HumiSeal 1B18 is a single component, fast drying, acrylic conformal coating intended for use on printed circuit assemblies. HumiSeal® 1B18 demonstrates excellent flexibility and electrical properties, fluoresces under UV light for ease of inspection and is easily repaired. HumiSeal® 1B18 coating is RoHS Directive 2002/95/EC compliant, and recognized under UL File Number E105698.
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 could cause problems that may lead to assembly failures.
Depending on the complexity, density and configuration of components on the assembly, it may be necessary to reduce the viscosity of HumiSeal® 1B18 with HumiSeal® Thinner 73 in order to obtain a uniform film. Once optimum viscosity is determined, a controlled rate of immersion and withdrawal (5-15 cm/min) will further ensure even deposition of the coating and ultimately a uniform film. During the application, evaporation of solvent causes an increase in viscosity that should be adjusted by adding small amounts of HumiSeal® Thinner 73. Viscosity in the dip tank should be checked regularly, using a simple measuring device such as a Zahn or Ford viscosity cup.
HumiSeal® 1B18 can be sprayed using conventional spraying equipment. Spraying should be done in an environment with adequate ventilation so that the vapour and mist are carried away from the operator. The addition of HumiSeal® Thinner 73 is necessary to ensure a uniform spray pattern resulting in pinhole-free film. The amount of thinner and spray pressure will depend on the specific type of spray equipment used and operator technique. The recommended ratio of HumiSeal® 1B18 to HumiSeal® Thinner 73 is 1:1 by volume, however the ratio may need to be adjusted to obtain a uniform coating.
HumiSeal® 1B18 may be brushed with a small addition of HumiSeal® Thinner 73. Uniformity of the film depends on component density and operator’s technique.
|Density, per ASTM D1475||0.92 ± 0.02 g/cm³|
|Solids Content, % by weight per Fed-Std-141, Meth. 4044||30 ± 2 %|
|Viscosity, per Fed-Std-141, Meth. 4287||250 ± 20 centipoise|
|Drying Time to Handle per Fed-Std-141, Meth. 4061||30 minutes|
|Recommended Coating Thickness||25 – 75 microns|
|Recommended Curing Conditions||24 hrs @ RT or 2 hrs @ 76°C|
|Time Required to Reach Optimum Properties||7 days|
|Recommended Thinner||HumiSeal Thinner 73|
|Recommended Stripper||HumiSeal Stripper 1080|
|Shelf Life at Room Temperature, DOM||24 months|
|Thermal Shock, 50 cycles per MIL-I-46058C||-65°C to 125°C|
|Coefficient of Thermal Expansion – TMA||67 ppm/°C|
|Glass Transition Temperature – DSC||42°C|
|Modulus – DMA||11.1 MPa|
|Flammability, per UL 94||V-0|
|Dielectric Withstand Voltage, per MIL-I-46058C||>1500 volts|
|Dielectric Breakdown Voltage, per ASTM D149||6300 volts|
|Dielectric Constant, at 1MHz and 25°C, per ASTM D150-98||2.6|
|Dissipation Factor, at 1MHz and 25°C, per ASTM D150-98||0.01|
|Insulation Resistance, per MIL-I-46058C||5.5 x 1014 ohms (550TΩ)|
|Moisture Insulation Resistance, per MIL-I-46058C||7.0 x 109 ohms (70GΩ)|
|Fungus Resistance, per ASTM G21||Passes|