Blendable writing instrument

Writing instruments are provided comprising a) a friction transferable binder comprising a colorant, and b) frangible microcapsules containing a liquid solvent. The writing instrument contains sufficient microcapsules to provide a Coloration Uniformity Percentage (defined herein) of at least about 25%.

FIELD OF THE INVENTION 
The present invention relates to writing instruments. More specifically, 
this invention relates to writing instruments such as crayons that are 
blendable upon rubbing the mark made by the writing instrument. 
BACKGROUND 
Wax crayons have long been used by children (and others) for drawing and 
generally as writing instruments. Over the years, many different types of 
pigments have been incorporated into a wax base to generate a complete 
array of available colors. Such wax crayons have had limited application 
for serious artistic expressions, because on the one hand, the line 
created by a crayon is not very precise, and on the other hand, the 
pigmented wax does not readily lend itself to blending of the colors. In 
order to achieve blendability, artists have been forced to switch to a 
different medium such as pastels, paints, and the like. 
U.S. Pat. No. 3,769,045 discloses a process for producing a liquid-write 
crayon. This crayon is designed to have a low wax content so that the 
crayon approaches the desirable fluid marking properties of felt-tip 
markers. To achieve this goal, the crayon contains 20 to 40 weight percent 
wax and 60 to 80 weight percent encapsulated marking liquid. The marking 
liquid contained within the microcapsules is disclosed to be any liquid 
dye or ink, but if desired may be colorless, but colorable. An example of 
a colorless but colorable marking liquid is the class of acidic 
mark-forming materials commonly used in the carbonless paper industry. The 
ink or dye contained in the microcapsules may optionally be dissolved in a 
liquid oil of a viscosity to act as an ink vehicle. 
U.S. Pat. No. 5,039,243 to O'Brien discloses crayons that are provided with 
microcapsules containing fragrant materials within the shell of the 
microcapsules. Applying the crayon to a surface as in coloring a picture 
ruptures some of the microcapsules and releases a fragrance. The 
microcapsules may constitute between 1 and 60 percent of the weight of the 
crayons. 
SUMMARY OF THE INVENTION 
Writing instruments are provided comprising a) a friction transferable 
binder comprising a colorant, and b) frangible microcapsules containing a 
liquid solvent. The friction transferable binder is softenable by the 
liquid solvent under conditions of use. The microcapsules comprise between 
2 and 55 percent by weight of the total weight of the binder, colorant and 
microcapsules, and the writing instrument contains sufficient 
microcapsules to provide a Coloration Uniformity Percentage of at least 
about 25%. 
DETAILED DESCRIPTION 
The uniformity of coloration by a writing instrument is evaluated by 
measuring the color obtained by uniformly and systematically covering a 
paper substrate with marks from a writing instrument, and comparing a 
sample so prepared with a like sample where the paper substrate is 
maintained at a temperature above the melting temperature of the writing 
instrument. The melted sample approximates a theoretical maximum 
blendability of the writing instrument, and therefore will give the best 
coloration that that writing instrument can deliver under the same marking 
pressure and frequency. The ratio of the color obtained through routine 
marking as compared to the color obtained under melt conditions 
establishes a Coloration Uniformity Percentage as defined through a 
specific protocol set forth below. It has surprisingly been found that the 
incorporation of microcapsules having liquid solvent that softens or 
solubilizes the friction transferable binder under conditions of use in an 
amount sufficient to provide a Coloration Uniformity Percentage of at 
least about 25% provides exceptional benefit in color uniformity, 
blendability and enhanced aesthetics of writing. More preferably, the 
writing instrument contains sufficient microcapsules to provide a 
Coloration Uniformity Percentage of at least about 35%, and more 
preferably at least about 45%. 
By incorporating a microencapsulated liquid solvent in a friction 
transferable binder, the crayon may be rendered blendable. When a mark is 
placed on paper by the crayon, the frangible microcapsules rupture, 
thereby releasing the liquid solvent. While not being bound by theory, it 
is believed that this solvent solvates or softens the friction 
transferable binder and allows partial or total flow of the 
colorant-containing binder on the paper. Marks that are made with this 
writing instrument may be blended or smeared using the finger or a stylus. 
Preferably, the volatility of the solvent may be selected to provide a 
pre-determined time frame for blendability of the marks made by the 
writing instrument of the present invention. Thus, when a highly volatile 
solvent is incorporated in the microcapsules, the writing instrument of 
the present invention has a relatively short time duration for 
blendability. When a longer time duration for blendability is desired, a 
solvent is selected having a comparitively lower volatility whereby the 
solvent remains available on the substrate for time sufficient before 
evaporation to allow blendability during the desired time frame. In the 
case of solvents selected for short term blendablity of the binder 
material, preferably no more than 20% by weight of the solvent contained 
in the ruptured microcapsules is present on the marked substrate after 10 
minutes. For solvents selected to achieve longer term blendability of the 
binder material, preferably at least 20% by weight of the solvent 
contained in the ruptured microcapsules is present on the marked substrate 
after two weeks. 
Because the solvent is encapsulated, the writing instrument may be provided 
in a comparatively hard or firm state, and does not suffer from the 
mushiness or weakness of a like crayon having the same amount of solvent 
incorporated in the binder matrix in an unencapsulated state. 
Additionally, the writing implement of the present invention may be 
provided as a shelf-stable article. The solvent does not prematurely 
escape the binder matrix through leaching or volatilization because it is 
microencapsulated. Further, the properties of both the binder and the 
solvent may be now selected such that a blendable crayon is provided that 
does not melt during storage, even in temperatures as high as 120 degrees 
F., or more preferably 150 degrees F. Writing instruments having 
encapsulated solvent provide superior blending as compared to like 
instruments containing the same amount of solvent that is merely dispersed 
thoughout the crayon. 
Writing instruments of the present invention further provide wax-based 
instruments having extremely desirable aesthetics of writing. Thus, a 
crayon can now be provided having a low drag coefficient during the 
creation of a mark on the paper. While not being bound by theory, it is 
believed that the solvent that is released during rupture of the 
microcapsules as the mark is being made acts to modify the surface energy 
and flow characteristices of the friction transferable binder, thereby 
reducing drag as compared to a like binder formulation not having solvent 
incorporated therein. 
The friction transferable binder is selected from thermoplastic materials 
that will abrade upon rubbing with pressure onto a paper substrate, 
thereby leaving material on the substrate to produce an observable mark. 
Preferably, the friction transferable binder is selected from synthetic 
and natural waxes and blends thereof. Specific examples of appropriate 
waxes include carnauba, montan, and beeswax, long-chain paraffins, high 
molecular weight acids, high molecular weight alcohols, polyesters, 
polyethers, saturated high molecular weight hydrocarbons, hydrogenated 
fatty acids, branched chain hydrocarbon waxes and the like. Preferred 
friction transferable binder materials include thermoplastic materials 
that are solid at 100 degrees F. More preferably, the friction 
transferable binder is solid at 120 degrees F., and more preferably at 150 
degrees F. Particularly preferred binders are C.sub.18-32 esters of 
benzoic acid, paraffin, stearic acid and blends thereof. Especially 
preferred binders include stearyl benzoate and behenyl benzoate. 
Optionally, the binder may be selected having shear yield strength such 
that it delivers a quantity of unbroken microcapsules to the substrate 
upon application of a mark to the paper. These capsules may later be 
broken by application of pressure to the marked area using the finger, a 
stylus, or other appropriate means, to release the solvent and impart 
blendablility to the mark. 
The friction transferable binder material may optionally comprise additives 
such as solvents, thickeners, coating or extrusion aids, fillers, and the 
like. 
The friction transferable binder contains a colorant, which may be selected 
from pigments, dyes, lakes, color-formers and the like or combinations of 
these colorants. Particularly preferred colorants are non-toxic colorants 
suitable for incorporation into writing instruments to be used by 
children. An optional colorant to be incorporated into writing instruments 
of the present invention include color-imparting materials that do not 
image until reacted with a developer, such as in the leuco dye chemistry 
or other such chemistry utilized in the carbonless paper industry. 
The solvent is selected from materials that soften or solubilize the 
friction transferable binder within the time scale of intended use. The 
solvent preferably will soften the binder enough to enable blending or 
smearing of the binder immediately upon marking of the substrate with the 
writing instrument. Alternatively, the solvent may be selected to 
gradually soften the binder so that the blending or smearing effect is 
delayed for a predetermined time. Preferably, the solvent is selected from 
the group consisting of hydrocarbons, petroleum distillates, natural or 
synthetic oils, alcohols, esters, ethers, fatty esters, mineral spirits, 
and fatty alcohol esters of benzoic acid. Particularly preferred solvents 
are blends of C.sub.16-18 esters of benzoic acid, butyl stearate, methyl 
laurate, isopropyl myristate and oleyl alcohol. Optionally, the solvent 
may also comprise a surfactant. Preferably, the surfactant may comprise 
between about 0.01 to 0.5% of the liquid fill by weight. While not being 
bound by theory, the surfactant appears to assist in distributing the 
solvent across the surface of the binder, thereby facilitating the 
softening action of the solvent. 
Optionally, the microcapsules may additionally contain a coloring agent, 
such as dye, pigment, lake, color former and the like. 
In accordance with the present invention, microcapsules containing solvent 
may be prepared by in situ processes such as aminoplast polymerization. 
The techniques disclosed, generally referred to as an in situ 
polymerization reaction, yield for example, an aminoplast resin capsule 
wall material. In the process, a hydrophobic oil phase is dispersed in an 
aqueous phase containing the aminoplast resin precursors by applying high 
shear agitation. Addition of an acid catalyst initiates the 
polycondensation of the aminoplast precursors, resulting in the deposition 
of the aminoplast resin about the dispersed droplets of the oil phase, 
producing the microcapsules. 
The hydrophobic inner phase for the capsule may be any in situ aminoplast 
encapsulatable composition as discussed in U.S. Pat. No. 3,516,941, 
provided that the inner phase meets the criteria for acting as a solvent 
to the binder. 
When the microcapsule is prepared by interfacial polycondensation, the 
capsule skin may be composed of any condensation polymer or addition 
polymer, e.g., polyamide, polyurethane, polysulfonamide, polyurea, 
polyester, polycarbonate, etc. Polyamides prepared by interfacial 
polycondensation of an amine with an acid chloride or polymers formed by 
reaction of isocyanate prepolymer with polyamines are preferred. 
Microcapsules formed by coacervation processes are also useful in forming 
microcapsule shells according to the present invention. Coacervation is 
the well known process of forming higher molecular weight gelatin polymers 
as taught in U.S. Pat. Nos. 2,800,458 and 2,800,457. 
The capsules used in these constructions and generally in the practice of 
the present invention have average diameters between about 4 and 200 
microns. Preferably the average diameters are between about 40 and 150 
microns, and more preferably, between about 80-120 microns. The capsules 
preferably constitute from 2 to 55% by weight of the composition, and most 
preferably between 5 and 40% by weight of the composition. Larger capsules 
deliver much more volume of solvent per capsule, and therefore are 
preferred for the present invention. 
Coloration Uniformity Percentage 
As noted above, Coloration Uniformity Percentage is the ratio of measured 
color of a sample mark made by a writing instrument as compared to a mark 
made by the same writing instrument made on paper heated to a temperature 
above the melting temperature of the binder. This evaluation is made 
experimentally as follows: 
Samples are prepared by applying marks using a writing instrument having an 
8 mm diameter sharpened to about a 2.5 mm point with pressure of about 800 
g to a standard paper substrate. A preferred standard paper substrate is 
20 pound white bond paper. Forty evenly spaced substantially parallel 
traverses of the writing instrument are made to create a 4 cm by 4 cm 
sample testing area. This number of marks in this space necessitates some 
overlap of marks in preparation of the sample area. Such overlap may 
provide an opportunity for blending of the marks made by the writing 
instrument through friction of the instrument over the previously made 
mark. The degree of color uniformity is evaluated by measuring the color 
imparted to the above marked samples on a Hunter colorimeter or other 
similar color measuring device. 
Paper with a sample mark prepared as described above is placed over the 
sample aperture of the color measuring instrument such that the sample 
completely overlaps the aperture. A white tile is then placed in position 
to back the sample and CIELAB data is obtained from the colorimeter, using 
an average of three readings per sample. The color difference 
(.DELTA.E*ab) of each test sample was calculated according to the 
following equation: 
EQU .DELTA.E*ab=.sqroot. [(.DELTA.L*).sup.2 +(.DELTA.a*).sup.2 
+(.DELTA.b*).sup.2 ] 
where delta E*ab represents the difference in color between the control 
paper and the marked paper, and delta L*, delta a*, and delta b* terms are 
the color coordinates. The delta L, term represents the lightness of the 
color, the delta a* term represents the redness or greenness of the color, 
and the delta b* term represents the yellowness or blueness of the color. 
For a further discussion see "Principles of Color Technology", second Ed., 
F. W. Billmeyer and M. Saltzmann, pages 59 through 60 and 102 through 104. 
The Color Uniformity Percentage is determined by comparing the .DELTA.E*ab 
of writing instrument marks made by the experimental prodecure 
(.DELTA.E*ab.sub.mark) with the .DELTA.E*ab of a theoretical maximum color 
that may be imparted by a writing instrument of same binder constitution 
where the sample was prepared by writing with the same pressure on a 
heated piece of paper to achieve melting of the binder onto the paper 
(.DELTA.E*ab.sub.melt). The paper is heated by carrying out the marking 
protocol on paper located on a hot plate set at a temperature above the 
melting temperature of the binder, so that the binder melts during the 
marking process. 
Thus, 
EQU Color Uniformity Percentage=.DELTA.E*ab.sub.mark /.DELTA.E*ab.sub.melt 
.times.100. 
The writing instruments of the present invention are useful for writing on 
hard substrates, primarily paper and the like. Alternatively, the writing 
instruments may be used to write on alternative appropriate substrates, 
such as plastic, wood, painted surfaces, cardboard, pressboards, canvas, 
fabrics and the like. Preferably, the surface of the substrate is slightly 
textured, on the order of the texture of bond paper. Excessive texture, 
such as the surface of concrete, is undesirable.

The following examples are provided for purposes of illustrating the 
invention, and are not to be considered to be limiting the scope thereof. 
Unless otherwise indicated, all ratios and percentages are by weight. 
EXAMPLE 1 
1 gram of phthalo blue pigment, having about 2 micron mean diameter, was 
dispersed in 12 grams of Finsolv.RTM. 116 wax (a fatty benzoate ester 
commercially available from FINETEX, Inc., Elmwood Park, N.J.) at 
110.degree. C., to which was then added 7 grams of 100 .mu.m capsules 
comprising polymethoxyurea (PMU) shell material and containing 80 weight % 
Finsolv.RTM. TN solvent (a mixture of the benzoate esters of linear 
C.sub.12-15 primary alcohols commercially available from FINETEX, Inc., 
Elmwood Park, N.J.) fill. The resulting composition was transferred to 3 
c.c. disposable syringes, and allowed to cool at room temperature or 
quenched in ice cold water 
EXAMPLE 2 
1 gram of Hansa yellow pigment, having about 2 micron mean diameter, was 
dispersed in 12 grams of Finsolve.RTM. 116 wax at 110.degree. C., to which 
was then added 7 grams of 100 .mu.m capsules comprising polymethoxyurea 
(PMU) shell material and containing 80 weight % Finsolve.RTM. TN solvent 
fill. The resulting composition was transferred to 3 c.c. disposable 
syringes, and allowed to cool at room temperature or quenched in ice cold 
water. 
EXAMPLE 3 
3 grams of Titanium white pigment, having about 2 micron mean diameter, 
were dispersed in 12 grams of Finsolve.RTM. 116 wax at 110.degree. C., to 
which was then added 7 grams of 100 .mu.m capsules comprising 
polymethoxyurea (PMU) shell material and containing 80 weight % 
Finsolve.RTM. TN solvent fill. The resulting composition was transferred 
to 3 c.c. disposable syringes, and allowed to cool at room temperature or 
quenched in ice cold water. 
EXAMPLE 4 
1 gram of Red c19011 pigment, having about 2 micron mean diameter was 
dispersed in 12 grams of Finsolve.RTM. 116 wax at 110.degree. C., to which 
was then added 7 grams of 100 .mu.m capsules comprising polymethoxyurea 
(PMU) shell material and containing 80 weight % Finsolve.RTM. TN solvent 
fill. The resulting composition was transferred to 3 c.c. disposable 
syringes, and allowed to cool at room temperature or quenched in ice cold 
water. 
EXAMPLE 5 
4 grams of Red c19011 pigment, having about 2 micron mean diameter were 
dispersed in 20 grams of Finsolve.RTM. 116 wax at 110.degree. C., to which 
was then added 4 grams of 100 .mu.m capsules comprising polymethoxyurea 
(PMU) shell material containing 80 weight % Finsolve.RTM. TN solvent fill. 
The resulting composition was transferred to 3 c.c. disposable syringes, 
and allowed to cool at room temperature or quenched in ice cold water. 
EXAMPLE 6 
4 grams of Red c19011 pigment, having about 2 micron mean diameter were 
dispersed in 20 grams of Finsolve.RTM. 116 wax at 110.degree. C., to which 
was then added 4 grams of 32 .mu.m capsules comprising polymethoxyurea 
(PMU) shell material containing 80 weight % Finsolve.RTM. TN solvent fill. 
The resulting composition was transferred to 3 c.c. disposable syringes, 
and allowed to cool at room temperature or quenched in ice cold water. 
EXAMPLE 7 
4 grams of Red c19011 pigment, having about 2 micron mean diameter were 
dispersed in 20 grams of Finsolve.RTM. 116 wax at 110.degree. C., to which 
was then added 4 grams of 180 .mu.m capsules comprising polymethoxyurea 
(PMU) shell material and containing 80 weight % Finsolve.RTM. TN solvent 
fill. The resulting composition was transferred to 3 c.c. disposable 
syringes, and allowed to cool at room temperature or quenched in ice cold 
water. 
EXAMPLE 8 
2.4 grams of Red c19011 pigment, having about 2 micron mean diameter were 
dispersed in 12 grams of Finsolve.RTM. 116 wax at 110.degree. C., to which 
was then added 7 grams of 100 .mu.m capsules comprising polymethoxyurea 
(PMU) shell material and containing 80 weight % Finsolve.RTM. TN solvent 
fill. The resulting composition was transferred to 3 c.c. disposable 
syringes, and allowed to cool at room temperature. 
EXAMPLE 9 
1 grams of Red c19011 pigment, having about 2 micron mean diameter was 
dispersed in 9.6 grams of Finsolve.RTM. 116 wax and 2.4 grams of 
Finsolv.RTM. 137 at 110.degree. C., to which was then added 6 grams of 32 
.mu.m capsules comprising polymethoxyurea (PMU) shell material containing 
80 weight % Finsolve.RTM. TN solvent fill. The resulting composition was 
transferred to 3 c.c. disposable syringes, and allowed to cool at room 
temperature or quenched in ice cold water. 
EXAMPLE 10 
1 grams of Phthalo blue pigment, having about 2 micron was dispersed in 9.6 
grams of Finsolve.RTM. 116 wax and 2.4 grams of Finsolv.RTM. 137 at 
110.degree. C., to which was then added 6 grams of 32 .mu.m capsules 
comprising polymethoxyurea (PMU) shell material containing 80 weight % 
Finsolve.RTM. TN solvent fill. The resulting composition was transferred 
to 3 c.c. disposable syringes, and allowed to cool at room temperature or 
quenched in ice cold water. 
EXAMPLE 11 
1 grams of Hansa yellow pigment, having about 2 micron mean diameter was 
dispersed in 9.6 grams of Finsolve.RTM. 116 wax and 2.4 grams of 
Finsolv.RTM. 137 at 110.degree. C., to which was then added 6 grams of 32 
.mu.m capsules comprising polymethoxyurea (PMU) shell material containing 
80 weight % Finsolve.RTM. TN fill. The resulting composition was 
transferred to 3 c.c. disposable syringes, and allowed to cool at room 
temperature or quenched in ice cold water. 
EXAMPLE 12 
3 grams of Titanium white pigment, having about 2 micron mean diameter were 
dispersed in 9.6 grams of Finsolv.RTM. 116 wax and 2.4 grams of 
Finsolv.RTM. 137 at 110.degree. C., to which was then added 6 grams of 32 
.mu.m capsules comprising polymethoxyurea (PMU) shell material containing 
80 weight % Finsolv.RTM. TN fill. The resulting composition was 
transferred to 3 c.c. disposable syringes, and allowed to cool at room 
temperature or quenched in ice cold water. 
EXAMPLE 13 
3 grams of Red c19011 pigment, having about 2 micron mean diameter were 
dispersed in 30 grams of Finsolv.RTM. 116 wax at 110.degree. C., then 
added 15 grams of 100 .mu.m capsules comprising polymethoxyurea (PMU) 
shell material containing 80 weight % Finsolv.RTM. TN fill. The resulting 
composition was transferred to 3 c.c. disposable syringes, and allowed to 
cool at room temperature or quenched in ice cold water. 
EXAMPLE 14 
3 grams of Phthalo blue pigment, having about 2 micron mean diameter were 
dispersed in 30 grams of Finsolv.RTM. 116 wax at 110.degree. C., to which 
was then added 15 grams of 100 .mu.m capsules comprising polymethoxyurea 
(PMU) shell material containing 80 weight % Finsolv.RTM. TN fill. The 
resulting composition was transferred to 3 c.c. disposable syringes, and 
allowed to cool at room temperature or quenched in ice cold water. 
EXAMPLE 15 
3 grams of Hansa yellow pigment, having about 2 micron mean diameter were 
dispersed in 30 grams of Finsolv.RTM. 116 wax at 110.degree. C., to which 
was then added 15 grams of 100 .mu.m capsules comprising polymethoxyurea 
(PMU) shell material containing 80 weight % Finsolv.RTM. TN fill. The 
resulting composition was transferred to 3 c.c. disposable syringes, and 
allowed to cool at room temperature or quenched in ice cold water. 
EXAMPLE 16 
7 grams of Titanium white pigment, having about 2 micron mean diameter were 
dispersed in 30 grams of Finsolv.RTM. 116 wax at 110.degree. C., to which 
was then added 15 grams of 100 .mu.m capsules comprising 
polymethoxyurea(PMU) shell material containing 80 weight % butyl acetate 
fill. The resulting composition was transferred to 3 c.c. disposable 
syringes, and allowed to cool at room temperature or quenched in ice cold 
water. 
EXAMPLE 17 
1 gram of Red c 19011 pigment, average having about 2 micron mean diameter 
was dispersed in 12 grams of Finsolv.RTM. 116 wax at 110.degree. C., to 
which was then added 6 grams of 100 .mu.m capsules comprising 
polymethoxyurea (PMU) shell material containing 80 weight % Finsolv.RTM. 
TN fill. The resulting composition was transferred to 3 c.c. disposable 
syringes, and allowed to cool at room temperature. 
EXAMPLE 18 
1 gram of Red c 19011 pigment, having about 2 micron mean diameter was 
dispersed in 12 grams of Finsolv.RTM. 116 wax at 110.degree. C., to which 
was then added 6 grams of 100 .mu.m capsules comprising polymethoxyurea 
(PMU) shell material containing 80 weight % butyl acetate fill. The 
resulting composition was transferred to 3 c.c. disposable syringes, and 
allowed to cool at room temperature or quenched in ice cold water. 
EXAMPLE 19 
1 gram of Phthalo blue pigment, having about 2 micron mean diameter was 
dispersed in 12 grams of Finsolv.RTM. 116 wax at 110.degree. C., to which 
was then added 6 grams of 100 .mu.m capsules comprising polymethoxyurea 
(PMU) shell material containing 80 weight % texanol isobutylate (from 
Aldrich chem. Co.) fill. The resulting composition was transferred to 3 
c.c. disposable syringes, and allowed to cool at room temperature or 
quenched in ice cold water. 
EXAMPLE 20 
1 gram of Pergascript black (from Ciba Geigy) and 2 grams of titanium 
white, average having about 2 micron mean diameter were dispersed in 12 
grams of Finsolv.RTM. 116 wax at 110.degree. C., to which was then added 5 
grams of 100 .mu.m capsules comprising polymethoxyurea (PMU) shell 
material containing 80 weight % Finsolv.RTM. TN fill. The resulting 
composition was transferred to 3 c.c. disposable syringes, and allowed to 
cool at room temperature or quenched in ice cold water. 
EXAMPLE 21 
1 gram of Pergascript green and 2 grams of titanium white, average having 
about 2 micron mean diameter were dispersed in 12 grams of Finsolv.RTM. 
116 wax at 110.degree. C., to which was then added 5 grams of 100 .mu.m 
capsules comprising polymethoxyurea (PMU) shell material containing 80 
weight % Finsolv.RTM. TN fill. The resulting composition was transferred 
to 3 c.c. disposable syringes, and allowed to cool at room temperature or 
quenched in ice cold water. 
EXAMPLE 22 
1 gram of Pergascript yellow and 2 grams of titanium white, having about 2 
micron mean diameter were dispersed in 12 grams of titanium white, 2 
microns, were dispersed in 12 grams of Finsolv.RTM. 116 wax at 110.degree. 
C., to which was then added 5 grams of 100 .mu.m capsules comprising 
polymethoxyurea (PMU) shell material containing 80 weight % Finsolv.RTM. 
TN fill. The resulting solution was transferred to 3 c.c. disposable 
syringes, and allowed to cool at room temperature or quenched in ice cold 
water. 
EXAMPLE 23 
1 gram of Pergascript red and 2 grams of titanium white, having about 2 
micron mean diameter were dispersed in 12 grams of Finsolv.RTM. 116 wax at 
110.degree. C., to which was then added 5 grams of 100 .mu.m capsules 
comprising polymethoxyurea (PMU) shell material containing 80 weight % 
Finsolv.RTM. TN fill. The resulting composition was transferred to 3 c.c. 
disposable syringes, and allowed to cool at room temperature or quenched 
in ice cold water. 
EXAMPLE 24 
1 gram of Pergascript orange and 2 grams of titanium white, having about 2 
micron mean diameter were dispersed in 12 grams of Finsolv.RTM. 116 wax at 
110.degree. C., to which was then added 5 grams of 100 .mu.m capsules 
comprising polymethoxyurea (PMU) shell material containing 80 weight % 
Finsolv.RTM. TN fill. The resulting composition was transferred to 3 c.c. 
disposable syringes, and allowed to cool at room temperature or quenched 
in ice cold water. 
EXAMPLE 25 
0.4 gram of Red c 19011 pigment, having about 2 micron mean diameter was 
dispersed in 8 grams of Crayon wax base at 110.degree. C., to which was 
then added 12 grams of 100 .mu.m capsules comprising polymethoxyurea (PMU) 
shell material containing 80 weight % Texanol isobutylate (from Aldrich 
Chem. Co.) fill. The resulting composition was transferred to 50 c.c. 
disposable container, and allowed to cool at room temperature. 
EXAMPLE 26 
To compare the effect of microencapsulated solvent on the coverage 
attainable by the blending action of slightly overlapping strokes, crayons 
were prepared as follows: a) crayons with no additive, b) crayons with 
2.5% free butyl stearate, c) crayons containing 2.5% 35 micron diameter 
microencapsulated butyl stearate, and d) crayons containing 2.5% 120 
micron diameter microencapsulated butyl stearate. The microcapsules 
contained about 76.6 weight % butyl stearate. The crayon with no additive 
was used to prepare scribble patches representative of the range of 
fractional coverage attainable by varying the pressure used and by 
scribbling a second time at right angles to the first set of marks 
(crosshatch). These scribble patches were prepared by hand to simulate the 
range of coloring pressures and overlap commonly found in ordinary use. In 
addition, scribble patches were prepared with normal and heavy pressures 
on a heated piece of paper to represent the maximum mark intensities which 
could be attained with complete thin and thick coverage respectively. 
Similar scribble patches were prepared mechanically (40 lines, 4 
cm.times.4 cm as described above) using the crayons containing either free 
or microencapsulated butyl stearate using normal pressure. The crayon 
containing free solvent was difficult to use because the solvent weakened 
the tip causing it to break off easily. Even though the crayons containing 
the microencapsulated solvent contained less total solvent than other 
crayons evaluated with solvent dispersed in the binder, they gave 
consistently better coverage. 
______________________________________ 
% Melted % Melted 
Description .DELTA.E Heavy Normal 
______________________________________ 
Normal Pressure 18.9 19.8 22.8 
Crosshatch Normal Pressure 
32.8 34.7 39.9 
Heavy Pressure 51.2 54.1 62.2 
Melted Normal Pressure 
82.28 87.0 100.0 
Melted Heavy Pressure 
94.59 100.0 115.0 
Normal (+2.5% butyl 
17.1 18.1 20.8 
stearate).sup.1 
Normal (+2.5% small 
24.6 26.0 30.0 
capsules).sup.2 
Normal (+2.5% large 
37.2 39.3 45.2 
capsules).sup.3 
______________________________________ 
.sup.1 Crayon with 2.5% free butyl stearate. Difficult to use due to tip 
breakage. 
.sup.2 Crayon contains 2.5% 35 micron dia. capsules (.about.1.92% butyl 
stearate). 
.sup.3 Crayon contains 2.5% 120 micron dia. capsules (.about.1.92% butyl 
stearate). 
This example demonstrates that even with very low amounts of solvent 
provided in the microcapsules, the difference in color measured (.DELTA.E) 
is dramatically improved as compared to like formulated crayons not having 
microcapsules.