U.S. patent number 3,799,167 [Application Number 05/214,168] was granted by the patent office on 1974-03-26 for disposable absorbent pad.
This patent grant is currently assigned to Cellu-Products Company. Invention is credited to Grover C. Currie, Alan H. Miller.
United States Patent |
3,799,167 |
Miller , et al. |
March 26, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
DISPOSABLE ABSORBENT PAD
Abstract
An absorbent pad structure is provided of the sort that is
arranged to be disposable and that is particularly suited for use
in forming disposable diapers. The disclosed structure incorporates
pad means of moisture permeable material having a peripheral margin
thereof rendered moisture impermeable and a moisture impermeable
backing sheet secured at the peripheral margin of the pad
means.
Inventors: |
Miller; Alan H. (Hickory,
NC), Currie; Grover C. (Lenoir, NC) |
Assignee: |
Cellu-Products Company
(Patterson, NC)
|
Family
ID: |
22798036 |
Appl.
No.: |
05/214,168 |
Filed: |
December 30, 1971 |
Current U.S.
Class: |
604/382; 604/372;
604/370; 604/375 |
Current CPC
Class: |
A61F
13/49473 (20130101); A61F 13/51305 (20130101); A61F
13/4755 (20130101); A61F 2013/51042 (20130101); A61F
2013/51409 (20130101); A61F 13/534 (20130101); A61F
2013/530131 (20130101); A61F 2013/53445 (20130101); A61F
2013/51061 (20130101) |
Current International
Class: |
A61F
13/15 (20060101); A41b 013/02 () |
Field of
Search: |
;128/284,287,29R,29W,29P,296 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Rosenbaum; Charles F.
Attorney, Agent or Firm: Richards, Shefte & Pinckney
Claims
We claim:
1. A disposable absorbent pad comprising a moisture impermeable
backing sheet, a core pad of abosrbent material superimposed on
said backing sheet, and a moisture impermeable covering sheet
applied to said core pad, said backing and covering sheets
corresponding in size and extending peripherally beyond said core
pad, and said covering sheet being treated to render the same
moisture impermeable at a continuous peripheral margin thereof
reaching inwardly over a substantial peripheral portion of said
core pad and being secured to said back sheet throughout the entire
peripheral extent of said margin so as to form a seal thereat
against lateral escape of moisture from said core pad in any
direction.
Description
BACKGROUND OF THE INVENTION
Disposable diapers as heretofore developed in the art commonly
employ an absorbent pad of plied and creped wood pulp wadding
covered with a moisture permeable non-woven fabric sheet and backed
by a moisture impermeable protective sheet. Representative prior
disclosures are found in U.S. Pats. No. 2,788,003, Reissue No.
26,151, and No. 3,426,756. A problem evident from these prior
disclosures has been that of providing satisfactorily against
leakage of waste materials by wicking or seepage at the edges of
the diaper. The present invention deals effectively with this
problem in an improved manner.
SUMMARY OF THE INVENTION
Briefly described, the present invention is characterized by the
combination of pad means of moisture permeable material having a
peripheral margin thereof rendered moisture impermeable and a
moisture impermeable backing sheet secured to the pad means at its
peripheral margin so as to be sealed thereat against lateral escape
of moisture from the pad means.
The peripheral margin of the pad means is rendered moisture
impermeable by treatment with a suitable waterproofing composition
as noted further below, and marginal sealing of the backing sheet
is preferably effected with a waterproof adhesive, although heat
sealing may be employed alternatively for this purpose if
desired.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a disposable diaper structure embodying
the present invention; and
FIG. 2 is an enlarged partial section detail taken substantially at
the line 2--2 in FIG. 1.
DETAILED DESCRIPTION OF THIS INVENTION
The disposable diaper structure illustrated in the drawings, and
indicated generally by the reference numeral 10, incorporates a pad
means 12 formed by a core pad 14 of absorbent material, such as
plied and creped wood pulp wadding of the usual sort, with a
covering sheet 16 of moisture permeable non-woven fabric of
hydrophobic character, such as may be formed with blended acrylic
and rayon fiber, applied thereto.
As shown, the diaper structure 10 is shaped rectangularly in plan
with the non-woven cover sheet 16 extending somewhat beyond the
core pad 14 in both length and breadth. For example, in a diaper
size using a core pad 14 in a length of 16 inches and a width of 12
inches, the dimension of cover sheet 16 should be increased by 1
inch in both directions so as to provide a 1/2 inch extension all
around for the securing purposes explained in detail further
below.
Additionally, a peripheral margin of the pad means 12 is rendered
moisture impermeable by treating the cover sheet 16 with a
waterproofing composition in an extent reaching inwardly over the
edges of core pad 14 as indicated by stipling at 16' in FIGS. 1 and
2. For exemplary dimensions such as are mentioned above, this
inward extent of the peripheral waterproofing of cover sheet 16
should reach over core pad 14 for about 1 inch from its edges.
The diaper structure 10 is completed by a waterproof backing sheet
18 of a moisture impermeable material such as polyethylene film,
which is provided in a size corresponding with that of cover sheet
16 and is secured marginally to cover sheet 16 with a waterproof
adhesive, as indicated in FIG. 2 at 20, as as to form a seal
thereat against lateral escape of moisture from the core pad
14.
The result of this arrangement is to contain the abosrbent core pad
14 edgewise within a moisture impermeable envelope that not only
eliminates all problem with leakage of waste materials therefrom,
but also prevents any objectionable separation of core pad portions
from the pad unit during use, which has been a further problem with
prior art arrangements.
Treatment of the covering sheet 16 to render its peripheral margin
16' moisture impermeable can be effected with any composition that
will apply readily to saturate the covering sheet material and cure
to waterproof the same without stiffening unduly or being
chemically irritating in any respect during use of the pad unit. A
suitable composition meeting these requirements employs (by weight)
100 parts of emulsified acrylic polyester at 40-70 percent solids
formulated with 1-15 parts of emulsified polyacrylic acid salt at
20-40 percent solids and adjusted for proper application viscosity
with 3-12 parts of a volatile amine or hydroxide base as well as
incorporating 0.1-5.0 parts of a latent acid catlyst.
Alternatively, a solvent solution of 100 parts (by weight) of
acrylic polyester at 40-70 percent solids with 15-45 parts of
formaldehyde, urea or melamine type resins at 50-90 percent solids
may be used. Either of these compositions can be applied
effectively to non-woven covering sheet material by roller printing
and cured in times ranging from 15 seconds to 5 minutes at
temperatures within the range of 200.degree. to 450.degree.F.
A further composition that may be used is composed of 100 parts (by
weight) of emulsified and stabilized butyl rubber polymer at 40-70
percent solids which may be cured with or without heat (up to
350.degree.F) in from 20 minutes to overnight, or from which
vulcanilates may be obtained by adding 2-6 parts of elemental
sulfur or 2-10 parts of zinc diethyl dithiocarbamate or 2-8 parts
of zinc dibutyl dithiocarbamate, together with a small amount of
soluble ionic dithiocarbamate or 2-5 parts of an alkaline
dispersion of guanadine acetate. Such additions are mixed with the
butyl rubber polymer at a pH of 7.0-9.5, and viscosity is adjusted
by further addition of 1-8 parts of ammonium or sodium
carboxymethyl cellulose or 0.1-3.0 parts of ammonium or sodium
chloride. Whenever necessary application tack may be improved by
the further addition of 5-30 parts phenol-formaldehyde resin or the
like.
Any of these formulations may be pigmented if desired although the
first and last ones require use of a primary dispersant for this
purpose. Also, all three formulations can be modified to exhibit
fire retardant properties by the addition of 15-45 parts of zinc
borate, alumina trihydrate, or alumina hexahydrate.
In addition, either of the first two formulations can be used quite
well as adhesives for securing the covering and backing sheets 16
and 18 peripherally when adjusted to a suitably increased viscosity
for this purpose.
The procedure for forming a pad structure 10 in accordance with the
present invention for disposable diaper use follows usual practice
in plying and creping (or embossing) the wood pulp wadding and then
cutting the same transversely to form successive core pads 14 of
proper size. Then the cut core pads 14 are laminated in registering
relation between a suitably wider top running stip of the non-woven
covering sheet material, to which a formulation of the foregoing
sort has been applied and cured to render the same moisture
impermeable at the areas that will form the peripheral margins 16'
in successive pad units 10, and a correspondingly wide bottom
running strip of the moisture impermeable backing sheet material,
to which securing adhesive has been applied to form the peripheral
seal 20 during the laminating step. After which, the laminated
structure, still in running strip form, is box pleated to the usual
disposable diaper disposition and then cut into separate diaper
units and finally doubled lengthwise to the arrangement in which
such units are normally packed for marketing.
The present invention has been described in detail above for
purposes of illustration only and is not intended to be limited by
this description or otherwise to exclude any variation or
equivalent form or procedure that would be apparent from, or
reasonably suggested by, the foregoing disclosure to the skill of
the art.
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