Application of 1H20AR3/D Conformal Coating

Cleanliness of the substrate is of extreme importance for the successful application of HumiSeal 1H20AR3/D. Surfaces must be free of moisture, dirt, wax, grease, flux residues and all other contaminants. Conformal coatings can be successfully applied to substrates that have been cleaned prior to coating and also to substrates assembled with low residue “no clean” materials.  Users should perform adequate testing to confirm compatibility between the conformal coating and their particular assembly materials, process conditions and cleanliness level.

Waterborne coatings should not be placed directly on bare/untreated steel. Applying waterborne coatings when the Relative Humidity is > 80% will adversely affect coating uniformity and can cause poor adhesion.

When HumiSeal® 1H2OAR3/D is first applied it has a milky white appearance. As the film dries, the white color fades until a clear, transparent film remains. The white color aids the operator’s coverage inspection and the color change serves as an indicator that the coating is dry to the touch. It is recommended that the coating is allowed to reach a tack-free condition before using heat to accelerate the cure process.

Dipping

The material has been formulated for dip application as supplied and requires no thinning. Thinning will reduce the application performance and increase curing time substantially and is not recommended. Because it is a water-based coating, evaporation of HumiSeal® 1H2OAR3/D from the dip tank is very low. However, over a long period of time, the addition of a small amount of fresh HumiSeal® 1H2OAR3/D is beneficial, to replace the low level of coalescing solvents that are lost along with some water. The coalescing solvents are essential to provide optimum film formation and the other physical and electrical properties of the resin. A slightly slower immersion speed is recommended to reduce the possibility of air entrapment under the components. The withdrawal speed depends on the complexity of the assembly being coated. Although the material has been formulated to lay down 1.5 mils in a single dip application, for densely populated assemblies, reducing the withdrawal speed or applying two successive thinner coatings will give better edge coverage and a better coating appearance.