Note: Descriptions are shown in the official language in which they were submitted.
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STITCH BONDED FABRIC AND
FLUID-RETAINING FABRIC iVLADE THEREWITH
Background of the Invention
1. Field of the Invention
The present invention relates to stitch bonded fabrics, and more
particularly, to such fabrics used as fluid-retaining fabrics such as in
incontinent
products.
H. Description of Prior Art
Various incontinent pads have been employed such as in hospital
settings to retain fluids expelled from the body while also protecting the bed
linens therebelow. To this end, a typical incontinent pad has a knit or woven
facing fabric layer to which is quilted a felt layer. The facing fabric layer
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provides a soft, comfortable layer asainst the patient's skin, and cooperates
with
the felt layer to hold the large volume of fluid that may be expelled from the
patient. The felt layer further provides rigidity to the pad so that it does
not
crumple up and become uncomfortable under the weight of the patient.
A barrier layer, typically of vinyl or polyurethane with an outer
tricot fabric layer, is attached to the felt such as by being stitched to the
edge of
the quilted layers or by being bonded to the felt with adhesive. To provide
for
better patient comfort, it is desirable to wick fluids away from the topside
of the
facing fabric so as to maintain as dry a surface as possible. To this end, one
highly desirable facing fabric developed and marketed by Standard Textile Co.,
Inc., under the mark Comply (& is an integral web fabric that provides a
hydrophobic upper surface and a hydrophilic lower surface in wicking
communication with the upper surface. With that fabric, fluids are wicked awav
from the face of the fabric and into the hydrophilic, fluid-absorbing lower
portion
where the fluids may be retained.
While incontinent pads have enjoyed wide-spread success, the
manufacture of such pads presents significant cost concerns, especially due to
the need to separately manufacture the facing fabric and the felt layer, and
to
then apply the quilting process to hold those layers together.
Summary of The Invention
The present invention provides an improved fluid-retaining fabric
such as may be substituted for the facing fabric and felt of the prior
incontinent
pads and which reduces the costs of manufacture thereof. To this end, and in
accordance with principles of the present invention, the fabric of the present
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invention is provided by stitch bonding a felt web having a hydrophobic upper
aspect
and a hydrophilic lower aspect, with stitch bonding yarns which in a single
process
holds the felt web aspects together and also defines top and bottom ya.m faces
of the
fabric formed with the stitch bonding yarns, with the top yarn face presenting
the
patient comfort surface, and the bottom yarn face providing a surface for
adhesive
connection to a barrier layer without interfering with either the structural
rigidity or
absorbency provided by the felt web.
The stitch-bonded fabric of the present invention may be utilized as a
fluid-retaining fabric and may be incorporated into an incontinent pad such as
by the
attachment of a barrier layer to the bottom yarn face.
In accordance with one aspect of the present invention, there is
provided a stitch bonded facing fabric comprising a first layer of hydrophobic
felt; a
second layer of hydrophilic felt being adjacent to the first layer so as to
define a felt
web having an upper surface defined by an upper side of the first layer and a
lower
surface defined by a lower side of the second layer; and a plurality of stitch
bonding
yarns repeatedly extending through the felt web with yarn segments extending
across
both the upper and lower surfaces of the felt web such that the yarn segments
extending across the felt web upper surface cooperate to form a top yarn face
above
the felt web upper surface and the yarn segments extending across the felt web
lower
surface cooperate to form a bottom yarn face below the felt web lower surface;
wherein each yarn face is effectively continuous such that the corresponding
web
surface is not generally exposed at the associated yarn face.
In accordance with another aspect of the present invention, there is
provided a stitch bonded facing fabric comprising a felt web having a
hydrophobic
upper aspect extending from an upper surface of the web and a hydrophilic
lower
aspect extending from a lower surface of the web; and a plurality of stitch
bonding
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yarns repeatedly extending through the felt web with yarn segments extending
across
both the upper and lower surfaces of the felt web such that the yarn segments
extending across the felt web upper surface cooperate to form a top yarn face
above
the felt web upper surface and the yarn segments extending across the felt web
lower
surface cooperate to form a bottom yarn face below the felt web lower surface;
wherein each yarn face is effectively continuous such that the corresponding
web
surface is not generally exposed at the associated yarn face.
In accordance with another aspect of the present invention, there is
provided a fluid-retaining fabric comprising a stitch bonded facing fabric
having a
first layer of hydrophobic felt, a second layer of hydrophilic felt being
adjacent to the
first layer so as to define a felt web having an upper surface defined by an
upper side
of the first layer and a lower surface defined by a lower side of the second
layer, and a
plurality of stitch bonding yarns repeatedly extending through the felt web
with yarn
segments extending across both the upper and lower surfaces of the felt web
such that
the yarn segments extending across the felt web upper surface cooperate to
form a top
yarn face above the felt web upper surface and the yarn segments extending
across the
felt web lower surface cooperate to form a bottom yarn face below the felt web
lower
surface; wherein each yarn face is effectively continuous such that the
corresponding
web surface is not generally exposed at the associated yarn face; and a
barrier layer
attached to the bottom yarn face.
By virtue of the foregoing, there is thus provided an improved facing
fabric that incorporates the advantageous features of a felt layer without the
added cost
of separate manufacture of the facing fabric and the felt, and without the
cost of the
still-further quilting process.
Brief Description of the Drawings
The accompanying drawings, which are incorporated in and constitute
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a part of this specification, illustrate embodiments of the invention and,
together with
the general description of the invention given above and the detailed
description of the
embodiments given below, serve to explain the principles of the present
invention.
Fig. 1 is a perspective view of one embodiment of a sheet of stitch
bonded fabric in accordance with the principles of the present invention;
Fig. 2 is a cross-sectional diagrammatic, partially broken away view of
the fabric of Fig. 1;
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Fig. 3 is a close-up, top elevational view of the fabric of Fig. 1;
Fig. 4 is a close-up, bottom elevational view of the fabric of Fig.
Fig. 5 is a view like Fig. 2 showing an alternative embodiment of
a stitch bonded fabric in accordance with the principles of the present
invention;
Fig. 6 is a partial cross-sectional view of edge stitching of an
incontinent pad incorporating the fabric sheet of Fig 1;
Fig. 7 is a cross-sectional, diaorammatic view of an incontinent
pad incorporating the fabric sheet of Fig. 1; and
Fig. 8 is a view like Fig. 2 showing the sheet of Fig. 1 with an
interposed scrim layer.
Detailed Description of the Drawings
With reference to Figs. 1-4, there is shown one embodiment of a
sheet 10 of stitch bonded fabric constructed in accordance with the principles
of
the present invention. Sheet 10 includes a central felt web 12 having an upper
layer or aspect 14 of hydrophobic felt and a lower layer or aspect 16 of
hydrophilic felt so as to be fluid retaining relative to upper aspect 14.
Layer 14
may be composed of polyester and/or polypropylene and layer 16 may be
composed of rayon. Layers 14 and 16 are secured together by a plurality of
stitch bonding threads or yarns 18. Felt layers 14, 16 may be two separate,
but
adjacent layers or may be needle punched together into a single, integral web.
In
either case, web 12 presents an upper surface 20 defined by the upper side of
the
first layer 14, and a lower surface 22 defined by the lower side of the second
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layer 16. The properties of web 12 are such that fluid presented to layer 14
will wick
down into layer 16 where it may be retained.
Stitch bonding yarns 18 repeatedly extend through felt web 12 with a
plurality of yarn segments 18' extending over or across the upper surface 20
of web
12, and a plurality of yarn segments 18" extending over or across lower
surface 22 of
web 12. It will be appreciated that yarn segments 18' and 18" do not become
embedded into the web 12 below surfaces 20 or 22 thereof, but rather extend
across
the surfaces 20 and 22, and are of sufficient density that yarn segments 18'
cooperate
to define a top yarn face 24 of sheet 10 above web upper surface 20, and yarn
segments 18" cooperate to define a bottom yarn face 26 of sheet 10 below web
lower
surface 22. Faces 24 and 26 are effectively continuous such that web 12 is not
exposed thereat, although small gaps or interstices (as at 28) between
adjacent yarn
segments 18' or 18" may allow viewing of felt surface 20 or 22 upon close
inspection.
It will be noted that Figs. 3 and 4 are greatly exaggerated to show
interstices 28 in
faces 24 and 26.
Yarns 18 are knitted in a flat stitch construction across the web upper
surface 20 such that yam segments 18' form underlaps as at 30 in Fig. 3. Yarn
segments 18", on the other hand, form overlaps as at 32 in Fig. 4. The
underlaps 30
and overlaps 32 are the result of the usual knit construction provided by
stitch bonding
such as with existing Malipol-type machines as are known in the art. With such
machines, sheet 10 is formed such that top yarn face 24 is at the technical
back and
bottom yarn face 26 is at the technical face during the knitting process. Yarn
18 may
be hydrophobic or hydrophilic, the former assisting in wicking fluid down into
lower
layer 16 of felt web 12. Yarns 18 may be continuous polymeric filaments of
hydrophobic material such as polyester or may be spun yarns of natural
hydrophilic
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material such as cotton, or may be a blend of polymeric and natural materials.
With reference to Fig. 5, an alternative embodiment of stitch bonded
fabric 10' is constructed like sheet 10 but with yarns 18 being stitched in a
loop knit
construction across web upper surface 20 such that yarn segments 18' also
define a
plurality of loops 36 in the top yarn face 24.
In use, sheet 10 may function as a fluid-retaining fabric such that fluid
(not shown) at face 24 will pass into web 12 and be wicked from layer 14 into
layer 16
of web 12 whereat the fluid is retained. To this end, a barrier layer 40 may
be attached
to bottom yarn face 26 of the sheet to thus define an incontinent pad 44 or
the like as
shown in Figs. 6 and 7. Barrier layer 40 may include a fluid barrier ply 46
such as
vinyl or polyurethane. Additionally, layer 40 may include a tricot ply 48 to
provide a
fabric outer layer to pad 44. Barrier ply 46 may be attached to yarn face 26
by
edge-stitching 50 to sheet 10 or may be attached directly to yarn segments 18"
of yarn
bottom face 26. Alternatively, barrier ply 46 may be adhesively applied to
face 26
such as with an adhesive lamination layer 52, depending upon the materials
involved
and the performance characteristics of the barrier layer 40.
By virtue of the foregoing, there is thus provided a combined facing
fabric and felt such as for incontinent products that may be made in one
process step
to thereby reduce the cost of manufacture thereof
While the present invention has been illustrated by the description of
embodiments thereof, and while the embodiments have been described in
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considerable detail, it is not intended to restrict or in any way limit the
scope of
the appended claims to such detail. Additional advantages and modifications
will
readily appear to those skilled in the art. For example, one or more
additional
layers such as a hydrophobic scrim 60 (Fig. 8) of remay material may be
interposed over (or under) web 12 such as between surface 20 and yarn
segments 18' (and/or between surface 22 and yarn segments 18") to provide a
protective layer to prevent the non-woven fibers (not shown) of felt web 12
from
projecting through yarn face 24 (or 26) created by the stitch bonding yarns
18'
(or 18"). The invention in its broader aspects is, therefore, not limited to
the
specific details, representative apparatus and method, and illustrative
examples
shown and described. Accordingly, departures may be made from such details
without departing from the spirit or scope of the general inventive concept.
Having described the invention, what is claimed is:
