POWDER COATINGS

POWDER COATINGS


We understand that what you are looking for in a product is better quality, durability, superior performance, corrosion resistance and aesthetic excellence. That is why we have designed our finishing process to excel in all those aspects. For close to 10 years, we have consistently been providing coatings of such high quality that are also better for the environment.


Nerocoat Advantages

QUALITY
Nerocoat's extensive product line has a reputation for providing quality that ranks with the best in the industry.
BATCH TO BATCH CONSISTENCY
When it comes to consistency, Nerocoat products exceed the industry norm by a wide margin.
FAITHFUL COLOUR MATCHING
Give us your difficult colours. Precision colour matching is our specialty.
PROBLEM SOLVING
Since pioneering the production of decorative powder coating in the country, DGP Group has found effective solutions to hundreds of difficult coating problems.

Advice & Guidance

COAT TOO THIN / IMPOSSIBLE TO INCREASE THE THICKNESS
  • Increase voltage, fluidization and powder feed.
  • Check resistance between different objects on conveyer. The ideal film reading is 0 ohm.
  • Check earth connection from conveyer and outward.
  • Check spray equipment fuses, voltage, electrodes in gun mouth and all electrical connections to high tension cable.
  • Check powder by using another powder spray gun.
POOR FLOW / ORANGE PEEL EFFECT
  • Adjust spray gun equipment parameters for uniform powder output and recommended film thickness.
  • Use fastest possible heat up rate in oven.
  • Check optimum distance between object and gun mouth.
DIFFERENT POWDER OUTPUTS FROM GUNS
  • Different hose lengths between powder feeds and guns
  • Air pressure too low
  • Electric fault or partial blocking of injector hose or gun
IMPROPER CURING
  • If problems arise due to over or under-curing from oven
  • Check that all thermostats are working properly
  • Check air circulation
  • Check metal temperature using temperature recorder.

Process

PREPARATION OF SURFACE
Preparation of the surface starts with a process to insure that the surface is properly cleaned and free of “soils” such as manufacturing oils. Subsequent surface treatments might include blasting, if required and iron phosphate or zinc phosphate depending on the long term corrosion performance desired Thermoplastic powders normally require a primer to promote adhesion. Thermoset powders do not need a primer because they have an adhesion promoter built-in. However, primers may be used with thermosets to enhance certain properties. The priming material used must be compatible with the curing temperatures required for powder coatings.
APPLICATION OF POWDER
Application of the powder is a function with many variations of two basic techniques. These techniques are fluidized bed and electrostatic spray. The fluidized bed is the original powder coating technique. It is still the primary technique used for the application of thermoplastic powders. The fluidized bed is also used for the application of some thermoset powders where high film build is required or components are very small. Thermoset powders designed for electrical insulation often use the fluidized bed technique. The parts are preheated to a temperature significantly higher than the melting point of the powder. The parts are then immersed into a "fluidized bed" of the coating powder where the plastic powder is melted onto the part.
ELECTROSTATIC SPRAY
Electrostatic spray is the primary technique used for thermoset powders. The particles of powder are given an electrical charge in the powder coating gun. The target part is attached to a fixture that is grounded. The electrically charged powder particles are attracted to the grounded part and attach themselves like little magnets to the part. The particles are actually repelled by the charged particles on the part and the coating process stops. This provides an even film thickness.
HEATING OF THE SURFACE
Heating of the surface is normally accomplished using ovens fueled by natural gas. Thermoplastic powders normally require the part surface to be heated prior to the application of the powder via the fluidized bed technique. Thermoset powders are normally applied via the electrostatic spray technique while the part is at room temperature. The part surface and the powder are then heated at the same time.

Why Powder Coating?

APPLICATIONS
Powder Coatings are a blend of resins, curing agents and pigments, which are melt-mixed (extruded) and pulverized into finely divided particles. They are totally solvent free.

Typically applied to metal products by electrostatic spray, the coated item is then heated and the powder melts into a smooth, continuous and encapsulating film. When thermosetting resins are used, the coating changes chemically (crosslinking) during cure, resulting in a decorative / functional finish with superior performance characteristics.
FEATURES
  • VOC emissions reduced to near zero.
  • No sludge or solvent disposal.
  • Virtually 100% material usage, over spray can be reclaimed.
  • Reduced health, fire, safety hazards.
BENEFITS
  • One step compliance, virtually 100% solids.
  • Significant reduction in disposal costs.
  • Typically lower applied material costs.
  • Cleaner plant operations, reduced costs.
POWDER CLASSIFICATIONS

There are two basic classifications of powder coating materials. They are "thermoplastic" and "thermoset" powders.

THERMOPLASTIC POWDERS

Thermoplastic powders are generally applied to a surface that has been pre-heated to a temperature significantly higher than the melting point of the powder. It melts and flows when heat is applied but continues to have the same chemical composition when it solidifies on cooling. Nylon powder coating materials are the most commonly used thermoplastic powders. Thermoplastic coatings are known for their wear and chemical resistance.

THERMOSET POWDERS

Thermoset powders are 100% solvent-less and are generally applied by means of electrostatic spray equipment that provides each powder particle with a small electric charge, which in turn sticks to the earthed substrate. Thermoset powder coating systems offer broad formulation flexibility. They are very durable and are widely used.

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