Epoxy Coating
An
epoxy coating is the use of epoxy compounds as coatings or paints. It is
generally two parts, which are mixed prior to application and consist of an
epoxy resin that is cross-linked with a coreactant or hardener.
Epoxy
coatings are formulated based on the end product's performance requirements .
When properly catalyzed and applied, epoxies produce a hard, chemical and
solvent resistant finish. It is the specific selection and combination of the
epoxy and hardener components that determine the final characteristics and
suitability of the epoxy coating for a given environment.
Epoxy
coatings are created through the generation of a chemical reaction that uses an
epoxide resin and polymine hardener. When these two chemicals are combined, the
result is a process known as curing, which can take between several minutes to
several hours and turns the liquid epoxy coating into an extremely strong and durable
solid, often with strong mechanical properties, as well as resistance to high
temperatures and chemicals. Because of these properties, these materials
provide significant advantages over one-component coatings.
Epoxy
coatings are formulated with optimum levels of a hardener for a given level of
epoxy resin. The ratio differs from product to product. The use of an improper
hardener may result in an undercatalyzed or overcatalyzed product. Many epoxy
coatings require a specified induction time to fully compatibilize the epoxy
resin and the hardener. Lower temperatures and/or high humidity generally
require longer induction periods. Water-based primers require sufficient curing
prior to top coating. Otherwise, discoloration, low gloss and possibly delamination
result.
Epoxy
coatings are popular because they provide a quick-drying, tough and protective
coating. Unlike traditional heat cured powder coatings, epoxy coatings are
quick and easy to apply, making them ideal for a number of applications. For
example, they are typically used on concrete and steel to give resistance to
water, alkali and acids. Metal cans and containers are often coated with epoxy
to prevent rusting.
Epoxy
resins are also used for floor application. Their low volatility and easy water
clean up make them useful for factory cast iron, cast steel and cast aluminum
applications, and reduces exposure and flammability issues associated with
solvent borne coatings. They are usually used in industrial, automotive and
marine applications. Furthermore, fusion bonded epoxy powder coatings are
extensively used for corrosion protection of steel pipes and fittings used in
the oil and gas industry, portable water transmission pipelines (steel) and
reinforcing bars.
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