| An industrial coating is defined by its protective
properties. More than just a 'pretty finish', polymer-based
industrial coatings are applied for corrosion control, fire resistance and
the other 'high endurance' surface properties they give to whatever
surface they are employed to protect.
There are many types of industrial
coatings, however the physical and chemical character, structure, and
molecular behavior of
polyurethane and
epoxy
make them among the most common polymers used in industrial coatings.
Epoxy resins offer tough corrosion
protection and are typically used in primer applications to provide robust
chemical resistance.
Urethanes are often top-coated over a
primer, providing an extremely durable finish with exceptional weathering
characteristics and strong chemical resistance.
Catalysts, cross-linkers, flame
retardants, light stabilizers and other additives control and modify the
reaction process of various industrial coatings and determine the
performance characteristics of the cured polymer.
When properly mixed and applied, the
polymerization reaction that takes place in the formulated compound
develops specific physical bonding properties which could be thought of as
a 'chemical weld' at the molecular level to produce a protective coating
with maximum corrosion/abrasion resistance and an attractive 'high gloss'
finish all at the same time.
Though long-lasting and extremely
durable, polyurethane coatings are very easy to touch-up and repair. It is
necessary only to clean and prep the surface and reapply any readily
available industrial-quality polyurethane coating.
 The
pultruded components (doors, frames, louvers, etc.) manufactured by
Universal Pultrusions LLC are delivered either primed for or finished with
an aviation-grade polyurethane coating. This is the highest quality
industrial finish available, similar to the finish used by NASA on the
Space Shuttle.
This industrial coating is much stronger
and vastly more durable than polyester gelcoat. Considerably more
resistant to the relentless effects of UV radiation and air-borne
corrosives, polyurethane finishes are not susceptible to chalking,
crazing, discoloring, or leaching like gelcoat.
Additionally, polyurethane coatings
maintain a high gloss finish that lasts for years. For more information,
NACE International and
The
Society for Protective Coatings (SSPC) are professional organizations
involved in the industrial coatings industry. |
A gelcoat is a pigmented polyester resin
with relatively fragile properties used in the fabrication of conventional FRP
products but not in the pultrusion
process. A type of 'modified resin',
gelcoat serves three functions in the hand-laid or form molded FRP manufacturing
industry:
 Primarily,
gelcoat serves as a quick-setting 'buffer' and 'release agent' between the
curing fiberglass resins and the waxed surface of the mold. Applied to molds
(photo at right) in the liquid state, without gelcoat the resin would eat
through the wax and the part being fabricated would adhere to the mold.
Gelcoat also serves as a UV inhibitor. Pigments
in the gelcoat as well as added UV stabilizers protect the underlying resin from
the harsh radiation of the sun. Without gelcoat the resin which forms the
fabricated part would quickly oxidize, leaving nothing but frayed strands of
fiberglass.
And lastly, gelcoat is used because it provides
a colored (pigmented) glossy surface to the finished product.
Kept under cover or out of direct sunlight,
gelcoat may last for years, but in direct sunlight or when subjected to
caustic/abrasive or chronically wet environments it tends to oxidize and degrade rather quickly.
In fact, as the marine industry has come to learn, gelcoat is permeable by
water, allowing microscopic wetness to seep into miniscule airpockets in the
layered fiberglass/resin substructure resulting in pervasive delamination.
In addition, the 'thick or thin' nature of the
gelcoat application process can cause cracking, crazing and 'aligation'
(wrinkled like the hide of an alligator).
Gelcoat is very difficult at best to post apply
for touch-up or repair purposes. The material has a very heavy viscosity, a
short pot-life and generally a wax solution must be added to enable proper
curing, all of which makes gelcoat difficult to work with and hard to apply
smoothly.
 Paint is
essentially any liquid which, after application to a surface, dries to form a thin
opaque layer or film. Paint is also used to add
functionality to an object or surface by coloring it to modify
light reflection or
heat radiation. Another example of functionality would be the
use of color to identify hazards or to 'color code' the function of equipment,
tools or pipelines.
While paint does somewhat protect various
surfaces from corrosive elements, this retardant property quickly diminishes
with age and exposure. Thus paint's primary function is decorative.
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