VR208 – IGP-DURA®than 8909B Weather resistant industrial quality
Introduction
System 8909B was developed for use as a topcoat powder coating for permanent graffiti prevention on metal surfaces.
Processing
Initial coating with a high-voltage setting of 60 to 70 kV. When overcoating with 8909B with a setting of 50 to 60 kV and a current limiter <10 μm.
Spray-back effects can be avoided by using ion-leakage rings (low-ion charge).
We recommend flat spray nozzles. The spraying distances can be set to 250 mm. To optimise the coating thickness distribution, the speed of the lifting devices must be adapted to the transport speed when coating in long-stroke operation (coordinated sinusoidal curve of the guns). Coating in short-stroke operation requires the lifting height to be adapted to the intermediate distance between the guns (coordinated gun turning points). Any necessary manual application in semi-automatic mode should be carried out as a pre-coating.
We recommend working with Film thicknesses of 50 μm to 70 μm.
With IGP-DURA®than 8909B, fine bubbles may appear in the powder-coated surface with Film thicknesses of > 90 μm after curing.
Processing with tribo guns is not recommended.
Reclaiming
Continuous dosing of fresh powder is recommended for Processing IGP-DURA®than 8909B in reclaiming mode.
Maintenance and Cleaning of all system components (guns, hoses, cyclone...) must be carried out with the utmost care.
Earthing
When processing IGP-DURA®than 8909B, especially on substrates that have already been coated, ensure that the substrate is sufficiently earthing.
Curing in the oven
Curing requires exact temperature control.
If the temperature falls below the required object temperature, cracking may occur in the powder-coated surface, while exceeding this temperature usually results in yellowing and foaming of the powder coating layer.
Based on these conditions, we recommend creating a temperature profile of the curing oven with an oven measuring device under production conditions before starting production. Curing of the coated objects should always be carried out on the basis of the time combination of retention time at object temperature determined with the oven measuring device, taking into account the recommended curing conditions. The recommended temperature and time combinations according to the technical data sheet must not be exceeded under any circumstances.
Ventilation and smoke development
During the curing process, 8909B releases decomposition products in the form of caprolactam. Decomposition products generate a lot of smoke, which must be removed from the inside of the curing oven by adequate ventilation. If the curing oven is not equipped with sufficient ventilation, it is essential to ensure adequate ventilation of the room and oven. The list of information on special risks (H-phrases H302/H312/H332/H315/H319/H317/H335/H336) must be observed. Deposited decomposition products in the curing oven, especially on the oven walls and in the venting area, must be removed in due course, depending on their thickness.
Paint stripping
IGP-DURA®than 8909B is difficult to paint strip chemically. Collector hangers used for coating can be freed from powder coating using a flame process.
Applicable documents
- Technical data sheet IGP-DURA®than8909B
Further recommendations for Processing IGP-DURA®than 8909B
Equipment and processing parameters (appliances / accessories) | Setting (parameters) according to categorisation | Possible influences on (remark) |
Uni | ||
High voltage setting kV | 50-70 | Charging / back sprayer (note actual values) |
Current limiter µA (gun) | < 20 < 10 | à Normal operation à Reduces overloading effects in case of overcoating |
Total air Nm3/h Conveying + dosing air (internal⌀ powder hose) | 12mm = 5 Nm3/h 11mm = 4 Nm3/h 10mm = 3 Nm3/h | Prevents pulsation of the powder cloud |
Powder hose with integrated earthing (injector - gun) | Earthing the injector | Prevents electrostatic charge in the powder hose |
Nozzle (gun) with flat spray nozzles | Suitable | Ensure a "soft" cloud |
Nozzle (gun) with buffle plate | suitable | Reduced depth |
Processing with ion-leakage ring (gun) | Possible with and without | When used, reduced overloading effects when overcoating |
Spraying distance coating (gun - workpiece) | ≥ 250mm | Prevents blow-off effects |
Coating with tribo guns | Not suitable | No sufficient charging |
Powder feed from fluidised container | Well suited, fluidising air as required | Check fluidisation before coating |
Powder delivery from the carton | Not recommended | Sometimes slightly irregular conveying and therefore irregular layer thicknesses |
Screening with US screen (sieving machine) | Recommended with mesh size >140µm | Better fluidisation, more even application |
Maximum proportion of reclaimed powder in recirculation mode | ≤ 90% | Prevents shifts in the particle distribution |
Processing parameters (control unit programme) | Recommended | Facilitates reproducibility of the coating results |
Create limit samples in advance | Conditionally recommended | Recommended for first use |
Coating on different coating plants | Possible | Adjust parameters accordingly |
Manual pre-coating of the workpieces in semi-automatic operation | possible | Pay attention to recommended layer thicknesses |
Manual follow-up coating of the workpieces in semi-automatic operation | possible | Pay attention to recommended layer thicknesses |
Manual coating only | possible | Ensure even layer thickness distribution |
This application-technical consultation is based on the current state of knowledge, but is only non-binding and does not exempt the coater from carrying out their own tests.
