CARBON BLACK PELLETS AND METHOD OF FORMING SAME
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to carbon black pellets and, more
particularly, to carbon black pellets having good dispersibility, good bulk handling
characteristics and good attrition resistance, and to a method of manufacturing
such pellets.
DESCRIPTION OF PRIOR ART
Carbon black finds wide industrial use. Carbon black is used as a
reinforcing agent in rubber products such as tires, tubes, conveyor belts, cables
and other mechanical rubber goods; as a black pigment in printing, lithographic,
letter press, carbon paper and typewriter ribbon inks, paints, coatings, lacquers,
plastics, fibers, ceramics, enamels, paper, record discs and photocopier toner; in
leather finishes; in the manufacture of dry-cell batteries, electrodes and carbon
brushes; in electrical conductors; in conductive and anti-static rubber and plastic
products; for electromagnetic interference shielding; video discs and tapes; for
UV stabilization of polyolefins; as a high temperature insulating material; etc.
As produced, carbon black particles have a fractal morphology. They are
composed of primary particles about 10 to 500 nm in diameter which irreversibly
fuse during the furnace/combustion process used and produce primary
aggregates having a diameter of from 50 to 20,000 nm. Carbon black cannot be
practically used in its produced form because of its light and dusty form making

its handling, shipment and end use not only difficult but environmentally
unacceptable. To improve these handling, shipping and use problems, the
produced, fluffy carbon black is densified. It is well known in the art that for a
given grade of carbon black, handling properties improve with increasing degree
of densification. However, dispersibility of the densified carbon black is
progressively degraded as the extent of densification is increased. Thus, there is
a trade off between improvements in bulk handling properties and degradation in
-dispersibility.
In general, currently the industry uses three basic methods to obtain
densification. These, in order of providing increased levels of densification are:
agitation or vacuum treatment of the fluffy produced product, dry pelletization
and wet pelletization. All of these methods are well documented in the art as
disclosed, for example, in U.S. Patents 2,850,403; 3,011,902; 4,569,834;
5,168,012; 5,589,531; and 5,654,357, all of which are incorporated herein by
reference for all purposes. The densification processes mentioned above, all
suffer from disadvantages, e.g., product that has poor properties in bulk
handling, the formation of pellets which are relatively weak and have poor
attrition resistance or relatively dense, hard and attrition resistant pellets which
possess good bulk handling properties but are difficult to disperse.
Thus there still remains a need for a densified carbon black which exhibits
good bulk handling properties, has good attrition resistance and is readily
dispersible.

SUMMARY OF THE INVENTION
In one aspect the present invention provides a carbon black pellet
comprising an inner core of de-aerated carbon black and an outer, surrounding
shell of an encapsulating material, the shell of encapsulating material having an
average thickness of from about 1% to about 10% of the average thickness of
the pellet.
In another aspect of the present invention, there is provided a method for
-producing encapsulated carbon black pellets wherein de-aerated carbon black is
contacted with a fluidized encapsulating material in a fluid-solids contactor for a
period of time sufficient to form a carbon black pellet as described above.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Virtually any carbon black can be used in the process of the present
invention. Thus, carbon blacks produced by various industrial processes
including acetylene black, channel black, furnace black, lamp black and thermal
black can be employed. Preferred carbon blacks used in forming the pellets of
the present invention, include carbon black in the l2N0(ASTM D1510) range of
20g/Kg to 1000g/Kg and OAN(ASTM D2414) range of 45ml/100g to 500ml/100g.
The carbon black pellets of the present invention are characterized by a
soft or fluffy carbon black inner core and an outer, surrounding shell of an
encapsulating material which forms a rigid to semi-rigid coating which resists
attrition and physical impact to thereby render the pellets more dust free. While
the pellets produced according to the present invention can vary in shape and
size, generally speaking for the most part the pellets are of a spherical or
spherical-like shape and have a diameter of from 125 to 2000 pm. However, as
noted, the pellets may not necessarily be spherical and the size range can vary
substantially over that noted above. The outer, encapsulating shell, whether it
be termed a crust, film, layer or the like, will generally have an average thickness
of from about 1% to about 10% of the average thickness of the carbon black
pellet. It will be understood that in cases where the pellets are asymmetric, e.g.,
not spherical or generally spherical, that this average thickness of the outer
surrounding layer will still hold true. In this regard, the volume of the inner core
of the pellet relative to the volume of the encapsulating layer will be such that if
the pellet, albeit irregular in shape were spherical in nature, the combined

volumes of the inner core and the encapsulating layer, viewed as a generally
spherical body would be such that the above relationship held true, i.e., the
average thickness of the encapsulating layer is from about 1% to about 10% of
the thickness, e.g., diameter, of the overall pellet.
From a compositional perspective, it is desired that the encapsulating
shell be as thin as possible consistent with the pellets having adequate bulk
handling properties. In general, the shell of the pellets of the present invention
-will contain a maximum amount of 10 wt. % of encapsulating material based on
the total weight of the carbon black present in the pellet. In cases where the
encapsulating material comprises a single encapsulating agent, the weight of the
encapsulating agent will generally be from about 1 to about 3 wt. % based on the
total carbon black present in the pellet while in cases where multiple
encapsulating agents are employed, the weight of the encapsulating material will
be from about 5 to about 7 wt. % based on the total carbon black present in the
pellet. While some of the encapsulating material will be present in the core of
the pellet, at least 30 wt. %, preferably more than 50 wt. %, and more preferably
90 wt. % or more of the total encapsulating material employed will be present in
the outer, surrounding shell of the pellet. Because of the unique construction of
the pellet of the present invention, i.e., a soft, fluffy inner core of carbon black
and an outer more rigid shell, crust or layer of encapsulating material, relatively
small amounts of encapsulating material(s), can be employed, since the
encapsulating material is concentrated in the outer surrounding shell of the
pellet.

The encapsulating material used in the process of the present invention,
as noted above, can comprise a single encapsulating agent or multiple
encapsulating agents. Encapsulating agents are well known to those skilled in
the art and include numerous materials. Thus, non-limiting examples of
encapsulating materials include carbohydrates, lignin oxides, cellulose by-
products, natural rubbers, synthetic rubbers, synthetic polymers, natural and
synthetic waxes, resins, rosins, and mixtures thereof. The encapsulating
-material whether it be one encapsulating agent or multiple encapsulating agents
will be in particulate form. In certain cases, this can be accomplished by melting
the encapsulating material and forming it into a mist, spray, aerosol or other
particulate form. In still other cases, the encapsulating material can be dissolved
in a suitable carrier which can then be formed into a mist, spray, aerosol or the
like. The term carrier as used herein is intended to mean any fluid, e.g., a liquid,
in which the encapsulating agent or agents can be dissolved, dispersed or
otherwise formed into a particulate form such that it can be introduced into a
fluid-solids contactor in the form of an aerosol, mist, spray or other particulate
form. Non-limiting examples of liquid carriers include mineral oils, animal oil,
plant oils, alcohols, and acids. In certain cases, the encapsulating material can
be in the form of an aerosol of finely divided solid particles, which at the
temperature of the encapsulating step will coalesce to form the shell. In this
case, the finely divided solid particles would simply be introduced into the
encapsulated step by being carried in a gaseous stream, e.g., air or an inert gas,
if desired. In any event, the encapsulating agent will be of a type which can form

a crust, coating, film, covering, etc., on the carbon black to form the
encapsulating shell.
While the shell has been described as "surrounding the core of the pellet,"
it is to be understood that there could be minor fissures or discontinuities in the
shell such that the inner core was exposed, albeit slight. However, any such
fissures or discontinuities in the encapsulating shell will be of such a dimension
that there is no substantial escape of the core material from the pellet.
In forming the carbon black pellets of the present invention, two main
steps are employed - de-aerating and encapsulating. As is well known,
produced carbon black is extremely fluffy with a low apparent density. The
fluffiness of the produced carbon black can be to some extent reduced and the
apparent density increased by de-aerating the produced carbon black per
methods well known to those skilled in the art. For example, carbon black de-
aeration can be accomplished by using equipment such as vacuum filtration
and/or compactors all of which are commercially available and commonly used
for the purpose of removing air from produced, fluffy carbon black.
The terms fluid, fluids and derivatives thereof, as used herein with respect
to the fluid/solids contactor means a physical form such as a spray, aerosol,
mist, dust or the like, wherein particulate matter, whether in solid or liquid form, is
suspended in a generally gaseous environment. The de-aerated carbon black is
introduced into a fluid-solids contactor. The fluid-solids contactor can comprise a
moving bed system such as a rotary drum, with or without pins, or a fluidized bed
system or for that matter any type of equipment wherein solid particles, e.g., the

de-aerated carbon black can be contacted with a fluid, as defined above, of the
encapsulating material such that the fluid ultimately forms a shell around an
agglomeration of the carbon black to thereby form the carbon black pellets of the
present invention. The contacting between the de-aerated carbon black and the
fluidized particulate encapsulating material is conducted for a period of time
sufficient to accomplish the pelletizing process, i.e., to form an inner core of
carbon black and an outer shell or crust of encapsulating material. It will be
-understood that the time for forming the pellets can vary over wide limits
depending upon the nature of the carbon black, the nature of the encapsulating
material, etc.
The encapsulation process can be carried out at ambient or elevated
temperatures of from 10 to 200°C depending on the nature of the encapsulating
material. For example, in cases where the encapsulating material is in the form
of a wax which can be melted to form a mist, dispersion or other particulate form
of the wax, the temperature may range from 60 to 160°C depending upon the
particular wax employed. It needs to be understood that the wax as
contemplated herein can be either natural or synthetic. In cases where the
encapsulating material is dissolved in a carrier, temperatures can be
considerably lower than would be employed in the case of a relatively high
temperature melting wax and need only be high enough to evaporate the carrier
leaving the encapsulating material to form the shell on the carbon black core.
Once the encapsulation process has been finished and the pellets
formed, they are removed from the contactor and cooled if necessary. In certain

cases, again depending upon the nature of the encapsulating material, the
cooling step is not required. However, in cases where relatively high
temperatures are employed in the encapsulation process, it may be necessary to
remove the pellets and cool them by methods well known to those skilled in the
art. A feature of the present invention is that because a relatively small amount
of the encapsulating material is employed, the encapsulating material tends to
solidify or harden very quickly to form the shell minimizing the need for cooling in
-many cases.
To more fully illustrate the present invention, the following non-limiting
examples are presented.
Example 1
A 6000 pound charge of de-aerated N650 (ASTM D1765) carbon black
was wet pelletized with 6000 pounds of water and 0.5 wt. % molasses binder
based on the total weight of carbon black, in a commercial pin mixer at 100°C for
10 minutes, to form control sample pellets.
Example 2
De-aerated carbon black from fluffy N650 (ASTM D1765) was wet
pelletized with water but without any binder. Thus, the pellets produced were as
per Example 1 but without any molasses binder. Fifty pounds of the pellets were
introduced into a Munson Rotary Batch Mixer which had a bladed interior to keep
the pellets in motion. Polyethylene wax was heated to a temperature of around

90°C, i.e., to the melting point, and sprayed into the rotating drum, the interior of
the drum being substantially at ambient temperature. The amount of
polyethylene wax employed was 1.7 wt. % based on the weight of the carbon
black charged to the drum. The encapsulation process was continued for a
period of approximately 2 minutes at which point the pellets were removed.
Example 3,
The procedure of Example 2 was followed with the exception that the
encapsulating agent comprised a phenolic resin which had been melted and
dispersed or suspended in paraffinic mineral oil as a carrier. The phenolic resin
was present in an amount of 1.5 wt. % based on the carbon black charge while
the paraffinic mineral oil was present in an amount of 4.8 wt. % based on the
carbon black charge.
The pellets made per Examples 1, 2 and 3, were subjected to various
tests to determine dust generation, attrition resistance and dispersibility. To
determine dust generation, two methods were employed - visual inspection and
a modified ASTM D1508 test (Test time increased from 20 minutes to 60
minutes). The visual inspection method involved placing a half gallon of the
carbon pellets in a container, agitating the pellets in the container with gloved
hands 10 times and determining visually the amount of carbon black on the
gloves. In the modified ASTM D1508 method, the pellets were subjected to a 60
minute test to simulate long distance shipment of the pellets to determine
attrition resistance and dust generation.

Table 1 shows the results of the two dust generation/attrition tests as well
as individual pellet crush strength (ASTM D3313). In the results in Table 1
below, the pellet of Example 1 is arbitrarily assigned a value of 100 for the
modified ASTM D1508 test and the ASTM D3313 test. With respect to the visual
inspection method of determining dust generation by the pellets, an arbitrary
scale of 1 -5 was employed with 5 being worst and 1 being best. The results are
shown in Table 1 below. As can be seen from Table 1, the pellets made by the
process of the present invention Examples 2 and 3 (Ex 2, Ex. 3) generated much
less dust albeit that they had less pellet rigidity or crush strength versus the prior
art pellet, e.g., the pellet made per Example 1 (Ex. 1).

The pellets of Examples 1-3 were compounded in a 1.5 liter internal mixer
with various amounts of rubber components and other additives for purposes of
conducting dispersibility testing. For further comparison purposes, two additional
formulations, Compound 2 and Compound 3, were also used. Compounds 2
and 3 have the same type and amount of encapsulating materials that were used
to form the pellets of the Ex. 2 and 3. However, the pellets of Compounds 2 and
3 were made the same as Ex1. The compound of Examples 1-3 and
Compounds 2 and 3 were then formed into rubber-containing compositions for
determination of dispersibility. The compositions of the pellet-rubber

formulations are shown in Table 2 below wherein all components are parts-per-
hundred of rubber (PHR).

The dispersibility of the pellets of Examples 1-3 and Compounds 2 and 3
were evaluated by two methods - optical inspection for micro-dispersion and
extrusion tests for macro-dispersion. In the optical evaluation, no significant
differences were observed. In determining macro-dispersion, a lab extruder
(single screw of 0.75 inch O.D., 10:1 L/D ratio, and 0.75 inch channel depth) with
screen packs of U.S. No. 325 and No. 60 at the end of the screw barrel was
employed. Operating conditions were 45 rpm screw speed, 110°C die
temperature and 70°C barrel temperature. The results are shown in Table 3
using two indices (1) the average pressure buildup in the extruder barrel per unit
volume of compound extruded and (2) elapsed time for the pressure build-up in

the extruder barrel to reach a given pressure of 5200 PSI. Example 1 was
assigned an arbitrary value of 100. The results are shown in Table 3.

As can be seen from the results in Table 3, there was much less pressure
build-up in the encapsulated pellets according to the present invention
(Examples 2 and 3) as compared with the control (Example 1) and Compounds 2
and 3. As can also be seen, the elapsed time to reach the 5200 PSI pressure
build-up in the extruder barrel was much greater for the encapsulated pellets of
the present invention (Examples 2 and 3) as compared to the control (Example
1) or Compounds 2 and 3. Thus it can be seen from the data in Table 3 that the
encapsulated pellets of the present invention are more readily dispersible than a
prior art wet pelletized carbon black pellet using a carbohydrate (molasses)
binder or prior art pellets such as Compounds 2 and 3. It is well known that the
dispersibility of carbon black pellets in a polymeric matrix such as that employed
in Examples 1-3 and Compounds 2 and 3, is reflected by the two indices
evaluated, i.e., pressure build-up and elapsed time for pressure build-up in the
extruder barrel. In this regard, the former represents extrusion rate while the
latter represents extrusion energy. As can be seen from Table 3, the extrusion
rate was higher for the encapsulated pellets of the present invention and
extrusion energy was lower for the encapsulated pellets of the present invention.

Example 4
The procedure of Example 1 was followed to form wet pelletized pellets of
carbon black, N650 using molasses as a binder.
Example 5
This example demonstrates production of the encapsulated pellets of the
present invention in a continuous process. Pellets produced per Example 4 but
without any binder were introduced at a rate of 1000 PPH (pounds per hour) into
a Munson Rotary Continuous Blender. An encapsulating material comprising 1.2
wt. % phenolic resin suspended in 3.6 wt. % paraffinic mineral oil, both based on
the carbon black weight, was introduced into the Munson Rotary Continuous
Blender by spraying. The temperature in the Munson Rotary Continuous
Blender was 35°C.
Example 6
The procedure of Example 1 was followed with the exception that the
carbon black employed was N339 (ASTM D1765) and the binder was lignin
oxide.
Example 7
The procedure of Example 5 was followed with the exception that the
pellets employed were those produced per Example 6 but without any binder and

the encapsulating material comprised 2.6 wt. % polyethylene wax dispersed in
2.3 wt. % paraffinic mineral oil, both based on the carbon black weight. The
encapsulating material, i.e., the mixture of polyethylene wax suspended in the
paraffinic mineral oil, was introduced as a mist into the Munson Rotary
Continuous Blender at a temperature of 35°C.
The pellets of Examples 4 and 5 were compared to determine the effect of
sieve residue on dispersibility. For example, as can be seen from Table 4 below,
-the encapsulated pellets according to the present invention (Example 5) had 8
times more sieve residue as the prior art pellets (Example 4). It can be
speculated that pellets of lower sieve residue (U.S. No. 325 screen) would cause
less average pressure build-up in the barrel of an extruder using a U.S. No. 325
screen. The results are shown in Table 4. Also shown in Table 4, as to the
pellets of Examples 4 and 5, is a dust generator test which was performed in two
ways - visual inspection and a modified ASTM D1508 as described above with
respect to Examples 1-3. Table 4 shows the results of the dust generation test
as well as indices pellet crush strength (ASTM D3313), pellet size distribution
(ASTM D1511) and sieve residue (ASTM D1514 - U.S. No. 325 screen).


The pellets produced per Examples 4-7 were subjected to the procedure
set forth with respect to Examples 1-3 and as set forth in Table 2. The same
styrene butadiene rubber and butadiene rubber were employed in the formations
using the pellets of Examples 4-7. Examples 4-1 and 6-1 are the pellets
produced per Examples 4 and 6 but blended with the binders used to produce
the pellets of Examples 5 and 7, respectively, to form generally homogeneous
•pellets wherein the binder was dispersed throughout the pellet rather than
forming encapsulating pellets as per Examples 5 and 7. The rubber formulations
are shown in Table 5 below.


Dispersibility of the pellets of Examples 4-1, 5, 6-1 and 7, was evaluated
by an extrusion test. The pellets were extruded in a Haake® lab extruder (single
screw of 0.75 inch O.D., 10:1 L/D ratio, and 0.75 inch channel depth) with the
screen packs of U.S. No. 325 and No. 6-0 at the end of the screw barrel.
Operating conditions were 45 rpm screw speed, 110°C die temperature and
70°C barrel temperature. Dispersibility was described in terms of the average
pressure build-up in the extruder barrel per unit volume of compound extruded
end elapsed time for the pressure build-up in the extruder barrel to reach a given
pressure, in this case 5200 PS1 for the pellets of Examples 4-1 and 5 and 4000
PSI for the pellets of Examples 6-1 and 7. The results for Examples 4 and 5 are
shown in Table 6.

Although the pellets of Example 5 contain 8 times more sieve residue (No.
325 mesh) than the pellets of Examples 4-1, nonetheless, as can be seen from
the data in Table 6, the encapsulated pellets of Example 5 showed much slower
pressure build-up in the extrusion test. These results demonstrate that macro-
dispersion is independent of sieve residue amount to a certain extent and that
the encapsulated pellets of Example 5 disperse more quickly and to smaller

sizes which ultimately contributes to an improvement in extrusion productivity
and reduces manufacturing costs. Similar results were exhibited with the pellets
of Examples 6-1 and 7 as shown in Table 7 below.

Table 7 also demonstrates that the enhanced benefits of the
encapsulated pellets are not dependent upon a specific grade of carbon black
since the pellets of Examples 6-1 and 7 were made from a different carbon black
than the pellets of Examples 4-1 and 5.
Pellets of Examples 6-1 and Example 7 were also tested in silica blend
formulations to determine if the encapsulated pellets (Example 7) could reduce
manufacturing costs or increased dispersibility in a multiple mixing system as
well as in a single mixing system as per the results obtained and shown in Table
7. In this respect, it is well known that silica is difficult to disperse compared to
carbon black. Accordingly, multiple pass mixing or dynamic mixing methods are
imperative to obtain a satisfactory dispersion of the silica which increases
manufacturing costs and reduces productivity. The formulations are shown in
Table 8 below. In Table 8, all amounts are in PHR unless other indicated.


Example 8
The dispersibility was evaluated through extrusion tests. Formulations
from Table 8 were extruded in the lab extruder (single screw of 0.75 inch O.D.,
10:1 L/D ratio, and 0.75 inch channel depth) with the screen packs of U.S. No.
200 and No. 35 at the end of the screw barrel under operating conditions of 45
RPM screw speed, 70°C die temperature and 70°C barrel temperature.
Dispersibility was determined by average pressure build-up in the extruder barrel
per unit volume of compound extruded and elapsed time for pressure build-up in
the extruder barret to reach a given pressure (5200 PSI). The results are shown
in Table 9 below.


As can be seen from Table 9, the encapsulated pellets (Example 7),
showed significant improvement over dispersibiiity in a multiple pass mixing of a
silica blend formulation as compared with pellets of Example 6-1 wherein the
binders were generally homogeneously mixed throughout the pellets.
The data above demonstrates that the encapsulated pellets of the present
invention show reduced attrition (less dusting) and better dispersibiiity as
compared with prior art pellets made by a wet pelletizing method regardless of
binder types employed and amounts, carbon black types or grades, and
formulations and/or methods of mixing.
The foregoing description and examples illustrate selected embodiments
of the present invention. In light thereof, variations and modifications will be
suggested to one skilled in the art, all of which are in the spirit and purview of this
invention.

We-Claim
1. A dispersible carbon black pellet comprising an inner core of
carbon black aggregates and an outer surrounding shell of an encapsulating
material, said shell having an average thickness of from about 1% to about 10%
of the average thickness of said pellet.
2. The pellet of Claim 1, wherein said encapsulating material is
-present in said pellet at a maximum amount of about 10 wt. % based on the total
carbon black present in said pellet.
3. The pellet of Claim 1, wherein the encapsulating material in said
shell comprises at least 30 wt. % of the total encapsulating material present in
said pellet.
4. The pellet of Claim 1, wherein the encapsulating material in said
shell comprises at least 90 wt. % of the total encapsulating material present in
said pellet.
5. The pellet of Claim 1, wherein an encapsulating material comprises
a single encapsulating agent.
6. The pellet of Claim 1, wherein said encapsulating material
comprises multiple encapsulating agents.

7. The pellet of Claim 1, wherein said de-aerated carbon black
aggregates are selected from the carbon black group consisting of l2N0(ASTM
D1510) in the 20g/Kg to 1000g/Kg range and OAN (ASTM D2414) in the 45
ml/100g to 500 ml/100g range.
8. The pellet of Claim 1, wherein said carbon black pellets are
-generally spherical.
9. The pellet of Claim 8, wherein said spherical pellets have a
diameter of from 125 to 2000µm.
10. The pellet of Claim 1, wherein said encapsulating material is
selected from the group consisting of carbohydrates, lignin oxides, cellulose by-
products, natural rubbers, synthetic rubbers, synthetic polymers, waxes, resins,
rosins, and mixtures thereof.
11. A method of forming carbon black pellets comprising:
de-aerating carbon black aggregates to form de-aerated carbon black;
introducing said de-aerated carbon black into a fluid-solids contactor;
introducing a particulate encapsulating material into said contactor; and
contacting said de-aerated carbon black with said encapsulating material
for a period of time sufficient to form encapsulated carbon black pellets

comprising an inner core of de-aerated carbon black and an outer surrounding
shell of encapsulating material, wherein said shell has an average thickness of
about 1% to about 10% of the average thickness of said pellet.
12. The method of Claim 11, wherein said contactor comprises a
moving-bed system.
13. The method of Claim 12, wherein said moving-bed system
comprises a rotary drum mixer.
14. The method of Claim 11, wherein said contactor comprises a
fluidized bed system.
15. The method of Claim 11, wherein said particulate encapsulating
material is introduced into said contactor in the form of a mist.
16. The method of Claim 11, wherein said encapsulating material
comprises a single encapsulating agent.
17. The method of Claim 11, wherein said encapsulating material
comprises multiple encapsulating agents.

18. The method of Claim 11, wherein said encapsulated carbon black
pellets are removed from said contactor and cooled.
19. The method of Claim 11, wherein said carbon black pellets are
generally spherical.
20. The method of Claim 19, wherein said spherical pellets have a
diameter of from 125 to 2000µm.
21. The method of Claim 11, wherein said carbon black aggregates are
selected from the carbon black group consisting of l2N0(ASTM D1510) in the
20g/Kg to 1000g/Kg range and OAN (ASTM D2414) in the 45 ml/100g to 500
ml/100g range.
22. The method of Claim 11, wherein said encapsulating material is
selected from the group consisting of carbohydrates, lignin oxides, cellulose by-
products, natural rubbers, synthetic rubbers, synthetic polymers, waxes, resins,
rosins, and mixtures thereof.
23. The method of Claim 11, wherein said encapsulating material is
present in said pellet at a maximum amount of 10 wt. % based on the total
carbon black present in said pellet.

24. The method of Claim 11, wherein said encapsulating material in
said shell comprises at least 30 wt. % of the total encapsulating material present
in said pellet.
25. The method of Claim 11, wherein said encapsulating material in
said shell comprises at least 90 wt. % of the total encapsulating material present
in said pellet.

A carbon black pellet comprising an inner core of deaerated carbon black and an outer surrounding shell of an encapsulating material, the shell of the encapsulating material having an average thickness of from about 1 % to about 10% of the average thickness of the pellet.