Specialty Minerals Products for Paint and
Our lives are touched daily by countless products made with
some kind of paint or coating. These products are on the walls of our houses, on
the surfaces of appliances and furniture, on our children’s bikes and wagons, on
the cars we drive to work, the bridges we drive over, the ships that may have
brought us those cars in the first place, on the file cabinets in our offices,
and on machinery and storage tanks in our factories.
Inc.’s (SMI’s) filler and extender pigments help make these coatings bright,
functional, and durable.
Using Specialty Minerals Products in Paints and
Many types of coatings benefit from using a SMI mineral
filler and extender in its formulation—architectural or decorative, industrial,
and the range of specialty coatings as follows:
Architectural / Decorative Coatings – interior, exterior and
Industrial Coatings including automotive OEM and powder
Specialty Coatings including maintenance, marine, traffic or
road marking, automobile refinishing, and aerosol paints.
Specialty Minerals Minerals for
SMI manufactures ground calcium carbonates (GCCs, also called
ground limestones), talcs and precipitated calcium carbonates (PCCs) in its
U.S., U.K. and Brazil plants for use in coatings as follows:
Specialty Minerals Products for Architectural Coatings
Architectural coatings are used on the interior
and exterior of structures such as houses, apartments and office
buildings. Other terms for architectural coatings are trade-sales
paints, decorative coatings, building paints, and DIY (do it yourself)
paints. Included are the semi-transparent and opaque stains for wood.
These are the coatings people most commonly see, use, and apply.
To satisfy the decorative and functional needs of
their users, paints for home and commercial construction are formulated
in a wide range of appearances, from flat or matte to shiny high-gloss
with ranges of eggshell and semi-gloss in between. Exterior
architectural coatings and wood stains must be formulated to withstand
the rigors of wind, rain, and direct sunlight. Interior paints are
generally used in a more benign environment, but one where surface flaws
are more readily noticed, and where touch-up and washability are
The color of the coating is determined by the prime pigment used. This will usually be titanium dioxide (TiO2),
if the paint is white or light-colored; in darker paint shades, it may
be iron oxide, carbon black or some brightly colored organic pigment.
Extender and Filler Minerals in Architectural Paints
addition to the prime color pigments described above, decorative
coatings and stains also contain filler or extender pigments, such as
ground calcium carbonate (GCC), talc and kaolin. The key
function of these minerals is to lower costs by either extending or
maximizing the efficiency of the more costly color pigments, reducing
the amounts needed to achieve the desired color, and filling up the
volume in the paint, thus reducing the use of resins and/or solvents.
In choosing a filler pigment, both the demands of
the end use and the cost constraints (i.e. selling price) must be
considered. The performance of a given filler in a coating depends on
its basic chemical nature, as well as its particle size, particle shape,
surface chemistry, color, and whiteness or brightness (both dry and
wet). Most decorative coatings contain a combination of filler minerals
of different types and sizes to achieve the targeted balance of
application, appearance, durability, and cost properties.
Ground calcium carbonates, also called ground
limestones, are generally the most economical and are very bright.
However, they do not contribute much to film integrity and their
chemistry makes them subject to acid attack. The synthetic form of
calcium carbonate, precipitated calcium carbonate (PCC), is widely used
in some areas of the world, especially in latex or emulsion paints.
Talc improves moisture barrier properties of
exterior paints and semi-transparent or opaque stains due to its platy
particle shape and hydrophobic nature. It is not as bright as the best
calcium carbonates and is higher in cost. Talc is also used in
predispersed liquid colorants for point-of-purchase paint-tinting
systems where it aids suspension and color development of the prime
color pigments in the colorant.
Specialty Minerals Filler and Extender Pigments for Architectural Coatings
In the U.S. Specialty Minerals Inc. (SMI) manufactures a variety of filler pigments used in trade sales paints. These include:
Vicron® - East and Vicron® – West
GCCs – high-brightness fillers, from 3 to 13 microns, from SMI mines
and plants in Adams, Massachusetts and Lucerne Valley, California.
Marblewhite® - East and Marblewhite West GCCs – 125, 200 and 325 mesh bright limestones, also manufactured in Adams, Massachusetts and Lucerne Valley, California.
Talcron® talcs – 1 to 8 micron bright paint talcs, mined and manufactured in Barretts, Montana.
Grades of PCCs for paint include:
Calopake F PCC.pdf
– 2 micron clustered scalenohedral calcite PCC for exceptional
brightness and titanium dioxide extension. Manufactured in SMI’s
Birmingham, U.K. facility.
Sturcal F PCC.pdf – 2.8 micron acicular aragonite, also produced in Birmingham.
Specialty Minerals Products for Industrial Coatings
coatings” generally refers to paints that are factory applied to
manufactured goods as part of the production process. Such paints are
also known as original equipment manufacture (OEM) coatings or product
finishes. Examples are the coatings used on automobiles, appliances,
farm implements, furniture, and metal building products. These coatings
tend to be applied in controlled environments, using strict quality
Minerals in Industrial Coatings
architectural coatings, industrial coatings will incorporate extender
pigments for additional reasons besides mere cost reduction. These
formulations lean towards minerals that add some functionality or
performance to the coating.
When an OEM formulation includes an extender, a talc
will generally be chosen. Talc is used in product primers
because it adds easy sandability and good adhesion. Talc can also be
used in implement finishes where it helps to form a moisture barrier,
and improves exterior durability.
In general, calcium carbonate materials are not used
in industrial finishes with the exception of nano-type precipitated
calcium carbonates (PCC) which may be used for titanium dioxide (TiO2) extension. Both uncoated and coated nano PCCs are used, but the choice depends on the system.
Specialty Minerals Minerals for Industrial Coatings
Minerals Inc. (SMI) manufactures high-quality talc fillers
for industrial coating in the U.S. and nano PCCs, uncoated and coated,
in the U.S. and U.K.
Specialty Minerals Precipitated Calcium Carbonates for Paint and Coatings
Precipitated calcium carbonate (PCC) is most commonly used in paint as an extender for titanium dioxide, or TiO2. The small and narrowly distributed PCC particles help space the individual TiO2 particles and maximize their hiding power. This extension of the prime white pigment can improve opacity and reduce cost.
Unlike ground calcium carbonates (GCCs), which come
in just one shape regardless of size, PCCs can be made in many shapes
and smaller sizes not achievable by mere grinding. The needle-shaped
aragonites and clustered scalenohedral calcites are typical crystal
types used as extenders to increase opacity and porosity for dry hiding
while smaller prismatics of very uniform particle size can increase film
Such differences in precipitated calcium
carbonate crystal morphology and size can lead to major differences in
how a particular PCC performs in different coating formulations. Many
PCC products for paint are available in the form of water slurries which
maintain the dispersion of the manufactured particle and avoid the need
for a production step to redisperse the dried powders.
much like ground carbonate, finds its largest application in interior
and exterior architectural coatings. There is some use in powder
coatings—especially the fine and ultrafine nano grades—whose small and
narrow particle size distributions promote “Class A” finishes. In
addition to the standard, uncoated hydrophilic grades, some PCCs are
available in stearic acid-coated versions. These versions increase
hydrophobicity, dispersibility, and compatibility in solvent-based or
100-percent solids coatings.
The degree to which precipitated calcium carbonate
are considered standard raw materials for paint formulations varies from
region to region. PCCs are common in decorative paints in Europe, South
America, and Asia, but less common in North America. The choice
generally depends on the relative availability of other extender
minerals in the region as well as relative costs.
Specialty Minerals Precipitated Calcium Carbonates for Paint
for paint are manufactured by Specialty Minerals Inc. (SMI) in Europe,
the U.S. and Brazil. The typical uncoated products recommended are:
- Calopake F PCC.pdf
is a 2 micron clustered scalenohedral calcite PCC used for exceptional
brightness and titanium dioxide extension. It is manufactured in
SMI’s Birmingham, U.K. facility.
- Sturcal F PCC.pdf is a 2.8 micron acicular aragonite, manufactured in Birmingham, U.K.
- Albacar® 5970 PCC is a 1.9 micron scalenohedral calcite manufactured in Adams, Massachusetts.
- Albacar® 8101 PCC is a 1.4 micron scalenohedral PCC manufactured in Adams, Massachusetts.
- Albafil® PCC is a fine, 0.7 micron prismatic calcite manufactured at SMI’s plant in Adams, Massachusetts.
Nano or ultrafine PCCs are produced in SMI’s PCC plants in Adams, Massachusetts, and Birmingham, U.K.
- Calofort S PCC.pdf – is a 0.07 micron nano PCC and is stearic-acid coated. It is manufactured in Birmingham, U.K.
- Ultra-Pflex® PCC is a 0.07 micron coated nano PCC and is manufactured in Adams, Massachusetts.
- Calofort U PCC.pdf and Multifex-MM Ultrafine PCC.pdf PCCs are 0.07 micron nano PCCs and are uncoated for more hydrophilic
applications. These PCCs are manufactured in Birmingham, U.K. They are
sold in the U.S. under the Multifex-MM® PCC name and in the rest of the world as Calofort® U PCC.
Specialty Minerals Talcs for Paint and Coatings
Talc is one of the most widely used extender
minerals in paint. It is used in exterior and interior architectural
paints, semi-transparent and opaque wood stains, specialty coatings, and
industrial/OEM (original equipment manufacture) applications. Talc is a
true functional extender mineral. Its platy structure, hydrophilic
surface, and inert chemistry help in the formation of coatings that
provide a real moisture barrier. The platy structure also promotes a
strong, flexible film.
is the least hard of the industrial minerals—rated as 1, the lowest, on
the Moh’s hardness scale. This softness makes it a particularly good
additive in sanding primers.
When ground to an ultrafine size, 1 micron median, talc can be used to control gloss and sheen in industrial coatings.
Another talc application in coatings is in
predispersed liquid colorants used for in-store tinting of paints. Talcs
help keep the pigments suspended and deagglomerated and maximize
development of tinting strength from the prime pigments used in the
Specialty Minerals Talcs for Coatings
Specialty Minerals Inc.’s (SMI’s) Talcron®
talc products come in a wide range of particle sizes and size
distributions and are useful in a broad range of coatings applications.
Standard 325 mesh filler talcs find use in exterior
and interior architectural or decorative coatings as film reinforcement
and moisture barrier additives and contribute to improved
weatherability. Finer grades are used in sanding primers and in
maintenance coatings. The finest products are used as gloss and sheen
materials in both architectural and industrial coatings.
All SMI’s talc products for paint are mined and
processed in our Barretts, Montana facility. We recommend the following
products for paint:
Specialty Minerals Products for Specialty Coatings
The “specialty coatings” group is a catch-all
containing a wide variety of products used in applications which fall
outside those covered by architectural paints or industrial OEM
(original equipment manufacture) finishes. The technologies for some
specialty coatings are closely related to those for industrial or
architectural coatings. A good example is the relationship between OEM
automotive coatings and automotive refinish paints, with the latter
considered a specialty coating.
This category also includes road marking or traffic
paints, maintenance coatings for bridges and storage tanks, other
metal-protective uses, marine coatings, roof coatings, and aerosol
paints. These finishes often mimic the properties and performance of OEM
coatings without the luxury of being applied in the controlled
environments from which OEM coatings benefit. Specialty coatings are
primarily protective coatings rather than appearance coatings. They
first perform the appointed task and then look good doing it.
Minerals in Specialty Coatings
many specialty applications require very high performance, ingredients
are chosen primarily for their functionality and effectiveness with cost
a secondary factor. Metal-protective maintenance coatings can
effectively employ talc’s barrier properties.
However, there are other cases, such as traffic
coatings, that must meet minimum performance standards within tight cost
parameters. In road marking paints, which make heavy use of fillers,
the ability to reduce overall formulation cost becomes paramount in the
choice of one extender pigment over another. Ground calcium carbonate
(GCC)–a more economical mineral–is generally employed. In some very
specialized coatings, such as aerosols or mirror coatings, there may be
just one extender system that truly complements the particular set of
other raw materials used in the formulation. Often, in dealing with
these more exotic systems, only in-house knowledge and experience can
provide the best overall solution.
Specialty Minerals Products for Specialty Coatings
of marine, maintenance, traffic, and other specialty coating products
will find value in one or more Specialty Minerals Inc. filler and
extender pigments. These include talcs, ground calcium carbonates, and
precipitated calcium carbonates.
Specialty Minerals Ground Calcium Carbonate for Paint and Coatings
Ground calcium carbonate (GCC)—also called ground
limestone, whiting, or chalk—is the most widely used extender mineral
in coatings applications. It is available worldwide and close to most
paint manufacturing locations. It is very bright and comes in a wide
range of particle size distributions. Finally, it is the most economical
of all common filler minerals.
The widest use for GCC is as a filler in
architectural or decorative coatings. While it is primarily used in
interior paints, it is included in some exterior formulations as well.
It tends to be the filler of choice for paints sold at a low price point
and/or where longevity is not the primary attribute. That said, GCC is
also used in top-of-the-line flat or matte finishes.
calcium carbonates are selected for ceiling paints and other
applications requiring high dry hiding and are formulated above the
critical pigment volume concentration (CPVC). By combining two or more
grades of different particle sizes, thus altering the particle size
distribution of the filler package, manufacturers can adjust the
flatness of finish of interior architectural coatings and improve the
scrubability of the final paint film. GCC can be used in exterior
building paints as long as the pigment volume concentration (PVC) is not
too high. The PVC must be sufficiently low with enough binder present
so that the film does not become too porous over time.
GCCs are also economical extenders included in
road-marking and traffic-paint formulations to lower costs while still
meeting the optical specifications for the finished film.
Although GCCs have many desirable traits, it is not a
universal extender mineral. It will react with acids, so its use it
limited to areas where it will not be exposed to acid rain or other
acidic fumes or liquids. In contrast to high-aspect ratio platy talcs,
calcium carbonates, with their round or nodular particle shape and low
aspect ratio, make relatively little contribution to improved film
formation and integrity and will increase film porosity. For these
reasons, the use of GCCs are limited in industrial, marine, and
metal-protective maintenance coatings.
Ground Calcium Carbonates from Specialty Minerals
are mined and processed in the U.S. at Specialty Minerals Inc.
locations in Adams, Massachusetts and Lucerne Valley, California. Key
products for the paint and coating industry are:
- Vicron® - East and Vicron® – West GCCs are a series of high brightness GCCs with particle sizes from 2 to
13 microns which produce paint fineness of grinds from 6 to 3 Hegman.
- Marblewhite® - East and Marblewhite® - West GCCs are bright ground limestones which are slightly coarser at 325 and 200 mesh yet useful in flat or heavily bodied coatings.