Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
BACKGROUND OF TH:5 INVENTION
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The present invention relates to disposabl~ absorbent
articles.
A various assortment of disposable absorbent articles
have been proposed for use in receiving and retaining body fluids.
Such articles, e.g., disposable diapers, have normally been con-
structed with a fluld impervious backing sheet, a fluid pervious
cover or top sheet, and an absorbent pad intermediate the backing
and cover sheets, such as comminuted wood pulp termed in the art
as fluff. Although increasingly popular due to dl~posability, cer-
tain problems remain associated with the absorbent pads which pre-
vent the articles from being totally satisfactory.
First, it is necessary that the pads rapidly spread body
fluids from the point of application toward remote locations of
the pads in order to minimize pad saturation in localized areas
and make maximum use of the full pad capacity. Second, .it is
desirable that the pads preferentialiy retain the body fluids at
locations spaced from the cover sheet in order to minimize back
wetting through the cover sheet with attendant discomfort to the
wearer. Third, the pads should be soft and conformable to the
shape of the wearer in order to provide a proper fit of the articles
and maximum comfort. Finally, the pads should be made in accord-
ance with simplified manufacturing techniques in order to reduce
the cost of the disposable articles to the consumer.
SUMMARY OF THE INVENTION
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A principal feature of the present invention is the pro-
vision of an absorbent article of simplified construction having
improved fluid dispersing and re~ention capabilities.
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According to the present invention there is provided a disposable
absorbent article comprising a backing sheet of fluid impervious material, a
fluid pervious cover sheet, a first absorbent pad ad]acent said cover sheet
comprising a loosely formed fibrous mass, and a separate second absorbent pad
intermediate said first pad and backing sheet, said second pad comprising a
mass of fibers having compressed regions extending throughout a substantial
part of the second pad and having relatively uncompressed areas adjacent
said regions, with the average interfiber spacings in said regions being
substantially less than the average interfiber spacings in said areas and
said first pad, said regions rapidly transmitting body fluids to remote
locations of the second pad for retention in said areas at a location spaced
rom the cover sheet, the th:ickness of the second pad areas being approximately
equal to 37 mils (.09~ cm) ~ 9 mils (.023 cm) as measured under slight
compression.
The regions and areas of the second pad cooperate to disperse and
retain a relatively large quantity of fluids in the second pad at a location
spaced from the cover sheet. Thus, the pads minimize back wetting of the
body fluids through the cover sheet and maintain the cover sheet in a
relatively dry condition during use of the article.
Additionally~ the pa~ls are soft and conformable to the shape of
the wearer due to separation of the regions by the areas in the second
pad.
In the accompanying drawings, which illustrate an exemplary
embodiment of the present invention:
Figure 1 is a fragmentary front plan view of an absorbent article
of the present invention being illustrated in the form of a disposable
diaper;
Figure 2 is a fragmentary sectional view taken substantially as
indicated along the line 2-2 of Figure l; and
Figure 3 is a perspective view of the article of Figure 1 as
folded into a box-pleat configuration.
Referring now to Figures 1 and 2, there is shown a disposable
absorbent article generally designated 10 which is illustrated in the form
of a disposable diaper. Although for convenience the article of the present
invention will be described as a disposable diaper~ it will be unclerstood
that the principles of the invention are equally applicable to other
disposable absorbent articles, such as sanitary napkins and underpads. As
shown, the article or diaper 10 has an absorbent pad assembly 12 having a
fluid impervious backing sheet 14, such as polyethylene, defining a back
surface 16 of the pad assembly, a fluid pervious top or cover sheet 18,
such as a nonwoven material, defining a substantial portion o:f a front
surface 20 of the pad assembly, and an absorbent pad generally designated
22 intermediate the backing sheet 14 and cover sheet 18. With reference
to Figure 1, the diaper 10 may have
~ n5 6 ~ 9
a pair of tape fasteners 24 for securing the diaper about an
infant during placement, and the backing sheét 14 may have lateral
side margins 26 folded over and secured to the cover sheet 18 such
that the margins 26 cover side portions of the pad 22.
As shown in Figs. 1 and 2, the absorbent pad 22 has a
first absorbent pad or layer 28 located adjacent the cover sheet
18, and a second absorbent pad or layer 30 located intermediate
the first pad 28 and the backiny sheet 14. The pacl 22 may have a
top wadding sheet 32 cover:Lng a ~ront surface 34 of the upper
first pad 28, and a back wadding sheet 36 coveriny a back sur-face
38 of the lower second pad 30. In one form, as shown, a back sur-
face 40 of the first pad 28 may be placed against a front surface
42 of the second pad 30, or, in an alternative form, a fluid per-
vious sheet, such as a wadding sheet, may be interposed between
the first and second pads 28 and 30, respectively.
The first pad 28 is made from a loosely formed mass of
fibers, such as comminuted wood pulp termed in the art as fluff.
Although the first pad may be compacted, if desired, the first
pad 28 may have minimal compression in order to obtain a soft,
fluffy front pad 28 with relatively large interfiber spacings. As
w.ill be seen below, the second.lower pad 30 is also made from a
mass of fibers, such as comminuted wood pulp.
In a suitable form, before inal compression of the pad
22, the first pad 28 may have a thickness of approximately 161 mils
(.409 cm) ~ 40 mils (.102 cm) and a density of app:roximately .037
+ .00~ gm/cm3 as measured under the relativel.y slight compression
of 2.1 gm/cm2, and a thickness of approximately 72 mils (.183 cm)
~~ 18 mils (.046 cm) and a density of approxima~ely .083 ~ .021
gm/cm3 as measured under a larger compression of 51.2 gm/cm2. The
density of the pad is calculated by dividing the weight of the pad
sample by its volume. Before final compression, the lower second
pad 30 may have a thickness of approximately 63 mils (.160 cm) +
16 mils ~.041 cm) and a density of approx:imately .053 + .013 gm/cm3
as measured under the slight compression of 2.1 gm/cm~, and a
thickness of approximately 18 mils (.046 cm) + 5 mils (.013 cm)
and a density of approximately .108 + .027 gm/cm3 as measured under
the larger compression of 51.2 gm/am2. After inal compression of
the pad 22, the upper first pad 28 may have a thickness of approx-
imately 89 mils ~.226 cm) ~ 22 milc~ (.056 cm) and a d~nsity of
approximately .063 + .016 gm/cm3 as measured under the slight com-
pression of 2.1 gm/cm2~ and a thickness of approximately 49 mils
(.124 cm) + 12 mils (.030 cm) and a density of approximately .115
+ .029 gm/cm3 as measured under the larger compression of 51.2
gm/cm2. After final compression of the pad 22, the lower second
pad 30 may have a thickness of approximately 37 mils (.094 cm)
~ 9 mils (.023 cm) and a density of approximately .083 + .021 gm/cm3
as measured under the slight compression of 2.1 gm/cm2, and a
thickness of approximately 10 mils (.025 cm) + 3 mils (.008 cm)
and a density of approximately .148 ~ .037 gm/cm3 as measured
under the larger compression of 51.2 gm/cm2. After final compres-
sion of the pad 22, the combined pads 2B and 30 may have a thick-
ness of approximately 112 mils (.284 cm) + 28 mil~ (.071 cm) and
a density of approximately .074 + .019 gm/cm3 as measured under
the slight compression of 2.1 gm/cm2, and a thickness o approxi-
mately 57 mils (.145 cm) + 14 mils (.036 cm) and a density of
approximately .124 + .031 gm/cm3 as measured under the larger com-
pression of 51.2 gm/cm2.
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S6~
As shown, the second pad 30 has compressed regions 50,
such as intersecting lines of embossing, extending throughout a
substantial part of the second pad between side and end edges of
thé pad. In a preferred form, the regions 50 are spaced from and
are located generally cen~rally with respect to opposed surfaces
42 and 38 of the second pad 30. The second pad 30 also has rela-
tivel~ uncompressed areas 52 adjacent the regions 50, with the
average interfiber spacings in the areas 52 being slightly less
than or approximately equal to the average interfiber spacings in
the first pad 28. Thus, the average interfiber spacings in the
compressed reg.ions 50 are substantially less than the average
interfiber spacings in the areas 5Z of the second pad 30 and the
first pad 28. In the embodiment shown, the regions 50 define a
diamond-like configuration of the areas in pad 30, with the areas
52 being separated by the regions 50, and with the regions 50
extending in a connected pattern throughout the pad. After com-
pr.ession, a relatively large quantity of pad material is located
in a given portion of the regions 50 due to the initial thickness
of the second pad 30 prior to compression. I desired, the back
wadding sheet 36 may be compressed in regions 50' corresponding
to the regions 50 of the second pad 30, as shown in Fig. l, or the
back wadding sheet 36 may be placed against the back surface 38 of
the second pad 30 after the second pad 30 has been compressed,
such that the back wadding sheet 36 is free of compressed regions,
as shown in Fig. 2
In use, the diaper lO i9 secured about an infant by the
tape fasteners 24. During voiding, urine passes through the cover
sheet 18 into a localized portion of the first pad 28, and due to
the relatively small interfiber spacings of the regions 50 in the
second pad 30, the flu~ds are rapidly absorbed from the first pad
28 by the regions 50 of the second pad 30. Also, ~he compressed
regions S0 rapidly transmit the fluids along the regions or lines
50 to p~d portions which are remote the point of urine applica-
tion to the diaper. Although a relatively large amount vf fluf
material has been compressed in given locality of the pad regions
50, the regions 5~ have a smaller fluid holding capacity than the
areas 52 due to the relative size of their interfiber spacings.
Accordingly, the body fluids pass from the regions 50 when satur-
ated into the uncompressed areas 52 of the second pad 30. Since
the areas 52 have relatively large fluid holdiny capacity, they act
much like reservoirs which retain the body fluids in localities
spaced ~rom the point of urine application to the diaper and at a
location beneath the irst pad 28 spaced from the top sheet 18,
in srder to reduce back wetting of body fluids from the pad 22
and maintain the top sheet 18 in a relatively dry condition. In
this manner, the first and second pads 28 and 30, respectively,
cooperate to rapidly disperse fluids throughout the second pad 30
while making maximum use of the pad material and maintaining the
top sheet 18 in a relatively dry state.
As previously indicated, the first pad 28 and the pad
a~eas 52 are relatively soft and conformable since they are rela-
tively uncompressed. Accordingly, the first and second pads 28
and 30, respectively, provide a pad structure ~or the diaper which
is soft and conformable to the shape of the wearer in order to
maximize comfort and provide an excellent fit of the diaper. In
addition, the pad 22 of the present invention may ~e made in a
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i
simplified manner by embossing the second pad 30 in the regions 50,
and by then placing the first pad 28 against the second pad 30 dur
ing manufacture of the diaper. Thus, the diaper is made without
the necessity of wetting and drying the compressed regions which
would otherwise add to the complexity and cost of manuEacture.
Referring to Fig. 3, the pad assembly 12 of Fig. 1 may
be folded along a plurality of longitudinally extending fold lines
to define a box-pleat configuration of the diaper. Thus, the
diaper is folded along a pair of first fold lines 54 to define a
longitudinally extending central panel 56 and along a pair of sec-
ond fold lines 58 to define a pair of longitudinally extending
first panels 60 intermediate the fold lines 54 and 58 and a pair
of outermost panels 62 extending from the second fold lines 58.
The foregoing detailed description is given for clear-
ness of understanding only, and no unnecessary limitations shouldbe understood therefrom, as modifications will be obvious to those
skilled in the art.
