Note: Descriptions are shown in the official language in which they were submitted.
EiIG~ OPACITY SOLID MARKING COMPOSITION
BACK5ROUND OF T~E INVENTION
1. Field of the Invention
This invention relates in general to the ~ield
of marking instruments, including crayons, and in
particular, to solid compositions used in the manufacture
of such instruments.
2. Brief Description Of The Prior Art
That solid compositions used in the manufacture
of crayonq and colored marking pencil~ may be produced
from mixtures of waxe~, fatty acids, colorants and
extenders is well known in the art of marking and writing
instruments. ~hen properly formulated, such compositions
may be u~ed to draw, write or color. Traditionally, these
solid marking compositions have suffered from an inability
to create a smooth~ even, and opaque mark and instead
produce uneven lines of erratic intensity.
Conventional solid marking compositions in many
instances also suffer from a lack of brilliance in color
2~ o the mark laid down, as well as a dull appearance of the
~olid marking composition itself. These inad2quacies Oe
~ t~ 3
available crayons can lead to disenchantment with the art
capabilities of the crayon and loss of interest in usage
of crayons.
One approach to achieving a more attractive
marking composition has been to employ a metallic pigment,
such as those prepared from metallic elements and their
alloys, for example, aluminum, copper, gold, bronze and
zinc. However, such compositions have employed the
metallic pigment as the sole pigment in the solid marking
composition for the purpose of producing a mark having the
same appearance charac~eristics as the me~al itself.
Thus, the range of appearance effects which may be
attained is limited by numbec of such metal pigments which
may economically be utilized.
It is therefore one object of the invention to
provide a solid marking composition which produces a
marking instrument, such as a crayon, with a more
appealing stick color.
It is also an object Oe the invention to provide a
solid marking composition which imparts to the mark 1 id
down by the crayon a unique appearance.
A eurther object of the invention i9 to provide
a solid marking composition with superior tactile
properties, including ease of application so as to produce
a smooth flowing, even mark.
Yet another object is to produce a solid marking
composition having improved opacity when applied to a
surface .
ix~ ~ d~
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SUMMARY OF TFIE INVE~NTION
The present invention is that the combination o~
a metallic pigment with a nonmetallic colored pigment
dispersed in a solid matrix produces a solid marking
composition yielding quite unexpected, but highly
desirable, results.
First, the solid marking composition o~ the
invention produces a colored mark which has an unexpected
metallic sparkle, sheen, or glitter. The colored mark is,
in addition, signieicantly more opaque in appearance.
Second, when the solid marking composition of
the invention is used, for example, in the form of a
crayon, the crayon stick has a surprisingly pearlescent
appearance which is pleasing to the eye.
Purther, the composition of the invention
produces a mark ~hich lays down on the surface in a very
slick, smooth, "lipstick like" rub out, resulting in an
unexpectedly enhanced ease of application, including
better smoothnes3, glide, and color transfer.
Yet another unexpected property of the
composition of the invention is that the stick color
(masstone~ may vary signieicantly from the applied color
(rubout), according to the choice of pigment components.
These uni~ue and surprising properties Oe the
composition of the invention increase the appeal of the
crayon for the consumers, including both children and
artists. The appearance o~ the mark is improved over a
conventlonal crayon in that the mark has a metallic sheen
o~ sparkle which i~ much more pleasing to the eye. The
application properties o~ the ~olid marking composition
stimulate creativity and sel~-expression not normally
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encountered with traditional solid marking co~positions,
such as conventional crayons. Such a smooth Elowing, more
attractiv? mark increases the range oE uses for the
composition and increases the breadth of the market for
such a marking composition.
The solid marking composition of the invention
is advantageously used in the manufacture of crayons
employing any suitable matrix material. For example, the
solid marking composition o~ the invention may utilize a
conventional crayon matrix of paraffin wax and stearic
acid, a so-calLed plastic crayon matrix of polyethylene
resin and a plasticizer material, or a so-called washable
crayon matrix material of water-soluble polyethylene
glycol resins. In each, the composition of the invention
produces a mark with unexpectedly superior tactile
properties, a pleasing metallic sheen, and unexpectedly
improved opacity.
The composition of the invention which achieves
these results includes erom about 13 to about 40~ by
weight of a metallic plgment, and from about 1~ to about
45% by weight nonmetallic colored pigments, dispersed in a
suitable matrix.
DETAILED DESCRIPTION
The present invention in its most basic form is
that the combination of a metallic pigment with a
nonmetallic colored pigment dispersed in a matrix produces
a solld marking compoqition producing a mark having a
metallic sheen, spa~kle, or glitter. In one ~peci~ic
embodlmentl a crayon, the composLtion of the invention
30 compri~es a combination o~ ~rom about 1~ to about 40~ by
S~J ~Ji ~ ?~ ~-
weight o~ a metallic pigment, from about 1~ to about 45~
by ~eight of a nonmetallic colored pigment, from about 16
to about 40% by weight inert fillers and extenders, and
from about 50% to about 85~ by weight matrix materials.
The primary discovery is that the combination of
a metallic pigment and a colored non-metallic pigment in a
suitable matrix ~roduces a composition which unexpectedly
achieves a colored mark which has a metallic sheen or
sparkle in appearance. A further discovery is that the
solid marking compositlon of the invention imparts a
surprising pearlescent or sparkling appearance to the
crayon stick itself. In addition, the colored mark
produced by the composition has increased opacity and is
laid down in a smooth "lip stick like" fashion, enhancing
the tactile qualities of the crayon.
The metallic pigmen~s contemplated for use in
the composition of the invention are prepared from
metallic elements and their alloys, ~or example, aluminum,
copper, gold, bronze and ~inc. Any of these may be used
in the composition Oe the invention, depending upon the
particular visual eefect desired~
The preferred metal is aluminum, and even more
preferred is leafing aluminum. Aluminum is preferred
because it imparts the desired qualities of pearlescent
stick appearance, produces marks with a metallic sheen,
and provides ease Oe laydown with a minimal intereerence
with the actual color of the colored nonmetallic pigment.
Leafing aluminum imparts a greater metallic sheen to the
mark laid down by the composition, while non-leafing
3~ aluminum impart~ more Oe a me~allic sparkle to the mark.
0~ course, combinations o~ two or rnore metallic
pigments may be utilized to further broaden the range of
appearance effects.
The more preferred leafing aluminum metallic
S pigment is typically produced by g;inding aluminum to a
powder in a wet ball mill containing a paint thinner or
mineral spirits and a lubricant. Ordinarily, stearic acid
is used as the lubricant in the mill, and the final
product of lea~ing aluminum has a mono~olecular layer o~
stearic acid coating each ~lake of aluminum pigment.
Non-leafing aluminum metallic pigment is also
suitable for the invention, however the effect upon the
solid marking composition is to impart a glitter or
sparkle look to the mark of the composition rather than a
metallic sheen. Non-leafing aluminum metallic pigmen~ is
also produced by grinding aluminum to a powder in a wet
ball mill containing a paint thinner or mineral spirits
and a lubsicant. To produce a non-leafing aluminum
metallic pigment, however, an oleic acid is used a~ the
lubricant in the mill.
Leafing and non-lea~ing aluminum metallic
pigments are available in paste or in a powder form.
Commercially available aluminum metallic pigment contains
only a nominal amount o stearic or oleic acid which
remains as a microthin coating on the pigment particle.
Aluminum metallic pigment is available in a
multitude of particle si%es.
The amount of metallic pigment which i~
necessary to yield the desired reqults is governed by the
level Oe metalllc sheen or sparkle deYired, though a
concentration Oe at least 1~ by weight i9 usually required
to achieve a noticeable efect on the appearance and
application characteristics of the composition. A
preeerred upper limit is about 40~ by weight, since
greater amounts of aluminum metallic pigtnent may cvertake
the coloring capability of the nonmetalllc colored pigment
component.
When the solid marking composition is to be
shaped into crayon form by a gravity molding process, a
range of from about 4~ up to about 10~ metallic pigment is
preferred, since ~reater amounts than about 10~ causes the
solid marking composition to become too viscous for
effective, efficient gravity molding application. Where,
however, the solid marking composition i5 to be formed
using such other processes as high pressure injection
molding, extrusion molding, or press or tabletized
lS molding, a range Oe metallic pigment of from about 153 up
to about 40% is preferred, since a greater range of
appearance effects can be achieved, and since maintaining
a lower viscosity is not as critical to these processes.
Metallic pigments other than aluminum which may
economically be used in the composition of the invention
include zinc, copper, and bronze. These metallic pigments
produce effects ~imilar to that of aluminum, however, they
have a greater effect upon the color of the re~ulting
compo itions. They typically p~oduce a mark with a
deepe~, darker color than would be anticipated from the
use of a colored nonmetallic pigment alone. Indeed, it
has been found that compositions employing metallic
pigment~ other than aluminum tend to be preferred for use
in fine arts applications.
3n The ~econd componen~ of the solid marking
composition is a nonmetallic colored pi9ment. Any
conventional pigment which i9 compatible with the matrix
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material may be used, including inorganic pigments,
organic pigments, and mixtures thereof. Typical inorganic
pigments include iron blue, iron oxides, zinc oxide,
ultramarine blue, lamp black, sodi~m rubine, and titanium
dioxide. Typical organic pigments include azo, naphthol,
and phthalo pigments. Additional pigmen~ materials such
as acid dye toners, basic dye toners, acid dye lakes, and
basic dye lakes may also be used. Various combinations of
these pigments may advantageously be used.
The nonmetallic colored pigments are ordinarily
used in amounts from about 1% up to about 45% by weight.
However, the amount of pigment utilized in a specific
solid marking composition is determined by the desired
color of thê solid marking composition, the coloring
lS capacity Oe the pigment, and the desired application
characteristics.
The third component o~ the solid marking
composition of the invention is the matrix in which the
pigments are dispersed. The matrix material is the
substance which holds the solid marking composition
together. Most solid matrix materials known Eor use in
marking compositions are suitable for use in the present
inventlon. So~e examples include a conventional para~fin
wax and qtearic acid matrix, a plastic-based crayon
~5 matrix, and a polyethylene glycol resin matrix.
As is well known, a conventional crayon matrix
includes a fatty acid component and a wax component.
Fatty acid~ which may be utilized a3 matrix
material~ include ~uch materials as stearic acid and beef
tallow~ Stearic acid is a solid member of the normal
saturated fatty acid series present in most animal and
vegetable eat~. It i~ a white crystalline solid generally
~3~
represented by the formula C17H35-CO2H. When stearic acid
is mixed with waxes as a matrix material, it produces a
structurally stable matrix. The stearic acid is generally
softer than the waxes and is commercially available from a
wide range of suppliers.
Beef tallow is the solid fat o~ oxen and is a
mixture of tristearin, tripalmitin and triolein (tri-oleyl
derivative of glycerol or any liquid oil obtained ~rom
solid fats by pressure, to crude oleic acid ~ to
potassium, sodium, or ammonium salt of sulphonate of oleic
acid). Beef tallow is also generally softer than the
waxes and also contributes mold release properties.
Paraffin ~axes are not true waxes but are
mixtures o high melting point hydrocarbons. These waxes
lS are white, translucent, waxy solids having 26 to 30 carbon
atoms and have a wide range o~ melting points. The best
results, in terms of strength, structural integrity, and
laydown properties, are achieved by utilizing a blend of
low, medium, and high-temperature melting paraffin waxes.
Microcrystalline waxes are derived from the
heavy residual lubricating oil ~raction o~ crude after
removal of paraffin wax. ~hese waxes closely resemble
natural waxes in that they h~-e a high melting point, high
viscosity, and high adhesion and cohesion. ~he waxes are
commercially available from a number of manufacturers.
When the solid mar~ing composition u~ed in the
form of a conventional crayon to be shaped by a gravity
molding process, a wide range of content of matrix
material ls suitable. However, a range of matrix
materlal~ o from about 40~ up to about 60~ is mo~t
preferred when the composition i~ to be used in the ~orm
o~ a crayon. This range leads to the be~t per~ormance by
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the resulting solid marking composition, including laydown
and general marking characteristicst as well as structural
integrity of the formed solid marking composition. When
the matrix content o the composition is below about 40~
or above about 60~ weightt the ~ormed sticks tend to lose
strength, and their application characteristics become
less desirable.
When the composition Oe the invention is in the
form of a conventional crayon, a mixture of matrix
materials is most useful. The most preferred combination
of matrix materials when forming the compositlon into a
conventional crayon comprises from about 50% to about 75
by weight fatty acid and from about 25% to about 50%
paraffin wax. While combinations of wax and fatty acid
outside of these ranges are workable, they tend to produce
solid marking compositions which lay down rather thln
films of colorant which have a weaker apparent color.
When the composition of the invention is in the
form of a plastic crayon, the matrix material is
preferably comprised of polyethylene resin and a
plasticizec which is compatible with the resin. In
general, it has been found that the inclusion in the
compo3ition of a plastic crayon Oe erom about 15~ up to
about 50% by weight of a polyethylene resin produces an
acceptable marking composition. The compatible
plasticizer, the function of which is to provide the
composition with good application characteristics, is
typically effective when present in the range ~rom about
20~ up to about 55~ by weightO The be~t results are
achieved when excluslvely high density polyethylene re~ins
(density of at least about 0.95) are employed, since the
best balance o~ prope~ties may be achieved while avoiding
bloom.
When the invention is in the form of a washable
crayon, the matrix material is comprised of polyethylene
glycol resin. Such a washable crayon composition may
also optionally include one or more of a plasticizer, a
surfactant, a viscosity modifier, a filler, an antifoam
agent, or a mold release agent. For the purpose of
producing a marking composition useful in the form oE such
a washable crayon, the polyethylene glycol resin should
usually be present in an amount of from about 7~ up to
about 85~ by weight. In addition, the be~t properties are
attained when polyethylene glycol resins having a
molecular weight below about 7,000 are avoided, since the
lower molecular weight materials are undesirably
hygroscopic.
Where the solid marking composition is to be
used in the orm of a colored marking pencil lead, the
wood or plastic sheathing provides structural support, and
the structural integrity of the composition is less
impoctant and the concentrations of the matrix materials
may be varied accordingly.
An inert filler or extender may also be
beneficially added to the composition of the invention to
provide added strength and structural integrity. Typical
fillers or extenders include talc, felspar, T-clay, mica,
calcium carbonate, and glass and plastic microspheres. A
filler or extender is normally used in an amount of from
about 1~ up to about 40~ by weight. These material~ are
utili~ed a~ inexpensive eillers once sufficient pigment
has been added to the composition to achieve the desired
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color. The amount of filler or extender utilized depends
upon the type of color desired and the type of pigment
utilized.
Mica does not contribute substantially to the
laydown or per~ormance when used in combination with a
leafing aluminum metallic pigment and merely acts as a
filler. When used in conjunction with other metallic
pigments however, the mica tends to imp~ove the laydown of
the mark o~ the composition. The remaining fillers and
extenders have little to no eefect upon the marking
characteristic~ of the solid marking composition.
- EXAMPLES 1-8
The eollowing solid marking compositions are
formulated as examples of the present invention.
Examples 1-8 are representative of the solid marking
composition in the form of a conventional crayon.
The crayons were produced by the following
process. First, the wax and stearic acid were melt
blended at a temperature in the range of about 210~F to
about 250F. The non-metallic colored pigmenti were then
ground with talc to produce a dry color blend. To the wax
and stearic acid melt were added the dry color blend,
additional talc, T-clay, or mica, and the metallic
pigmentq. The molten blend was then agitated or mixed to
provide adequate dispersion o~ the dry components, poured
into molds, cooled, and ejected.
Example 1 Example 2
31ack Crayon Blue Crayon
Co~ponent lbs wt ~ lbs wt ~
stearic acid 60 41.1 60 41.9
S paraffin wax 60 41.1 60 41.9
talc 14 9.6 14 9.8
dry color pigments
leafing aluminum 8 5.5 7 4.9
lamp black 4 2.8
phthalo blue 2 1.4
Example 3 Fxample 4
Green Crayon Red Crayon
Component lbs wt ~ lbs wt ~.
stearic acid 60 40.0 60 40.0
15 paraffin wax 60 40.0 60 40.0
talc 16 10.7 16 10.7
dry color pigments
leafing aluminum 8 5.3 7 4.6
sodium rubine 7 4.6
phthalo green 6 4.0
Example 5
Blue-Green Example 6
Crayon Purple Crayon
Component lbs wt ~ lbs wt
25 stearic acid 60 41.1 60 42.0
paraffin wa~ 60 41.1 60 42.0
talc (300 mesh~ 10 6.8 10 6.9
dry color pigment~
leafing aluminum 8 6.8 6 4.2
blue-green 8 6.8
royal purple 7 4.9
Example 8
Example 7 Strawberry
Violet Crayon Crayon
Com~onent lbs wt ~ lbs wt ~
stearic acid 60 39.5 60 40.9
paraffin wax 60 39.5 60 40.9
talc (300 mesh) 10 6.6 15 10.2
dry color pigments
leaeing aluminum 8 5.3 7 4.8
violet 2 1.3
violet-red 12 7.9 2 1.4
wild strawberry 2.5 1.7
The compositions of Examples 1 8 had acceptable
working properties when formed into crayon sticks by
conventional gravity molding teohniques. In addition,
the crayon sticks had a pleasing pearlescent appearance, a
smooth, lipstick-like rub out, and a mark of enhanced
opacity compared to a standard crayon.
EXAMPLES 9-12
To formulate the so1id marking composition of
the invention in the eorm o~ a plas~ic crayon, a matrix
material of polyethylene resin and a compatible
plasticizer i used. Examples 9-12 are representative of
the solid marking composition utilized as a plastic
25 crayon.
Example 9 Example lO
Red Crayon Blue Crayon
Component lbs wt ~ lbs wt
stearic acid 17 32.1 17 30.9
paraffin wax 18 33.9 18 32.7
high density poly- 12 22.6 12 21.8
ethylene
dry color pigments
leafing aluminum 3 5.7 7 12.7
naphthol red 3 5.7
phthalo blue l 1.8
Example 11 Example 12
Black Crayon 31ue Crayon
Component lbs wt ~ lbs wt %
15 SteariG acid 13 25.5 13 25.5
parafin wax 19 37.2 l9 37.2
high density polyethylene 14 27.4 14 27.4
dry color pigments
leafing aluminum 3 5.9 2.5 4.9
sodium rubine
phthalo green 2 3.9
royal purple 2.5 4.9
The compositions of Examples 9-12, when formed
into crayon sticks by conventional injection molding
technique~, have a good balance of physical and
application properties, with no bloom. The crayon sticks
have a pleasing, pearlescent appearance, a smooth rub out,
and a mark of enhanced opacity.
`
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EXA~PLES 13-15
To ~ormulat~ the solid marking composition of
the invention in the form o~ a washable crayon, a ~atri~
material of polyethylene glycol resin i5 used. Examples
13-15 are representative of the solid marking composition
utilized as a washable crayon.
Example 13 Example 14
Red Crayon Blue Crayon
Component lbs wt ~ }bs ~_~
10 polyethylene glycol 15 10.3 15 10.3
resin
~m.w.=15,000-20,00o)
stearyl alcohol 39 26.7 39 26.7
oleyl alcohol 9 6.2 9 6.X
15 polyethylene glycol 24 16.4 24 16.4
monostearate
polyethylene glycol 35 24.0 35 24.0
distearate
dry color pigment~
leafing aluminum 3 2.0 7 4.8
naphthol red 3 2.0
phthalo blue 1 0.7
talc (300 mesh) 18 12.3 16 lO.9
h '~ ,3 ~
--17--
Example 15
Red Crayon
Component lbs wt ~
polyethylene glycol 15 10.3
S resin
~m.w.=15,000-20,00a~
stearyl alcohol 39 26. 7
oleyl alcohol 9 6.2
polyethylene glycol 24 16.4
monostearate
polyethylene glycol 35 24.0
distearate
dry color pigments
leafing aluminum 3 2.4
sodium rubine
phthalo green 2 1.6
royal purple
The compositions of Examples 13-15, when formed
into crayon sticks by conventional gravity molding
2V techniques, have good strength and working properties, and
their marks are readily washable from textiles and other
surfaces. The crayon sticks have a pleasing pearlescent
appearance, a smooth rub out, and a highly opaque mark.
From the foregoing description and examples, it
is apparent that the objects o~ the present invention have
been achieved. The solid marking compositions of the
invention produce marks which have a metallic sheen. The
marks lay down with a lipstick-like rub out alld the
b ~ C~
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opacity is unexpectedly increased. When the composition
is used in the form of a crayon, the crayon stick has an
unexpected metallic sheen or pearlescent appearance.
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 o~ the present invention
What is claimed is:
