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Particles are coated to solve problems. Coatings perform one or more of
four basic functions when solving problems. These four basic functions
are barrier, carrier, surface modification, and interface.
Barrier Coatings
A barrier coating is a
partition between the core material and the environment surrounding the
core. Coat properties such as solubility, porosity, and other factors
can be designed for the intended coat function. Common barrier coating
functions include:
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Controlled release |
| Enteric |
| Sustained |
| Delayed |
| Timed |
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-Moisture, oxygen, or other barriers |
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-Improved stability or shelf life |
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-Chemical reaction control |
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-Taste-, odor, or color masking |
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-Safety |
Ca rrier
Coatings
A carrier coating is primarily
used to overcome a mixing problem. Mixed dry components of varying particle
size, shape, and/or density may de-mix upon routine handling. Also,
uniformly mixing a small amount of one ingredient accurately and precisely
with a larger amount of another material can be difficult. In either case,
coating one component appropriately onto the other provides a uniform
mixture of the dry components without the possibility de-mixing.
S urface
Modification
Particle surface modification is
an inherent result of applying a coating. Nevertheless, some coatings are
used specifically for surface modification. Material that "cakes" or
"clumps" can be made to flow more freely with a proper surface coating. Dust
control can be achieved in a similar manner. Color or texture can also be
modified with coatings.
I nterface
Coatings
Imagine two or more solid
particles or materials that need to be associated or attached to one another
in some manner. An interface coating can be added to one or more of the
materials to make the association. The interface coating can be "activated"
under appropriate conditions of heat or "wetting" to achieve the desired
association of particles. The Wurster process can be used to apply the
interface and/or make the association.
Coating Place has been
developing functional coating formulations to solve an extensive array of
problems in many different industries for over 28 years. We are commonly
challenged to develop new applications.
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