiment shown in
Fig. 4, it is conceivable that the elastic means 24 be
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incorporated in the longitudinal free edge portion 42 of
the backing sheet 36.
