U.S. patent application number 14/037409 was filed with the patent office on 2014-03-27 for anti-leaching liquid-activated formulation.
This patent application is currently assigned to The Procter & Gamble Company. The applicant listed for this patent is The Procter & Gamble Company. Invention is credited to William Winfield Cheeseman, JR., Laveeta Joseph, Santosh B. Kanakkanatt, Sebastian V. Kanakkanatt, Thomas James Klofta.
Application Number | 20140088531 14/037409 |
Document ID | / |
Family ID | 49304415 |
Filed Date | 2014-03-27 |
United States Patent
Application |
20140088531 |
Kind Code |
A1 |
Klofta; Thomas James ; et
al. |
March 27, 2014 |
ANTI-LEACHING LIQUID-ACTIVATED FORMULATION
Abstract
A liquid-activated formulation is provided, comprising a
liquid-activated colorant, a hydrochromic ionic compound, an
opacifier, and a binding matrix comprising a leaching
inhibitor.
Inventors: |
Klofta; Thomas James;
(Cincinnati, OH) ; Joseph; Laveeta; (Cincinnati,
OH) ; Kanakkanatt; Sebastian V.; (Akron, OH) ;
Kanakkanatt; Santosh B.; (Akron, OH) ; Cheeseman,
JR.; William Winfield; (Mason, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Procter & Gamble Company |
Cincinnati |
OH |
US |
|
|
Assignee: |
The Procter & Gamble
Company
Cincinnati
OH
|
Family ID: |
49304415 |
Appl. No.: |
14/037409 |
Filed: |
September 26, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61837400 |
Jun 20, 2013 |
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61837390 |
Jun 20, 2013 |
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61837394 |
Jun 20, 2013 |
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61837405 |
Jun 20, 2013 |
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61837408 |
Jun 20, 2013 |
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61705861 |
Sep 26, 2012 |
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Current U.S.
Class: |
604/361 ;
436/39 |
Current CPC
Class: |
C09D 11/30 20130101;
C08K 13/02 20130101; A61F 13/42 20130101; Y10T 428/2822 20150115;
Y10T 428/2826 20150115; Y10T 428/2817 20150115; C09D 11/50
20130101; A61L 15/56 20130101 |
Class at
Publication: |
604/361 ;
436/39 |
International
Class: |
A61F 13/42 20060101
A61F013/42 |
Claims
1. A liquid activated formulation comprising: (A) a
liquid-activated colorant; (B) a hydrochromic ionic compound; (C)
an opacifier; and (D) a binding matrix comprising a leaching
inhibitor.
2. The liquid-activated formulation of claim 1, wherein the
colorant resists leaching from the binding matrix by being
chemically bound to the leaching inhibitor.
3. The liquid-activated formulation of claim 1, wherein the
leaching inhibitor comprises a cationic species.
4. The liquid-activated formulation of claim 3, wherein the
cationic species is a quaternary ammonium compound.
5. The liquid-activated formulation of claim 3, wherein the
cationic species is a cationic clay compound.
6. The liquid-activated formulation of claim 3, wherein the
cationic species is a cationic polymer compound.
7. The liquid-activated formulation of claim 1, wherein the
colorant is ionically or covalently bound to the leaching
inhibitor.
8. The liquid-activated formulation of claim 1, having a colorant
Leaching Value of no more than 300 micrograms of colorant leached
per gram of the liquid-activated formulation as measured by a 3
Hour Leaching Value Test Method.
9. The liquid-activated formulation of claim 1, wherein the binding
matrix is a hot melt binding matrix.
10. The liquid-activated formulation of claim 1, wherein the
binding matrix is a solvent-based binding matrix.
11. The liquid-activated formulation of claim 1, further comprising
a permanent colorant.
12. The liquid-activated formulation of claim 1, further comprising
one or more selected from the group consisting of a stabilizer,
surfactant, and a structural adjunct.
13. The liquid-activated formulation of claim 12, wherein said
stabilizer is selected from the group consisting of monostearyl
phosphate, citrate esters, alcohol ethoxycarboxylates, glycolate
esters, lactate esters, fatty acids, ether carboxylic acids, fatty
acid methyl esters, sulfate esters, fruit acids like citric acid
and malic acid, inorganic acids like sulfuric acid,
monoethanolamine, diethanolamine, triethanolamine,
dipropylenetriamine, diisopropyl amine,
1,3-bis(methylamine)-cyclohexane, 1,3-Pentanediamine, sodium
hydroxide, magnesium hydroxide, and combinations thereof.
14. The liquid-activated formulation of claim 12, wherein said
structural adjunct is selected from the group consisting of HLB
modifiers, viscosity modifiers, hardening agents, and combinations
thereof.
15. An absorbent article comprising the liquid-activated
formulation of claim 1, wherein said liquid-activated formulation
is affixed to a structural component of the absorbent article.
16. An absorbent article comprising the liquid-activated
formulation of claim 1, wherein the article comprises a backsheet,
a topsheet, an absorbent core disposed between the backsheet and
the topsheet, wherein the liquid-activated formulation is a single
layer and disposed between the backsheet and the absorbent
core.
17. An absorbent article comprising the liquid-activated
formulation of claim 1, wherein the article comprises a backsheet,
a topsheet, an absorbent core disposed between the backsheet and
the topsheet, wherein the liquid-activated formulation is a single
layer and disposed between the topsheet and the absorbent core.
18. The liquid activated formulation as specified in claim 1
wherein the liquid activated colorant is selected from the group
consisting of Malachite green, brilliant green, crystal violet,
erythrosine B, methyl green, methyl violet 2D, picric acid,
naphthol yellow S, quinaldine red, eosine Y, metanil yellow,
m-cresol purple, thymol blue, xylenol blue, basis fuchsin, eosin B,
4-p-aminophenol(azo)benzenesulphonic acid-sodium salt, cresol red,
martius yellow, phloxine B, methyl yellow, bromophenol blue, congo
red, methyl orange, bromochlorophenol blue (water soluble or free
acid form), ethyl orange, fluorocene WS, bromocresol green,
chrysoidine, methyl red sodium salt, alizarine red S--H2O,
cochineal, chlorophenol red, bromocresol purple, 4-naphtha,
alizarin, nitrazine yellow, bromothymol blue, brilliant yellow,
neutral red, rosalic acid, phenol red, 3-nitro phenol, orange II,
phenolphthalein, o-cresolphthalein, nile blue A, thymolphthalein,
aniline blue WS, alizarine yellow GG, mordant orange, tropaolin O,
orange G, acid fuchsin, thiazol yellow G, indigo carmine, FD&C
Blue No. 1, FD&C Blue No. 2, FD&C Green No. 3, FD&C Red
No. 40, FD&C Red No. 4, FD&C Yellow No. 5, FD&C Yellow
No. 6, C.I. Food Blue 5, and C.I. Food Red 7, D&C Yellow No.
10, D&C Yellow No. 7, D&C Yellow No. 2, D&C Yellow No.
8, D&C Orange No. 4, D&C Red No. 22, D&C Red No. 28,
D&C Red No. 33, D&C Green No. 8, D&C Green No. 5,
D&C Brown No. 1, and any combination thereof.
19. The liquid activated formulation as specified in claim 1
wherein the hydrochromic ionic compound is selected from the group
consisting of lithium hydrogen sulfate, lithium hydrogen carbonate,
potassium hydrogen sulfate, potassium hydrogen carbonate, rubidium
hydrogen sulfate, rubidium hydrogen carbonate, cesium hydrogen
sulfate, cesium hydrogen carbonate, sodium hydrogen sulfate, sodium
hydrogen carbonate, sodium carbonate, cesium hydroxide, lithium
hydroxide, potassium hydroxide, calcium hydroxide, magnesium
hydroxide, sodium thiosulfate penta hydrate, sodium hydroxide,
rubidium hydroxide, cobalt chloride, cobalt nitrate, copper
sulphate copper nitrate, iron (II) sulfate, iron (III) sulfate,
iron (II)chloride, iron (III) chloride, sodium aluminum silicate,
citric acid, monosodium dihydrogen citrate, disodium hydrogen
citrate, trisodium citrate, gluconic acid, sodium gluconate,
glycolic acid, sodium glycolate, malic acid, sodium malate, maleic
acid, sodium maleate, acetic acid, phosphoric acid, trisodium
phosphate, sodium dihydrogen phosphate, disodium hydrogen
phosphate, monostearyl phosphate, monocetyl phosphate, monostearyl
citrate, hydrochloric acid, nitric acid, sulfuric acid and
combinations thereof.
20. The liquid activated formulation as specified in claim 1
wherein the opacifier is selected from the group consisting of
titanium dioxide, calcium carbonate, calcium hydroxide, sodium
silicate, potassium silicate, silica, starch, ethocell, methocell,
barium carbonate, barium silicate, calcium silicate, aluminum
silicate, aluminum hydroxide, aluminum oxide, sodium aluminum
silicate, zirconium silicate, magnesium aluminum silicate, and
styrene/acrylate copolymers.
21. The liquid activated formulation as specified in claim 1
wherein the a liquid activated colorant is present in the liquid
activated formulation in an amount which is within the range of
about 0.01 weight percent to about 20 weight percent, wherein the
hydrochromic ionic compound is present in the liquid activated
formulation in an amount which is within the range of about 0.05
weight percent to about 35 weight percent, wherein the opacifier is
present in the liquid activated formulation in an amount which is
within the range of about 5 weight percent to about 75 weight
percent, and wherein the binding matrix is present in the liquid
activated formulation in an amount which is within the range of
about 5 weight percent to about 75 weight percent, based upon the
total weight of the liquid activated formulation.
22. The liquid-activated formulation of claim 1, wherein the
liquid-activated formulation has a color transition selected from
the group consisting of a) colored to uncolored, b) uncolored to
colored, c) colored to a different color, or d) a combination of a)
and b) and c).
Description
FIELD OF INVENTION
[0001] Disclosed are anti-leaching liquid-activated formulations,
for use as wetness/fluid indicators in absorbent articles.
BACKGROUND OF THE INVENTION
[0002] Many disposable absorbent articles comprise a wetness
indicator. Wetness indicator compositions may comprise a colorant
adapted to change in appearance, i.e., appear, disappear, change
color, etc., upon contact with liquids such as urine, runny bowel
movements, menses, etc., in the article. The color changing active
used in many wetness indicator compositions are pH indicators such
as bromocresol green or the like, which changes color from yellow
to blue in the pH range of 3.8 to 5.4. Upon contact with a liquid,
such as urine, the pH indicator will change colors to indicate the
presence of the liquid, due to the higher pH of the urine.
[0003] However, current pH-based wetness indicators may be
unreliable, having issues such as premature triggering and/or
leaching, plus there are limits as to the variety of color options
available. Therefore, there is a continuing need for simple
wetness/fluid indicators that can provide a variety of color
options, such as, for example, those disclosed in U.S. Patent
Application Ser. No. 61/705,861. Such wetness/fluid indicators may
be incorporated into absorbent articles through the use of a
binding matrix, which can be, for example, a hot melt binding
matrix or a solvent-based binding matrix. Such a binding matrix can
hold or retain the wetness indicator in the desired position in the
product and can also contribute to reduced leaching of the colorant
due to the formation of intermolecular binding forces.
SUMMARY OF THE INVENTION
[0004] A liquid-activated formulation is provided, comprising a
liquid-activated colorant, a hydrochromic ionic compound, an
opacifier, and a binding matrix comprising a leaching
inhibitor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a top view of an absorbent article according to an
aspect of the invention.
[0006] FIG. 2 is a front view of an absorbent article according to
an aspect of the invention.
[0007] FIG. 3 is a cross section of an absorbent article of FIG. 1
according to an aspect of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0008] "Absorbent article" refers to devices which absorb and
contain body exudates and, more specifically, refers to devices
which are placed against or in proximity to the body of the wearer
to absorb and contain the various exudates discharged from the
body. Absorbent articles may include diapers, training pants, adult
incontinence undergarments, feminine hygiene products, breast pads,
care mats, bibs, wound dressing products, and the like. As used
herein, the term "body fluids" or "body exudates" includes, but is
not limited to, urine, blood, vaginal discharges, breast milk,
sweat and fecal matter.
[0009] "Absorbent core" means a structure typically disposed
between a topsheet and backsheet of an absorbent article for
absorbing and containing liquid received by the absorbent article
and may comprise one or more substrates, absorbent polymer material
disposed on the one or more substrates, and a thermoplastic
composition on the absorbent particulate polymer material and at
least a portion of the one or more substrates for immobilizing the
absorbent particulate polymer material on the one or more
substrates.
[0010] "Absorbent polymer material," "absorbent gelling material,"
"AGM," "superabsorbent," and "superabsorbent material" are used
herein interchangeably and refer to cross linked polymeric
materials that can absorb at least 5 times their weight of an
aqueous 0.9% saline solution as measured using the Centrifuge
Retention Capacity test (Edana 441.2-01).
[0011] "Comprise," "comprising," and "comprises" are open ended
terms, each specifies the presence of what follows, e.g., a
component, but does not preclude the presence of other features,
e.g., elements, steps, components known in the art, or disclosed
herein.
[0012] "Consisting essentially of" is used herein to limit the
scope of subject matter, such as that in a claim, to the specified
materials or steps and those that do not materially affect the
basic and novel characteristics of the subject matter.
[0013] "Diaper" refers to an absorbent article generally worn by
infants and incontinent persons about the lower torso so as to
encircle the waist and legs of the wearer and that is specifically
adapted to receive and contain urinary and fecal waste. As used
herein, term "diaper" also includes "pants" which is defined
below.
[0014] "Fiber" and "filament" are used interchangeably.
[0015] A "nonwoven" is a manufactured sheet, web, or batt of
directionally or randomly orientated fibers, bonded by friction,
and/or cohesion and/or adhesion, excluding paper and products which
are woven, knitted, tufted, stitch-bonded incorporating binding
yarns or filaments, or felted by wet-milling, whether or not
additionally needled. The fibers may be of natural or man-made
origin and may be staple or continuous filaments or be formed in
situ. Commercially available fibers have diameters ranging from
less than about 0.001 mm to more than about 0.2 mm and they come in
several different forms: short fibers (known as staple, or
chopped), continuous single fibers (filaments or monofilaments),
untwisted bundles of continuous filaments (tow), and twisted
bundles of continuous filaments (yarn). Nonwoven fabrics can be
formed by many processes such as meltblowing, spunbonding, solvent
spinning, electrospinning, and carding. The basis weight of
nonwoven fabrics is usually expressed in grams per square meter
(gsm).
[0016] "Pant" or "training pant", as used herein, refer to
disposable garments having a waist opening and leg openings
designed for infant or adult wearers. A pant may be placed in
position on the wearer by inserting the wearer's legs into the leg
openings and sliding the pant into position about a wearer's lower
torso. A pant may be preformed by any suitable technique including,
but not limited to, joining together portions of the article using
refastenable and/or non-refastenable bonds (e.g., seam, weld,
adhesive, cohesive bond, fastener, etc.). A pant may be preformed
anywhere along the circumference of the article (e.g., side
fastened, front waist fastened). While the terms "pant" or "pants"
are used herein, pants are also commonly referred to as "closed
diapers," "prefastened diapers," "pull-on diapers," "training
pants," and "diaper-pants." Suitable pants are disclosed in U.S.
Pat. No. 5,246,433, issued to Hasse, et al. on Sep. 21, 1993; U.S.
Pat. No. 5,569,234, issued to Buell et al. on Oct. 29, 1996; U.S.
Pat. No. 6,120,487, issued to Ashton on Sep. 19, 2000; U.S. Pat.
No. 6,120,489, issued to Johnson et al. on Sep. 19, 2000; U.S. Pat.
No. 4,940,464, issued to Van Gompel et al. on Jul. 10, 1990; U.S.
Pat. No. 5,092,861, issued to Nomura et al. on Mar. 3, 1992; U.S.
Patent Publication No. 2003/0233082 A1, entitled "Highly Flexible
And Low Deformation Fastening Device", filed on Jun. 13, 2002; U.S.
Pat. No. 5,897,545, issued to Kline et al. on Apr. 27, 1999; U.S.
Pat. No. 5,957,908, issued to Kline et al on Sep. 28, 1999; and
U.S. Ser. No. 11/197,197 to LaVon et al filed Aug. 4, 2005; Ser.
No. 11/224,462 to Lavon et al filed on Sep. 12, 2005; Ser. No.
11/286,614 to LaVon on Nov. 23, 2005; Ser. No. 11/286,612 to LaVon
on Nov. 23, 2005; and Ser. No. 11/709,500 issued to LaVon et al on
Feb. 27, 2007.
[0017] "Substantially surfactant free" is used herein to describe
an article component, such as a dusting layer, that contains less
than 10% by weight of a surfactant or mixture thereof, less than 5%
by weight of surfactant, less than 1% by weight of surfactant, no
surfactant, or no more than an immaterial amount of surfactant
where the surfactant may be anionic, cationic, nonionic, amphoteric
or may include mixtures thereof and function to increase the
wettability of the article component by reducing the contact angle
of synthetic urine (as disclosed in U.S. Pat. No. 6,772,708 to
Klofta) in contact with the surface of the article component (e.g.,
fibers of a nonwoven material or the surface of a film).
Binding Agents and Leaching Inhibitors
[0018] A binding agent may be any material which immobilizes a
liquid-activated colorant, or combination of colorants, within the
matrix to hinder leaching of the colorant(s) into a diaper core or
other regions of an absorbent article. To optimize the contrast and
vibrancy of the colors, it is much preferred to "lock" the colorant
within the matrix before and after contact with a fluid like urine.
The binding agents can not only hinder the leaching of the color
outside of the matrix, but also aid in binding the entire
liquid-activated formulation to a component of the absorbent
article. For example, the binder can aid in forming a strong bond
between the surface of the diaper backsheet and the
liquid-activated formulation. There are various materials which may
be suitable for use as a binding agent in a hot melt binding matrix
or solvent-based binding matrix for the liquid-activated
formulations of the present invention.
[0019] In one embodiment, possible binding agents include, but are
not limited to, rosins, rosin esters, polymerized rosins,
pentaerythritol rosin esters, modified styrene-acrylic polymers and
their salts, styrenated terpenes, polyterpene resins, terpene
phenolics, and combinations thereof. Also suitable as binders are
adhesives, quaternary ammonium compounds, quaternary polymers,
rubbers, latexes and latex emulsions, waxes, surfactants,
polyethylene glycols, polyvinyl alcohols, and combinations
thereof.
[0020] A suitable rosin mixture may be the combination of Arizona
Chemical's Sylvatac RE98 and Eastman's Poly-Pale.TM.. The Sylvatac
RE-98 is a pentaerythritol rosin ester and the Sylvaros PR-295 is a
polymerized rosin. Both are economical matrix ingredients, both can
contribute to a darker color in the dry state, both aid in
maintaining effective cohesive and adhesive forces, and their
acidic nature helps preserve the colorant in its dry state color.
In addition to being a suitable binding agent, rosin esters,
polymerized rosins, and pentaerythritol rosin esters may also be
effective solubilizers for some of the other ingredients in these
formulations. Furthermore, while not wishing to be limited by
theory and as noted, the acidity of some rosin esters, polymerized
rosins and pentaerythritol rosin esters is believed to contribute
to the stabilization of particular dyes, such as, but not limited
to, pH indicators. For example, some of these rosins contain acidic
carboxylate groups which aid in keeping a colorant like bromocresol
green (free acid) in its acidic yellow state. When using the free
acid form of bromocresol green, this acidic yellow state is the
preferred color for the dry state of the wetness indicator
composition before the product is used.
[0021] In some embodiments, it may be preferable for the initial
dry state of the wetness indicator composition to be completely
white with no sign of any coloration. This can be accomplished by
using synthetic ingredients that can be synthesized to be white.
This is converse to the use of rosins and polymerized rosins which
are natural materials most commonly derived from trees. These
natural rosins tend to be more yellow in color in the dry state and
not white. But, in certain cases, the addition of white opacifiers
like titanium dioxide or sodium aluminum silicate can help hide the
yellow coloration from the use of natural materials.
[0022] The binding material may immobilize the colorant when in its
initial color state. How the binding material immobilizes the
colorant when in its initial color state depends upon both what the
binding material and colorant are. For example, the first binding
material may work by one or more forces selected from the group
consisting of adhesion, hydrogen bonding, ionic, polar covalent
bonding, Van der Waals forces, dipole-dipole forces, London
dispersion forces and combinations thereof.
[0023] The binding agent may be employed in compositions at levels
which are effective at immobilizing and stabilizing the colorant in
its first state, including from about 1% to about 90%, from about
10% to about 75%, and from about 20% to about 65%, by weight of the
composition.
[0024] The binding matrix may comprise a first and second binding
agent. The second binding agent may be any material which may
immobilize the colorant when the colorant is in its final color
state. This immobilization helps to bind the colorant within the
wetness indicator composition to prevent it from leaching to other
regions of the diaper such as the diaper core. It should be noted
that similar to the first binding agent, the second binding agent
can function not only to hinder the leaching of the colorant
outside of the wetness indicator composition but the second binding
agent can also aid in bonding the entire wetness indicator
composition to the material of interest within the absorbent
article. For example, the second binding agent may aid in bonding
the wetness indicator composition to the backsheet of the diaper.
There are various materials which may be suitable for use as an
additional binding agent for the liquid-activated formulations of
the present invention.
[0025] In one embodiment, a binding agent may be selected from, but
are not limited to, the second binding agents disclosed in U.S.
Pat. No. 6,904,865 to Klofta.
[0026] In one optional embodiment of the present invention, a
binding agent is selected from the group consisting of quaternary
ammonium salt compounds, cationic clay, polyacrylic acid polymers,
organic acids, and combinations thereof. Examples of suitable
quaternary ammonium compounds include, but are not limited to,
dimethyl(2-ethylhexylhydrogenatedtallowalkyl)ammonium methyl
sulfate, cocoalkylmethyl[ethoxylated(15)]ammonium chloride,
dodecyltrimethyl ammonium chloride, hexadecyltrimethyl ammonium
methyl sulfate, octadecyltrimethyl ammonium chloride,
dicocoalkyldimethly ammonium chloride, di(hydrogenated
tallowalkyl)dimethyl ammonium chloride, and distearyldimethyl
ammonium chloride.
[0027] It should be noted that the counter anion associated with
the quaternary compound, or any binding agent having one or more
cationic group, is not specifically limited to chloride. Other
anions can also be employed and non-limiting examples include
methyl sulfate and nitrite. Similarly, any suitable counter cation,
such as, but not limited to, sodium, potassium, calcium, magnesium,
zinc, protons, ammonium, substituted ammonium and the like, may be
associated with a binding agent having one or more anionic groups.
Cationic polymers like polyethyleneimines can also hinder leaching
of anionic colorants. An example of a polyethylenimine (PEI) are
the Lupasol.TM. line of PEI's from BASF.
[0028] The second binding material may immobilize the colorant when
in its final color state. How the second binding material
immobilizes the colorant when in its final color state depends upon
the chemical composition of both the second binding material and
colorant. For example, if the colorant's final color state is that
of an anionic long chain molecule and the second binding material
is a cationic molecule, then the bond formed may be, for example,
an ionic bond, a covalent bond, or the like, or combinations of the
relevant bonding forces. Another example, if the colorant's final
color state is that of a cationic molecule, and the second binding
material is an anionic long chain molecule, then the bond formed
may be, for example, an ionic bond, covalent bond, or the like, or
combinations of the relevant bonding forces.
[0029] In one embodiment of the present invention the second
binding agent immobilizes the colorant when the colorant is in its
final color state by one or more selected from the group consisting
of covalent bonding, ionic bonding, Van der Waals, and combinations
thereof.
[0030] Without wishing to be bound by theory, it is believed that
when the colorant is an anion in its final color state and the
second binding agent is a cation or the colorant is a cation in its
final color state and the second binding agent is an anion, the
second binding agent forms an ionically bonded coacervate with the
colorant. For example, when the final state associated with a
colorant's final color state is the pH of urine, contacting the
colorant with urine will change the colorant to its final color
state, i.e. an anion, and this forms an ionic bond with the second
binding agent, which is a cation. The coacervate formation is due
to the strong coulombic interaction between the opposite charges of
the colorant and the second binding agent. The coacervate formed
between the colorant and the second binding agent neutralizes the
charge in both species and dramatically reduces both of their
solubilities in polar solvents such as water or urine while the
coacervate's solubility in the matrix remains high due to this
charge neutralization and the coacervate's more lipophilic nature.
Both of these effects dramatically inhibits the leaching of the
colorant from the matrix. The increased lipophilicity of the
coacervate leads to increased intermolecular bonding forces between
the coacervate and components of the matrix. These intermolecular
forces may further limit the diffusion and mobility of the colorant
into an fluid environment such as water or urine.
[0031] In certain optional embodiments of the present invention,
use of cationic quaternary ammonium compounds, quaternary polymers,
and combinations thereof as the second binding agent may also
function to darken or intensify the color change of certain
colorants, especially those belonging to the sulfonephthalein class
of pH indicators. Without wishing to be bound by theory, it is
believed this darkening is due to several possible factors: 1)
alkaline impurities within the quaternary ammonium raw material, 2)
absorption shifting and absorptivity coefficient increases due to
coacervate formation and/or 3) increased formation of the colorant
in its final color state.
[0032] The second binding agent may be employed in compositions at
levels which are effective at immobilizing the colorant in its
second state, including from about 0.5% to about 20%, from about
0.5% to about 10%, and from about 0.1% to about 5%, by weight of
the composition.
[0033] In certain embodiments, incorporating the colorant, also
referred to as the indicator or colorant, into a hydrophobic matrix
that preferentially "locks" the molecule into the matrix may
inhibit the leaching of the anionic colorant into the urine. In
these embodiments, the anionic colorant may become preferentially
absorbed into the matrix due to intermolecular bonding forces. Some
of the types of intermolecular forces responsible include hydrogen
bonding, electrostatic forces, van der Waals forces and hydrophobic
interactions. Thus, even though the charged portion of the colorant
in its virgin state would be hydrated by water in the urine,
leaching of the colorant may be inhibited due to intermolecular
bonding forces between the materials of the matrix and the
colorant.
[0034] However, in one embodiment, the colorant is chemically bound
to at least one component of the binding matrix, such as a cationic
species. Chemical bonds include covalent, ionic, and metallic
bonds. In embodiments wherein the carrier matrix comprises a
cationic species, the cationic species may function as a leaching
inhibitor to reduce or completely eliminate leaching of an anionic
colorant from the binding matrix. In particular, leaching of the
anionic colorant indicator is preferably inhibited via addition of
a permanently charged cationic molecule in the ink formulation. For
example, quaternary ammonium compounds are particularly effective
leaching inhibitors by inhibiting colorant leaching from the matrix
and enhancing the contrast and clarity of the wetness indicator
pattern.
[0035] Without wishing to be bound by theory, it is believed the
cationic quaternary ammonium compound forms an ionically bonded
coacervate with the negatively charged pH indicator due to the
strong coulombic interaction between the anionic colorant and the
cationic quaternary ammonium compound. The coacervate complex
formed between the anionic colorant and the cationic quaternary
ammonium compound neutralizes the charge in both species and
dramatically reduces both of their solubilities in polar solvents
such as water or urine, thereby dramatically inhibiting leaching of
the colorant from the binding matrix. The intermolecular forces
between the coacervate and the binding matrix, as described above,
may further limit the diffusion and mobility of the colorant into
an aqueous environment such as urine.
[0036] This leaching inhibition is particularly beneficial in
locking the pH indicator or colorant directly within the wetness
indicator on the backsheet rather than allowing free diffusion of
the colorant or indicator through the diaper core and possibly
contaminating the diaper topsheet. In addition, a clearer and more
distinct wetness indicator pattern may be produced in embodiments
wherein colorants or pH indicators are locked into the matrix. As
noted, colorants or pH indicators that diffuse out of the wetness
indicator pattern tend to appear blurred and less distinct.
[0037] In certain embodiments, the addition of the quaternary
ammonium compound may also function to darken the color change of
sulfonephthalein pH indicators. This may be attributed to alkaline
impurities within the quaternary ammonium raw material, absorption
shifting and absorptivity coefficient increases due to coacervate
formation and/or increased anionic colorant formation.
[0038] Alternatively, it is possible to inhibit leaching of a
cationic colorant or cationic pH indicator by incorporating an
anionic compound into the binding matrix. For example, many
polyacrylic acid polymers and organic acids such as stearic acid
are negatively charged at pH's above approximately 5. If the pH
indicator undergoes a transition to a cationic species at the
typical urine pH of 5.5 to 8.0, the formation of an insoluble
coacervate may occur, inhibiting leaching in a manner similar to
the systems described above.
[0039] In some embodiments, the binding matrix is a solvent-based
binding matrix, where possible binding agents include, but are not
limited to, acrylic-based solvents, alcohol-based solvents, aqueous
solvents like water, organic solvents, and combinations thereof.
Examples may include vinyl based resins, acrylic resins,
acrylates/ethylhexyl acrylate copolymers; sodium acrylate/sodium
acryloyldimethyl taurate copolymer; ethylene-vinyl chloride
emulsions, vinyl-acrylic resins, natural and synthetic alkyd
resins, acrylic resins, polyester resins, natural and synthetic
latex emulsions, polyurethanes, melamine resins, epoxy resins,
amine resins, waxes, acrylates/octyl acrylate copolymer; ammonium
polyacrylate. Examples of organic solvents may include, for
example, alcohols, ketones, mineral spirits, petroleum distillates,
glycol ethers, silicone fluids, oils like linseed oil, esters,
ethers, amides, and or lactones with alcohol being preferred.
Organic solvents may be selected from ethanol, propanol, butanol,
acetone, tetrahydrofuran, benzene, toluene and acetonitrile. Polar
solvents are preferred. Methanol is preferred. Other suitable
binding agents may include acrylate/acrylamide copolymers and
copolymers of vinylpyrrolidone and dimethylaminopropyl
methacrylamide etc. The binder could be modified or incorporated
with a commercialized varnish material or other encapsulating
materials.
[0040] Water-soluble resins may also be suitable, as they may act
as a binder and cause the colorant to adhere to the substrate.
Examples include polyamide, cellulose derivatives, an acrylic
polymer or a polyol, e.g. a water soluble resin selected from the
group consisting of polyvinylpyrrolidone, polyvinyl alcohol,
carboxymethylcellulose, poly(2-ethyl-2-oxazoline), polymers
(homopolymers and copolymers) based on acrylic acid, polymers
(homopolymers and copolymers) based on methacrylic acid), and
polymers (homopolymers and copolymers) based on acrylamide and any
combination thereof. Some organic soluble resin binders would
include those based on acrylic, alkyd, amide, epoxy,
nitrocellulose, phenolic, polyester, polyurethane, and vinyl
monomers, oligomers and polymers. Other suitable ink base material
as binding agents for the color-changing compositions of the
invention may be a varnish base such as a nitrocellulose
compoundbased varnish, ethyl cellulose-based varnish,
polyurethanebased binding systems or a phenolic-modified co-solvent
type polyamide resin-based varnish. It is believed that the ink
base material may help the stability of the color-changing
composition. It is also believed that the ink base material may
improve the adhesion of the color-changing composition to the
substrate.
[0041] In general, the solvent-based binding matrix may be from
about 5% to about 75% by weight of the liquid-activated
formulation.
Hot Melt Adhesives
[0042] In some embodiments, the binding agent may be a hot melt
adhesive, in some embodiments, a solvent-based binding matrix.
Additional components of a hot melt adhesive binding matrix may
include base polymers, tackifiers, waxes, rubbers, solvents,
wetting agents, and/or anti-oxidants. Examples of base polymers
used in hot melt adhesives may include ethylene-vinyl acetate (EVA)
copolymers; ethylene-acrylate copolymers;
ethylene-vinylacetate-maleic anhydride terpolymer;
ethylene-acrylate-maleic anhydride terpolymer; polyolefins such as
low density and high density polyethylene, atacttic polypropylene,
oxidized polyethylene, polybutene-1; amorphous polyolefins like
amorphous atactic propylene (APP), amorphous propylene/ethylene
(APE), amorphous propylene/butane (APB), amorphous propylene/hexane
(APH), and amorphous propylene/ethylene/butane; polyamides; styrene
block copolymers (SBC); styrene/acrylic polymers and modified
styrene/acrylic polymers; polycarbonates; silicone rubbers;
polypyrrole based polymers; thermoplastic elastomers like natural
and synthetic polyisoprene, polybutadiene rubber, butyl rubber,
chloroprene rubber, ethylene-propylene rubber, epichlorohydrin
rubber, polyacrylic rubber, polyether block amides; polymers of
acrylates, alkyd resins, amides, amino resins, ethylene
co-terpolymer resins such as EVA, epoxy resins, fluoropolymers,
hydrocarbon resins, phenols, polyesters, olefins, polyurethanes,
silicones and functionalized silicones, polystyrene and
polyvinyls.
[0043] Tackifiers suitable for hot melt adhesives include, without
being limited to, natural resins like copals like gum copal,
dammars, mastic, and sandarac; rosins and their derivatives;
terpenes and modified terpenes; aliphatic, cycloaliphatic, and
aromatic resins like C5 aliphatic resins, C9 aromatic resins, and
C5/C9 aromatic/aliphatic resins, hydrogenated hydrocarbon resins
and their mixtures.
[0044] Waxes suitable for hot melt adhesives include, without being
limited to, mineral waxes like paraffin and microcrystalline waxes;
polyethylene waxes; polyethylene glycol type waxes; oxidized
polyethylene waxes; highly branched polymer waxes like Vybar.TM.
from Baker Hughes; fatty amide waxes; natural and synthetic waxes
like beeswax, soywax, carnuba, ozokerite, ceresin; waxes derived
from both the Fisher-Tropsch and Ziegler-Natta processes; and
silicone waxes.
[0045] Additional additives for adhesives and hot melt adhesives
may include plasticizers, like glyceryl tribenzoate, phthalates,
paraffin oils, and polyisobutylene; UV stabilizers; biocides and
antimicrobial preservatives; antioxidants, like BHT, phosphites and
phosphates; antistatic agents; rosins and their derivatives;
pigment, particle and powder wetting agents like polyhydroxystearic
acid, polyglyceryl-4 isostearate, hexyl laurate, isopropyl
myristate, propylene carbonate, isononyl isononanoate, glyceryl
behenate/eicosadioate, trihydroxystearin, C12-15 alkyl benzoate,
triethoxycaprylysilane, castor oil; and viscosity modifiers.
Optionally, solvents like mineral oil, isoparaffins, alkanes like
hexane, silicone fluids, esters, alcohols, polyethylene glycols,
glycerin, glycols, and water can be added to reduce the viscosity
of the composition or to increase the solubility of other
ingredients or change other strategic properties of the wetness
indicator composition.
Colorants
[0046] The liquid activated formulations which are utilized in this
invention comprise a liquid-activated colorant. A colorant may be a
dye, an ink, a pigment, or a pH indicator. The liquid activated
colorant can be soluble within the wetness indicator composition
and in certain cases, it can be suitable to homogeneously suspend
or disperse the colorant within the wetness indicator composition.
As noted, the colorant changes color upon coming in contact with
water or urine. In some embodiments, the liquid-activated
formulation may further comprise a permanent colorant that does not
change color upon coming in contact with water or urine.
[0047] Some representative examples of liquid-activated colorants
that can be used in the practice of this invention include:
Malachite green, brilliant green, crystal violet, erythrosine B,
methyl green, methyl violet 2D, picric acid, naphthol yellow S,
quinaldine red, eosine Y, metanil yellow, m-cresol purple, thymol
blue, xylenol blue, basis fuchsin, eosin B,
4-p-aminophenol(azo)benzenesulphonic acid-sodium salt, cresol red,
martius yellow, phloxine B, methyl yellow, bromophenol blue, congo
red, methyl orange, m-cresol red, m-cresol purple,
bromochlorophenol blue (water soluble or free acid form), ethyl
orange, fluorocene WS, bromocresol green, chrysoidine, methyl red
sodium salt, alizarine red S--H2O, cochineal, chlorophenol red,
bromocresol purple, 4-naphtha, alizarin, nitrazine yellow,
bromothymol blue, brilliant yellow, neutral red, rosalic acid,
phenol red, 3-nitro phenol, orange II, phenolphthalein,
o-cresolphthalein, nile blue A, thymolphthalein, aniline blue WS,
alizarine yellow GG, mordant orange, tropaolin O, orange G, acid
fuchsin, thiazol yellow G, indigo carmine, cresol red, methyl red,
p-nitrophenol, and alizarin yellow R. In certain instances, it is
advantageous to use the free acid form, free base form, or salt
form of the colorants.
[0048] Additional water-soluble colorants may include FD&C Blue
No. 1, FD&C Blue No. 2, FD&C Green No. 3, FD&C Red No.
40, FD&C Red No. 4, FD&C Yellow No. 5, FD&C Yellow No.
6, C.I. Food Blue 5, and C.I. Food Red 7, D&C Yellow No. 10,
D&C Yellow No. 7, D&C Yellow No. 2, D&C Yellow No. 8,
D&C Orange No. 4, D&C Red No. 22, D&C Red No. 28,
D&C Red No. 33, D&C Green No. 8, D&C Green No. 5,
D&C Brown No. 1, and any combination thereof. Preferably, the
colorant is soluble within the wetness indicator composition, but,
as noted in certain instances, the colorant can function as
intended by homogenerously suspending or dispersing it within the
wetness indicator composition.
[0049] Many of these aforementioned colorants do not change colors
when contacted by an aqueous solution like urine. These are
referred to as permanent colorants which can function to change the
color hue of the wetness indicator composition of either its dry
state or color changed state after contact with a fluid like urine.
Some examples of oil soluble permanent colorants include D&C
Yellow No. 11, D&C Red No. 17, D&C Red No. 21. D&C Red
No. 27, D&C Violet No. 2, D&C Green No. 6, and D&C
Orange No. 5. These permanent and oil soluble colorants can not
only change the color hue of the wetness indicator composition in
either the dry or wet state, but they can be advantageous due to
their reduced solubility in hydrophilic liquids like urine. Thus,
their leaching is inhibited and they possess a higher probability
of remaining bound within the wetness indicator composition after
being wetting with an aqueous liquid like urine.
[0050] Additional suitable fluid colorants include water soluble
colorants like direct dyes, acid dyes, base dyes, and various
solvent-soluble colorants. Dispersed or suspended pigment colorants
can also be employed into these wetness indicator compositions
(liquid-activated formulations). Examples include, but are not
limited to, C.I. Acid Yellow 73, C.I. Solvent Yellow 94, C.I. Acid
Yellow 74, C.I. Solvent Orange 32, C.I. Solvent Red 42, C.I. Acid
Orange 11, C.I. Solvent Red 72, C.I. Pigment Orange 39, C.I.
Solvent Orange 18, C.I. Acid Red 87, C.I. Solvent Red 43, C.I.
Pigment Red 90:1, C.I. Solvent Red 44, C.I. Solvent Red 45, C.I.
Solvent Orange 16, C.I. Acid Red 91, C.I. Acid Red 98, C.I. Acid
Red 92, C.I. Solvent Red 48, C.I. Pigment Red 174, C.I. Acid Red
95, C.I. Solvent Red 73, C.I. Pigment Red 191, C.I. Acid Red 51,
C.I. Food Red 14, C.I. Pigment Red 172, C.I. Solvent Red 140, C.I.
Acid Red 93, C.I. Solvent Red 47, C.I. Acid Red 94, C.I. Solvent
Red 141, C.I. Mordant Violet 25, C.I. Solvent Orange 17, C.I.
Solvent Red 46, D&C Red 27 (C.I. 45410:1), D&C Orange 5
(C.I. 45370:2), and combinations thereof. More preferred fluid
colorants are selected from the group consisting of D&C Red 27,
D&C Orange 5, and combinations thereof.
[0051] Additional suitable colorants may include bromopyrogallol
red, bromoxylenol blue, methylene blue, monoazo dyes such as acid
alizarin voliet N, monoazo pyrazoline dyes (such as acid yellow
34), diazo dyes (such as acid black 24), anthraquinone dyes (such
as acid black 48), amphoteric anthraquinone dyes (such as acid blue
45), triphenylmethane dyes (such as acid fuchsin), phthalein type
dyes (such as o-cresolphthalein), xanthene dyes (such as 2'7'
dichlorofluorescein eosin B), heterocyclic acridine aromatics (such
as acridine orange), diphenylmethane dyes (such as auramine O),
triphenylmethane dyes (such as basic fuchsin), cationic thiazine
dyes (azure C), cationic anthraquinone dyes such as basic blue 47,
phthalocyanine type dyes (such as strazon orange G), anthraquinone
type (sch as alizarin), neutral complex dyes (such as azure A
eosinate), terpene type dyes (such as trans-beta-carotene), as well
as combinations including at least one of the foregoing dyes.
[0052] Examples of colorants further include, but are not limited
to, organic dyes, inorganic pigments, colored macromolecules,
colored nanoparticles and materials. Examples of dyes include
acridine dyes, anthraquinone dyes, arylmethane dyes, azo dyes,
nitro dyes, nitroso dyes, phthalocyanine dyes, quinone-imine dyes,
Aazin dyes, Indophenol dyes, oxazin dyes, Oxazone dyes, Thiazole
dyes, xanthene dyes, Fluorene dyes, fluorone dyes, rhodamine dyes.
Examples of pigments include Cadmium pigments: cadmium yellow,
cadmium red, cadmium green, cadmium orange; Carbon pigments: carbon
black (including vine black, lamp black), ivory black (bone char);
Chromium pigments: chrome yellow and chrome green; Cobalt pigments:
cobalt violet, cobalt blue, cerulean blue, aureolin (cobalt
yellow); Copper pigments: Azurite, Han purple, Han blue, Egyptian
blue, Malachite, Paris green, Phthalocyanine Blue BN,
Phthalocyanine Green G, verdigris, viridian; Iron oxide pigments:
sanguine, caput mortuum, oxide red, red ochre, Venetian red,
Prussian blue; Clay earth pigments (iron oxides): yellow ochre, raw
sienna, burnt sienna, raw umber, burnt umber; Lead pigments: lead
white, cremnitz white, Naples yellow, red lead; Mercury pigments:
vermilion; Titanium pigments: titanium yellow, titanium beige,
titanium white, titanium black; Ultramarine pigments: ultramarine,
ultramarine green shade; Zinc pigments: zinc white, zinc ferrite.
Other examples include alizarin, alizarin crimson, gamboge,
cochineal red, rose madder, indigo, Indian yellow, Tyrian purple,
organic quinacridone, magenta, phthalo green, phthalo blue, pigment
red.
Hydrochromic Ionic Compound
[0053] The hydrochromic ionic compound is typically a reactive
ionic compound, such as an ionizing salt. Some representative
examples of hydrochromic ionic compounds that can be employed in
the practice of this invention include: lithium hydrogen sulfate,
lithium hydrogen carbonate, potassium hydrogen sulfate, potassium
hydrogen carbonate, rubidium hydrogen sulfate, rubidium hydrogen
carbonate, cesium hydrogen sulfate, cesium hydrogen carbonate,
sodium hydrogen sulfate, sodium hydrogen carbonate, sodium
carbonate, cesium hydroxide, lithium hydroxide, potassium
hydroxide, calcium hydroxide, magnesium hydroxide, sodium
thiosulfate penta hydrate, sodium hydroxide, rubidium hydroxide,
cobalt chloride, cobalt nitrate, copper sulphate copper nitrate,
iron (II) sulfate, iron (III) sulfate, iron (II)chloride, iron
(III) chloride, citric acid, monosodium dihydrogen citrate,
disodium hydrogen citrate, trisodium citrate, gluconic acid, sodium
gluconate, glycolic acid, sodium glycolate, malic acid, sodium
malate, maleic acid, sodium maleate, acetic acid, phosphoric acid,
trisodium phosphate, sodium dihydrogen phosphate, disodium hydrogen
phosphate, monostearyl phosphate, monocetyl phosphate, monostearyl
citrate, hydrochloric acid, nitric acid, sulfuric acid and
combinations thereof.
Opacifiers
[0054] The opacifiers that can be utilized in the liquid activated
formulations of this invention can be porosigens or antiporosigens
and are typically white powders when they are in the form of dry
solids (before being incorporated into the ink formulation). In the
cases where the opacifiers act as porosigens they allow for liquid
transmission through coatings which are applied to a substrate,
such as a coating which is printed on the outer layer of a diaper.
In other words, the porosigen is a compound which allows for liquid
to be transmitted through it which facilitates liquid transmission
throughout the coating. In the case of antiporosigens liquid
transmission is attained by virtue of liquid permeable interstices
which are formed in proximity to the antiporosigens by virtue of
disrupting the structure of liquid barrier materials. In other
words, the antiporosigens cause holes to be present in the dry
coating structure which are of a size and structure which allows
for liquid to flow through the coating. Some representative
examples of opacifiers that can be utilized include titanium
dioxide, calcium carbonate, calcium hydroxide, sodium silicate,
potassium silicate, silica, starch, ethocell, methocell, barium
carbonate, barium silicate, calcium silicate, aluminum silicate,
aluminum hydroxide, zinc oxide, sodium aluminum silicate like
Evonik's Sipernat.TM. 820a, zirconium silicate, magnesium aluminum
silicate, and aluminum oxide. Suitable polymeric opacifiers include
the styrene/acrylate copolymers like Opulyn.TM. 301 from Rohm and
Haas, or the SunSphere.TM. line of opacifiers, also from Rohm and
Haas.
Additional Ingredients
[0055] Additional ingredients may include, for example, a
stabilizer, a surfactant, a structural adjunct, and/or solvents.
When present, such ingredients are typically employed in the
composition at levels that are effective at providing the benefits
of the ingredient or ingredients, such as, for example, from about
0.001% to about 50%, from about 0.1% to about 40%, or from about 1%
to about 35%, by weight of the composition. Solvents may include a
liquid, gel or semi-solid material. The solvent may be water, a
thixotropic material, paste, an alcohol, ethylene glycol monobutyl
ether, mineral oil, esters, silicone fluids, isoparaffins, alkanes
like hexane, toluene, xylenes, low molecular weight polyethylene
glycols like PEG-200, glycerin, glycols, a non-flammable solvent,
an adhesive material, or other organic species. Preferred
non-aqueous solvents may comprise alcohols, acetates, and
combinations thereof. The alcohol solvents are preferably selected
from the group consisting of iso-propyl alcohol, n-propyl alcohol,
ethanol, methanol, and combinations thereof. Likewise, suitable
acetate solvents include, but are not limited to, isopropyl
acetate, n-propyl acetate, and combinations thereof. Other suitable
solvents that may be effective include water, aqueous detergent
solutions, acidic water solutions, alkaline water solutions,
isopropanol, ethanol, methyl-ethyl ketone, acetone, toluene,
hexane, ethyl 15 acetate, acetic acid (vinegar), cetyl alcohol
(fatty alcohol), dimethicone silicone, isopropyl lanolate,
myristate, palmitate, lanolin, lanolin alcohols and oils, octyl
dodecanol, oleic acid (olive oil), panthenol (vitamin B-complex
derivative), stearic acid and stearyl alcohol, butylene glycol and
propylene glycol, cyclomethicone (volatile silicone), glycerin,
aloe, petrolatum, and so forth. Viscous solvents, such as for
example, common tape adhesives, have been found to be particularly
effective at delaying or controlling the onset of the color change.
Adhesives that may be useful include, for example, those based on
alkyds, animal glues, casein glues, cellulose acetates, cellulose
acetate butyrates, cellulose nitrates, ethyl celluloses, methyl
celluloses, carboxy methyl celluloses, epoxy resins, furane resins,
melamine resins, phenolic resins, unsaturated polyesters,
polyethylacrylates, poly-methylmethacrylates, polystyrenes,
polyvinylacetates, polyvinylalcohols, polyvinyl acetyls, polyvinyl
chlorides, polyvinyl acetate chlorides, polyvinylidene copolymers,
silicones, starched based vegetable glues, urethanes, acrylonitrile
rubbers, polybutene rubbers, chlorinated rubbers, styrene rubbers,
and so forth. Waxes such as, for example, polyolefin waxes, bees
waxes, and so forth, and gels such as, for example, glycol
dimethacrylate, chitosan, polyacrylates, hydroxypropylcellulose,
gelatin, and so forth, may also be useful to effect the color
change. Surfactants that are suitable for the present invention may
include, for example, ethoxylated alcohols, fatty alcohols, high
molecular weight alcohols, ethoxylated sorbitan esters like
Tween.TM. 40 from Croda, the ethoxylated pareth surfactants like
Performathox.TM. 450 from New Phase Inc., esters, polymers and
other natural and synthetic waxes or olefininc materials as known
in the art; anionic and cationic surfactants, alkoxylated alkylates
such as PEG-20 stearate, end group-capped alkoxylated alcohols,
alkoxylated glyceryl and polyglyceryl alkylates such as PEG-30
glyceryl stearate, glyceryl alkylates such as glyceryl stearate,
alkoxylated hydrogenated castor oil, alkoxylated lanolin and
hydrogenated lanolin, alkoxylated sorbitan alkylates, sugar derived
surfactants such as the alkyl glycosides and sugar esters,
poloxamers, polysorbates, and sulfo succininc acid alkyl esters.
Further examples include nonionic surfactants and amphoteric
surfactants and any combination thereof;
specific-diethylhexylsodiumsulfosuccinate, available as MONOWET
MOE75 from Uniqema, the sodium dioctyl sulfosuccinate line of
surfactants like Aerosol.TM. OT-100 from Cytec Inc. Another example
is 4-1-aminoethylphenolpolyoxyethylenefattyethers, polyoxyethylene
sorbitan esters, TWEEN, and polyoxyethylene fatty acid esters.
[0056] Other suitable surfactants may be neutral block copolymer
surfactants, which can be selected from
polyoxypropylene-polyoxyethylene block copolymer,
poly[poly(ethylene oxide)-block-poly(propylene oxide)]copolymer or
propylene glycol-ethylene glycol block copolymer. Suitable neutral
polymeric surfactants include TWEEN surfactants, such as TWEEN 20
surfactant, TWEEN 40 surfactant and TWEEN 80 surfactant, and TRITON
X-100 surfactant, which are available from Sigma-Aldrich,
Incorporated. Other suitable neutral surfactants include
polyethylene lauryl ether, polyoxyethylene nonyl phenyl ether,
polyoxyethylene oleyl phenyl ether, polyoxyethylene sorbitan
monolaurate, polyethylene glycol monostearate, polyethylene glycol
sorbitan monolaurate, polyoxyethylenesorbitan monopalmitate,
polyoxyethylenesorbitan monostearate, polyoxyethylenesorbitan
monooleate, polyoxyethylenesorbitan trioleate, polypropylene glycol
sorbitan monolaurate, polyoxypropylenesorbitan monopalmitate,
polyoxypropylenesorbitan monostearate, polyoxypropylenesorbitan
monooleate, polyoxypropylenesorbitan trioleate, polyalkyne glycol
sorbitan monolaurate, polyalkyne glycol sorbitan monopalmitate,
polyalkyne glycol sorbitan monostearate, polyalkyne glycol sorbitan
monooleate, polyalkyne glycol sorbitan trioleate and mixtures of
such neutral surfactants.
[0057] The neutral block copolymer based surfactants include
FLURONIC series block copolymers, such as PLURONIC P84 or FLURONIC
P85 surfactants, which are available from BASF Corporation.
[0058] Other suitable neutral block copolymer based surfactants
include nonylphenol ethoxylates, linear alkyl alcohol ethoxylate,
ethylene oxide-propylene oxide block copolymer,
polyoxypropylene-polyoxyethylene block copolymer, polyalkylene
oxide block copolymer, polyalkylene oxide block copolymer and
propylene glycol-ethylene glycol block copolymer.
[0059] It may be desirable to include a stabilizer when the
colorant is a pH indicator and when the absorbent article could be
stored under conditions of high humidities and temperatures. The
inclusion of a stabilizer is also especially important for new
diaper designs where materials and/or chemicals are present that
could potentially prematurely activate the color change of the
colorant within the ink formulation.
[0060] In one embodiment of the present invention, the stabilizer
is an acidic stabilizer. In another embodiment of the present
invention, the stabilizer is a basic stabilizer. The inclusion of a
stabilizer, while not wishing to be limited by theory, is believed
to play a role in stabilizing the colorant against premature
changes caused by exposure to humid environments and/or certain
components of the diaper, by maintaining a stable pH, such as a low
pH environment with an acidic stabilizer, around the colorant even
when the system is exposed to high humidities and/or certain
components of the diaper. This maintenance of a stable pH
environment keeps the colorant, especially when the colorant is a
pH indicator, in its initial dry color state. Desiccants can also
stabilize the composition by trapping free water that could
prematurely activate the wetness indicator composition. Examples of
suitable desiccants include silica gel, bentonite clays, activated
alumina, calcium sulfate, copper(II) sulfate, and magnesium
sulfate.
[0061] One of the key properties of a properly functioning wetness
indicator is for it to maintain its dry state color during a
variety of storage and packaging conditions while still undergoing
a noticeable color change in a reasonable amount of time after
being contacted by urine. The colorant should also remain stable to
various chemicals and materials that might be present in the
diaper. Although acidic moieties present in the rosins as part of
the matrix can aid in preserving the dry state color, additional
stabilizer ingredients have been found to be necessary with some
new diaper designs where high pH components within the diaper can
cause the undesirable and premature color change activation of the
colorant. To maintain the colorant in its acidic dry state color,
acids of suitable strength should be added. Suitable strength is
defined by the colorant and pH range where it changes color. The
colorant's pKa value is especially important in assessing the
characteristics of the chosen stabilizer.
[0062] For a pH indicator colorant like the sulfonephthalein class
which includes bromocresol green which changes color between a pH
of 3.8 and 5.4 (See "The Sigma-Aldrich Handbook of Stains, Dyes and
Indicators," by Floyd J. Green, Aldrich Chemical Co., Milwaukee,
Wis.), the stabilizer should contribute suitably strong acidic
moieties to keep the bromocresol green in its yellow state within
the matrix. Although many strong acids like sulfuric acid and
hydrochloric acid have suitably low pH's to accomplish this, their
solubilities are low in these anhydrous matrices. In addition,
their high acidity can chemically decompose the structures of some
of the components present in the wetness composition and diaper. As
noted, carboxylic acid moieties present in the matrix ingredients
like rosins or polymerized rosins can also aid in maintaining the
colorant in its acidic color state but carboxylic acids are
typically too weak to maintain the dry yellow state of bromocresol
green if it is exposed to high humidities and/or high pH components
within new diaper designs. To increase the strength of the
carboxylic acids, one can add electron withdrawing groups between
the carboxylic acid moiety and another portion of the molecule.
Although a fatty acid like stearic acid can aid in preserving the
dry state color, it can be made more effective by making it a
stronger acid by inserting polyoxyethylene groups between the
carboxylic acid group and the alkyl chain. These types of molecules
are called ether carboxylates and these acidic molecules can be
effective in maintaining the dry state acid form of the pH
indicator colorant like bromocresol green. In addition, the alkyl
group present in these ether carboxylates increases their
solubility in the wetness indicator matrix. Finally, the ether
carboxylate's surfactancy can aid in increasing the kinetics for
activating the color change of the wetness indicator composition
after it is contacted by urine.
[0063] Other suitable stabilizers are those of the monoalkyl
phosphate free acid and dialkyl phosphate free acid types. The
phosphate acid moiety is a stronger acid than the carboxylic acid
group and thus can be more effective in maintaining the low pH
environment required to keep the pH indicator colorant in its dry
acidic state. These alkyl phosphate free acids have been found to
be particularly effective in preserving the dry state color of the
bromocresol green colorant from premature activation as caused by
high humidities or destabilizing materials and/or chemicals present
in new diaper designs. Particularly effective alkyl phosphate free
acids are stearyl phosphate free acid, cetyl phosphate free acid,
and cetearyl phosphate free acids. Thus, the phosphate is a
suitably strong acid to maintain the pH indicator colorant in its
acidic dry state form, and the lipophilic alkyl moiety aids in
increasing its solubility within the wetness indicator composition.
In addition, the surfactant nature of the alkyl phosphate free
acids can aid in speeding up the kinetics of the color change after
the wetness indicator composition is contacted by urine.
[0064] Other acidic stabilizers which are particularly effective in
stabilizing the wetness indicator formula to high humidities and/or
destabilizing components within the diaper include, but are not
limited to: organic acids, such as, but not limited to, fatty acids
such as stearic acid, palmitic acid, lower molecular weight acids
such as citric acid, malic acid, maleic acid, lactic acid, glycolic
acid, gluconic acid, fumaric acid, adipic acid, ascorbic acid, and
salicylic acid; acid esters, such as, citrate esters, e.g.,
monostearyl citrate and monocetyl citrate, glycolate esters,
lactate esters; phosphorus containing organic acids, such as,
monostearyl phosphate and monocetyl phosphates; ether carboxylic
acids; N-acyl sarcosinic acids; N-acyl glutamic acids; N-acyl
ethylenediaminetriacetic acid; alkane sulfonic acids; alpha-olefin
sulfonic acids; alpha-sulfonic acid fatty acid methyl esters;
sulfate esters; inorganic acids, such as, phosphoric acid; and
combinations thereof. Examples of suitable basic stabilizers
include, but are not limited to: monoethanolamine; diethanolamine;
triethanolamine; dipropylenetriamine; diisopropyl amine; organic
diamines, such as, but not limited to,
1,3-bis(methylamine)-cyclohexane, 1,3-pentanediamine; inorganic
bases, such as, but not limited to, sodium hydroxide, magnesium
hydroxide, and combinations thereof.
[0065] The stabilizer, when present is typically employed in
compositions at levels which are effective at stabilizing the
colorant, from about 0.001% to about 30%, from about 0.1% to about
15%, and also from about 1% to about 10%, by weight of the
composition.
[0066] The present invention may include structural adjuncts, such
as HLB (hydrophilic lipophilic balance) modifiers, viscosity
modifiers, hardening agents, wetting agents, anti-oxidants,
anti-leaching aids, and/or colorant solubilizers. Suitable ones may
include polymeric thickeners such as block copolymers having
polystyrene blocks on both ends of a rubber molecule, the
aforementioned copolymers of ethylene and vinyl acetate (EVA),
hydrogenated castor oil, polymers, metals salts of fatty acids,
silicas and or derivatized silicas, organoclays such as modified
and unmodified hectorites and bentonites, modified clays such as
modified laponite clays, dibenzylidene sorbitol, alkyl
galactomannan, aluminium magnesium hydroxide stearate/oil blends
and lauroyl glutamic dibutylamide. Hardening agents may include the
aforementioned waxes, C14-22 fatty alcohols, C14-22 fatty acids,
C23-60 carboxylic acids, hydrogenated vegetable oils, polymers,
sorbitan esters and other high molecular weight esters.
[0067] The wetting agent can be a surfactant or a mixture of
surfactants. The surfactants can be non-ionic surfactants or ionic
surfactants. The ionic surfactants can be either positively charged
or negatively charged. The examples of non-ionic surfactants
include alkyl poly(ethylene oxide) such as copolymers of
poly(ethylene oxide) and polypropylene oxide) (commercially called
Poloxamers or Poloxamines), alkyl polyglucosides such as octyl
glucoside and decyl maltoside, fatty alcohols such as cetyl
alcohol, oleyl alcohol, cocamide MEA and cocamide DEA. The examples
of ionic surfactants include anionic (e.g., based on sulfate,
sulfonate or carboxylate anions) surfactants such as s(SDS),
ammonium lauryl sulfate and other alkyl sulfate salts, Sodium
laureth sulfate, also known as sodium lauryl ether sulfate (SLES),
Alkyl benzene sulfonate, Soaps, or fatty acid salts; and Cationic
(e.g., based on quaternary ammonium cations) surfactants such as
Cetyl trimethylammonium bromide (CTAB) a.k.a. hexadecyl trimethyl
ammonium bromide, and other alkyltrimethylammonium salts,
Cetylpyridinium chloride (CPC), Polyethoxylated tallow amine
(POEA), Benzalkonium chloride (BAC), Benzethonium chloride (BZT);
or Zwitterionic (amphoteric) surfactants such as Dodecyl betaine,
Dodecyl dimethylamine oxide, Cocamidopropyl betaine, Coco ampho
glycinate. Alternatively, the wetting agents may also be
hydrophilic molecules.
[0068] The hydrophilic molecules may be small molecules such as
sucrose, glucose and glycerol. The hydrophilicmolecules may also be
polymers such as polyethylene glycol and its copolymers.
Substrate
[0069] In one embodiment of the present invention, the
liquid-activated formulation of the present invention may be on
and/or in a substrate. When present on a substrate, the
liquid-activated formulation will typically be placed on and/or in
a substrate where the substrate will be contacted by a liquid, such
as water, urine, menses, blood and the like. The substrate may
include, but is not limited to, a structural component, such as
woven fabrics, nonwoven fabrics, films, sponges, and combinations
thereof. The substrate may comprise synthetic and/or natural
materials. In one embodiment of the present invention the optional
substrate may be an article in its own right, such as, a continuous
nonwoven fabric. In another embodiment of the present invention the
substrate to which the liquid-activated formulation may be applied
or otherwise affixed comprises any one, or a combination of,
structural components of an absorbent article, including, but not
limited to, the backsheet, topsheet, fasteners, absorbent material,
etc., or may be a separate element added or applied to the product.
In one optional embodiment of the present invention the
liquid-activated formulation is applied to the absorbent article as
a whole. In some embodiments, the liquid-activated formulation is a
single layer. Such a single layer may be applied to a substrate or
structural component. In some embodiments, the single-layer
formulation may be disposed between the backsheet and the absorbent
core, in other embodiments, between the topsheet and the absorbent
core.
[0070] The indicating material may be coated over a surface of said
substrate as either a) a monochromic color scheme alone,
bi-chromic, or multiple colors, b) in various shapes and sizes, c)
graphics of patterns or alpha numeric symbols and words, or
combinations thereof. The color transition may be from being either
a) colored to uncolored, b) uncolored to colored, or c) first color
to second color or, d) a combination of a), b) and c).
[0071] The manufacture of substrates, absorbent articles and
structural components thereof, for use herein form no part of this
invention. The following discussion is for convenience of
formulation, but is not intended to limit the type of substrate
used herein.
[0072] In one embodiment of the present invention the disposable
absorbent article is a disposable diaper. Typically, modern
disposable diapers comprise a liquid pervious topsheet; a liquid
impervious backsheet; an absorbent core which may be positioned
between at least a portion of the topsheet and the backsheet; side
panels; elasticized leg cuffs; an elastic waist feature; and a
fastening system. In one embodiment opposing sides of the
disposable diaper may be seamed or welded to form a pant. This
allows the article to be used as a pull-on type diaper, such as a
training pant. Additional illustrative, but non-limiting,
information on construction, assembly, and the various components
(including backsheets, dusting layers, upper and lower covering
sheets, and webs) of disposable diapers may be found in U.S. Pat.
No. 3,860,003 to Buell; U.S. Pat. No. 5,151,092 to Buell; U.S. Pat.
No. 5,221,274 to Buell; U.S. Pat. No. 5,554,145 to Roe et al. on
Sep. 10, 1996; U.S. Pat. No. 5,569,234 to Buell et al.; U.S. Pat.
No. 5,580,411 to Nease et al.; U.S. Pat. No. 6,004,306 to Robles et
al.; U.S. Pat. No. 5,938,648 to LaVon et al.; U.S. Pat. No.
5,865,823 to Curro; U.S. Pat. No. 5,571,096 to Dobrin et al.; U.S.
Pat. No. 5,518,801 to Chappell, et al.; U.S. Pat. No. 4,573,986 to
Minetola et al.; U.S. Pat. No. 3,929,135, to Thompson; U.S. Pat.
No. 4,463,045 to Ahr, et al.; U.S. Pat. No. 4,609,518 to Curro et
al.; U.S. Pat. No. 4,629,643 to Curro et al.; U.S. Pat. No.
5,037,416 to Allen et al.; U.S. Pat. No. 5,269,775 to Freeland et
al.; U.S. Pat. No. 4,610,678 to Weisman et al.; U.S. Pat. No.
4,673,402 to Weisman et al.; U.S. Pat. No. 4,888,231 to Angstadt;
U.S. Pat. No. 5,342,338 to Roe; U.S. Pat. No. 5,260,345 to
DesMarais et al.; U.S. Pat. No. 5,026,364 to Robertson; U.S. Pat.
No. 3,848,594 to Buell; U.S. Pat. No. 4,846,815 to Scripps; U.S.
Pat. No. 4,946,527 to Battrell; U.S. Pat. No. 4,963,140 to
Robertson et al.; U.S. Pat. No. 4,699,622 to Toussant et al.; U.S.
Pat. No. 5,591,152 to Buell et al.; U.S. Pat. No. 4,938,753 to Van
Gompel, et al.; U.S. Pat. No. 5,669,897 to LaVon, et al.; U.S. Pat.
No. 4,808,178 to Aziz et al.; U.S. Pat. No. 4,909,803 to Aziz et
al.: U.S. Pat. No. 4,695,278 to Lawson and U.S. Pat. No. 4,795,454
issued to Dragoo; and U.S. Ser. No. 10/770,043 to LaVon; U.S. Pat.
No. 7,318,820 to LaVon et al.; U.S. Pat. No. 6,962,578 to LaVon;
U.S. Pat. No. 7,377,914 to LaVon; Ser. No. 11/715,976 to LaVon;
Ser. No. 10/880,128 to LaVon; Ser. No. 11/131,799 to LaVon et al.,
Ser. No. 11/133,818 to LaVon et al.; Ser. No. 11/135,689 to LaVon;
Ser. No. 11/140,888 to LaVon et al.; Ser. No. 11/158,563 to LaVon
et al.; Ser. No. 11/159,916 to LaVon et al., Ser. No. 11/197,197 to
LaVon et al.; Ser. No. 11/210,345 to LaVon et al.; Ser. No.
11/224,462 to LaVon et al.; Ser. No. 11/231,511 to LaVon et al.;
Ser. No. 11/231,512 to LaVon et al.; Ser. No. 11/231,500 to LaVon
et al.; U.S. Pat. No. 7,320,684 to LaVon et al.; Ser. No.
11/286,934 to LaVon et al.; Ser. No. 11/286,614 to LaVon; Ser. No.
11/286,612 to LaVon; Ser. No. 11/700,585 to LaVon et al.; Ser. No.
11/709,500 to LaVon et al.; Ser. No. 11/713,906 to LaVon et al.;
Ser. No. 11/728,127 to LaVon et al.; 61/073,154 to LaVon; and
61/073,169 to LaVon; US Pub. Nos. 2004/0162536 to Becker filed on
Feb. 11, 2004; 2007/0167928 to Becker filed on Mar. 13, 2007;
2007/0179464 to Becker filed on Mar. 13, 2007; 2007/0156108 to
Becker filed on Mar. 13, 2007; and 2004/0167486 to Busam filed on
Feb. 11, 2004; U.S. Ser. Nos. 60/936,102 to Hundorf filed on Jun.
18, 2007; 60/936,109 to Hundorf filed on Jun. 18, 2007; 60/936,149
to Hundorf filed on Jun. 18, 2007; 60/936,085 to Ashton filed on
Jun. 18, 2007; 60/936,084 to Ashton filed on Jun. 18, 2007;
60/936,150 to Ashton filed on Jun. 18, 2007; 60/936,146 to Asthon
filed on Jun. 18, 2007; 60/936,037 to Ashton filed on Jun. 18,
2007; and 61/091,799 to Hundorf filed on Aug. 26, 2008.
[0073] In one alternative embodiment of the present invention a
portion of the absorbent article, such as part or all of the
topsheet, part or all of the barrier leg cuffs and the like, may be
optionally coated with a lotion, as is known in the art. Examples
of suitable lotions include, but are not limited to, those
described in U.S. Pat. No. 5,607,760 to Roe on; U.S. Pat. No.
5,609,587 to Roe; U.S. Pat. No. 5,635,191 to Roe et al.; U.S. Pat.
No. 5,643,588 to Roe et al.; and U.S. Pat. No. 5,968,025 to Roe et
al.
[0074] The liquid-activated colorant may be included in the liquid
activated formulation at a level which is within the range of about
0.01 weight percent to about 20 weight percent, or may be
incorporated into the liquid activated formulation at a level which
is within the range of about 0.02 weight percent to about 15 weight
percent, based upon the total weight of the liquid activated
formulation. The liquid activated colorant may be included in the
liquid activated formulation at a level which is within the range
of about 0.02 weight percent to about 10 weight percent, or may be
incorporated into the liquid activated formulation at a level which
is within the range of about 0.02 weight percent to about 2 weight
percent.
[0075] The hydrochromic ionic compound may be included in the
liquid activated formulation at a level which is within the range
of about 0.01 weight percent to about 35 weight percent, or may be
incorporated into the liquid activated formulation at a level which
is within the range of about 0.1 weight percent to about 30 weight
percent, based upon the total weight of the liquid activated
formulation. The hydrochromic ionic compound may be included in the
liquid activated formulation at a level which is within the range
of about 0.1 weight percent to about 25 weight percent, or may be
incorporated into the liquid activated formulation at a level which
is within the range of about 0.1 weight percent to about 20 weight
percent.
[0076] The opacifier may be included in the liquid activated
formulation at a level which is within the range of about 0.5
weight percent to about 75 weight percent or may be incorporated
into the liquid activated formulation at a level which is within
the range of about 10 weight percent to about 50 weight percent,
based upon the total weight of the liquid activated formulation.
The opacifier may be included in the liquid activated formulation
at a level which is within the range of about 20 weight percent to
about 45 weight percent, or may be incorporated into the liquid
activated formulation at a level which is within the range of about
30 weight percent to about 40 weight percent.
[0077] In some embodiments, the liquid-activated colorant may be
about 0.1 weight percent of the liquid-activated formulation, or
may be from about 0.01 to about 5 weight percent of the
liquid-activated formulation. In some embodiments, the opacifier
may be from about 0.5 to about 60 wt % of the liquid-activated
formulation. For opacifiers such as or similar to titanium dioxide,
the weight percent may be from about 0.5% to about 2%. For
opacifiers such as or similar to aluminum silicate, the weight
percent may be from about 30% to about 70%. In some embodiments,
the hydrochromic ionic compound may be present in the
liquid-activated formulation about 0.1 wt % or from about 0.05 wt %
to 0.15 wt % for a strong base like sodium hydroxide or a strong
acid like hydrochloric acid. For weaker acids and bases, the
hydrochromic ionic compound may have a weight percent of about 10%
or be in a range of from about 2% to about 18%. In some
embodiments, the binding matrix may be from about 25 wt % to about
75 wt % of the liquid-activated formulation.
EXAMPLE
[0078] The present invention is illustrated by the following
example, which is merely for the purpose of illustration and is not
to be regarded as limiting the scope of the invention or the manner
in which it can be practiced. Unless specifically indicated
otherwise, parts and percentages are given by weight. Examples may
include any of the compositions and components disclosed in U.S.
Patent Application Ser. No. 61/705,861, titled "Liquid Activated
Color Change Ink and Methods of Use".
Example 1
TABLE-US-00001 [0079] % by Ingredient{grave over ( )} wt.
Alternative Name Function Supplier Sodium 43.40% Sipernat 820a
Opacifier/ Evonik Inc. Aluminum Silicate Performathox 12.00%
C20-C40 Pareth-10 Surfactant New Phase 450 Inc Performathox 20.00%
C20-C40 Pareth-40 Surfactant New Phase 480 Inc Polyhydroxystearic
2.00% Dispersun .TM. DSP-OL100 Particle Innospec acid Wetting
Agent. Microcrystalline 12.00% Microcrystalline Wax Tackifier
Sonneborn Wax W835 Inc. Arquad HTL-8 2.00% Stearyl
Ethylhexyldimonium Quaternary AkzoNobel MS Methosulfate
Anti-Leaching Inc. Aid Sodium 8.00% hydrochromic Sigma- hydrogen
ionic Aldrich carbonate compound Bromocresol 0.20% Colorant Curtiss
Green, free acid Labs Irganox 1010 0.40% Tetrakis[methylene(3,5-di-
Anti- Ciba Inc 100.00% (tert)-butyl-4- Oxidant
hydroxyhydro-cinnamate)]methane
[0080] Example may be prepared in the following manner:
[0081] Those ingredients that are solids at room temperature are
first melted at a temperature of around 90 C. These ingredients
include the binding agents, hot melt adhesives, waxes, surfactants,
and optional ingredients like the anti-oxidants. Typically, a
temperature of around 80 C to 100 C would be required to melt these
ingredients. After melting to the liquid state on a hot plate, the
materials are well mixed using a propeller mixer like an IKA RW-20
(or similar mixer) until the mixture is homogeneous. While keeping
this mixture heated and mixed, the Sodium Aluminum Silicate powder
is homogeneously mixed into the composition. Next, the hydrochromic
ionic compound, sodium hydrogen carbonate, is mixed into the
composition while maintaining heating. Finally, the colorant like
bromocresol green (free acid) is well mixed into the composition
until the mixture is homogeneous. Heat can be maintained on the
composition to make films using a draw-down wire or the composition
can be cooled down to room temperature for future use.
Example 2
[0082] The following example is a liquid-activated formulation that
would begin yellow and when activated by liquid turn to purple.
Upon drying, the formulation turns back to yellow.
TABLE-US-00002 Ingredient Wt (g) Wt (%) Joncryl 624 3.95 20.17%
Acrylic Polymer Water 9.43 48.16% Dihydrogen Oxide Sipernat 820a
4.94 25.23% Aluminum Silicate m-cresol purple 0.011 0.06% HTL8-MS
0.87 4.44% Quaternary Amine NaOH/50% 0.38 1.94% TOTAL 19.581
100.00%
Example 3
[0083] The following example is a liquid-activated formulation that
would begin light blue and when activated by liquid turn to dark
blue.
TABLE-US-00003 Ingredient Wt (g) Wt (%) Joncryl 624 4.08 19.7%
Acrylic Polymer Water 10.09 48.8% Dihydrogen Oxide Sipernat 820a 5
24.2% Aluminum Silicate Bromothyml blue 0.0179 0.09% HTL8-MS 0.85
4.113% Quaternary Amine NaOH/50% 0.63 3.0% TOTAL 20.6679
100.00%
[0084] According to an aspect of the invention, FIGS. 1-3 show an
absorbent article 10 in an unfastened and uncontracted state that
has a liquid permeable topsheet 12, a liquid impermeable backsheet
14, a liquid absorbent core 16 disposed between the topsheet 12 and
the backsheet 14, further comprising a liquid indicator 20. The
liquid indicator 20 comprises a coating 18 of liquid indicating ink
disposed on the backsheet 14, between the backsheet 14 and the
absorbent core 16, such that it is visually revealed when the
coating 18 is wetted with body fluids. The liquid indicator is the
liquid-activated formulation as described above. This liquid
indicator may change color entirely when in contact with liquid, or
may change noticeable shades of color, or may change from an almost
white (so as it appears that there is no colorant there) to a
color, or may change from a color to a white/colorless state. FIG.
2 shows an example of how the absorbent article may appear when
wet, wherein the liquid indicator 20 appears in a raindrop pattern
that is visible when wet. The liquid-activated formulation may be a
single layer.
Test Methods
[0085] The 20 Minute Leaching Value may be determined as described
in U.S. Pat. No. 6,772,708. Similarly, the 1 Hour Leaching Value
Test Method and the 3 Hour Leaching Value Test Method are disclosed
in U.S. Pat. No. 6,772,708, and are incorporated by reference
herein.
[0086] The dimensions and values disclosed herein are not to be
understood as being strictly limited to the exact numerical values
recited. Instead, unless otherwise specified, each such dimension
is intended to mean both the recited value and a functionally
equivalent range surrounding that value. For example, a dimension
disclosed as "40 mm" is intended to mean "about 40 mm."
[0087] Every document cited herein, including any cross referenced
or related patent or application, is hereby incorporated herein by
reference in its entirety unless expressly excluded or otherwise
limited. The citation of any document is not an admission that it
is prior art with respect to any invention disclosed or claimed
herein or that it alone, or in any combination with any other
reference or references, teaches, suggests or discloses any such
invention. Further, to the extent that any meaning or definition of
a term in this document conflicts with any meaning or definition of
the same term in a document incorporated by reference, the meaning
or definition assigned to that term in this document shall
govern.
[0088] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
* * * * *