Know-how:

 

Processing of waterborne opaque and translucent coatings

The benefits of waterborne coating systems compared to solventborne materials are much greater in the surroundings of a paint shop than you might think. Waterborne translucent and opaque coats offer benefits in the conditions of the factory department, the emissions values, the design of filter systems and electrical equipment, danger of explosion and fire and the health of employees.

Additional painting uses such as avoiding room ventilation, limitation of room temperature control and radical shortening of painting times are often suggested, but without limiting the painting result they cannot be realised in practice. In order to avoid painting errors we would therefore like to make a few suggestions:

 

1. Removal of moisture and temperature control
The view that because waterborne translucent coats do not have organic thinners means there is no need for ventilation is incorrect. As long as the opaque coating is in the water it cannot harden. It is therefore very important to ensure a good ventilation of dry rooms.

 

2. Wet layer thickness
The rheology of many dispersion paints allows the application of wet layer thicknesses with a higher amount. Such thick opaque coatings cannot sufficiently harden within the normal drying time of 12-18 hours, however, which leads to problems in transportation, working on and de-stacking windows. If you want the opaque coating to dry well overnight, then waterborne opaque coating should not be applied more thickly than 150 μm wet.

3. Drying
If, simply due to the appearance or because of manual touching for dryness, it is already closed and a second coating is applied after just a few hours, then the first coating can swell due to the water of the second coating and then continue drying with major delay.

 

4. Seals
Sealant and lip seals have to be aligned to the water paint system in order to avoid solvation, discolourations and adhesion to/with the coating.

 

5. Fittings
Fittings and fastenings must be corrosion-resistant. The contact pressure between the frame and sash should be equal across the entire unit (sash) and not be too high.