Note: Descriptions are shown in the official language in which they were submitted.
21 52653
COLOR CHANGING COMPOSITIONS FOR USE
ON NON-POROUS SURFACES
FIELD OF THE INVEI~1TION
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 on non-porous surfaces such as transparencies for
use with overhead projectors to enable laying down an
initial mark using a first coloring composition yielding a
first color and then using an overcolor coloring composition
to enable a changEa of color of a portion or the entirety of
the initial mark.
BACKGROUND OF THE INVENTION
In business situations, non-porous surfaces are often
used for presentai:ions. Especially, transparent sheets of
plastic film are often used in conjunction with overhead
projectors to enable a large group of people to visually
perceive written :Lnformation. These transparent sheets are
commonly termed transparencies. Useful in marking on such
non-porous surfaceas are markers and pens containing inks,
crayons, and suff~Lciently soft pencils of various colors.
However, it is ofi:en difficult to highlight information on
A
215263
3
such non-porous surfaces as transparencies.
One method of highlighting or identifying especially
important information is indicate the information in a color
differing from the color of the general text or image.
Changing the color of a mark is not readily done with the
coloring instruments such as those described. Generally,
highlighting has been accomplished in the past by merely
bolding over writing or attempting to cover over one color
with a second color. When performing such highlighting, the
marks produced are often not the desired color or clarity
and the tips o:E the markers get soiled with the other inks,
further reducing the effectiveness of the highlighting.
Therefore, there has been a long felt need for compositions,
including inks,, and markers containing such compositions,
which produce nnarks 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.
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
nature and amount of pigment contained in an ink determines
its color.
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 reducing agent to the first
mark yielding a change in color. The marker inks used in
these markers are typically prepared by blending a reducing
agent (sometimess termed a bleaching agent) or pH sensitive
dye with a dye l~hat is stable in reducing agent or high pH.
For example, German Patent Specification No. 2724820,
(hereinafter "the German Patent"), concerns the combining of
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4
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 reducing agent 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 fix~sd second color. For example, a green mark
may only be ch~~nged to a violet color as the inks are
described in the practice of the German Patent. In
addition, sincEa one of the required pair of markers contains
only the reduc»ng agent, that reducing agent 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 reducing agent marker is of no use. Or, once
the reducing agent 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 reducing agent marker
tends to get soiled by picking up the colors of the base
coloring composition, thus tainting the color of subsequent
marks.
Coloring composition may also optionally include such
ingredients as ihumectants, preservatives, 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 ma~cker 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.
21 526 5 3
Therefore, an object of the present invention is to
provide a col~~ring composition system which is capable of
enhanced multiple color changing abilities for use on non-
porous surfaccas.
5 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 on non-porous surfaces.
A further object of the present invention is to provide
a coloring composition system in the form of inks for use on
non-porous surfaces which 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.
80MMARY OF THE INVENTION
The present invention overcomes the drawbacks
associated with prior overwriting ink compositions in that
the particular undercolor coloring composition made
according to the invention is suitable for use on non-porous
surfaces and ma,y be changed to multiple second colors,
depending upon the dye present in the overcolor composition
which.
Advantageously, an overcolor composition of the present
invention makes a visible mark on non-porous surfaces, 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 currently used color
change markers, the nib of the tip of marker containing the
overcolor ink does not become visibly soiled with the
undercolor coloring composition color because the undercolor
is immediately destroyed upon contact with the overcolor
21 526 5 3
_ _ _ -
composition.
In general, the present invention is a multiple
coloring composition system for use on non-porous surfaces
whose coloring effect may be changed upon treatment with an
overcolor second coloring composition, once the overcolor
has been deposited over the undercolor coloring composition.
In one embodiment, the multiple coloring composition system
comprises:
(a) an undercolor aqueous coloring composition
l0 comprising a film forming resin and an undercolor dye whose
coloring ability is destroyed in the presence of a pH of
about 10 or greaater and/or in the presence of a reducing
agent; and
(b) an overcolor aqueous coloring composition
comprising a film forming resin, a colorant capable of
maintaining its. characteristic color in the presence of a pH
of about 10 or greater and/or in the presence of a reducing
agent, a base such that the pH of the overcolor composition
is about 10 or greater and/or a reducing agent.
Suitable dyes for use in the undercolor coloring
composition include polymethine dyes, triphenylmethane dyes,
cyanine dyes, methane dyes, and azo dyes which are unstable
in the presence of a pH of about 10 or greater and/or are
unstable in the presence of a reducing agent. Suitable
colorant for use in the overcolor coloring composition
include pigment;, xanthene dyes, pthalocyanine dyes, and azo
dyes which are ;stable in the presence of a pH of about 10 or
greater and/or <~re stable in the presence of a reducing
agent . -
Suitable rE~ducing agents for use in compositions of the
invention include hydrogen sulfide, sodium sulfite, sodium
bisulphate and stannous chloride. Suitable bases for use in
compositions of the invention include ammonium hydroxide,
sodium hydroxide and sodium carbonate.
Also disclosed is an ink composition system comprising:
7
(aj an undercolor aqueous ink comprising from about
0.1 to about 5~% by weight of the undercolor ink of a film
forming resin and an undercolor dye whose coloring ability
is destroyed in the presence of a reducing agent and/or a pH
of about 10 or greater in an amount of from about 0.1 to
about 15 % by weight of the undercolor ink; and
(b) an overcolor aqueous ink comprising from about 0.1
to about 5% by weight of the overcolor ink of a film forming
resin, from about 1% to about 20% by weight of said
overcolor ink ~of a reducing agent; from about 0.1% to about
10% by weight of said overcolor ink of a base; and from
about 0.1% to ~~bout 15% by weight of said overcolor ink of a
colorant which maintains its characteristic color in the
presence of a reducing agent and/or a pH of about 10 or
greater.
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 film forming resin and a dye whose coloring
ability is destroyed in the presence of a reducing agent
and/or a pH of about l0 or greater. The overcolor writing
instrument contains an overcolor ink comprising a film
forming resin, from about 1% to about 20% by weight of
reducing agent, from about 0.1% to about 10% by weight of a
base, (3) from about 0.1% to about 15% by weight of a
colorant which :maintains its characteristic color in the
presence of a reducing agent and/or a pH of about 10 or
greater.
The coloring compositions of the invention may also
optionally comprise a humectant, a drying agent, and a
preservative.
DETAILED DESCRIPTION OF THE INVENTION
The present: invention imparts the desirable ease of
application and convenience of use of traditional color
8
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 for use on non-porous surfaces such as
transparencies.
In general, the present invention is a multiple
coloring composition system for use on non-porous surfaces
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 omer the undercolor coloring composition. An
embodiment of lthis marking system comprises:
(a) an undercolor aqueous coloring composition
comprising a film forming resin and an undercolor dye whose
coloring abilil:y is destroyed in the presence of a reducing
agent and/or a pH of about to or greater; and
.(b) an overcolor aqueous coloring composition (the
overcolor) comprising a film forming resin, a colorant
capable of maintaining its characteristic color in the
presence of a reducing agent and/or a pH of about 10 or
greater, and a reducing agent and/or a base in an amount
sufficient to yield a pH of about 10 or greater.
To increase the pH of the overcolor aqueous coloring
composition, a base in an amount sufficient to elevate the
pH of the overcolor aqueous coloring composition to a level
of about 10 or greater, and preferably from about 10 to
about 12, is preferably used.
In a preferred embodiment, the overcolor aqueous
coloring composition comprises both a reducing agent and a
base in an amount sufficient to elevate the pH of the
overcolor aqueous coloring composition to about 10 or
greater and preferably from about 10 to about 12. In this
preferred embodiment, the marking system comprises:
(a) an un~lercolor aqueous coloring composition
_.
9
comprising a !'ilm forming resin and an undercolor dye whose
coloring ability is destroyed in the presence of a reducing
agent and/or i.n the presence of a pH of about 10 or greater;
and
(b) an owercolor aqueous coloring composition
comprising a film forming resin, from about 1% to about 20%
by weight of a reducing agent, a base in an amount
sufficient to produce a pH of about 10 or greater, and from
about 0.1% to about 15% by weight of a colorant capable of
maintaining its characteristic color in the presence of a
reducing agent and a pH of about 10 or greater.
An appropriate undercolor dye is generally selected to
be used in conjunction with the selected overcolor colorant.
Where an under~~olor dye is incapable of maintaining its
characteristic color when exposed to a pH of about 10 or'
greater, an ovearcolor colorant is selected which is capable
of maintaining its characteristic color at such a pH and a
base is added t:o the overcolor composition to yield a pH of
about 10 or greater. Where an undercolor dye is incapable
of maintaining its characteristic color when exposed to a
reducing agent, an overcolor colorant is selected which is
capable of maintaining its characteristic color in the
presence of a reducing agent and a reducing agent is added
to the overcola~r composition.
Certain undercolor dyes may be selected which are
incapable of maintaining their characteristic color when
exposed to a combination of a pH of about 10 or greater and
a reducing agent. In such a case, an overcolor colorant is
selected which is capable of maintaining its characteristic
color in the presence of both a pH of about 10 or greater
and a reducing .agent and both a base and a reducing agent
are added to th~~ overcolor composition.
Finally, a collection of multiple undercolor coloring
compositions ma;,~ be assembled, some of which contain a dye
incapable of maintaining its characteristic color in the
10
presence of a pH of about 10 or greater and some of which
contain a dye incapable of maintaining its characteristic
color in the presence of a reducing agent. For economic
efficiency, in formulating overcolors for use with such a
collection of undercolors, it is preferable to use an
overcolor coloring composition which comprises a film
forming resin, a colorant capable of maintaining its
characteristic color in the presence of both a pH of about
or greater and a reducing agent, a base, and a reducing
10 agent. In such a case, the overcolor coloring composition
may be used to overwrite a mark made by any of the
collection of undercolor coloring compositions without
regard to whei:her the undercolor composition contains a dye
which is incapable of maintaining its characteristic color
in either the presence of an elevated pH or in the presence
of a reducing agent. ,
Most suitable for use as dyes in the undercolor
coloring compositions are dyes that are easily destroyed by
reducing agent:. Such coloring compositions are commonly
known in the field and are occasionally used as chemically
"erasable" inks. Also suitable for use as dyes in the
undercolor coloring compositions are dyes which are easily
destroyed in the presence of a pH of about 10 or greater.
Especially suitable for use as dyes in the undercolor
coloring composition are polymethine dyes, triphenylmethane
dyes, cyanine dyes, methine dyes, and azo dyes which are
unstable in the presence of a pH of about 10 or greater
and/or are unstable in the presence of a reducing agent.
Such dyes include the dyes marketed under the tradenames
BASACRYL X-RL 'YELL04~"' (Basic Yellow 49), marketed by the
BASF Corporation, ASTRAZON BLUE FRR~' (Basic Hlue 69),
ASTRAZON BRILL:LANT RED 4G~' (Basic Red 14), and ASTRAZON PINK
FBB"' (Basic Red 49) by Miles(Mobay); and the dyes marketed
under the tradenames Acid Green 3 by International Dyestuffs
Corporation, Acid Blue 93 and Acid Violet 19 marketed by
2~ ~2fi~~
11
Spectra Color Corporation as well as mixtures thereof.
The listed ASTRAZON dyes are classified as polymethine
dyes. Polymethine dyes are colored substances in which a
series of -CFi= (methine) groups connect to terminal groups
of a chromophore. Polymethine and cyanine are often used
interchangeabl~r 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, Acid Blue 93 and Acid Violet
19 are triphen~~lmethane dyes. 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 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 1% 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 t:o be used as an ink for a typical marker to
ensure_good coloration.
The overcol.or coloring composition of the present
invention is preferably formulated by combining a reducing
agent and a base: with a colorant which maintains its
characteristic color in the presence of reducing agent and
in high pH conditions. Of course, where colorants used in
the undercolor composition are only affected by a reducing
21 5 26 5 3
12 '
agent, the base may be deleted. Also, where dyes used in
the undercolor composition are only affected by an elevated
pH, the reducing agent may be eliminated. However, for
maximum commercial application and for maximum effect upon a
wider variety of undercolor compositions, the overcolor
composition is preferably formulated with a reducing agent
and base in combination.
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 a
reducing agent o:r high pH conditions. Dyes meeting this
criteria include xanthene dyes, pthalocyanine dyes, and azo
dyes which are stable in the presence of a pH of about 10 or
greater and/or a:re stable in the presence of a reducing
agent. Dyes which have been found to meet these criteria
include PYRANINE 120n marketed by Miles(Mobay)(commonly
termed Solvent Green), Acid Red 52 marketed by Carolina
Color, Food Red :l4 marketed by Hilton-Davis, BASANTOL GREEN
910n marketed by BASF, Acid Red 87 marketed by Hilton-Davis,
Acid Red 92 markeated by International Dyestuffs Corporation,
Acid Red 388 and Direct Blue 199 marketed by Crompton &
Knowles, and mixi_ures thereof.
Acid Red dysa, classified as xanthene dyes, are
generally used as colorants for foods, drugs and cosmetics.
Specifically, Acid Red 87, is the disodium salt of 2,4,5,7 -
tetrabromo-9-o-carboxyphenyl-6-hydroxy-3-isoxanthone. Acid
Red 87 is also called D & C Red No. 22 by the Food and Drug
Administration ('"FDA"), and sold under the tradenames Eosine
YS"" and Eosine G'"'. In addition, Acid Red 92, the disodium
salt of 2,4,5,7-t:etrabromo-9-3,4,5,6 tetrachloro-o-
carboxylphenyl)-E.-hydroxy-3-isoxanthone, is called D & C Red
No. 28 by the FDp,, and sold under the tradename Phloxine B~'.
Acid Red 52 is a colorant for plastics. Further, Food Red
14 or FD&C Red No. 3, commercially available under the
tradenames ERYTHFi.OSINE"' and ERYTHROSINE BLUISH"' , is the
2152653
13
disodium salt of 9(o-carboxyphenyl)-6-hydroxy-2,4,5,7-
tetraiodo-3H-xanthen-3-one, which contains smaller amounts
of lower iodinated fluoresceins.
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 determined largely by the ability to maintain a
stable composiltion and the depth of color desired and can
vary widely depending upon the concentration of other
components. I1. 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. They preferred concentration range for most
applications i:~ from about 1% 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.
Also newly discovered is that pigments may be used as
an excellent colorant in 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 pigmE~nt dispersion is preferred for use in the
present invention. Typical commercial dispersions contain
30 to 74% by weight active pigment ingredients.
2152653
14
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 ~~oloring composition is in the form of an ink.
Indeed, relatively larger pigment particles can
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 bEa 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 instrum~ant in which the ink will be placed.
Undercolor, 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 rib being used in the writing or marking
_2152~~3
instrument. 7:n general, the size of pigment particles
should be kept: as low as possible while maintaining the
stability of t:he composition. For example, it has been
found that an ink to be utilized in a marking instrument
5 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
10 the range from about 0.05 to about 0.25 microns, since such
a dispersion promotes better wicking or capillary flow
through the nib. Examples of suitable pigment dispersions,
which are especially suited for compositions of the
invention used in the form of an ink include HOSTAFINE
15 RUBINE F6B'~ (C. I. Pigment Red 184 dispersion), BLUE B2Gn'.
(Pigment Blue :15-3) and Black 7 (Pigment Black T), marketed
by Hoescht Celanese Corporation under the tradename
"HOSTAFINES DIl3PERSIONS""'.
~The minimum concentration of pigment which will produce
a workable overcolor coloring composition is governed by the
color intensit~~ desired, though as little as 0.1% active
pigment may be sufficient for certain applications. The
maximum workab7.e 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
2152fi5~
16
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 reqvuired 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 tlae composition.
Typical reducing agents for use in the overcolor
coloring composition of the invention include hydrogen
sulfide, sodium sulfite, sodium bisulphite and stannous
chloride. Ceri:ain limited bleaches which act as weak
oxidizing agenta such as sodium hypochlorite and hydrogen
peroxide may a7.so operate to effect a color change.
Hydrogen peroxide is also known to sometimes operate as a
weak reducing agent. The preferred reducing agent for use
in the overcolor coloring composition of the invention is
Na2S03 (sodium sulfite). Reducing agent is generally
present in the overcolor coloring composition of the
invention in an. amount from about 1% to about 20% with a
minimal amount required to allow for the elimination of the
undercolor coloring composition of the invention and the
maximum amount determined by (1) the stability of the
composition, (2) the need to avoid excessive crystal growth
in the overcolor coloring composition which would impart a
light scattering effect where the composition is used on a
transparency for use with an overhead projector to achieve a
projected image, and (3) the safety of the composition for
use by children. Preferably, the reducing agent is
contained in the overcolor coloring composition in an amount
of from about 5% to about l0%, and most preferably in an
amount of from about 8% to about 10% by weight of the
a
overcolor coloring composition.
Overcolor ~~oloring compositions of the invention may be
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17
formulated using only a reducing agent. However, the
reducing agenta used in overcolor coloring compositions of
the invention perform most effectively in the presence of an
elevated pH. To elevate the pH of the overcolor coloring
composition, a base is added. Bases which may be used in
the overcolor coloring composition of the invention are
typically strong bases, usually having a pH of from about 10
to about 12. Typical bases which may be employed in the
overcolor coloring composition of the invention include
ammonium hydroxide, sodium hydroxide, and sodium carbonate.
The preferred base is sodium hydroxide.
The base is generally present in the overcolor coloring
composition of the invention in an amount from about 0.1% to
about 10% by weight. Preferably, the base is added in an
amount sufficient to raise the pH of the composition to a pH
of from about :LO to about 12. Preferably, the base is
contained in the overcolor coloring composition in an amount
of from about 0.5% to about 8%, and most preferably from
about 1% to about 5% by weight of the overcolor coloring
composition.
The water used in the undercolor coloring composition
and the overco7.or coloring composition of the invention
present inventj.on 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 th.e amount of other components included in the
undercolor color 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 20% to about 85%, and
most preferably from about 60% to about 85% by weight of the
composition.
The amount of water present in the overcolor coloring
_2~~2653
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 visc~~sity when the overcolor coloring composition
is used in the form of, for example, an ink, water is
preferably pre;~ent in an amount of from about 20% to about
85%, and most preferably from about 60% to about 85% by
weight of the composition.
The underc:olor coloring composition further comprises a
film forming rEasin. This resin is to promote adherence of
marks made using the undercolor and overcolor coloring
composition on non-porous surfaces such as transparencies'.
Further, the film forming resin is important to prevent dye
used as colorant in the undercolor coloring composition from
crystallizing out of solution and losing color value. It is
important that a film forming resin be selected in which the
dye used as colorant in the undercolor coloring composition
is soluble.
Suitable film forming resins include
polyvinylpyrrolidones marketed under the tradename of PVPI~"'
by Industrial Specialty Products, Polyvinyl Alcohol (PVOH)
marketed under the tradename of AIRVOL'~ by Air Products,
polyethylene glycol marketed under the tradename of POLYOX"'
by Union Carbide, alkali soluble acrylics such as those
marketed under the tradename ACRYSOL WS-24~' by Rohm & Haas
Co., and modified starches such as those marketed under the
tradename DRYSWEET 42T" by American Maize.
A resin hawing a compatible molecular weight must be
chosen based upon the planned end use for the undercolor
coloring composition. Where the undercolor coloring
composition is i;,o be used in the form of an ink for
instance, a pol;rvinylpyrrolidone such as PVPK-15 or -30 is
_z~~2s~~
19
appropriate while PVPK-60 and -90 cause high viscosities
which render the coloring composition too thick for
dispensing through common marker nibs. A resin having too
low of a molecular weight may provide insufficient binding
properties to the composition and result in a coloring
composition which flakes off of non-porous surfaces. PVPK-
30 is the most preferred film forming resin and its
manufacturer claims a viscometric molecular weight of
approximately 40,000. Where an AIRVOL film forming resin is
used, AIRVOL 523 is preferred. AIRVOL 523 has an 87-89 %
degree of hydr~~lysis and a number average molecular weight
range of 44,000 to 65,000. Where a POLYOX film forming
resin is used, POLYOX WSR-N-10 is preferred and its
manufacturer claims a molecular weight of 100,000.
The amount= of film forming resin present in the
undercolor coloring composition of the invention is governed
in part by the film forming resin used and the amount of
other components included in the undercolor coloring
composition. ~~ sufficient amount of film forming resin must
be added to promote adhesion of the undercolor coloring
composition to non-porous surfaces. Film forming resin is
generally present in the undercolor coloring composition of
the invention i.n an amount from about 0.1% to about 5% with
a minimal amour,~t required to allow for promoting adhesion of
the undercolor coloring composition of the invention to non-
porous surfaces. and the maximum amount determined by the
viscosity of the resulting undercolor coloring composition,
the stability of the undercolor coloring composition and the
cost effective limit of using the film forming resin.
Preferably, the film forming resin is present in undercolor
coloxing compositions of the invention in an amount of from
about 1% to about 3% by weight of the undercolor coloring
composition.
The overcolor coloring composition also further
comprises a film forming resin. Again, this resin is to
w_ _ 21
promote adherence of marks made using the overcolor coloring
composition on non-porous surfaces such as transparencies.
Further, the film forming resin is important to prevent dye
used as colorant in the overcolor coloring composition from
5 crystallizing out of solution and losing color value. It is
important that a film forming resin be selected in which the
dye used as colorant in the overcolor coloring composition
is soluble.
Suitable :film forming resins for use in the overcolor
10 coloring compositions of the invention include the same film
forming resins suitable for use in the undercolor coloring
compositions oo the invention. The amount of film forming
resin present :Ln the overcolor coloring composition of the
invention is governed in part by the film forming resin used
15 and the amount of other components included in the overcolor
coloring composition. A sufficient amount of film forming
resin must be added to promote adhesion of the overcolor
coloring composition to non-porous surfaces. Film forming
resin is generally present in the overcolor coloring
20 composition of the invention in an amount from about 0.1% to
about 5% with a minimal amount required to allow for
promoting adhesion of the overcolor coloring composition of
the invention to non-porous surfaces and the maximum amount
determined by the viscosity of the resulting overcolor
coloring composition, the stability of the overcolor
coloring composition and the cost effective limit of using
the film forming resin. Preferably, the film forming resin
is present in owercolor coloring compositions of the
invention in an amount of from about 1% to about 3% by
weight ~of the overcolor coloring composition.
Optionally, both the undercolor coloring composition
and the overcolor coloring composition may further comprise
such additives <is humectants, drying agents and
preservatives such as biocides and fungicides.
Addition oi° a humectant ensures that coloring
~___ _
_2152653
21
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 inc7.ude polyhydric alcohols such as ethylene
glycol, propylene glycol, hexylene glycol and polyethylene
glycol), and hydroxylated starches. The humectant is
preferably propylene glycol or glycerin.
The humecaant is generally used in an amount of from
about 0% to ax~out 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, propylene glycol, is added in an
amount of from about 5% to about 15% by weight of the
coloring composition.
To achieves 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 t:he 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
___._.._ _..
_21526~~
22
or a conventional denaturant. An alcohol utilizing a
tittering 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
contains a tittering 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 30% by weight, with the most
preferred concentration being about 8-10% by weight, though
these amounts ~~re not critical to the practice of the
invention. About 8% per weight of drying agent is
ordinarily required to ensure rapid drying of the ink on ~a
nonporous surf<ice, while amounts in excess of about 30% by
weight may advE~rsely 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 many 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 5.0% 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 Hals Corp., and sold under the tradename
NUOSEPT 95~" Bic;~clic-oxozolidine, by Dow Chemical Co. and
sold under the i:rademarks DOWICIL 75"' (1-(3-chloroallyl)-
_ 2~~~s~~
23
3,5,7-triaza-:l-azoniaadamantane chloride) and DOWICIL 200"'
(3-chloroviny7l-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 GERNfALL II'~ (imazolidinyl urea), or a preservative
manufactured try Merck and sold under the trademark TEKTAMER
38'"' (1,2 dibromo-2,4-dicyanobutane), will work in the
composition of the invention.
Other acceptable preservatives include TROYSAN
POLYPFiASE P100'", a 3-Iodo-2-Propynyl Butyl Carbamate sold by
Troy Chemical which is typically mixed with PVP K-30'x, a 2-
Pyrrolidinone, 1-Ethenyl-, Homopolymer ((C6MgN0)x
solubilizer 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 consumer using a non-porous surface such
as a transparency may make marks using one or more colors on
the transparency. These marks may be made using normal type
input such as ~>hotocopying marks onto the transparency from
a type written page. These marks may also be made using the
various undercolor and overcolor coloring compositions of
the invention.
The consumer may then select one or more markers
containing various undercolor coloring compositions of the
invention to highlight certain areas or important textual
passages or graphical depictions contained on the
transparency. The consumer may then select one or more
markers containing various overcolor coloring compositions
of the invention to further visually attract the viewer's
attention. To create this visual attraction, the consumer
may overwrite a portion or all of the previously made
markings using 'the undercolor coloring composition of the
_... _
24
invention thereby 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 non-porous
substrate on which it is applied.
Preferably, when the coloring compositions of the
invention are vused in the form of inks, the inks are placed
in conventional markers. These markers utilize reservoirs
for storing th~a ink and nibs such as bonded fiber or
sintered plastic to dispense the ink. Typically, an ink
reservoir contains a sponge like reservoir which hold the
thee ink. The preferred reservoirs for undercolor coloring
compostions of the invention are made of acetate, polyester
or polypropylene. The preferred reservoirs for overcolor
coloring compo:>tions of the invention are made of
polypropylene ~rhich more suitably resists attack by any
reducing agent contained in the overcolor coloring
composition.
In general, any suitable nib may be used in conjunction
with the underc:olor coloring compositions of the invention.
However, where nylon or polyamide fibers are used, they
should be checked for preferential dye absorption. Also,
any compatible nib may be used in conjunction with the
overcolor coloring compositions of the invention. Sintered
polyethylene nibs are preferred and nylon and polyamide nibs
should be checked for preferential dye absorption. In
general, bonded polyester fiber nibs are not suitable for
use with the ov~ercolor coloring compositions of the
invention. Various undercolor coloring compositions are
placed in an undercolor set of markers,~each containing an
appropriate dif:Eerent color dye. Various overcolor coloring
_ _._.~. . .__~..._...___. . . __.__..__
25
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. A marking kit or system is thus formed which
comprises both overcolor coloring compositions and
undercolor coloring compositions.
EBAMBLEB
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.
Unde:rcolor Coloring composition Examples
Example 1 Example 2
Violet Blue
COnID~~nent ~ ~
Deionized Water 83.7 91.7
Prop;tlene Glycol 10.0 5.0
Presearvative
GE~rma 11 I I 0 . 3 ---
Nuosept 95 --- 0.3
Dye
Acid Violet 19 4.0 ---
Ac:id Blue 93 --- 2.0
Film Forming Resin
A7:RVOL 523 2.0 ---
POLYOX WSR-N-10 --- 1.0
Example 3 Example 4
Red Violet
C
Deior,~ized Water
Propylene Glycol 10.0 10.0
Preservatives 0 . 2 0 . 3
_ Dye
Basic Red 49 4.0 ---
Basic Violet 10 --- 2.0
Film Forming Resin
POLYOX WSR-N-10 2.0 ---
PVP K-30 --- 5.0
__.__ ..._
y21~2~65
26
The inks of examples 1 through 4 had acceptable
working properties. For examples 1 through 4, the pH ranged
from 4.5 to 7.5 and the density ranged from 8.8 to 9.0
pounds per gallon. For examples 1 through 4, the viscosity
ranged from 2.3 to 4.0 centipoise. The inks of examples 1
and 2 are espe~~ially suitable for overcolor elimination by
an overcolor coloring composition containing a reducing
agent. The inks of examples 3 - 4 are especially suitable
for overcolor elimination by an overcolor coloring
composition haring a pH of about 10 or greater whether or
not a reducing agent is present.
Overcolor Coloring Composition Examples
Example 5 Example 6
Red Hlue
Compcment
DI Water 78.0 84.5
Propylene Glycol 10.0 8.0
. Na2S03 5.0 5.0
NaOH (5N
Soln) 20%
Solution 1.0 0.5
Dye
Acid Red 388 4.0 --
Direct Blue 199 --- 1.0
Film Forming Resin
ACRYSOL WS-24 2.0 ---
POLY~OX WSR-N-10 --- 1.0
Example 7
Yellow
Component $
DI Waiter 7g , p
_ Propylene Glycol 10.0
NaZ803 6 . 0
4 0 N$OH ~( SN
Soln)~ 20%
soluiaon i . o
Dye
Pyranine 120 2.0
Film >E'orming Resin
ACRY6~OOL WS-24 3.0
~~......_._.____..._.. __... ____
27
The inks of examples 5-7 had acceptable working
properties. For examples 5-7, the pH ranged from 11.2 to
12.0 and the dEansity ranged from 9.7 to 9.9 pounds per
gallon. For examples 5-7, the viscosity ranged from 3.8 to
4.6 centipoise.
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 composit~.on.
Overc,olor coloring Composition Examples
Example 9 Example 10
Yellow Hlue
Component %
DI Water 76.5 81.5
Propylene Glycol 8.0 5.0
Na2S0,3 5 . 0 5 . 0
NaOH (5N
Soln) 20%
Solution 1.0 1.0
' Pigme;nt
Host;~fine Yellow HR 7.5 ----
Host~~fine Blue B2G --- 6.0
Film ;Forming Resin
POLY~~X WSR-N-10 1.0 1.5
In using the various above described overcolor coloring
compositions anc9 undercolor coloring compositions, a
consumer could place a transparency having indicia marked
thereon on an overhead projector. If the consumer wishes to
draw the attention of the viewer to particular area of the
indicia on the transparency, he could highlight a particular
area with one or more undercolors. To further draw the
attention of the: viewer to a very particular point in the
highlighted violet area, the consumer may easily use the
above-indicated overcolor coloring ink compositions, such as
the red overcolo~r to mark over an area previously marked
upon using an undercolor coloring composition of the
invention, without tainting any of the colors not marked
~~ 526 5 3
28
upon and without tainting the nib of the overcolor marker.
In a further embodiment of the present invention, a
variety of underc:olor colors may be painted or otherwise
applied on a non-porous substrate, such as a transparency,
and the substrate, with these colors applied could be
supplied to a child in combination with the overcolor
coloring composition in the form of an ink in a marker. An
appropriate overc:olor coloring composition could then be
applied onto the substrate in areas where the child desired
a change of color' to produced the desired color change while
at the same time his classmates can view the changes made by
projecting the images on the substrate using a suitable
overhead projector.
From the foregoing description and examples, it is
apparent that the. objects of the present invention have been
achieved. While only certain embodiments have been set
forth, alternative embodiments and various modifications
will be apparent to those skilled in the art. These and
other alternatives are considered equivalents and within the
spirit and scope of the present invention.
