Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF T~E INVENTION
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FIELD OF THE INVENTION
This invention relates to disposable products~ such
as diapers, sanitary pads, and the like, and more particularly
to a disposable diaper having a we~ strength hydrophobic tissue
waddin~ for preventing fluid we-tback while maintaining the shape
of the absorbent pad.
DESCRIPTION OF Tl-IE PRIOR ART
Disposable diapers having an absorbent pad formed of
a core of wood fluff or like material are well known. These
pads have been used with and provided with a tissue wadding which,
in the past, has been of highly fluid permeable and fluid absor-
bent material. Waddings have been used to wrap the absorben-t
pad, but the tissue wadding when we-t loses strength and, ;n use,
-the pad often loses shape, absorbing qualities, and permits an
unwanted degree of flu:id wetback.
Attempts have been made to provide a barrier to the
1uid wetback, such as the barrier layer shown in the patent to
John Michael Hernandez, No. 3,987,792, for Disposable Diaper
Having Improved Liquid Retention. However, the hydrophobic
fibers of the barrier layer of this prior patent form a rela-
tively thick resilient fibrous pad and because of the difficulty
of penetration thereof, a water pervious top layer having fluid
feeding openings therein must be used.
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According to the inven-tion~ there is provided a
disposable diaper comprising, in order, a top sheet of
hydrophobic non-woven fibers capable of passing fluid but not
absorbing the fluid, an absorben~ pad having a wrapping there-
about of a tissue wadding formed of hydrophobic non-woven
material for retaining the shape of the pad while resisting fluid
wetback, said top sheet and said tissue wadding being formed of
fibers of polyethylene or polypropylene or a combination thereof,
a water impervious backing sheet, and means holding said diaper
in assembled condition. The tissue wadding being of hydrophobic
nature tends to retain its full strength even after fluid has
passed into the absorbent pad. The wadding cooperates w:ith the
top sheet in preventing fluid wetback, thus providing a dry
surface in contact with the skin of the user.
Accordingly, the present invention is directed to
provide a disposable diaper having means to retain the shape of
the absorbent pad and which eliminate to a high degree fluid
wetback.
Furthermore the invention provides a disposable diaper
which has a high degree of resistance to fluid wetback yet does
not re~uire a thick barrier layer, thereby providing a maximum
amount of absorbing material while limiting the bulk and si~e o
the diaper. Thus the invention utilizes a structure of two thin
layers of hydrophobic non-woven material to reduce fluid wetback
and maintain an infant using the disposable diaper in a dryer
condition.
Other advantages and features, which will become
apparent as the following description proceeds, are attained by
this disposable diaper, preferred embodiments of which have been
illustrated in the accompanying drawing, by way of examply only,
wherein:
Figure 1 is an exploded perspective view of a diaper
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constructed in accordance w.ith the concepts of the present
invention, with parts being broken away to show other parts in
detail;
Figure 2 is a vertical sectional view, taken along
the plane of line 2-2 i~n Figure l; and,
Figure 3 is a view similar to Figure 2, but illustrating
a preferred form of the invention with the tissue wadding wrapped
about the pad.
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~ ith continuing reference to the acc~mpanying drawing, wherein
like reference numerals designate similar parts throughout the various
views, reference numeral 10 is used to generally designate a disposable
diaper constructed in accordance with ~he concep~s of the present
invention. The diaper comprises, in order, a top sheet l2 formed of
non-woven hydrophobic fibers of polyethylene or polypropylene or a
combination thereof. This layer is water pervious, but not l~ater absorbing,
and permits passage of waste fluid toward the absorbent pad 14, which is
separated from the top sheet 12 by a tissue wadding of hydrophobic non-
woven fibers, preferably of polyethylene or polypropylene, or a combination
thereof.
A wadding 18 overlies the pad which sits on a water impervious
backing sheet 20 formed of a suitable synthetic plastic material, such as
polyethylene film. The backing sheet is folded over the top slleet 12 at 22,
and secur0d thereto to hold the diaper in assembled condition. Adhesives,
heat sealing, embossing or other means may be used for assembly purposes.
The core 14 is preferably formed of a wood fluff or tissue layers of paper-
like material, which are highly absorbent. This material, when subjected to
stress, will readily distort. In order to assure the shape of the pad, a
tissue wadding 26 may be wrapped about the pad 14 in lieu of the wadding
sheets 16 and 18.
The wrapped wadding 26 maintains the shape of the pad by pro-
viding a high strength wrapping because this hydrophobic material has a very
good degree of wet strength and in fact does not absorb fluidJ thereb-y not
becoming weakened by the passage of fluid therethrough. The hydrophobic
material resists fluid wetback and in conjunction with the hydrophobic top
sheet achieves a high degree of resistance to fluid wetbackJ even though the
material will readily pass fluid into the pad 14. This is because the
wadding, unlike the tissue waddings of the prior art, does not absorb fluid.
Various changes and modifications of the disposable product are
contempla~ed within the scope of the appended claims. f
