Note: Descriptions are shown in the official language in which they were submitted.
2'I 5254 5
COLOR CHANGING COMPOSITIONS USING ACIDS
FIELD OF THE INVENTION
This invention relates generally to the field of
coloring compositions and more particularly to a pair of
coloring compositions which may be used in conjunction with
each other to enable laying down an initial mark using an
undercolor coloring composition yielding a first color and
then using an overcolor coloring composition to enable a
change of color of a portion or the entirety of the initial
mark.
BACKGROUND OF THE INVENTION
Children enjoy various drawing and coloring activities
using a variety of mediums. Useful in such activities are
markers containing inks, crayons, pencils of various colors,
and various paints including water colors, oil paints and
acrylic paints. However, children would often like to
change the color of a mark after they have made the mark.
One instance would be the desire to add a yellow sun over a
previously colored blue sky.
Coloring compositions generally are mixtures of a
coloring matter dispersed or dissolved in a carrier fluid.
The colorant, if readily dissolving in the carrier fluid, is
termed a dye. An insoluble coloring material is termed a
pigment. Pigments are finely ground solid materials and the
..
2
nature and amount of pigment contained in an ink determines
its color. Coloring composition may also optionally include
such ingredients as humectants, preservatives, battering
agents, and drying agents. Humectants function to improve
freeze/thaw stability and to control drying out of the tip
when the coloring composition is used as a marker ink.
Preservatives serve the obvious function of preventing
spoilage of the ink during the expected shelf life of the
marker product. Drying agents speed drying of a mark laid
down by a marker. Battering agents impart the coloring
composition with an unpleasant taste, so that children and
animals will not consume the coloring composition.
Changing the color of a mark is not readily done with
the typical children's coloring instruments such as those
described. In the past, children changed the marks by
placing the mark of one color over the mark of another
color. When performing this using traditional marking pens,
the marks produced are often not the desired colors and the
tips of the markers get soiled with the other inks,
rendering the marker useless. If attempted with traditional
children's paints, the colors tend to bleed together
resulting in undesirable color smears. Therefore, there has
been a long felt need for coloring compositions, including
paints, inks, and markers containing such compositions,
which produce marks of a first color that can be readily
changed into a wide variety of second colors. Especially
needed is such a group of compositions which may be used in
markers without soiling the nib of the second used marking
instrument.
In one available marker application, a child is able to
change a specific initial mark laid down to a second
specific color by applying a bleach to the first mark
yielding a change in color. The marker inks used in these
markers are typically prepared by blending a bleach or pH
sensitive dye with a dye that is stable in bleach or high
pH. For example, German Patent Specification No. 2724820,
__.
3
(hereinafter "the German Patent"), concerns the combining of
a chemically stable dye and a chemically unstable dye in an
ink formulation. Once a mark using this combination of
stable and unstable dyes is laid down, the mark may be
overwritten with a clear bleach solution, eliminating the
color contribution of the unstable dye. The resulting mark
of the stable dye, with its characteristic color, remains.
There are several drawbacks to such a marking system.
First, there are strict limitations on the number of color
changes which may be produced. Specifically, in
formulations made according to the German Patent, the
particular ink composition may only be changed from a first
color to a fixed second color. For example, a green mark
may only be changed to a violet color as the inks are
described in the practice of the German Patent. In
addition, since one of the required pair of markers contains
only the bleaching agent, that bleaching marker cannot
render a visible mark and may only be used in combination
with the base color marker. Once the base color marker is
used up, the bleaching marker is of no use. Or, once the
bleaching marker is used up, the base color marker may only
be used for the color which it initially marks with. A
further disadvantage of the marking process of the German
Patent is that the nib of the bleaching marker tends to get
soiled by picking up the colors of the base coloring
composition, thus tainting the color of subsequent marks.
Therefore, an object of the present invention is to
provide a coloring composition system which is capable of
enhanced multiple color changing abilities.
An additional object of the present invention is to
produce a coloring composition system which includes at
least two different coloring compositions each of which may
be used independently or which may be used in combination to
provide color changing ability.
A further object of the present invention is to provide
a coloring composition system in the form of inks which
4
prevents a nib of a color changing marker from becoming
visibly soiled from contacting a base color composition.
These and other objects will become apparent to those
skilled in the art to which the invention pertains.
8UlI8ARY OF T88 ID1V8I~1'rION
The present invention overcomes the drawbacks
associated with prior overwriting ink compositions in that
the particular undercolor coloring composition made
according to the invention may be changed to multiple second
colors, depending upon the dye present in the overcolor
composition.
Advantageously, an overcolor composition of the present
invention makes a visible mark, thus it may be used alone or
in combination with an undercolor coloring composition.
An additional advantage of the overcolor composition of
the present invention is that unlike prior color change
markers, the nib of the tip of marker containing the
overwriter ink does not become visibly soiled with the
undercolor coloring composition because the undercolor is
immediately destroyed upon contact with the overcolor
composition.
In general, the present invention is a multiple
coloring composition system whose coloring effect may be
changed upon treatment with an overcolor coloring
composition, once the overcolor coloring composition has
been deposited over the undercolor coloring composition. In
one embodiment, the multiple coloring composition system
comprises:
(a) an undercolor aqueous coloring composition
comprising an undercolor dye whose coloring ability is
destroyed in the presence of a pH of about 4 or less; and
(b) an overcolor aqueous coloring composition
comprising a colorant capable of maintaining its
characteristic color in the presence of a pH of about 4 or
less, and an effective amount of an acid sufficient to yield
~1~~~~~
a pH of said overcolor coloring composition of about 4 or
less.
Suitable dyes for use in the undercolor coloring
composition include those xanthene dyes, pthalocyanine dyes,
and azo dyes which are unstable in the presence of a pH of
about 4 or less. Suitable colorants for use in the
overcolor coloring composition include pigments, polymethine
dyes, triphenylmethane dyes, and azo dyes which are stable
in the presence of a pH of about 4 or less. Suitable acids
for the for use in compositions of the invention include
phosphoric acid, sulfuric acid, and citric acid.
Also disclosed is an ink composition system comprising:
(a) an undercolor aqueous ink comprising an undercolor
dye whose coloring ability is destroyed in the presence of a
pH of about 4 or less in an amount of from about 0.5% to
about 6% by weight of the undercolor ink; and
(b) an overcolor aqueous ink comprising from about
0.5% to about 30% by weight of said overcolor ink of an
acid; and from about 0.5% to about 6% by weight of said
overcolor ink of a colorant which maintains its
characteristic color in the presence of a pH of about 4 or
less.
A color changing marking system is also disclosed which
comprises at least two marking instruments. The undercolor
marking instrument contains an undercolor ink composition
comprising a dye whose coloring ability is destroyed in the
presence of a pH of about 4 or less. The overcolor writing
instrument contains an overcolor ink comprising (1) from
about 0.5% to about 30% by weight of an acid; and (2) from
about 0.5% to about 6% by weight of a colorant which
maintains its characteristic color in the presence of a pH
of about 4 or less.
When formulated as inks, the coloring compositions of
the invention may also optionally comprise an anti-oxidant,
a stabilizing base, a humectant, a drying agent, a bittering
agent, and a preservative. When formulated as paints, the
21 5254 5
6
coloring compositions of the present invention may also
optionally comprise a binder, a thickener, a filler, an
extender, a dispersant, a freeze-thaw protector, or other
ingredients conventionally used in paints.
Accordingly, in one aspect the present invention
resides in a coloring composition comprising (a) from about
0.5% to about 30% by weight of an acid; and (c) from about
0.5% to about 6% by weight of a colorant which maintains its
characteristic color in the presence of a pH of about 4 or
less.
DETAILED DESCRIPTION OF THE INVENTION
The present invention imparts the desirable ease of
application and convenience of use of traditional color
changer systems while avoiding the strict limitations of
current color change markers. The composition of the
present invention therefore imparts improved and convenient
coloring properties.
In general, the present invention is a multiple
coloring composition system wherein the color of a mark laid
down by an undercolor coloring composition, for example
using a marker to dispense the composition, may be
overwritten by a variety of second colors upon the
application of an overcolor coloring composition over the
undercolor coloring composition. An embodiment of this
marking system comprises:
(a) an undercolor aqueous coloring composition
comprising an undercolor dye whose coloring ability is
destroyed in the presence of a pH of about 4 or less; and
(b) an overcolor aqueous coloring composition
comprising a colorant capable of maintaining its
characteristic color in the presence of a pH of about 4 or
less, and an acid in an amount sufficient to yield a pH of
said overcolor aqueous coloring composition of about 4 or
less. To lower the pH of the overcolor aqueous coloring
composition, an acid in an amount sufficient to lower the pH
of the overcolor aqueous coloring composition to a level of
21 5254 5
6a
about 4 or less, and preferably from about 2 to 4, is
preferably used.
Most suitable for use as dyes in the undercolor
coloring compositions are dyes or indicators whose coloring
abilities are easily destroyed in the presence of a pH of
21 5254 5
7
about 4 or less. By "destroyed" is meant any reaction
wherein the color of the dye or indicator is reversibly or
irreversibly destroyed or modified. Such coloring
compositions are commonly known in the field and are
occasionally used as chemically "erasable" inks. Especially
suitable for use as dyes in the undercolor coloring
composition are those xanthene dyes, pthalocyanine dyes, and
azo dyes which are unstable in the presence of a pH of about
4 or less. Dyes which have been found to meet these
criteria include Acid Red 92 marketed by International
Dyestuffs Corporation, Acid Yellow 1 marketed by
International Dyestuffs, PYRANINE 120TH marketed by
Miles(Mobay), and mixtures thereof.
Acid Red dyes, classified as xanthene dyes, are
generally used as colorants for foods, drugs, and cosmetics.
Specifically, Acid Red 92, the disodium salt of 2,4,5,7-
tetrabromo-9-3,4,5,6, tetrachloro-o-carboxylphenyl)-6-
hydroxy-3-isoxanthone, is called D & C Red No. 28 by the
FDA, and sold under the tradename Phloxine'" B.
To achieve good coloring of the undercolor coloring
composition, the minimum concentration of dye which will
produce a workable ink is governed by the color intensity
desired, though as little as 0.1% dye may be sufficient for
certain applications. The maximum workable concentration of
dye is determined largely by the ability to maintain a
stable composition and the depth of color desired and can
vary widely depending upon the concentration of other
components. It is also a function of the characteristics of
the desired end product, though a practical upper limit in
the formulation of, for example, a marker ink, is about 15%
by weight. The preferred concentration range for most
applications is from about 0.5% to about 6% dye by weight of
the composition. A concentration of about 1.5% to about 4%
is even more preferred when the undercolor coloring
composition is to be used as an ink for a typical marker to
ensure good coloration.
215~~4~
8
The overcolor coloring composition of the present
invention is formulated by combining an acid with a colorant
which maintains its characteristic color in the presence of
low pH conditions. A limited number of dye colorants meet
this criteria. Dyes to be used in the overcolor coloring
composition must be highly resistant to chemical attack such
as from low pH conditions. Dyes which have been found to
meet these criteria include those polymethine dyes,
triphenylmethane dyes, cyanine dyes, methine dyes, and azo
dyes which are stable in the presence of a pH of about 4 or
less. Such dyes include the dyes marketed under the
tradenames Acid Green 3 by International Dyestuffs
Corporation, Acid Blue 93 and Acid Violet 19 marketed by
Spectra Color Corporation, Acid Yellow 23 marketed by
Crompton & Knowles, and mixtures thereof.
Polymethine dyes are colored substances in which a
series of -CH= (methine) groups connect to terminal groups
of a chromophore. Polymethine and cyanine are often used
interchangeably as generic terms for all polymethine dyes.
The previous primary usage for polymethine dyes are dying
acetate rayon as well as polyacrylnitrile and
polyacrylamide.
Acid Green 3 and Acid Violet 19 are azo dyes, which is
the largest and most versatile class of dyes, and
characterized by the presence of one or more -N=N- (azo)
groups. Acid Green 3 is commonly used in making pulp colors
or lakes. Acid Violet dyes are primarily fashion colors.
To achieve good coloring of the overcolor coloring
composition, the minimum concentration of dye which will
produce a workable ink is governed by the color intensity
desired, though as little as 0.1% dye may be sufficient for
certain applications. The maximum workable concentration of
dye is deter~ained largely by the ability to maintain a
stable composition and the depth of color desired and can
vary widely depending upon the concentration of other
components. It is also a function of the characteristics of
9
the desired end product, though a practical upper limit in
the formulation of, for example, a marker ink, is about 15%
by weight. The preferred concentration range for most
applications is from about 0.5% to about 6% dye by weight of
the composition. A concentration of about 1.5% to about 4%
is even more preferred when the overcolor coloring
composition is to be used as an ink for a typical marker to
ensure good coloration.
Pigments may be used as an excellent colorant in the
overcolor coloring compositions of the invention. To
achieve good coloring of the overcolor coloring composition
and promote compatibility with the remaining ink components,
the pigment is utilized in the form of an aqueous
dispersion, inasmuch as pigments are by definition insoluble
materials. Pigment dispersions are commercially available
which are combinations of a pigment, an aqueous based
character, and a surfactant or dispersant system. A pigment
dispersion may also be prepared specifically for use in the
overcolor coloring composition of the invention. From the
standpoint of convenience, a commercial pigment dispersion
is preferred for use in the present invention. Typical
commercial dispersions contain 30 to 74% by weight active
pigment ingredients.
In general, a workable pigment dispersion may have a
wide or narrow particle size range depending upon the use to
which the ink will be put. The lower limit on pigment
particle size is determined not by any functional
characteristic of the overcolor coloring composition, but by
the ability to form a stable dispersion. Similarly, the
upper limit on pigment particle size is determined by the
type of applicator by which the overcolor coloring
composition is to be applied or dispensed, since pigment
particle size determines the ability of pigment particles to
flow through, for example, the matrix of a marker nib where
the overcolor coloring composition is in the form of an ink.
Indeed, relatively larger pigment particles can
21 5254 5
restrict ink flow through many types of nibs commonly
utilized in writing and marking instruments, ultimately
rendering them inoperable. Larger particle sizes may,
however, may be used where the overcolor coloring
composition is to be used in, for example, a paint marker,
in which the composition is dispensed through a valve
assembly, or in a roller ball pen or where there composition
is used in the form of a paint and a brush is used to
distribute the overcolor coloring composition. Pigments
having a mean particle size range from about 0.05 to about
2.0 microns have been found to work well in compositions of
the invention.
In choosing the most suitable pigment particle size
when coloring compositions of the invention are to be used
in the form of, for instance, an ink, one must be guided by
the particular nib type to be utilized in the writing or
marking instrument in which the ink will be placed. First,
of course, a pigment particle size must be selected which
will allow the passage of the composition through the nib
being used. Further, the pigment particle size should be
selected to promote capillary flow through the particular
nib being used in the writing or marking instrument. In
general, the size of pigment particles should be kept as low
as possible while maintaining the stability of the
composition. For example, it has been found that an ink to
be utilized in a marking instrument having either a porous
plastic nib or a bonded fiber nib, an ultra fine pigment
dispersion having a mean particle size in the range of from
about 0.05 to about 0.5 microns provides acceptable results.
A more preferred ultra fine pigment dispersion for such
applications has a mean particle size in the range from
about 0.05 to about 0.25 microns, since such a dispersion
promotes better wicking or capillary flow through the nib.
An example of a suitable pigment dispersions, which is
especially suited for compositions of the invention used in
the form of an ink include Fluorescent Scarlet"" SF-1013 and
w 21 5254 5
11
Fluorescent Green"' SF 1012, marketed by Sin Loihi (Japan).
The minimum concentration of pigment which will produce
a workable color changing composition is governed by the
color intensity desired, though as little as 0.1% active
pigment may be sufficient for certain applications. The
maximum workable concentration of pigment is determined
largely by the ability to maintain a stable composition, and
can vary widely depending upon the concentration of other
components. The maximum concentration of pigment usable is
also a function of the characteristics of the desired end
product, though a practical upper limit in the formulation
of the overcolor coloring composition used, for example, as
a marker ink, is about 30% by weight since higher
concentrations may cause ink instability and undesirably
high viscosity.
When a commercial pigment dispersion is utilized, as it
preferably is, a practical limit is imposed by the
concentration of pigment in the dispersion, which, as
previously noted, is typically in the range of about 30% to
74% pigment by the weight of dispersion. The preferred
concentration range for most applications is from about 1%
to about 10% active pigment by weight of the composition. A
concentration of about 3% by weight of active pigment is
ordinarily required to ensure good coloration in a typical
marker ink and most preferred is a concentration of active
pigment in a concentration range of about 1.5% to about 5%
by weight of the composition.
Acids which may be used in the overcolor coloring
composition are typically strong acids, usually having a pH
from about 2 to about 4. Typical acids which may be
employed in the overcolor coloring composition of the
invention include phosphoric acid, sulfuric acid, and citric
acid. The preferred acid for use in the overcolor coloring
composition of the invention is phosphoric acid. Acid is
generally present in the overcolor coloring composition of
the invention in an amount from about 0.5% to about 40% with
2~~254~
12
a minimal amount required to allow for the erasing of the
undercolor coloring composition of the invention and the
maximum amount determined by the stability of the
composition and the safety of the composition for use by
children. Preferably, the acid added in an amount
sufficient to lower the pH of the overcolor coloring
composition to a pH of from about 2 to about 4. Preferably,
the acid is contained in the overcolor coloring composition
in an amount of from about 5% to about 40%, and most
preferably in an amount of from about 20% to about 30% by
weight of the overcolor coloring composition.
The water used in the undercolor coloring composition
and the overcolor coloring composition of the invention is
preferably deionized water. The amount of water present in
undercolor coloring compositions is typically from about 10%
to about 90% and this amount is in large part determined by
the desired end use of the undercolor coloring composition,
for instance, as an ink or a paint, and the amount of other
components included in the undercolor coloring composition.
To achieve a desirable viscosity when the undercolor
coloring composition is used in the form of, for example, an
ink, water is preferably present in an amount of from about
50% to about 90%, and most preferably from about 70% to
about 85% by weight of the composition.
The amount of water present in the overcolor coloring
composition of the invention is also governed in large part
by the desired end use of the composition, for instance, as
an ink or a paint, and the amount of other components
included in the undercolor coloring composition. The amount
of water present in overcolor coloring compositions is
typically from about 10% to about 90%. To achieve a
desirable viscosity when the overcolor coloring composition
is used in the form of, for example, an ink, water is
preferably present in an amount of from about 30% to about
60%, and most preferably from about 40% to about 55% by
weight of the composition.
2i~2~4'~
13
The overcolor coloring composition also preferably
contains an anti-oxidant. Typical anti-oxidants which may
be employed in the overcolor coloring composition include
citric acid and phosphoric acid. When citric acid is used
as the acid component of the overcolor, it may function as
an anti-oxidant as well as an acid. Ascorbic acid and
sodium hypophosphite may further be used as anti-oxidants.
The preferred anti-oxidant for use in the overcolor coloring
composition is citric acid. The anti-oxidant is usually
present in the overcolor coloring composition in an amount
of from about 0.1% to about 3% by weight of the composition.
The undercolor coloring composition may also contain a
stabilizing base. The stabilizing base comprises a base
which keeps the undercolor coloring composition at a pH of
from about 7.0 to about 8.5. At the elevated pH, the
colorant in the undercolor coloring composition remains
stable after it is applied to a substrate. The undercolor
colorant will not be destroyed until the overcolor coloring
composition is applied over the undercolor coloring
composition.
Typical stabilizing bases which may be employed in the
undercolor coloring composition include sodiwm hydroxide,
sodium carbonate, and monosodium EDTA. The stabilizing base
is usually present in the undercolor coloring composition in
an amount of from about 0.2% to about 2% by weight of the
composition.
Optionally, both the undercolor coloring composition
and the overcolor coloring composition may further comprise
such additives as a humectant, a drying agent, a bittering
agent, and preservatives such as biocides and fungicides.
Addition of a humectant ensures that coloring
compositions of the invention, when in the form of an ink,
do not prematurely dry in a capillary marking system, such
as a bonded fiber marking nib. Typical humectants which may
be employed in the coloring compositions of the present
invention include polyhydric alcohols such as ethylene
2I~~~~4
14
glycol, propylene glycol, diethylene glycol, hexylene glycol
and polyethylene glycol), and hydroxylated starches. The
humectant is preferably glycerin.
The humectant is generally used in an amount of from
about 0% to about 30% by weight of the composition, though
this range is by no means critical. The amount of humectant
to be added is determined by the type of nib used in the
writing or marking instrument to be employed and the
protection time period desired. In one preferred
composition, the humectant, glycerin, is added in an amount
of about 20% by weight of the coloring composition.
To achieve a more rapid drying rate and to improve
marking characteristics upon nonporous materials, a drying
agent may be added to increase the overall volatility and
therefore the evaporation rate of the water and the pH
regulant. Any compatible material which performs this
function may be used.
The drying agent preferably should be a volatile polar
material so as to ensure compatibility with the primary
components of the marker ink. Straight chain C2-C4 alcohols
are good, highly volatile drying agents, and of these,
ethanol is preferred because of its relatively low cost and
because it does not contribute any unpleasant odor to the
composition. Alcohols can also provide added benefits, such
as reducing surface tension, increasing adherence of the ink
to porous surfaces, and providing bactericidal activity when
added to the ink composition.
To discourage improper usage of the marker ink, such as
ingesting the ink, the alcohol may contain a bittering agent
or a conventional denaturant. An alcohol utilizing a
bittering agent will discourage such improper usage of the
ink by simply imparting a disagreeable taste, while not
requiring the use of toxic denaturants as methanol or
benzene, and is therefore preferred. A conventional
denatured alcohol may, of course, also be utilized. The
most preferred drying agent is an ethyl alcohol which
15
contains a bittering agent and which is sold under the trade
name SDA 40B, manufactured by Aaper Alcohol.
When utilized, the drying agent preferably is added
from about 5% up to about 40% by weight, with the most
preferred concentration being about 10% by weight, though
these amounts are not critical to the practice of the
invention. About 10% per weight of drying agent is
ordinarily required to ensure rapid drying of the ink on a
nonporous surface, while amounts in excess of about 30% by
weight may adversely affect stability of the ink and may
cause flocculation of the pigment unless other stabilizing
additives are employed.
To maintain the shelf life of the composition, a
preservative may be added. The preservative preferably
serves as both a bactericide and a fungicide, and is added
in any effective amount, though a typical concentration
range is from about 0.1% up to about 5% by weight. The use
of preservatives in levels greater than about 5% by weight
may cause the ink to become toxic or unstable and may, in
any event, be unnecessary. Should alcohol be added to the
composition as a drying agent, that alcohol will function as
a preservative to some extent also.
Any conventional preservative may be utilized in the
invention as long as there is compatibility with the
remaining ink components. For example, preservatives
manufactured by Dow Chemical Co. and sold under the
trademarks Dowicil 75 (1-(3-chloroallyl)-3,5,7-triaza-1-
azoniaadamantane chloride) and Dowicil 200 (3-chlorovinyl-
hexamethylene tetrammonium chloride) or a preservative
manufactured by Rohm and Haas and sold under the trademark
Kathon PFM (isothiazolinones), or a preservative
manufactured by Sutton Labs and sold under the trademark
Germall II (imazolidinyl urea), or a preservative
manufactured by Merck and sold under the trademark Tektamer
38 (1,2 dibromo-2,4-dicyanobutane), will work in the
composition of the invention. Additionally, preservatives
16
manufactured by Huls America and sold under the trademark
NUOSEPT 95" can be used.
Other acceptable preservatives include TROYSAN
POLYPHASE P100~, a 3-Iodo-2-Propynyl Butyl Carbamate sold by
Troy Chemical, commonly mixed with PVP K-30", a 2-
Pyrrolidinone, 1-Ethenyl-, Homopolymer solubilizer ((C6MgN0)x
sold by ISP Technologies Inc., and M-PYROL", a 1-Methyl-
Pyrrolidinone solubilizer sold by GAF Chemicals Corporation.
Addition of preservatives to the undercolor and overcolor
coloring compositions inhibits the growth of bacteria and
fungi in water-based products.
Typically, a child may make marks or color a picture
using one or more markers containing various undercolor
coloring compositions on a suitable substrate, such as
paper. The child may then select one or more markers
containing various overcolor coloring compositions of the
invention. The child may then overwrite a portion or all of
the previously made markings eliminating the color of the
undercolor coloring composition as applied and leaving only
the color of the overcolor coloring composition used to
overwrite the undercolor color composition. Because of the
surprisingly strong and immediate impact of the overcolor
coloring composition used to overwrite the undercolor
coloring composition, the overcolor marker appears to paint
a color over the undercolor on the portions of the substrate
on which it is applied.
A child may also apply the overcolor coloring
composition directly to the substrate. If an undercolor
coloring composition is then used to overwrite the mark laid
down by the overcolor coloring composition, the overcolor
coloring composition will eliminate the color contributed by
the undercolor coloring composition leaving only the color
of the overcolor coloring composition where the mark was
previously made. The undercolor color will be see on other
locations on the substrate. This change has been observed
to occur more slowly than when the overcolor coloring
17
composition is applied over the undercolor coloring
composition. This slowed reaction is presumably caused by
the penetration of the overcolor coloring composition into
the paper substrate. The child gains great play benefit by
viewing this slowly disappearing color.
Preferably, when the coloring compositions of the
invention are used in the form of inks, the inks are placed
in conventional markers using such nibs as bonded fiber or
sintered plastic. Various undercolor coloring compositions
are placed in an undercolor set of markers, each containing
an appropriate different color dye. Various overcolor
coloring compositions of the invention are placed in a
second group of markers, each of these compositions
containing an appropriate different color colorant, either a
dye or pigment.
BBAMPL88
Examples of marking systems of the present invention
when formulated as an ink are as follows. Quantities are in
percent by weight of the total composition.
18
Onderaolor Color Inlic Esamplas
Ezaapl~ 1 8saapl~ Z
Magenta Ink Yellow Ink
Component
Deionized Water 74.00 74.00
Glycerin 20.00 20.00
Preservative
Nuosept 95 0.50 0.50
Premix 2.50 2.50
Dye
Acid Red 92 3.00 ----
Acid Yellow 1 ---- 3.00
Example 3 8xaspl~ 4
Orange Ink Coral Ink
Component
Deionized Water 74.50 74.50
Glycerin 20.00 20.00
Preservatives
Nuosept 95 0.50 0.50
Premix 2.50 2.50
Dye
Acid Red 92 0.50 2.00
Acid Yellow 1 2.00 ----
Pyranine 120 ---- 1.00
NaOH (5N soln) ---- 0.50
"Premix" in the previous and following examples is a
mixture of 96.04% m-pyrol, 1.98% PVP K30, and 1.98% Troysan
Polyphase P-100. The inks of examples 1-4 had acceptable
working properties. For examples 1-4, the pH ranged from
7.5 to 9.0 and the density ranged from 8.8 to 9.1 pounds per
gallon. For examples 1-4, the viscosity ranged from 2.5 to
3.8 centipoise.
19
Overoolor Coloring Inh Ezamplas
Example 5 Example 6 Example 7
Blue Ink Yellow Ink Green Ink
C
m
onent
o 45.00 43.50 44.50
p
Deionized Water
Glycerin 20.00 20.00 20.00
Phosphoric Acid 30.00 30.00 30.00
Citric Acid i.oo i.oo i.oo
Preservative
Nuosept 95 0.50 0.50 0.50
Premix 2.50 2.50 2.50
Acid Blue 93 1.00 ---- ----
Acid Yellow 23 ---- 2.50 ----
Acid Green 3 ---- ---- 1.50
Example 8 Example 9 Example 10
Pink Ink Green Ink Lt Blue Ink
Component
Deionized Water 45.50 43.50 45.75
Glycerin 20.00 20.00 20.00
Phosphoric Acid 30.00 30.00 30.00
Citric Acid 1.00 1.00 1.00
Preservative
Nuosept 95 0.50 0.50 0.50
Premix 2.50 2.50 2.50
Acid Violet 19 0.50 ---- ----
Acid Yellow 23 ---- 2.00 ----
Acid Blue 93 ---- 0.50 0.25
The inks of examples 5-10 had acceptable working
properties. For examples 5-10, the pH ranged from 2.0 to
3.5 and the density ranged from 9.0 to 9.2 pounds per
gallon. For examples 5-l0, the viscosity ranged from 3.5 to
4.5 centipoise. Here also, premix is a mixture of 96.04% m-
pyrol, 1.98% PVP K30, and 1.98% Troysan Polyphase P-100.
Two examples of overcolor coloring compositions in the
form of an ink using a pigment dispersion as a colorant are
as follows. Quantities are in percent by weight of the
total composition.
20
Overaolor Inx B~camples
Example 11 Example 12
Red Ink Green Ink
Component
Water 50.0 45.0
Glycerin 5.0 5.0
Phosphoric Acid 30.0 30.0
Pigment Dispersion
-Fluorescent Scarlet
SF-1013 15.0
-Fluorescent Green
SF-1012 20.0
(30%-40% pigment)
In using the various above described overcolor coloring
compositions and undercolor coloring compositions, a child
could place a mark of the erasable blue coloring composition
on paper, perhaps to paint the sky. If the child wishes to
add in a yellow sun, a green tree growing up into the blue
sky, and red flowers growing into the blue sky into the
picture, the child may easily use the above-indicated color
changing ink compositions, without tainting any of the
colors. Alternatively, if the child draws a sun using the
yellow color changing composition, he or she may draw in the
sky using the blue erasable ink right over the yellow
without spoiling the colors.
The multiple coloring composition system of the
invention may also be formulated as a paint. When
compositions of the invention are formulated as a paint,
such as a child's paint, they must necessarily be formulated
with a higher viscosity to enable to the application of the
of the paint with a brush. This viscosity is achieved in
two ways. First, a binder may generally be added to the
composition. This binder may be in the form of a modified
starch such as STADEX 140TH marketed by A.E. Staley
Manufacturing Company. Binders are typically used in
amounts of from about 0% to about 25% by weight of the
composition.
Additionally, paints may contain a thickener to provide
21
body to the paint. One suitable thickener is STAR-POLT~ 560,
a modified starch thickener, marketed by A.E. Staley
Manufacturing Company. Another suitable thickener,
especially for use in elevated pH compositions such as the
color changing composition of the invention is LAPONITE
RDST~, a synthetic hectorite. The amount of thickener used
depends upon the amounts of binder and other components used
in the composition, although typically about 1% to about 5%
by weight thickener is used.
Paints may also contain a filler or extender. Fillers
and extenders are generally solid particles added to paint
compositions which provide body to the paint but which do
not provide color. Common extenders are talcs, such as
magnesium silicate hydrate, and clays and two suitable
extenders for compositions of the invention are TALCRON MPT"
45-26 marketed by Pfizer Inc. and IMSIL A-108T". Extenders
may be used in amounts of from about 0% to about 40% by
weight of the composition. Where extenders or pigments are
used in a paint, a dispersant may also be used to maintain
the solid particles dispersed in the paint. Dispersants,
such as NOPCOSPERSE 44T", are typically used in amounts of
from about 0.1% to about 5%. Also, many paints optionally
include a freeze/thaw protector. Freeze/thaw additives
improve the stability of the paint over widely varying
temperatures. One suitable freeze/thaw protector is
propylene glycol which is effective when used in
compositions of the invention in amounts from about 1% to
about 10% by weight, with the most preferred range being
from about 1.5% to about 6.5% by weight.
In a further embodiment of the present invention, a
variety of erasable colors may be painted or otherwise
applied on a substrate, such as paper, and the substrate,
with these colors applied could be supplied to a child in
combination with the coloring changing composition in the
form of a paint or an ink in a marker. An appropriate color
changing composition could then be applied onto the
w 21 5254 5
22
substrate in areas where the child desired a change of color
to produced the desired color change.
While particular embodiments of the invention have been
shown, it will of course be understood that the invention is
not limited thereto since modifications may be made by those
skilled in the art, particularly in light of the foregoing
teachings. It is, therefore, contemplated by the appended
claims to cover any such modifications as incorporate those
features which constitute the essential features of these
improvements within the true spirit and scope of the
invention.
