HumiSeal® 1H2OUR5/D is a water-based polyurethane conformal coating, suitable for most dip or brush application methods. The coating contains a UV tracer for ease of inspection. HumiSeal® 1H2OUR5/D provides excellent moisture insulation resistance and can be chemically removed or soldered through for rework. HumiSeal® 1H2OUR5/D is IPC-CC-830 and RoHS Directive EU 2002/95/EC compliant.
Cleanliness of the substrate is of extreme importance for the successful application of a conformal coating. Surfaces must be free of moisture, dirt, wax, grease, flux residues and all other contaminants. Contamination under the coating will cause problems that may lead to assembly failures.
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® 1H2OUR5/D is first applied it has a milky white appearance. As the film dries, the white colour fades until a clear, transparent film remains. The white colour aids the operator’s coverage inspection and the colour change serves as an indicator that the coating is dry to the touch. It is recommended that the coating be allowed to reach a tack-free condition before using heat to accelerate the cure process.
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® 1H2OUR5/D from the dip tank is very low. However, over a long period of time, the addition of a small amount of fresh HumiSeal® 1H2OUR5/S 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.
HumiSeal® 1H2OUR5/D can be also applied by brush. The finish quality obtained depends on operator technique and the thickness of coating applied. For best results, the material should be “flowed” from the brush onto the board and the coating should be applied as thinly as possible. It is always possible to add an additional layer if more coating is required.
Provided the material is transferred from bulk to a small pot for application purposes, no thinners are necessary. HumiSeal® 1H2OUR5/D has a pot life of 1 week in the brush pot. Brushes can be cleaned promptly after use with DI water.
|Density, per ASTM D1475||1.05 ± 0.03 g/cm³|
|Solids Content, % by weight per Fed-Std-141, Meth. 4044||32 ± 2 %|
|Viscosity, per Fed-Std-141, Meth. 4287||530 ± 75 centipoise|
|Recommended Coating Thickness||25 - 75 microns|
|Drying Time to Handle per Fed-Std-141, Meth. 4061||60 min|
|Recommended Curing Conditions||1 hr @ RT and 6 hrs @ 80°C|
|Time required to Reach Optimum Properties||7 days|
|Recommended Stripper||HumiSeal Stripper 1072|
|Shelf Life at Room Temperature, DOM||18 months|
|Thermal Shock, 50 cycles per MIL-I-46058C||-65°C to 125°C|
|Flammability, per UL94||V-0|
|Dielectric Withstand Voltage, per MIL-I-46058C||>1500 volts|
|Dielectric Breakdown Voltage, per ASTM D149||6925 volts|
|Dielectric Constant, at 1MHz and 25°C per ASTM D150-98||2.5|
|Dissipation Factor, at 1MHz and 25°C per ASTM D150-98||0.01|
|Insulation Resistance, per MIL-I-46058C||2.3 x 1013 ohms (23TΩ)|
|Moisture Insulation Resistance, per MIL-I-46058C||8.2 x 1010 ohms (82GΩ)|
|Fungus Resistance, per ASTM G21||Passes|