U.S. patent number 3,595,235 [Application Number 04/825,247] was granted by the patent office on 1971-07-27 for multilayer absorbent pad.
This patent grant is currently assigned to Georgia-Pacific Corporation. Invention is credited to Paul W. Jespersen.
United States Patent |
3,595,235 |
Jespersen |
July 27, 1971 |
MULTILAYER ABSORBENT PAD
Abstract
An absorbent pad, useful as a diaper, sanitary napkin, or
medical dressing, which comprises two superposed liquid-absorbent
layers and a liquid-resistant layer disposed between the absorbent
layers. The facing surfaces of the absorbent layers have different
areas and the surfaces of the resistant layer facing the absorbent
layers each have less area than the absorbent layer facing surface
of greater area so that liquid flowing into and through the
absorbent layer having the facing surface of lesser area and
contacting the resistant layer will flow about the edges of the
resistant layer into the absorbent layer having the facing surface
of greater area.
Inventors: |
Jespersen; Paul W. (Westport,
CT) |
Assignee: |
Georgia-Pacific Corporation
(Portland, OR)
|
Family
ID: |
27431088 |
Appl.
No.: |
04/825,247 |
Filed: |
May 16, 1969 |
Current U.S.
Class: |
604/364;
526/328.5; 604/380; 526/204; 604/375; 604/381 |
Current CPC
Class: |
A61F
13/535 (20130101); A61L 15/52 (20130101); A61F
13/53708 (20130101); A61F 13/53704 (20130101); A61F
13/00008 (20130101); A61F 13/53743 (20130101); A61F
2013/530131 (20130101); A61F 13/15211 (20130101); A61F
2013/51441 (20130101); A61F 2013/51443 (20130101); A61F
2013/53782 (20130101); A61F 2013/53445 (20130101); A61F
2013/51409 (20130101); A61F 2013/00744 (20130101); A61F
2013/530481 (20130101); A61F 13/534 (20130101); A61F
2013/53721 (20130101) |
Current International
Class: |
A61F
13/15 (20060101); A61F 13/00 (20060101); A61L
15/52 (20060101); A61L 15/16 (20060101); A61f
013/16 () |
Field of
Search: |
;128/284,285,287,290,296 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Rosenbaum; Charles F.
Claims
I claim:
1. An absorbent pad comprising:
first and second superposed liquid-absorbent layers, the surface of
said first absorbent layer facing said second absorbent layer
having less area than the surface of said second absorbent layer
facing said first absorbent layer; and
a liquid-resistant layer disposed between said absorbent layers and
comprising an air-pervious, substantially liquid-impervious,
flexible sheet, the surfaces of said resistant layer facing said
absorbent layers each having less area than said second absorbent
layer facing surface, said pad being adapted to be worn with said
first absorbent layer adjacent the body of a user so that liquid
flowing into and through the first absorbent layer and contacting
the resistant layer will flow about the edges of the resistant
layer into the second absorbent layer.
2. An absorbent pad as defined in claim 1, wherein the surfaces of
said resistant layer facing said absorbent layers each have
approximately the same area and dimensions as said first absorbent
layer facing surface.
3. An absorbent pad as defined in claim 1, wherein said first and
second absorbent layers comprise nonwoven sheets of
liquid-absorbent material.
4. An absorbent pad as defined in claim 3, wherein said
liquid-absorbent material includes particles of an organic
noncellulosic substance selected from the group consisting of blood
albumin, egg albumin, starches, pectin, algin, karaya, tragacanth
and guar gums, natural and synthetic gums of polysaccharide
character, chemically modified starches, and chemically modified
natural and synthetic gums of a polysaccharide character.
5. An absorbent pad as defined in claim 3, wherein said
liquid-absorbent material includes fibers of a cellulosic
substance.
6. An absorbent pad as defined in claim 1, wherein said sheet
comprises a nonwoven sheet of cellulosic fibers having a
liquid-repellant coating thereon.
7. An absorbent pad as defined in claim 1, wherein said sheet
comprises a sheet of perforated plastic film.
8. An absorbent pad as defined in claim 1, wherein said pad further
includes a cover disposed about said first and second absorbent
layers.
9. An absorbent pad as defined in claim 8, wherein the portion of
said cover disposed adjacent said first absorbent layer comprises a
liquid-pervious, nonwoven sheet of nonwettable material.
10. An absorbent pad as defined in claim 9, wherein said
nonwettable material comprises rayon fibers.
11. An absorbent pad comprising:
first and second superposed liquid-absorbent layers, the surface of
said first absorbent layer facing said second absorbent layer
having less area than the surface of said second absorbent layer
facing said first absorbent layer;
a liquid-resistant layer disposed between said absorbent layers,
the surfaces of said resistant layer facing said absorbent layers
each having less area than said second absorbent layer facing
surface, said pad being adapted to be worn with said first
absorbent layer adjacent the body of a user so that liquid flowing
into and through the first absorbent layer and contacting the
resistant layer will flow about the edges of the resistant layer
into the second absorbent layer; and
a cover disposed about said first and second absorbent layers, the
portion of said cover disposed adjacent said second absorbent layer
comprising an air-pervious, substantially liquid-impervious,
flexible sheet.
12. An absorbent pad as defined in claim 11, wherein said sheet
comprises a nonwoven sheet of cellulosic fibers having a
liquid-repellant coating thereon.
13. An absorbent pad as defined in claim 11, wherein said sheet
comprises a sheet of perforated plastic film.
14. An absorbent pad comprising:
first and second superposed liquid-absorbent layers, the surface of
said first absorbent layer facing said second absorbent layer
having less area than the surface of said second absorbent layer
facing said first absorbent layer;
a liquid-resistant layer disposed between said absorbent layers,
the surfaces of said resistant layer facing said absorbent layers
each having less area than said second absorbent layer facing
surface, said pad being adapted to be worn with said first
absorbent layer adjacent the body of a user so that liquid flowing
into and through the first absorbent layer and contacting the
resistant layer will flow about the edges of the resistant layer
into the second absorbent layer;
a cover disposed about said first and second absorbent layers;
and
a liquid-dispersant layer disposed between said second absorbent
and resistant layers, the surfaces of said dispersant layer facing
said second absorbent and resistant layers each having
approximately the same area and dimensions as said second absorbent
layer facing surface so that the dispersant layer will distribute
liquid flowing about the edges of the resistant layer across said
second absorbent layer facing surface.
15. An absorbent pad as defined in claim 14, wherein said pad
further includes a second liquid-dispersant layer disposed between
said first absorbent layer and said cover, the surfaces of said
second dispersant layer facing said first absorbent layer and said
cover having approximately the same area and dimensions as the
surface of said first absorbent layer facing said cover so that the
second dispersant layer will distribute liquid flowing through said
cover across said surface of the first absorbent layer facing the
cover.
16. An absorbent pad as defined in claim 15, wherein said
first-mentioned and second dispersant layers comprise nonwoven
sheets of material having a substantially higher capillarity than
the material from which said first and second absorbent layers are
comprised.
17. An absorbent pad as defined in claim 16, wherein said material
of substantially higher capillarity comprises cellulosic
fibers.
18. An absorbent pad as defined in claim 15, wherein said first and
second absorbent, resistant, and first-mentioned and second
dispersant layers are disintegratable in water.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an absorbent pad, and more particularly
to a multilayer absorbent pad having a relatively high capacity for
retaining liquids.
2. Description of the Prior Art
Absorbent pads are well known; such pads being principally used for
absorbing and retaining liquids and exudates discharged from the
body. Thus, absorbent pads have been employed as diapers, sanitary
napkins and medical dressings.
Frequently, woven sheets of plant and animal fiber yarns, i.e.
cotton cloth, have been used for making absorbent pads. Recently,
however, nonwoven sheets of cellulosic and other organic fibers
have been used for making such pads. The nonwoven sheets are not
only less expensive to manufacture than the woven sheets, but
generally are disintegratable in water. Therefore, absorbent pads
made of nonwoven sheets are ideally suited for disposal after a
single use.
Generally, however, absorbent pads made of nonwoven sheets do not
disperse the liquid being absorbed uniformly throughout the pad.
The liquid thus penetrates a portion of the pad before all portions
of the pad have been wetted. This situation constitutes not only a
source of discomfort to the user of the pad but also an inefficient
use of the nonwetted portions of the pad.
SUMMARY OF THE INVENTION
The absorbent pad of the present invention minimizes the foregoing
problem. Generally described, the absorbent pad of the invention
comprises; first and second superposed liquid-absorbent layers, the
surface of the first layer which faces the second layer having less
area than the surface of the second layer which faces the first
layer; and a liquid-resistant layer disposed between the absorbent
layers, the surfaces of the resistant layer which face the
absorbent layers each having less area than said second absorbent
layer facing surface, the pad being adapted to be worn with the
first absorbent layer adjacent the body of a user so that liquid
flowing into and through the first absorbent layer and contacting
the resistant layer will flow about the edges of the resistant
layer into the second absorbent layer.
The surfaces of the resistant layer which face the absorbent layers
preferably each have approximately the same area and dimensions as
said first absorbent layer facing surface.
Preferably, the pad also includes a liquid-dispersant layer
disposed between the second absorbent and resistant layers, the
surfaces of the dispersant layer which face the second absorbent
and resistant layers each having approximately the same area and
dimensions as said second absorbent layer facing surface so that
the dispersant layer will distribute liquid flowing about the edges
of the resistant layer across said second absorbent layer facing
surface.
With the foregoing in mind, it is an object of the present
invention to provide an improved absorbent pad.
It is also an object of the invention to provide a multilayer
absorbent pad having a high capacity for retaining liquids.
It is a further object of the invention to provide a multilayer
absorbent pad in which substantially all portions of the pad become
wetted before liquid penetrates any one portion of the pad.
These and other objects of the invention will become apparent upon
a consideration of the following detailed description of a
preferred embodiment thereof given in connection with the following
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of the preferred embodiment of the absorbent
pad of the invention; and
FIG. 2 is a sectional view taken along line 2- 2 of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment of the absorbent pad of the invention is
shown in the drawings, as designated by reference numeral 10. Pad
10 comprises a plurality of superposed layers, preferably all of
which are disintegratable in water, and including first and second
liquid-absorbent layers 12 and 14. Pad 10 is adapted to be worn
with layer 12 adjacent the body of a user. Therefore, to facilitate
the description of pad 10, the side of the pad adapted to be worm
adjacent the body will be referred to as the inner side and the
side of the pad adapted to be worn away from the body will be
referred to as the outer side. A similar reference system will be
used for describing the relationships between the various layers
comprising pad 10.
Layers 12 and 14 comprise nonwoven sheets of liquid-absorbent
material, such as cellulosic fibers, and/or organic noncellulosic
particles and/or fibers as disclosed in Torr U.S. Pat. Nos.
3,347,236 and 3,070,095. As described in the aforesaid Torr
patents, such organic noncellulosic particles and/or fibers
preferably comprise the particles and/or fibers of a substance
selected from the group consisting of blood albumin, egg albumin,
starches, pectin, algin, karaya, tragacanth and guar gums, natural
and synthetic gums of polysaccharide character, chemically modified
starches, and chemically modified natural and synthetic gums of
polysaccharide character. Similarly to many cellulosic substances,
such noncellulosic substances are both liquid-absorbent and
harmless to the body in either a dry or wetted state. Layers 12 and
14 are rectangularly shaped and are of substantially the same
length. However, layer 12 is narrower than layer 14 so that the
outer surface of layer 12 has less area than the inner surface of
layer 14, i.e. the surface of layer 12 which faces layer 14 has
less area than the surface of layer 14 which faces layer 12. Also,
layer 12 is transversely centered on layer 14.
Pad 10 also includes a liquid-resistant layer 16 disposed between
absorbent layers 12 and 14. Layer 16 may comprise a
fluid-impervious sheet, but preferably comprises an air-pervious,
substantially liquid-impervious flexible sheet; the term
substantially liquid-impervious meaning penetrable by liquid after
continuous exposure thereto for a period greater than several
seconds, e.e. 1-- 5 minutes. Such sheets may comprise a nonwoven
sheet of cellulosic fibers having a liquid-repellant coating
thereon, i.e. a coating of latex, size or a foam-applied organic
suspension, or a sheet of perforated plastic film. The length and
width of layer 16 are less than the length and width of layer 14 so
that the inner and outer surfaces of layer 16 each have less area
than the inner surface of layer 14, i.e. the surfaces of layer 16
which face layers 12 and 14 each have less area than the surface of
layer 14 which faces layer 12. Preferably, the length and width of
layer 16 are approximately the same as the length and width of
layer 12 so that the inner and outer surfaces of layer 16 each have
approximately the same area as the outer surface of layer 12, i.e.
the surfaces of layer 16 which face layers 12 and 14 each have
approximately the same area and dimensions as the surface of layer
12 which faces layer 14.
Pad 10 further includes a liquid-dispersant layer 18 disposed
between outer absorbent layer 14 ad resistant layer 16. Layer 18
comprises a nonwoven sheet of material having a substantially
higher capillarity than the material from which absorbent layers 12
and 14 are comprised, such as a creped sheet of cellulosic fibers.
The length and width of layer 18 are approximately the same as the
length and width of layer 14 so that the inner and outer surfaces
of layer 18 each have approximately the same area as the inner
surface of layer 14, l.e. the surfaces of layer 18 which face
layers 14 and 16 each have approximately the same area and
dimensions as the surface of layer 14 which faces layer 12.
Pad 10 additionally includes a cover 20 disposed about absorbent
layers 12 and 14 and having an inner portion 22 and an outer
portion 24. Cover portions 22 and 24 hold the various layers of pad
10 together in assembled condition.
Outer portion 24 is disposed adjacent the outer surface of outer
absorbent layer 14 and has approximately the same length and width
as layer 14. Similarly to resistant layer 16, outer portion 24 may
comprise a fluid-impervious sheet, but preferably comprises an
air-pervious, substantially liquid-impervious, flexible sheet.
Inner portion 22 is disposed adjacent the inner surface of inner
absorbent layer 12 with the edges thereof extending beyond the
edges of outer absorbent layer 14 and outer portion 24. The edges
of portion 22 are wrapped around the edges of portion 24 and are
secured to the outer surface of the latter in any convenient
manner, as by adhesive bonding or heat sealing. Inner portion 22
comprises a liquid-pervious, nonwoven sheet of nonwettable
material, such as a sheet of rayon fibers.
Pad 10 further includes a second liquid-dispersant layer 26
disposed between inner absorbent layer 12 and inner cover portion
22. Similarly to layer 18, layer 26 comprises a nonwoven sheet of
material having a substantially higher capillarity than the
material from which absorbent layers 12 and 14 are comprised, such
as a creped sheet of cellulosic fibers. The length and width of
layer 26 are approximately the same as the length and width of
layer 12 so that the inner and outer surfaces of layer 26 each have
approximately the same area as the inner surface of layer 12, i.e.
the surfaces of layer 26 which face layer 12 and cover portion 22
each have approximately the same area and dimensions as the surface
of layer 12 which faces portion 22.
As mentioned above, pad 10 is adapted to be worn with absorbent
layer 12 adjacent the body of a user. Inner cover portions 22 thus
is placed in intimate contact with the body so that liquids or
exudates discharged from the body flow into the pad in the
direction of arrow 28 (FIG. 2). The liquid passes through inner
cover portion 22 without being absorbed thereby so that the portion
of the pad in intimate contact with the body remains relatively dry
to provide maximum comfort. After passing through cover portion 22,
the liquid flows into dispersant layer 26 which, due to the
relatively high capillarity thereof, not only disperses the liquid
across the inner surface of absorbent layer 12 but also accelerates
the flow of liquid through portion 22.
The liquid flows into and is retained in layer 12 until such layer
becomes saturated. Thereafter, since resistant layer 16 is
substantially liquid-impervious, the liquid flows about the edges
of layer 16 into dispersant layer 18 as shown by arrows 30 (FIG.
2). Resistant layer 16 thus prevents the liquid from flowing
directly into layer 18 and thereby minimizes the possibility that
the liquid will penetrate one portion of pad 10 before all portions
of the pad have been wetted. Dispersant layer 18, similarly to
layer 26, not only disperses the liquid across the inner surface of
absorbent layer 14, including the portion thereof adjacent the
outer surface of layer 16, but also prevents the liquid which flows
about the edges of layer 16 from passing back through cover portion
22. In this fashion the liquid flows into layer 14 until such layer
becomes saturated.
The above-described flow pattern of liquids within pad 10 provides
maximum comfort to a user by minimizing liquid-body contact, and
maximizes efficient use of the material from which the pad is
comprised by ensuring that substantially all portions of the pad
become wetted before liquid penetrates any one portion of the pad.
Also, due to such flow pattern, pad 10 has a relatively high
capacity for retaining fluids.
If air-pervious, substantially liquid-impervious, flexible sheets
are employed for resistant layer 16 and outer cover portion 24, an
additional benefit is obtained. Air circulating through cover
portion 24 and to a lesser extent layer 16 will promote evaporation
of the liquids retained in pad 10 and thus increase the useful life
of the pad.
After a single use, pad 10 preferably is disposed of. Since the
various layers of the pad preferably are disintegratable in water,
one sanitary and expedient method of disposing of a used pad is to
discard the pad into a toilet. After soaking for a few moments the
various layers of the pad will disintegrate and can be flushed into
the sewer.
As will be apparent pad 10 is ideally suited for use as a
disposable diaper, sanitary napkin or medical dressing; the size
and shape of the pad being tailored to suit the desired use.
While the foregoing constitutes a detailed description of the
preferred embodiment of the invention, it is recognized that
various modifications thereof will occur to those skilled in the
art.
* * * * *