Ultraviolet (UV) light has been used to cure coatings for more than 30 years, and companies have been successfully using UV-cured powder coatings for more than 20 years. UV-cured powder coatings can replace solvent liquid coating (in some cases thermoset powder coating) and are a finishing material of interest for many new materials and products.
1. Keyland Polymer UV Powder, LLC
Cleveland, Ohio
RadTech uv.eb WEST 2017
UV LED Curing of UV-Cured
Powder Coatings
2. Develop, formulate, manufacture
and sell UV- cured powder
coatings.
Sold under UVMax brand used on
wood, metal, plastic & composite
substrates
Develop , produce and sell solid
polyester, epoxy & other resins
used in UV-cured solid materials
Produces & sells MDF wood
components
to commercial and industrial
furniture companies using
UVMax powder coatings made by
Keyland Polymer UV Powder
Development of Ultra Violet (UV)
microwave or UV LED curing
solutions of solid materials used as
coatings, additive materials and
other product applications
Focus on solid UV & EB cured materials
Resins – Powders – Materials - Applications
5. Polyester – broad range of performance attributes – can achieve
ASTM 1000 hour corrosion resistance – BPA Free
MDF
Metal
Composite
Epoxy – Hard functional coatings – primarily for interior applications
Metal
Composite
Hybrid – Polyester/Epoxy – for specialized applications
MDF
Metal
Plastics
Composites
Resin Platform
6. The differentiating characteristic of UV-curable powder coating is the
separation of melt & flow from cure
UV-Cured Powder Coating
Melt & Flow
1-2 minutes
UV Cure
(seconds)
Minimal
cooling
Electrostatic
Powder
Deposition
Finished
Product
Substrate
Pretreatment
Melt, Flow & Cure
5 to >60 mins
+ cooling
Thermal Powder Coating
UV Powder Coating
7. UV-Cured Powder Coating Thermal
Profile
1 second 47 seconds 96 seconds
65°C 78°C 104°C
Total time in front of IR panel 120 seconds
Total dwell time in front of IR panel 96 seconds
Surface temperature end of cure – 85o C
Melting powder not heating part
8. Reduction in energy consumption
Shorter & faster thermal cycles
No oxygen inhibition
Less time in oven(s)
Smaller ovens
Finish heat sensitive substrates
MDF/Wood
Plastics
Composites
Assembled products
Less risk to substrates
Reduced moisture loss in MDF & wood
Reduced potential thermal cracking in MDF & wood
Reduced potential of outgassing cast metals
Eliminate damage to heat sensitive gaskets and seals
Advantages of UV-Cured Powder
Coating
9. UV LED technology is increasing market interest and demand for UV
cured materials
Higher energy output efficiency
Longer useful life
Lower total cost of energy
Targeted curing
Cure complex shapes/geometries
No heavy metals
No IR
UV LED Curing Technology
10. Substrates
MDF – Low heat – less moisture volatilization more stable substrate
Wood – Low heat – less resin volatilization
Plastics – Low heat – less warp of certain plastics
Composites – No degradation of substrate
Metals – ASTM B-117 – 1000 hour corrosion resistance
Assembled parts – Low heat – no damage to heat sensitive gaskets and seals
Substrates for UV LED Powder
Coatings
16. Lamp Type
Power
Spectrum
Exposure
mJ/cm2
Irradiance
mW/cm2
300W Medium
Pressure@ 100%
UVV
2811 1088
600W Medium
Pressure@100%
UVV
10000 2232
600W Medium
Pressure@50%
UVV
5622 1244
395nm
LED@100%
8W UVA2
12312 2711
5'/minute @ 4" distance
Comparison 300W, 600W & 395nm
UV LED
Irradiance (intensity)–
lamp power or output
called peak. Irradiance
is measured by power
and at a distance -
mW/cm2
Exposure (energy
density) – amount of
energy on the surface
measured in mJ/cm2,
determined by
irradiance and time
18. Material & Set Cure Method
Lamp
Distance cm
Film Build
Mils
Final Tg oC Cure Evaluation
Clear 1 300W V bulb 6 2 82 Cured
White 1 300W V bulb 6 2 69 Just Cured
Clear 2 300W V bulb 18.5 2 79 Cured
White 2 300W V bulb 18.5 2 60 Uncured
Clear 3 395 UV LED 1.3 2 84 Cured
Clear 3 395 UV LED 5 2 88 Cured
Clear 3 395 UV LED 10.2 2 82 Cured
White 4 395 UV LED 1.3 2 73 Cured
White 4 395 UV LED 5 2 73 Cured
White 4 395 UV LED 10.2 2 61 Uncured
Clear 5 395 UV LED 10.2 3 84 Cured
White 6 395 UV LED 5 3 74 Cured
White 6 395UV LED 10.2 3 70 Cured
Black 7 395 UV LED 1.3 2 96 Cured
Black 7 395 UV LED 5 2 92 Cured
Black 7 395 UV LED 10.2 2 83 Cured
Black 9 395 UV LED 1.3 2 96 Cured
Black 9 395 UV LED 5 3 88 Cured
Black 9 395 UV LED 10.2 3 84 Cured
Black 10 395 UV LED 1.3 3 90 Cured
Black 10 395 UV LED 5 3 87 Cured
Black 10 395UV LED 10.2 3 87 Cured
UV LED Cure Clear, Black, White
19. Material & Set Photoinitiator
Cure
Method
Lamp
Distance
CM
Final Tg oC
MEK
rating
50
Double
Rubs
Cure Evaluation
White HR1 std Standard
300W V
bulb
6 76 NA Cured
White JR1 Standard
300W V
bulb
6 78 NA Cured
White FR1 Standard
300W V
bulb
6 72 NA Cured
White JR1 Standard 395 UV LED 1.3 77 10 Cured
White JR1 Standard 395 UV LED 5 75 9 Cured
White JR1 Standard 395 UV LED 10.2 76 10 Cured
White JR2 Non standard 1 395 UV LED 1.3 66 10 Uncured
White JR2 Non standard 1 395 UV LED 5 71 10 Cured
White JR2 Non standard 1 395 UV LED 10.2 74 10 Cured
White JR5 Non standard 2 395 UV LED 1.3 No data 10 NA
White JR5 Non standard 2 395 UV LED 5 77 10 Cured
White JR5 Non standard 2 395 UV LED 10.2 75 9 Cured
White JR7 Non standard 3 395 UV LED 1.3 68 10 Just cured
White JR7 Non standard 3 395 UV LED 5 No data 10 NA
White JR7 Non standard 4 395 UV LED 10.2 71 10 Cured
White JR9 Non standard 5 395 UV LED 1.3 45 0 Uncured
UV LED Cure Photoinitiator Study
21. Cure is the measure of the crosslinked oligomer chains or fully reacted double
bonds residing in the coating matrix following exposure to the curing system,
which can be thermal energy or Ultra Violet light exposure. Differential Scanning
Calorimetry (DSC) is a scientifically recognized, reliable and repeatable
methodology to measure the cure of a coating system.
Ultra-Violet (UV) powder coatings are photopolymerized coatings containing a
chemical photoinitiator that instantly responds to UV light energy initiating a
chain reaction and curing the coating. The melt stage is separate from the curing
of the coating. Melting is typically 1-2 minutes and is followed by UV-curing. As
long as the proper amount of UV energy is present, the UV-cured powder
coating will cure in a matter of seconds.
Definition of Cure & UV-Cure
23. A 395nm UV LED will cure a clear, black, white and other non-
conflicting UV absorbing pigmented UV-cured powder coating
Increasing power output of UV LED expand application possibilities
Additional R&D is needed to overcome UV absorption conflicts
New photoinitiators
Pigments analysis
UV LED cured powder coatings are suitable for use on various
substrates, simple and complex geometries
UV LED enables targeted and robotic lamp movement to cure
complex geometries
UV LED curing of UV-cured powder coating is an enabling technology,
expanding the product and market opportunities for powder coating
Conclusions
24. Equipment:
NobleCure NC-B1-8W395/L3, 100% Power, Various heights, 5 ft/min
LED Power Supply: LED-PSCC2-8-10-48
UVICURE PLUS II with UVA2 Sensor
Extech Digital Contact Tachometer Model 461891
RayTek ST ProPlus Infrared Thermometer
Convection Oven Set At 400 °F (for 4 min flash)
Mettler DSC822e cooled with liquid nitrogen
EIT Power puck
Testing locations:
Keyland Polymer, LLC. Cleveland, Ohio
Heraeus Noblelight America, LLC. Gaithersburg, Maryland
Thermodynamics Laboratory Department of the ETSEIB, Universitat
Politecnica de Catalunya (UPC, Barcelona, Spain).
Equipment &Technical Assistance