U.S. patent number 3,675,654 [Application Number 05/024,573] was granted by the patent office on 1972-07-11 for disposable article with mositure-actuated indicating agent.
This patent grant is currently assigned to The Procter & Gamble Company. Invention is credited to Joseph S. Baker, Robert C. Duncan, Mario S. Marsan.
United States Patent |
3,675,654 |
Baker , et al. |
July 11, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
DISPOSABLE ARTICLE WITH MOSITURE-ACTUATED INDICATING AGENT
Abstract
Disposable diapers, sanitary napkins, bandages and the like
articles, comprising an absorbent pad disposed on a translucent
back sheet of water impervious material are provided with a
moisture-actuated indicating agent therebetween. The indicating
agent comprises either a small amount of finely divided
water-soluble dye having a high dye strength or such a due admixed
with a finely divided diluent masking agent, such as talcum powder.
The indicating agent is dry and adheres to the pad surface facing
the back sheet and the back sheet surface facing the pad by
mechanical and electrostatic action. When the absorbent pad of the
disposable article and the indicating agent become wet in use the
resulting due solution between the pad and sheet is visible through
the translucent back sheet to provide indication of wetness.
Inventors: |
Baker; Joseph S. (Cincinnati,
OH), Marsan; Mario S. (Cincinnati, OH), Duncan; Robert
C. (Cincinnati, OH) |
Assignee: |
The Procter & Gamble
Company (Cincinnati, OH)
|
Family
ID: |
21821291 |
Appl.
No.: |
05/024,573 |
Filed: |
April 1, 1970 |
Current U.S.
Class: |
604/361 |
Current CPC
Class: |
A61L
15/56 (20130101); C09B 67/0097 (20130101); A61F
13/42 (20130101) |
Current International
Class: |
A61F
13/42 (20060101); A61L 15/56 (20060101); A61L
15/16 (20060101); C09B 67/02 (20060101); C09B
67/00 (20060101); A61f 013/16 () |
Field of
Search: |
;128/284,286,287,290,296,156 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Rosenbaum; Charles F.
Claims
Having thus described the invention, what is claimed is:
1. A disposable article comprising a translucent back sheet of
substantially water impervious material having an absorbent pad
superimposed thereon with a moisture-actuated indicating agent in
finely divided particulate form disposed therebetween in at least
one indicating area, wherein the moisture-actuated indicating agent
comprises an admixture of about 0.01 percent to about 100 percent,
by weight, of a water-soluble, substantially non-toxic dye together
with a non-toxic diluent masking agent, has particle sizes of about
0.2 to about 20 microns and is present in amounts of about 1
.times. 10.sup.-.sup.5 gms. to about 1 .times. 10.sup.-.sup.2 gms.
per square inch of indicating area.
2. The disposable article comprising a translucent back sheet of
substantially water impervious material having an absorbent pad
superimposed thereon with a moisture-actuated indicating agent in
finely divided particulate form disposed therebetween of claim 1,
wherein the disposable article is a disposable diaper and two
centrally located indicating areas are provided.
3. The disposable article comprising a translucent back sheet of
substantially water impervious material having an absorbent pad
superimposed thereon with a moisture-actuated indicating agent in
finely divided particulate form disposed therebetween of claim 1,
wherein the water-soluble, substantially non-toxic dye is selected
from the group consisting of nitro, monoazo, diazo, phthalocyanine,
quinoline, xanthene, triaryl methane, indigoid and vegetable
dyes.
4. The disposable article comprising a translucent back sheet of
substantially water impervious material having an absorbent pad
superimposed thereon with a moisture-actuated indicating agent in
finely divided particulate form disposed therebetween of claim 1,
wherein the non-toxic diluent masking agent is a neutral color
substance selected from the group consisting of talcum, whiting,
silica, sugar, salt and starch.
5. The disposable article comprising a translucent back sheet of
substantially water impervious material having an absorbent pad
superimposed thereon with a moisture-actuated indicating agent in
finely divided particulate form disposed therebetween of claim 1,
wherein the moisture-actuated indicating agent is a water-soluble,
substantially non-toxic dye.
6. A disposable article comprising a translucent back sheet of
substantially water impervious material having an absorbent pad
superimposed thereon with a moisture-actuated indicating agent in
finely divided particulate form disposed therebetween in a
plurality of indicating areas, wherein the moisture-actuated
indicating agent comprises an admixture of about 1 percent, by
weight, of a water-soluble, substantially non-toxic dye together
with a non-toxic diluent masking agent, has particle sizes of about
2 microns and is present in amounts of about 1 .times.
10.sup..sup.-4 gms. to about 1 .times. 10.sup..sup.-3 gms. per
square inch of indicating area.
7. The disposable article comprising a translucent back sheet of
substantially water impervious material having an absorbent pad
superimposed thereon with a moisture-actuated indicating agent in
finely divided particulate form disposed therebetween in a
plurality of indicating areas of claim 6 wherein the disposable
article is a disposable diaper, and wherein the moisture-actuated
indicating agent comprises an admixture of about 1 percent, by
weight, of a blue phthalocyanine dye together with about 99 percent
of talcum powder as the non-toxic diluent masking agent, has
particle sizes of about 2 microns and is present in amounts of
about 1 .times. 10.sup.-.sup.4 gms. to about 1 .times.
10.sup.-.sup.3 gms. per square inch of indicating area.
Description
BACKGROUND OF THE INVENTION
The present invention relates to disposable diapers, sanitary
napkins, bandages and like articles which are adapted to be used
once and then discarded. More particularly, the invention is
directed to such articles, which are adapted to give a convenient
visible indication of their soiled, used condition and readiness
for discard. Specifically, the invention provides for disposable
articles comprising an absorbent pad disposed on a translucent back
sheet of water impervious material with a water-soluble dye
therebetween as a moisture-actuated indicating agent.
In general, wetness indicators are available in the art, for
example, J. D. Shaw in U.S. Pat. No. 2,681,032 discloses a diaper
wetness indicator, which actuates on a mechanical principle. When
the diaper becomes wet, a low wet strength element breaks, moving a
colored indicator into registry with an aperture through which it
is visible.
I. I. Solomon in U.S. Patent 2,156,880 discloses an indicator
sensitive to perspiration or body heat for use in combination with
wearing apparel to indicate clothing which has been worn for more
than a trial period before being returned to the retail merchant by
the purchaser. In this function, the indicator is impregnated with
a dye which changes color upon contact with the acid or alkaline
constituents of perspiration.
M. G. Snelling in U.S. Pat. No. 2,214,354 and U.S. Pat. No.
2,249,867 discloses a detector to be packed with goods to indicate
whether the goods are exposed to conditions of extreme moisture or
dampness. The detector comprises an intimate admixture of a
deliquescent material with a water-soluble dye of high color
strength This admixture is in association with a dry porous
material. Upon exposure to dampness, water is absorbed by the
deliquescent material, and the resulting dye solution is
transported by capillary action through the porous material.
W. W. Kinzer in U.S. Pat. No. 2,254,609 discloses a leak indicator
for liquid handling equipment. The indicator comprises a
water-soluble dye, titanium dioxide and whiting (CaCO.sub.3)
applied with varnish or other vehicle. When a water leak occurs the
water dissolves the dye in the varnish away from the titanium
dioxide and the whiting, giving a color indication.
The present invention contributes to the art illustrated above with
a disposable article comprising a translucent back sheet of water
impervious material, an absorbent pad, and a moisture-actuated
indicating agent dusted between the back sheet and the pad in small
amounts. The indicating agent is finely divided and retained in
place by mechanical and electrostatic action, so no dye vehicle or
movement is required to develop a wetness indication in a
nonstaining article. The herein disclosed disposable article with
operably disposed moisture-actuated indicating agent was developed
to provide a reliable visual indication of in use wetting with body
fluids in diapers. This effect is rendered possible in accordance
with the present invention by very simple and inexpensive
means.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide disposable
diapers, sanitary napkins, bandages and like articles, which
articles visibly and conveniently indicate their soiled condition
and readiness for change.
Another object of the present invention is to provide a disposable
article, which article exhibits a readily discernible visual change
in a pattern on its outer surface, when it is wet and ready for
change.
Another object of the present invention is to provide a disposable
diaper, which diaper exhibits a readily discernible color change in
selected indicating areas of its outer surface, when it is wet and
ready for change.
SUMMARY OF THE INVENTION
Briefly stated, in accordance with the present invention,
disposable diapers, sanitary napkins, bandages and like articles,
comprising a translucent back sheet of water impervious material,
an absorbent, skin contacting pad, which is superimposed on the
back sheet, and a small amount of moisture-actuated indicating
agent between the back sheet and the absorbent pad are provided.
The indicating agent is a dry, finely divided solid and adheres to
the pad and the back sheet by mechanical and electrostatic action.
The indicating agent comprises either a water-soluble dye or an
admixture of said dye with a diluent masking agent. The amount of
indicating agent per square inch of indicating area on the
absorbent pad is about 1 .times. 10.sup.-.sup.5 gm. to about 1
.times. 10.sup.-2 gm. The percentage of dye in the indicating agent
is about 0.1 percent to about 100 percent, by weight.
For clarity of description, the invention is hereinafter described
primarily in terms of its adaptation to disposable diapers,
although the principles involved will be readily understood in
terms of other disposable articles.
BRIEF DESCRIPTION OF THE DRAWING
While the specification concludes with claims particularly pointing
out and distinctly claiming the subject matter, which is regarded
as forming the present invention, it is believed that the invention
will be better understood from the following description taken in
connection with the accompanying drawing, in which:
FIG. 1 is a perspective view illustrating a disposable diaper of
the present invention with the outer translucent back sheet side
thereof uppermost and the translucent back sheet broken away;
FIG. 2 is an enlarged fragmentary sectional view, taken along line
2--2 of FIG. 1; and
FIGS. 3-5 are plan views illustrating alternative patterns for
application of the moisture-actuated indicating agent on the
absorbent pad.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1 of the drawing, here is illustrated a
preferred embodiment of a disposable diaper with moisture-actuated
indicating agent 1 incorporated therein, in accordance with the
following description. Absorbent pad 3 consists of a multiplicity
of plies of wadding, creped wadding or air-laid felt, prepared from
wood pulp fibers, and similar absorbent materials. Absorbent pad 3
is illustrated as enveloped on its moisture receiving surface by
inner sheet 4 which is a porous, non-woven fabric. The inner sheet
4 is attached to absorbent pad 3 by adhesive edge fastening 5.
Adhesive edge fastening 5 also serves to attach absorbent pad 3 and
inner sheet 4 to translucent, water impervious back sheet 2.
Moisture-actuated indicating agent 1 is present on the surface of
the absorbent pad 3 which contacts translucent, water impervious
back sheet 2 in a uniform pattern of substantially overall surface
distribution.
Referring to FIG. 2 of the drawing, there is illustrated how the
dye particles 6 and the diluent masking agent particles 7, if
present, of the moisture-actuated indicating agent 1 are situated
and affixed between the surfaces of absorbent pad 3 and translucent
back sheet 2. Dye particles 6 and diluent masking agent particles 7
are retained in place by mechanical and electrostatic entrapment
between and on the surface fibers of absorbent pad 3 and between
absorbent pad 3 and translucent back sheet 2.
Although the application of moisture-actuated indicating agent 1 in
a particular disposable article can be extended over the entire
expanse of the outer face of absorbent pad 3, FIG. 1 illustrates a
narrow margin, covered by inner sheet 4, along the edges of
absorbent pad 3, where no indicating agent is applied. Preferably,
however, to reduce the required amount of moisture-actuated
indicating agent 1 and to eliminate the possibility of skin contact
and staining, the moisture-actuated indicating agent 1 is placed in
smaller visually convenient indicating areas 8. Thus, referring to
FIGS. 3 and 4, there is illustrated how the pattern of application
of the moisture-actuated indicating agent 1 can be limited to a
plurality of small rectangular or circular indicating areas 8.
Finally, referring to FIG. 5, there is illustrated how said pattern
of application can be limited to two circular indicating areas 8,
centrally located approximately in the middle of the two equal
areas of absorbent pad 3, which areas are obtained when a dividing
line is drawn parallel with the shorter edges of absorbent pad
3.
The moisture-actuated indicating agent 1 of the present invention
can be either an admixture of a substantially non-toxic,
water-soluble dye having high dye strength with a substantially
non-toxic, water-insoluble or water-soluble diluent masking agent,
or a substantially non-toxic, water-soluble dye having high dye
strength without a diluent masking agent. The moisture-actuated
indicating agent 1 is applied in a dry, finely divided particulate
state. When moisture-actuated indicating agent 1 is exposed to
liquids penetrating absorbent pad 3, the dye, or the dye and the
diluent masking agent, is dissolved. The color of the resulting dye
solution is readily perceptible to the eye through translucent back
sheet 2.
The dye in the moisture-actuated indicating agent of the present
invention can be a water-soluble dye in finely divided solid or
crystalline state selected from the group consisting of (1) nitro,
(2) monoazo, (3) diazo, (4) phthalocyanine, (5) quinoline, )6)
xanthene, (7) triaryl methane, (8) indigoid and (9) vegetable dyes.
Other dyes meeting the requirements of solidity, non-toxicity and
water-solubility can also be used to effect embodiments of the
invention.
Powdered dyes used in beverages, confections and pharmaceuticals
are suitable and are readily available from food dye manufacturers.
Examples of food dyes belonging to the classes of dyes enumerated
above are sold under the following trade names and code
designations.
1. Naphthol Yellow SSX Spec. Pure, a nitro-dye having the
formula
sold by Badische Anilin & Soda Fabrik, A.G., Ludwigshafen a.
Rhein, Germany;
2. Orange GGN Conc. Spec. Pure, a monoazo-dye having the
formula
sold by Farbenfabriken Bayer A.G., Leverkusen, Germany, and Salmon
Red. G.AF, a dye having the formula
HT,
sold by CIBA Ltd., Basel, Switzerland;
3. Hexacol Chocolate Brown Ht, a diazo-dye having the formula
sold by L. J. Pointing & Son Ltd., Hexhem, England;
4. Heliogen Blue BWS Extra, a phthalocyanine-dye having the formula
##SPC1##
sold by General Aniline & Film Corporation, New York, N.Y.;
5. Canary Yellow Geigy, a quinoline-dye having the formula
sold by J. R. Geigy S. A., Basel, Switzerland;
6. Edicol Supra Rose B, a rhodamine dye having the formula
sold by Imperial Chemical Industries, Ltd., Manchester, England;
and
Erythrosine TB Extra, having the formula
sold by Durand & Huguenin S. A., Basel, Switzerland;
7. Acid Violet 5 BN, a triaryl methane dye having the formula
##SPC2##
and
Acid Green S, having the formula ##SPC3##
sold by Williams Ltd., Hounslow, England;
Kiton Pure Blue V. FQ, having the formula
sold by Clayton Aniline Co. Ltd., Manchester, England; and
8. Edicol Supra Blue X, an indigoid dye having the formula
sold by Imperial Chemical Industries, Manchester, England.
Vegetable dyes, such as carotene, chlorophyll, and also tea and
coffee extracts in powder state are suitable as the dye component
in the moisture-actuated indicating agent of the present invention.
Further, any dye compound which is characterized by
water-solubility, solidity, non-toxicity, dye strength, reasonable
color fastness, and heat stability can be used as the dye component
in the moisture-actuated indicating agent. Green and blue dyes are
preferred as being generally more attractive for the designed
purposes.
The finely divided diluent masking agent, which is preferably white
and can be used in admixture with the finely divided dye in the
moisture-actuated indicating agent, can be any neutral color,
substantially non-toxic material which is compatible with the dye
to form a free-flowing powder. A suitable diluent masking agent can
be a neutral color substance selected from the group consisting of
talcum, whiting, silica, sugar, salt and starch.
The diluent masking agent is used to mask or partly mask the color
of the dry indicating agent, so that the dye is not perceived as a
color until wetted. The diluent masking agent can also be used to
disperse or dilute the dye particles to facilitate uniform
application of the dye on an absorbent pad. A diluent masking agent
is optional, however, when very fine dye particles and small
amounts of dye are used. In this instance the dye color is
imperceptible through the translucent back sheet prior to
wetting
Preferred diluent masking agents are chemically inert mineral
products exhibiting a neutral color, for example talcum, whiting
and silica. Crystalline sugars, such as lactose, sucrose and
mannose, and crystalline salts, such as table salt, can also be
used.
Flour and starch products can also be used as diluent masking
agents. They are slightly water-soluble and swellable. Such starch
diluent masking agents may delay the appearance of color. The
moisture-actuated indicating agents comprising starch diluent
masking agents will, in general, be less sensitive to the presence
of water in the absorbent pad; they will tend to develop the
moisture indicating color signal more slowly. The amount of
moisture-actuated indicating agent used in the present invention
can be about 1 .times. 10.sup.-.sup.5 gms. to about 1 .times.
10.sup.-.sup.2 gms. per square inch of applied pattern on the
absorbent pad of disposable article. An amount of from about 1
.times. 10.sup.-.sup.4 gms. to about 1 .times.10.sup.-.sup.3 gms.
per square inch is preferred. The percentage of dye in the
indicating agent is about 0.1 percent to about 100 percent,
preferably about 1.0 percent, by weight of the indicating
agent.
A suitable size range for the dye particles in the
moisture-actuated indicating agent of the present invention is
about 0.20 to about 20 microns, preferably about 2 microns. The
particles are of a small size so that they will adhere to the
absorbent pad surface and the back sheet surface by electrostatic
action and to the absorbent pad surface by mechanical locking or
entanglement between the pad surface fibers, fibrillae, and in
fiber interstices. Where the absorbent pad is fabricated of
spongious material, such as an open cell polyurethane form, the
indicating agent is retained in foam openings and also between the
pad surface and the back sheet. Since the pad material is fibrous
or porous, the actual surface area, where the moisture-actuated
indicating agent can adhere, is large. Concavities and crevices of
different size and shape lock and entangle the particles as
illustrated in FIG. 2. The skin contacting surface of the absorbent
pad, on the absorbent pad surface opposite to that of
moisture-actuated indicating agent placement, can be provided with
a porous, non-woven fabric overwrap.
Mechanical and electrostatic action has been found sufficient to
retain the moisture-actuated indicating agent in position during
normal handling of the disposable articles, i.e., in fabrication,
marketing and use, until the moment the absorbent pad is wetted by
body fluids. Thus, it is possible to operably affix the particulate
dye material without resort to binders or adhesives with their
attendant production expenses in time and cost.
The dye and diluent masking agent materials, constituting the
present indicating agents, can be finely divided and uniformly
mixed by grinding a mixture of them in the proportions stated above
with a mortar and pestle. In a dry state the indicating agents
exhibit in bulk quantities the same neutral color as the masking
agent, preferably white, provided the percentage of the dye is
sufficiently low, e.g., less than 1 percent.
Dye powders sometimes exist in agglomerated or caked form, even
though the individual dye particles are small. Simple mixing is
often all that is required to obtain a satisfactory admixture with
a diluent masking agent. To achieve this result, a crystalline
diluent masking agent is preferred. Attritive forces are created,
and the agglomerates are broken down. With other diluent masking
agents such as flours and starches, simple mixing followed by
milling, e.g., by a hammer mill or roller mill, will produce good
results. Where milling is required, it is often advantageous to
blend and mill a mixture containing a comparatively large amount of
dye and then dilute this mixture to desired concentrations by
mixing in additional amounts of the selected diluent masking
agent.
Application of the moisture-actuated indicating agent of the
present invention to the translucent back sheet contacting face of
the absorbent pad can be accomplished by a number of convenient
means, such as:
I. Method of Application by Pneumatic Means
The moisture-actuated indicating agent is enclosed in a powder bin
having a lid, which is provided with a venturi tube and nozzle for
spraying of dry powder. The powder bin is vibrated to promote a
uniform mixture of indicating agent therein. An air pressure of
5-20 psi is applied to the venturi tube. The air transported
indicating agent is directed through the nozzle onto the surface of
the absorbent pad. A powder application with a duration of a few
seconds will be sufficient to apply the required amount of
indicating agent to the absorbent pad. The amount of indicating
agent applied per unit area can be controlled by the size of the
nozzle opening, the angle of the conically shaped powder stream,
the distance between the nozzle opening and the pad surface, and
the applied air pressure. Metal or plastic stencils and templates
can be used to obtain desired patterns of the indicating agent on
the pad surface.
II. Method of Application by Vibrating Sieve
An ultrasonic power source is connected with a sieve. The sieve has
a screen with a mesh size, which barely permits the particles of a
prepared mixture of indicating agent to fall through the screen.
The screen is loaded with the indicating agent and the sieve is
placed above the absorbent pad surface at a distance of about 0.5
inch and caused to vibrate for a few seconds or only fractions of a
second. The indicating agent is sifted onto the pad surface. The
amount of deposition can be controlled by the mesh size of the
screen, the duration of vibration, and the selection of dye and
diluent masking agent materials. It is important that the particle
sizes in the indicating agent and the density of the dye and the
diluent masking agent be fairly uniform to avoid separation of dye
and diluent masking agent particles during sieve application.
The disadvantage of dusting in vibrating sieve application can be
minimized by careful weighing, transferring and sifting of the
indicating agent. In commercial operations the inconvenience of
indicating agent dust settling onto nearby products and the dangers
of dust inhalation can be eliminated by confining indicating agent
handling operations to a separate enclosure provided with vents for
dust removal.
Excessive perspiration and/or air humidity must not cause a false
color indication in a disposable article. Equilibrium conditions
between moisture and the absorbent pad material will allow the
capture of such humidity and perspiration without causing color
indication. Experimental diaper testing with the moisture-actuated
indicating agents of this invention at 90.degree. F. and a relative
humidity of 90 percent for 3 hrs., did not yield false color
indications due to moisture absorbed by the pad under such
conditions. The dye particles were not dissolved to such as extent
that a noticeable coloring of the indicating agent was
obtained.
The sensitivity of the indicating agent to the presence of water is
influenced by such parameters as the dye strength, dye and diluent
masking agent particle size, amount of dye, dye/diluent masking
agent particle size ratio and diluent masking agent type. The
appearance of color indication upon wetting a diaper or other
disposable article can be delayed or hastened by adjustments of
these parameters. Also, it is necessary to take the translucency of
the back sheet into consideration when adjusting said parameters. A
suitable translucent back sheet can be polyethylene containing from
about 3 percent to about 8 percent titanium dioxide pigments. The
thickness of the translucent back sheet can vary from about 0.5
mil. to about 2.0 mil.
The likelihood that dissolved dye and body fluids colored by dye
may escape the area where indicating agent has been applied and
color an infant's skin or stain the bedclothes, is very small.
First, there are very small amounts of dye on the absorbent pad.
Second, the body fluids travel from the skin of the infant, to
which the article is applied, through the capillary channels of the
fibrous or porous absorbent pad material towards the absorbent pad
and water impervious back sheet interface where the
moisture-actuated indicating agent is located. Experiments with
such disposable article structures have shown that quite strong
pressures, more than 5.8 psi, are necessary to cause even small
amounts of fluid to travel from the interface to the skin side of
the absorbent pad. Thus, the pressures exerted on a diaper by an
infant's movements and weight will not, in practice, cause fluids
to travel from the back sheet and pad interface towards the skin of
the infant.
The following examples are intended to be illustrative and not
limiting, and the scope of the invention is only to be construed by
the scope of the appended claims.
EXAMPLE I
A disposable diaper having a moisture-actuated indicating agent
consisting of a finely divided dye and talcum mixture was prepared.
3.0 percent of the phthalocyanine-dye, Heliogen Blue BWS Extra,
sold by General Aniline & Film Corporation, New York, N.Y., and
97.0 percent talcum powder were admixed by grinding the materials
together with a mortar and pestle to an average particle size of
about 2.0 microns. The resulting indicating agent had a white
appearance.
The disposable diaper has an absorbent pad measuring 11.5 inches by
15.0 inches, and the absorbent pad was enveloped with nonwoven
fabric in the manner of FIG. 1 of the accompanying drawing. 0.20
gm. of said indicating agent was blown onto the non-enveloped
absorbent pad surface in two centrally located indicating areas
totaling 20 square inches. The indicating areas were positioned on
the absorbent pad surface as indicated in FIG. 5 of the
accompanying drawing. The absorbent pad with moisture-actuated
indicating agent on its surface was then superimposed on a titanium
dioxide pigmented translucent polyethylene sheet having a thickness
of 1.1 mil.; the side of the absorbent pad with moisture-actuated
indicating agent thereon faced the translucent back sheet. The
absorbent pad was attached to the back sheet by adhesive edge
fastening.
The resulting disposable diaper was placed in position on an
infant. When the absorbent pad was exposed to body waste fluids
from the infant and wet through, a clear blue color was observed
through the back sheet in the area where moisture-actuated
indicating agent was applied to the absorbent pad. The color
appearance was uniform over the areas where waste fluid had spread
in the absorbent pad, which illustrated that little migration of
the dry indicating agent particles had ocurred, before the
discharge of waste fluid. Thus, the disposable diaper of this
example yielded a readily visible indication that it had become
soiled and moist in use and was ready to be discarded. There was no
leakage of colored waste fluid and no staining of bedclothes
associated with the infant.
When a moisture-actuated indicating agent containing 0.1 percent of
Heliogen Blue BWS Extra dye and 99.9 percent talcum powder by
weight is prepared, and 0.2 mg. of this moisture-actuated
indicating agent is blown on a 20 square inch indicating area of a
disposable diaper in the manner of this Example I, the resulting
diaper will exhibit a similar visual indication of its wetness in
use. A visual indication of wetness in the disposable diapers of
this Example I will also occur when the moisture-actuated
indicating agent consists entirely of the dye, Heliogen Blue BWS
Extra.
EXAMPLE II
A disposable diaper having a moisture-actuated indicating agent
consisting of a finely divided dye and whiting mixture is prepared
in the following manner. 1.0 percent of the Rhodamine dye, Edicol
Supra Rose B, sold by Imperial Chemical Industries, Ltd.,
Manchester, England, and 99 percent starch powder are admixed by
grinding the material together in a roller mill to an average
particle size of about 5 microns. The resulting indicating agent
has a white appearance.
The disposable diaper has an absorbent pad measuring 12 inches
.times. 15 inches, and the absorbent pad is enveloped with
non-woven fabric in the manner of FIG. 1 of the accompanying
drawing. 0.02 gm. of said indicating agent is blown onto the
non-enveloped absorbent pad surface in a multiplicity of small
rectangular indicating areas as illustrated in FIG. 3 of the
accompanying drawing. The indicating areas total 20 square inches.
The absorbent pad with moisture-actuated indicating agent on its
surface is then superimposed on a titanium dioxide pigmented
translucent polyethylene sheet having a thickness of 1.1 mil.; the
side of the absorbent pad with moisture-actuated indicating agent
thereon is placed to face the translucent back sheet. The absorbent
pad is attached to the back sheet by adhesive edge fastening.
When the absorbent pad is exposed to body waste fluid by placement
on an infant as a diaper, a clear red color is observed through the
translucent back sheet in the areas where moisture-actuated
indicating agent is applied to the absorbent pad. The disposable
diaper of this example will yield a readily visible color
indication in the areas of moisture-actuated indicating agent
placement and body waste fluid wetness indicating that it has
become soiled and moist in use and is ready to be discarded.
Leakage of colored waste fluid and staining of bed clothing
associated with the infant will not be a problem.
A moisture-actuated indicating agent containing 0.5 percent of the
Aryl dye, Acid Green S, sold by Williams Ltd., Hounslow, England,
and 99.5 percent whiting by weight is prepared, and 0.002 gm. of
this moisture-actuated indicating agent is blown on a 20 square
inch indicating area of a disposable diaper in an overall pattern
in the manner of this Example II. The resulting diaper will exhibit
a visual indication of its wetness in use similar to that of
Example II, and the moisture-actuated indicating agent pattern will
be found satisfactory from the standpoint of avoiding staining of
the skin and clothing associated with the infant.
Disposable diapers prepared in the manner of this Example II with
other moisture-actuating indicating agent particles sizes within
the range of about 0.2 micron to about 20 microns (e.g. 0.2 micron,
20 microns and particularly 2 microns) will be found to provide a
readily discernible color indication.
In addition to the preferred embodiments described herein, other
arrangements and variations within the spirit of the invention and
the scope of the appended claims will occur to those skilled in the
art.
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