STEARIC ACID-TREATED CALCIUM CARBONATE COMPOSITIONS HAVING
LOW OR NO DETECTABLE FREE STEARIC ACID AND RELATED METHODS
This application claims priority to U.S. Provisional Patent Application No.
61/096,613, filed on September 12,2008, which is incorporated herein by
reference.
DESCRIPTION
Field of the Disclosure
Disclosed herein are methods for treating calcium carbonate with
stearic acid to produce stearic acid-treated calcium carbonate compositions having
low or no free stearic acid. Also disclosed herein are stearic acid-treated calcium
carbonate compositions having low or no detectable free stearic acid.
Background of the Disclosure
The present disclosure generally relates to methods for treating
calcium carbonate with stearic acid and stearic acid-treated calcium carbonate
compositions.
Calcium carbonate (CaCO3) may be considered among the most
widely used fillers/extenders for the polymer industry. It may be obtained either by
grinding naturally occurring calcium carbonate mineral or by carbonation of a
calcium hydroxide solution. Due to its hydrophilic nature and having a high surface
energy of 200 mJ/m2, it may be incompatible with the most common hydrophobic
polymers, for example, such as polyethylene (PE) and polypropylene (PP), which
may exhibit a low surface energy of about 35 mJ/m2. While larger particles having
a median particle size, for example, (d50) ≥ 3 µm, can be incorporated into
polymers, the smaller particles, by virtue of enhanced particle-particle interactions,
tend to agglomerate, which may lead to dispersion and/or performance problems.
Moreover, moisture pick-up by calcium carbonate may pose additional problems
during handling and processing. As a result, it may be desirable to render the
calcium carbonate surface hydrophobic via treatment with surface modifiers, the

most common being stearic acid (SA). It may be desired that a minimum amount of
coating be applied to the calcium carbonate, in particular, an amount that just
covers the surface of the calcium carbonate particle. This minimum amount, highly
dependent on the surface area of the mineral, is sometimes referred to as
"monolayer concentration." In the case of a calcium carbonate-SA system, a
monolayer concentration of SA may be added in order to reduce the unreacted/free
SA in the final product. However, practically all conventional calcium carbonate-SA
coated grades have some unreacted/free SA, partly due to an incomplete reaction,
and/or partly due to less than ideal mixing conditions and/or the addition of excess
SA to the calcium carbonate. Conventional methods of treating calcium carbonate
with SA may therefore often result in residual, unreacted, or free SA in the bulk
and/or on the surface of the treated calcium carbonate.
Using methods available to those skilled in the art and disclosed
herein, the presence of free/unreacted and/or residual SA is detectable in
commercially available and laboratory-coated samples of stearic acid-treated
calcium carbonate. For example, a sample of calcium carbonate having a median
particle size (d50) of 3 urn was blended with SA in the form of beads supplied by
Chemtura Corporation at 1X monolayer concentration (about 0.5% by weight
relative to the total weight of the mixture) using a conventional Dry Melt Coating
method described herein, which may be representative of conventional processes
for treating calcium carbonate with SA. Although the purpose of limiting the amount
of SA added to the calcium carbonate at the 1X monolayer coating concentration
was to avoid any unreacted/free SA, the latter could not be avoided entirely as
shown by testing. For example, as shown in Figure 1, high-sensitivity differential
scanning calorimetry (DSC) detected a minor amount of SA in the Dry Melt Coated
calcium carbonate, which shows the melting transition temperature (Tm) at about
69°C that is characteristic of the starting SA. Figure 2 shows a differential
thermogravimetric peak at about 175°C, which is the temperature that corresponds
to unreacted/free SA. The presence of starting SA is further evidenced by ToF-
SIMS scans shown in Figure 3, which show a small m/z peak at 285, which is
indicative of the presence of stearic acid in the Dry Melt Coated sample. Thus,
although SA was added to the sample in the monolayer concentration using the Dry

Melt Coating method, detectable amounts of unreacted/free stearic acid are
present in the stearic acid-treated calcium carbonate.
The presence of free SA associated with coated calcium carbonate
may be undesirable for a number of reasons. For example, residual, unbonded SA
in SA-treated calcium carbonate compositions may interfere with downstream
processes. Unreacted SA may lead to, for example, smoke generation,
undesirable emissions to the environment, and/or extruder die-buildup in polymer
processing applications. In addition, product performance may be adversely
affected due to surface aesthetics and adhesion. Also, the properties of the
plastics containing SA-coated calcium carbonate may be negatively impacted.
Thus, for at least the aforementioned reasons, a calcium carbonate composition
with low or no free SA may be desirable.
Accordingly, there may be a desire to provide a method of treating
calcium carbonate to increase its compatibility with other materials in downstream
applications, while reducing or eliminating the amount of residual SA associated
with the treated calcium carbonate. The inventors have surprisingly found that a
novel aqueous method of coating calcium carbonate under some mixing conditions
can reduce or eliminate free SA in SA-treated calcium carbonate compositions,
even when SA is added in excess of monolayer concentrations.
Thermal Analysis
For differential scanning calorimetry (DSC), a STARe system from
Mettler-Toledo, Inc. equipped with a FRS5 sensor was used. Unless otherwise
specified, all samples were run over a temperature range of-70°C to 200°C at a
heating rate of 20°C/min under a nitrogen purge gas flow of 200 cc/min. A 40 jJ
capacity, pure aluminum crucible crimped with a pinhole-containing lid was used for
all experiments. A heating rate of 20°C/min and a sample size ranging from 60-150
mg was used to improve the detection capability and the accuracy of the
quantitative analysis.
Thermogravimetric analysis (TGA) was performed on a METTLER-
TOLEDO TGA/DSC 1 model using the MAXRES™ software from room
temperature to 600°C, using about a 30 mg sample in an aluminum pan. The
minimum and maximum heating rates were 0.25°C/min and 20°C/min, respectively.

Surface Analysis
The Time-of-FIight Secondary Ion Mass Spectrometry (ToF-SIMS)
data was acquired on a Physical Electronics (Chanhassen, MN, USA) Trift III model
instrument utilizing a 22 keV 197Au+ pulsed primary ion beam. The samples were
biased at about +3kV to extract positive ions generated at the sample by the
primary ion beam into the time-of-flight mass spectrometer. The spectra were
calibrated using common low mass hydrocarbon fragments such as CH3+, C2H3+,
and C3H5+. Charge compensation by a low energy electron gun was used to
minimize sample charging. The ToF-SIMS sampling depth is generally about 10-20
A.
Starting Materials
The SA used for coating the calcium carbonate powder was in the
form of beads obtained from Chemtura Corporation. Unless otherwise specified,
the base calcium carbonate mineral used was a free flowing powder with a median
particle size (dso) of 3 µm supplied by Imerys, having a surface area of about 3 m2/g
measured via nitrogen BET method. Based on the surface area, it can be
calculated that about 0.5% of SA is required to provide a monolayer coverage,
based on, for example, a SA footprint of 25 A2 per molecule. The monolayer
stearate coverage was independently verified by solution treatment experiments.
Upon exposure to a solution of SA in hexane, the coated sample depletes sufficient
acid to completely cover the available surface. TGA analysis of the resultant
powder showed that about 0.5 - 0.6% SA was picked-up, which was in reasonable
agreement with the theoretical monolayer coverage. CaCO3 samples with
monolayer concentration coating (e.g., "1X" being roughly equal to about 0.5%), as
well as excessive coating concentrations (e.g., "6X" being roughly equal to about
3.0%) were prepared and characterized. Commercially available samples of
unknown coating conditions were also analyzed.

Dry Melt Coating Method
According to the Dry Melt Coating method, about 2 kg size-lots were
prepared by adding CaCO3 to a Papenmeier high speed blender (8 liter capacity)
set at the maximum speed and at a temperature of 82°C. A designated amount of
SA was then added and allowed to blend for 15 minutes. The treated material was
transferred into a tray and allowed to cool. The material was subsequently placed
back in the blender and run for 10 minutes without heat as a deagglomeration step.
Wet/Aqueous Coating Method
According to an exemplary Wet/Aqueous Coating method, about 2
kg size-lots were prepared by the Wet/Aqueous method. About 1/3 of the calcium
carbonate was added to water in amount sufficient to bring the solids concentration
to about 70% by weight. This was followed by the addition of the designated
amount of SA, for example, ranging from about 1X to about 6X monolayer, and
mixing for 10 minutes at room temperature using the maximum speed of the
Papenmeier blender. Then the remaining 2/3 of the calcium carbonate was added,
increasing the solids concentration to about 85%. The temperature was raised to
121°C while mixing until the material appeared dry. The sample was then placed in
an oven at 120°C overnight to assure drying. The material was subsequently
placed back in the blender and for 10 minutes without heat as a deagglomeration
step.
SUMMARY OF THE DISCLOSURE
In the following description, certain aspects and embodiments will
become evident. It should be understood that the aspects and embodiments, in
their broadest sense, could be practiced without having one or more features of
these aspects and embodiments. It should be understood that these aspects and
embodiments are merely exemplary.
One aspect of the disclosure relates to a method for treating calcium
carbonate. The method includes combining calcium carbonate with an amount of
stearic acid and an amount of water to form a mixture, the amount of water being at

least about 0.1% by weight relative to the total weight, and blending the mixture to
form a stearic acid-treated calcium carbonate composition.
According to another aspect, a calcium carbonate composition
includes calcium carbonate coated with stearic acid, wherein the composition
includes less than about 10% free stearic acid relative to a monolayer
concentration.
According to yet another aspect, a calcium carbonate composition is
produced by a method including combining calcium carbonate with an amount of
stearic acid and an amount of water to form a mixture, the amount of water being at
least about 0.1% by weight relative to the total weight. The method further includes
blending the mixture at a temperature sufficient for a majority of the stearic acid to
melt.
According to still a further aspect, a method of making a product
including stearic acid-coated calcium carbonate includes combining calcium
carbonate with an amount of stearic acid and an amount of water to form a mixture,
the amount of water being at least about 0.1 % by weight relative to the total weight.
The method further includes blending the mixture to form a stearic acid-coated
calcium carbonate composition, wherein the mixture is blended at a temperature
sufficient for a majority of the stearic acid to melt. The method further includes
incorporating the stearic acid-coated calcium carbonate composition into a
composition for forming a product.
According to yet a further aspect, a method for treating calcium
carbonate includes combining calcium carbonate with an amount of stearic acid
and an amount of water to form a mixture, the amount of water being at least about
0.1% by weight relative to the total weight. The method further includes blending
the mixture to form a stearic acid-treated calcium carbonate composition, wherein
the mixture is blended at a temperature sufficient for at least a portion of the stearic
acid to react.
Additional objects and advantages of the disclosure will be set forth
in part in the description which follows, and in part will be obvious from the
description, or may be learned by practice of the disclosed embodiments.
Aside from the structural and procedural arrangements set forth
above, the embodiments could include a number of other arrangements, such as

those explained hereinafter. It is to be understood that both the foregoing
description and the following description are exemplary only.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 depicts a DSC thermogram of calcium carbonate coated
with stearic acid at monolayer concentration.
Figure 2 depicts a TGA thermogram of calcium carbonate coated
with stearic acid at monolayer concentration.
Figure 3 depicts ToF-SIMS scans showing elimination of unreacted
stearic acid via a wet process.
Figure 4 depicts a time-temperature effect on a blended mix of 85%
calcium carbonate, 1% stearic acid, and 14% water.
Figure 5 depicts the role of water addition to monolayer stearic acid
dry-coated calcium carbonate.
DESCRIPTION OF EMBODIMENTS
Reference will now be made in detail to exemplary embodiments of
the disclosure, examples of which may be illustrated in the accompanying
drawings.
According to some embodiments, calcium carbonate is combined
(e.g., blended) at room temperature with SA and water in an amount greater than
about 0.1 % by weight relative to the total weight of the mixture (e.g., in the form of a
cake-mix). For example, according to some embodiments, the mixture may be
blended at a temperature sufficient for at least a portion of the stearic acid to react
(e.g., sufficient for a majority of the stearic acid to react, for example, with at least a
portion of the calcium carbonate). For example, the mixture may be blended at a
temperature sufficient such that at least a portion of the stearic acid may coat at
least a portion of the calcium carbonate (e.g., the surface of the calcium carbonate).
In some embodiments, the mixture may be blended at a temperature
high enough to melt the SA. For example, the mixture may be blended at a
temperature ranging from about 65°C to about 200°C. In other embodiments, the
mixture may be blended at a temperature ranging from about 65°C to about 150°C,
for example, at about 120°C. In further embodiments, the mixture may be blended

at a temperature ranging from about 65°C to about 100°C. In still other
embodiments, the mixture may be blended at a temperature ranging from about
65°C to about 90°C. In further embodiments, the mixture may be blended at a
temperature ranging from about 70°C to about 90°C.
In some embodiments, the mixing time may be selected (e.g.,
optimized) based on the equipment used and/or ambient conditions, such as,
temperature, pressure and/or humidity, to allow the SA to react with the calcium
carbonate surface (e.g., to allow at least a portion of the SA to coat at least a
portion of the surface of the calcium carbonate). For example, in some
embodiments, the mixture (e.g., a cake-mix) may be blended for a time period
ranging from about 1 second to about 10 minutes. In further embodiments, the
mixture may be blended for a time period ranging from about 2 seconds to about 8
minutes. In other embodiments, the mixture may be blended for a time period
ranging from about 5 seconds to about 5 minutes. In still further embodiments, the
mixture may be blended for a time period ranging from about 10 seconds to about 3
minutes. In further embodiments, the mixture may be blended for a time period
ranging from about 10 seconds to about 2 minutes.
The amount of SA may be combined with calcium carbonate at, or in
excess of, a monolayer concentration. As used herein, "monolayer concentration"
is intended to mean an amount sufficient to form a monolayer on the surface of the
calcium carbonate particles. Such values will be readily calculable to one skilled in
the art based on, for example, the size of the calcium carbonate particles. For
example, a base calcium carbonate with (d50) equal to 3 microns has a surface
area of about 3 m2/g. With that exemplary surface area, a skilled artisan can
calculate that an amount of about 0.5% SA, relative to the total weight of the
calcium carbonate, may be theoretically desirable for monolayer coverage.
In some embodiments, SA may be added to calcium carbonate in an
amount greater than or equal to about 1X the monolayer concentration. In other
embodiments, SA may be added in an amount in excess of about 1X the
monolayer concentration, for example, 2X (two times) to 6X (six times) the
monolayer concentration.
The calcium carbonate may be characterized by a (d50) value,
defined as the size at which 50 percent of the calcium carbonate particle
concentration includes particles having a diameter less than or equal to the stated

value. Particle size measurements such as (d50) may be carried out by any means
now or hereafter known to those having ordinary skill in the art. In some
embodiments, the calcium carbonate may have a (d50) less than about 10 microns.
In other embodiments, the (d50) may be less than about 8 microns. In further
embodiments, the (d50) may be less than about 6 microns. In still other
embodiments, the (d50) may be less than about 6 microns. In still further
embodiments, the (d50) may be less than about 4 microns. In further embodiments,
the (d50) may be less than about 3 microns. In still other embodiments, the (dso)
may range from about 0.01 micron to about 3 microns. In other embodiments, the
(d50) may range from about 0.01 micron to about 2 microns. In still further
embodiments, the (dso) may range from about 0.05 micron to about 1 micron.
According to some embodiments, the amount of water added to the
SA-calcium carbonate combination may be an amount greater than about 0.1%
relative to the total weight of the mixture. For example, in some embodiments,
water may be added in an amount ranging from about 0.1% to about 20% of the
total weight of the mixture. In other embodiments, water may be added in an
amount ranging from about 0.3% to about 15%. In still other embodiments, water
may be added in an amount ranging from about 0.5% to about 15%. In further
embodiments, water may be added in an amount ranging from about 1% to about
15%. In still further embodiments, water may be added in an amount ranging from
about 2%, 3%, or 4% to about 15%. In other embodiments, water may be added in
an amount ranging from about 5% to about 15%. In still other embodiments, water
may be added in an amount ranging from about 6% to about 15%. In further
embodiments, water may be added in an amount ranging from about 7% to about
15%. In some embodiments, water may be added in an amount ranging from
about 8% to about 15% (e.g., about 8%). In other embodiments, water may be
added in an amount ranging from about 9% to about 15%. In still other
embodiments, water may be added in an amount ranging from about 10% to
about 15%. In yet other embodiments, water may be added in an amount ranging
from about 11% to about 15%. In yet further embodiments, water may be added in
an amount ranging from about 12% to about 15%. In some embodiments, water
may be added in an amount ranging from about 13% to about 15%. The water may
be added in various forms, e.g., as a liquid and/or steam, and/or may take the form
of a spray and/or mist, for example, as may be produced by an atomizer. In some

embodiments, the water also may contain monovalent cations, such as Na, or
bivalent cations, such as Ca, Mg, and Zn. Further, the water may be modified to
contain Ca cations derived from other sources, such as CaO, Ca(OH)2, or CaCO3.
One skilled in the art will appreciate that SA may be introduced at various stages in
a given process, including, for example, a water purification stage, when the water
content may be relatively high, for example, at least about 20% relative to the total
weight of the mixture.
According to some embodiments, the calcium carbonate
composition may be hydrophobic. According to some embodiments, the amount of
free SA associated with the SA-treated calcium carbonate composition may be less
than about 20% relative to the monolayer concentration. According to other
embodiments, the amount of free SA associated with the SA-treated calcium
carbonate composition may be less than about 15% free SA. According to further
embodiments, the amount of free SA associated with the SA-treated calcium
carbonate composition may be less than about 10% free SA. According to still
other embodiments, the amount of free SA associated with the SA-treated calcium
carbonate composition may be less than about 7% free SA. According to still
further embodiments, the amount of free SA associated with the SA-treated calcium
carbonate composition may be less than about 6% free SA. According to other
embodiments, the amount of free SA associated with the SA-treated calcium
carbonate composition may be less than about 5% free SA. According to further
embodiments, the amount of free SA associated with the SA-treated calcium
carbonate composition may be less than about 4% free SA. According to still other
embodiments, the amount of free SA associated with the SA-treated calcium
carbonate composition may be less than about 3% free SA. In still further
embodiments, no free SA may be associated with the SA-treated calcium
carbonate composition. As used herein, "no free stearic acid (SA)" is intended to
mean no SA detectable by the ToF-SIMS, TGA, and/or DSC techniques described
herein.
The SA-treated calcium carbonate composition may be further
treated. For example, in some embodiments, the SA-treated calcium carbonate
composition may be heated. For example, the SA-treated calcium carbonate
composition may be heated or reheated at a temperature ranging from about 120°C

to about 150°C. In some embodiments, the SA-treated calcium carbonate
composition may be heated until the sample appears dry.
According to some embodiments, the SA-treated calcium carbonate
composition may be blended, for example, to reduce agglomeration. For example,
the SA-treated calcium carbonate composition may be blended at room
temperature for a time period ranging from about 5 seconds to about 10 minutes.
According to some embodiments, the SA-treated calcium carbonate
composition may be used as a filler. For example, the SA-treated calcium
carbonate composition may be combined (e.g., blended) with a polymer. In some
embodiments, the SA-treated calcium carbonate composition may be combined
with a silicone sealant.
EXAMPLES
Example 1
Sample A of calcium carbonate having a median particle size (d50)
of 3 µm was blended with SA in the form of beads supplied by Chemtura
Corporation at 1X monolayer concentration (about 0.5% by weight relative to the
total weight of the mixture) as well as 6X (about 2.8% by weight relative to the total
weight of the mixture) using an exemplary Wet/Aqueous Coating method described
herein. At both concentrations, the starting SA was undetectable. The absence of
unreacted/free SA is substantiated by ToF-SIMS scans where the m/z peak at 285,
representative of stearic acid, is missing. As may be desirable, no free SA is
detectable in the 6X-SA sample prepared in accordance with this exemplary
method (Figure 3; 5th scan), in sharp contrast with the sample prepared with only
1X-SA via the conventional Dry Melt Coating method (Figure 3; 3rd scan). While
not wishing to be bound by theory, it is possible that at least some (e.g., all) excess
SA during the exemplary Wet/Aqueous process is converted into calcium stearate
(Ca(St)2), which possesses a much higher thermal stability than the starting SA,
thereby mitigating, or overcoming, most of the potential problems that might occur
during downstream operations sometimes associated with stearic acid-treated
calcium carbonate evidencing the presence of unreacted/free stearic acid. It also is
possible that Ca cations, in embodiments where the water contains such cations,
may react with the SA to form Ca(St)2.

Example 2
In this example, a smaller particle size grade of calcium carbonate
was chosen with a median particle size (d50) of <2 µm ("Sample B"), requiring about
1% of SA by weight for a 1X monolayer coverage. A physical blend of 85% calcium
carbonate Sample B + 1% SA + 14% water by weight, was prepared via high-
speed blending at room temperature. This exemplary mixture (e.g., a cake-mix)
was then transferred into a blender pre-heated at 100°C. Blending was carried out
for 60 seconds. Due to the transfer of the mixture at room temperature, the actual
temperature during blending first went down to about 70°C and reached about 90°C
at the end of 60 seconds blending. Figure 4 demonstrates the reduction and
elimination of free SA associated with the SA-treated calcium carbonate by the
exemplary Wet/Aqueous method via absence of the weight loss step centered at
about 200°C, typical of starting SA. In Figure 4, it is believed that the mixture
prepared at room temperature should have exhibited all of the 1% SA as
unreacted/free SA, but only about 0.3% of unreacted/free SA is observed due to
the ongoing reaction during the heating part of the TGA experiment. In contrast,
the same mixture pre-heated for about 60 seconds at a temperature in the 70-90°C
range does not exhibit any significant weight loss step at 200°C, which is
characteristic of the unreacted/free SA.
Example 3
Physical blends of 94-99% CaCO3 Sample B + 1 % SA were
prepared via high-speed blending at room temperature, with water contents varying
from about 0% to about 5%. The exemplary mixture (e.g., a cake-mix) was then
transferred into a blender pre-heated at 100°C. Blending was carried out for 60
seconds. Figure 5 shows a continuous reduction in the amount of unreacted/free
SA associated with the SA-treated calcium carbonate composition as the water
content increased from 0 to 5%.
Other embodiments of the disclosure will be apparent to those
skilled in the art from consideration of the specification and practice of the
exemplary embodiments disclosed herein. It is intended that the specification and
-12-

examples be considered as exemplary only, with a true scope and spirit of the
invention being indicated by the following claims.

We claim:
1. A method for treating calcium carbonate, the method comprising:
combining calcium carbonate with an amount of stearic acid and an amount
of water to form a mixture, the amount of water being at least about 0.1% by weight
relative to the total weight; and
blending the mixture to form a stearic acid-treated calcium carbonate
composition.
2. The method of claim 1, wherein the mixture is blended at a temperature
of at least about 65°C.
3. The method of claim 1, wherein the mixture is blended at a temperature
ranging from at least about 65°C to about 200°C.
4. The method of claim 3 , wherein the mixture is blended at a temperature
ranging from at least about 65°C to about 150°C.
5. The method of claim 4, wherein the mixture is blended at a temperature
of about 120°C.
6. The method of claim 4, wherein the mixture is blended at a temperature
ranging from at least about 65°C to about 90°C.
7. The method of claim 1, wherein the mixture is blended for a time period
ranging from at least about 1 second to about 10 minutes.
8. The method of claim 1, wherein the mixture is blended for a time period
ranging from at least about 2 seconds to about 1 minute.
9. The method of claim 1, wherein the mixture is blended for a time period
sufficient for a majority of the stearic acid to react with the calcium carbonate.

10. The method of claim 1, wherein the amount of stearic acid is at least
about monolayer concentration.
11. The method of claim 1, wherein the amount of stearic acid is greater
than monolayer concentration.
12. The method of claim 1, wherein the amount of water is greater than
about 0.1% by weight.
13. The method of claim 12, wherein the amount of water ranges from at
least about 0.1 % to about 20% by weight.
14. The method of claim 13, wherein the amount of water ranges from at
least about 1 % to about 20% by weight.
15. The method of claim 14, wherein the amount of water ranges from at
least about 1% to about 15% by weight.
16. The method of claim 15, wherein the amount of water ranges from at
least about 3% to about 15% by weight.
17. The method of claim 16, wherein the amount of water ranges from at
least about 5% to about 15% by weight.
18. The method of claim 17, wherein the amount of water ranges from at
least about 10% to about 15% by weight.
19. The method of claim 17, wherein the amount of water is about 8% by
weight.
20. The method of claim 1, wherein the stearic acid-treated calcium
carbonate composition is hydrophobic.

21. The method of claim 1, wherein the amount of free stearic acid
associated with the stearic acid-treated calcium carbonate composition is less than
about 20% relative to a monolayer concentration.
22. The method of claim 21, wherein no free stearic acid is associated with
the stearic acid-treated calcium carbonate composition.
23. The method of claim 1, further comprising heating the stearic acid-
treated calcium carbonate composition.
24. The method of claim 23, further comprising blending the stearic acid-
treated calcium carbonate composition.
25. The method of claim 1, further comprising combining the stearic acid-
treated calcium carbonate composition with a polymer.
26. The method of claim 1, further comprising combining the stearic acid-
treated calcium carbonate composition with a silicone.
27. The method of claim 1, wherein the calcium carbonate has a (d50)
ranging from about 0.01 µm to about 10 µm.
28. The method of claim 1, wherein the calcium carbonate has a (d50) less
than or equal to about 3 µm.
29. The method of claim 1, wherein the calcium carbonate has a (d50) less
than or equal to about 2 µm.
30. A calcium carbonate composition comprising calcium carbonate coated
with stearic acid and comprising less than about 10% free stearic acid relative to a
monolayer concentration.

31. The composition of claim 30, wherein the calcium carbonate
composition comprises less than about 5% free stearic acid.
32. The composition of claim 30, wherein the calcium carbonate
composition comprises no free stearic acid.
33. The composition of claim 30, further comprising calcium stearate.
34. A calcium carbonate composition produced by a method comprising:
combining calcium carbonate with an amount of stearic acid and an amount
of water to form a mixture, the amount of water being at ieast about 0.1 % by weight
relative to the total weight; and
blending the mixture to form a stearic acid-coated calcium carbonate
composition,
wherein the mixture is blended at a temperature sufficient for a majority of
the stearic acid to melt.
35. A method of making a product comprising stearic acid-coated calcium
carbonate, the method comprising:
combining calcium carbonate with an amount of stearic acid and an amount
of water to form a mixture, the amount of water being at least about 0.1% by weight
relative to the total weight; and
blending the mixture to form a stearic acid-coated calcium carbonate
composition, wherein the mixture is blended at a temperature sufficient for a
majority of the stearic acid to melt; and
incorporating the stearic acid-coated calcium carbonate composition into a
composition for forming a product.
36. The method of claim 35, wherein the product comprises a polymer
product.
37. The method of claim 35, wherein the product comprises a silicone
product.

38. A method for treating calcium carbonate, the method comprising:
combining calcium carbonate with an amount of stearic acid and an amount
of water to form a mixture, the amount of water being at least about 0.1 % by weight
relative to the total weight; and
blending the mixture to form a stearic acid-treated calcium carbonate
composition,
wherein the mixture is blended at a temperature sufficient for at least a
portion of the stearic acid to react.
39. The method of claim 38, wherein the mixture is blended at a
temperature sufficient such that at least a portion of the stearic acid coats at least a
portion of the calcium carbonate.
40. The method of claim 39, wherein the mixture is blended at a
temperature sufficient such that a majority of the stearic acid coats at least a portion
of the calcium carbonate.

A method for treating calcium carbonate includes
combining calcium carbonate with an amount of stearic
acid and an amount of water to form a mixture, the
amount of water being at least about 0.1 % by weight
relative to the total weight. The method further
includes blending the mixture to form a stearic acid-
treated calcium carbonate composition.