is Powder Coating?
the Challenges of Heat Sensitive Substrates
Powder Coating Fills a Need for MDF Products
Powder Coating Is Friendly to the Environment
Powder Coating Means Lower Costs and Higher Efficiency
Powder Coating Offers Versatility and Durability
Powder Coating Enhance Your Product Line
Over the last twenty years, powder coating has revolutionized the finishing
industry by providing a superior, durable, environmentally friendly finish,
particularly for metal products such as appliances, automotive parts,
sporting goods and countless other products. Powder coating is now the
fastest growing finishing method in North America .
Now a second powder coating revolution is under way. Technological advancements
in powder coating materials and application and curing methods have brought
the advantages of powder coating to heat sensitive substrates. Powder
coating is now used on a variety of products that were thought impossible
just a few years ago.
of the biggest breakthroughs for powder in the heat sensitive substrate
market is on medium density fiberboard, or MDF, a combination panel bonding
particles of wood with a synthetic resin. MDF is very suitable for powder
coating application because of its low porosity and homogeneous surface.
MDF products include office furniture, kitchen and bath cabinets, doors,
store fixtures and displays, barbecue trays and ready-to-assemble furniture
for the office and home etc.
Powder coating is revolutionizing
the MDF market because it offers design freedoms that other finishing
methods and laminating processes just can't provide. Powder coating provides
a beautiful, durable, seamless finish in every color of the rainbow. And
powder coating protects MDF products from chips, stains, spills, and scratches.
What Is Powder
Powder coating is a dry finishing process, using finely ground particles
of pigment and resin, which are electrostatically charged and sprayed
onto a part to be coated. The charged particles adhere to the parts until
melted and fused into a tough, even coating through the application of
heat and energy.
Challenges of Heat Sensitive Substrates
woods and wood products such as MDF have sufficient and consistent moisture
content to provide conductivity and can be coated directly. Wood parts
that require sanding can be cleaned with compressed air to remove any
surface contaminants. To enhance electrostatic attraction, wood can be
pretreated with a spray solution that provides a conductive surface. The
part is then preheated to a desired coating temperature, which softens
or partially melts the powder when it is applied and helps the powder
adhere to the part where it melts a little on impact. A uniform board
surface temperature allows for high transfer efficiency and a consistent
powder application, an electrostatic charge is applied from the spray
gun to deposit powder on the MDF surface. Powder materials for MDF can
be either thermal cure products or UV-cured powders. Thermal cure powders
rely on infrared ovens,(thus higher temperatures) convection ovens or
hybrid ovens that combine infrared and convection heating. The thermal
energy melts the powder so it will flow into a level film and eventually
cure, or crosslink, into a finished film.
With specially formulated UV-curable powders, the melt and flow can be
separated from the curing process and requires minimal heat to cure
the powder. After the parts enter an infrared or convection oven where
the coating melts and flows for two to ten minutes, the board is exposed
to ultraviolet light for just a few seconds for final curing and hardening
of the finish. Then the parts cool naturally or in a cooling tunnel before
they are unloaded from the coating line.
Powder Coating Fills
a Need for MDF Products
office furniture makers are moving away from standard shapes such as squares
and rectangles to more rounded corners and contoured edges, with interior
circles and ellipses to allow for computer cords to drop through. They
are also offering seamless desktop coatings and a variety of colors and
effects. Powder coating can accommodate these shapes, while current lamination
techniques, which rely on edge-banding methods cannot; and powder application
is a one-step finishing process, not requiring successive coats or a long
time to dry.
Is Friendly to the Environment
- Negligible VOCs
- Powder coatings contain no solvents and therefore emit negligible,
if any, polluting VOCs into the atmosphere.
- Less exhaust
- Powder coating is a clean process, allowing exhaust air from the coating
booth to be returned to the plant, and less oven air is exhausted to
- Reusable overspray
- Up to 98% of powder overspray can be retrieved and reused.
- No costly waste
disposal equipment - Unused powder can be reclaimed and returned
to a hopper for recirculating through the system, with negligible waste.
Powder Coating Means
Lower Costs and Higher Efficiency
Powder coating is an economical
and efficient operation.
- Lower heating costs
for curing oven -The exhaust requirements for a powder coating
oven are lower than solvent-based coatings, resulting in energy savings.
- Greater operating
efficiency means lower unit costs - No drying or flash-off
time is required. Parts can be racked closer together on conveyors and
pass more quickly through the production line.
- Lower reject rates
- More parts can be coated automatically with fewer rejects because
powder coating does not run, drip or sag.
utilization efficiency - With proper application equipment,
powder materials and efficient recovery methods, one-coat application
and 95%-98% powder utilization efficiency are readily available. If
more than one color is desired, color changes can be made quickly.
- Lower personnel
costs - Minimal operator training and supervision are required
for a powder line. Employees prefer working with dry powder because
of lack of fumes, reduced housekeeping problems and minimum clothing
- Simplified permit
process - The permitting process for a powder coating operation
is simpler. Compliance with federal and state regulations is also easier,
saving both time and money.
Powder Coating Offers Versatility and Durability
Most importantly, powder coating
provides a durable and high-quality finish, with a wide range of performance
properties including excellent resistance to impact, abrasion, heat, stains,
extreme weather and fading from sunlight. Texture selections range from
smooth surfaces to a wrinkled or matte finish. Rough textures are also
available, designed specifically for hiding any surface imperfections.
And color selection is virtually unlimited, including clearcoats.
Powder Coating Beyond
addition to successfully penetrating the MDF market, powder has proven
to be an effective finishing choice for other heat sensitive substrates
such as plastic parts made of nylon and polycarbonate and assembled or
partially assembled products such as appliances, electric motors or automotive
radiators. Because of advancements in low temperature cure powders, plastic
parts and wires and rubber seals and gaskets are not damaged in the powder
And the revolution has just
begun. Successful testing has occurred on hardwoods such as beech, oak,
ash and walnut. Research engineers are studying the use of powder on paper-laminated
MDF, laminated flooring and particleboard. Research is also being conducted
on countertops, wood moulding and trim, all of which will increase demand
for, and use of, powder coatings in more new markets.
Let Powder Coating Enhance Your Product