UV Powder Coatings                      Back to Powder-Coater Home Page




abrasive blasting
adhesion problems
caps and plugs
chemical cleaning
cure ovens
fluidized bed
hi-temp tapes
infrared oven

powder formulations


Paint Arrestors
powder selection
powder vs. liquid
spray booth
spray gun
types of powder


Curing of powder coatings with UV light can be described as "the best of two worlds". This new method makes it possible to benefit from the advantages of high cure speed and low cure temperature as well as environmental friendliness.

The handling and preparation of UV powder coatings is similar to the methods used for conventional powder coatings. During application the UV powder coating is generally melted by exposure to IR light. This process takes only 1-2 minutes with a required final temperature of 90-140°C, depending on the selected UV powder system.

Because of this relatively low temperature it is possible to cure heat sensitive substrates with UV powder such as MDF, plastic, glass and pre-assembled parts which combine metal and heat sensitive materials.

UV powder can also be applied on metal, with the main advantage that the metal does not have to be heated to such high temperatures, or for as much time as required with thermal curing powder coatings.

Crosslinking of the melted UV powder occurs by exposure to UV light. The curing by UV radiation is only a few seconds which gives a total curing time of 1-3 minutes.

The cured coating has properties of adhesion and hardness that compare very well to liquid UV coating and the chemical resistance is generally even better.


UV curable powder coatings are very environmentally friendly for several reasons. First, there is hardly any emission of volatile organic compounds. In the future it is expected that the emission of VOC´s from industrial processes will be decreased and controlled by governmental regulations. As a result many companies will have to decrease their emission of VOC´s drastically. The use of UV curable powder is a good solution.

Another factor affecting the environmental friendliness is the much shorter heating period compared to conventional powder, as well as the lower heating temperature. UV curable powder coating saves energy and reduces CO2 emissions. Compared to solvent based systems the waste of UV powder coating is much lower because overspray is easily reclaimed and reused.

Cost Considerations

The total costs of a coating system depend very much on the costs of the material used. In general, UV powder has the advantage of high material utilisation. 95% of the powder can be used, compared to 60% for most sprayed wet paints.

As mentioned above, the overspray of UV powder coating can be recycled , whereas overspray of liquid paints is generally scrapped. Therefore, the price per liter or kg of paint cannot be fairly compared.

Comparisons can better be based on the price per coated square meter. The price per coated square meter is also dependent on the number of coating layers. A good result with UV powder coating is often obtained with one layer. With other coating systems, such as UV liquid or nitrocellulose lacquers, multiple layers are necessary, which increase the costs per square meter.

The main advantages of UV curable powder systems are:

  • Low system costs
  • Excellent coating properties
  • High cure speed
  • Low cure temperature
  • Hardly any emission of volatile organic compounds
  • Maximum powder use with overspray recycling
  • Application of thicker coating layers (depending on pigmentation level)
  • Application of one layer

The handling and processing of the powder is much like the handling and processing of conventional powder and a standard extruder can be used.


The applied powder is cured in an installation that consists of two sections: the IR section (melting and flow) and the UV section (cure).

The IR section is equipped with medium-wave IR lamps (600W). With a pyrometer coupled to the power supply of the IR section a good control of the melting temperature can be achieved.

In general, the H, D and V bulbs of an electrodeless Fusion F600 UV-lamp (240W/cm) are recommended for the UV section. The lamps can have a variable power supply. It is important that the lamps are suitable to cure the coating with an optimal result. Not only the lamps are of importance, but also the photoinitiators and the pigments. These must all be compatible to each other

For clear coatings an H-bulb (Hg-lamp) is used at 120W/cm which is 50% of the maximum power. For the white pigmented coatings, the V-bulb (Gallium lamp) which has longer wavelength radiation gives the best result. For a white coating the power used is 144W/cm (60% of the maximum power).

Chemistry Chemistry

UV powder coating formulations consist of:

  • UV powder resin
  • Photoinitiator
  • Additives
  • Pigment / extenders
  • UV powder resin

Source: DSM Coating Resins

Web www.powder-coater.com

Powder Coater's Manual 1/98

Print the entire Powder Coaters Manual

Back to Powder-Coater Home Page

August 28, 2006