HumiSeal 1B66 is a fast drying, single component, acrylic conformal coating that provides excellent moisture and environmental protection for printed circuit assemblies. HumiSeal® 1B66 demonstrates outstanding flexibility and is easily repaired. HumiSeal® 1B66 coating is RoHS Directive 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 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® 1B66 with HumiSeal® Thinner 503 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 503. Viscosity in the dip tank should be checked regularly, using a simple measuring device such as a Zahn or Ford viscosity cup.
HumiSeal® 1B66 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 521 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® 1B66 to HumiSeal® Thinner 521 is 1:1 by volume; however the ratio may need to be adjusted to obtain a uniform coating.
HumiSeal® 1B66 may be brushed with a small addition of HumiSeal® Thinner 503. Uniformity of the film depends on component density and operator’s technique.
|Density, per ASTM D1475||0.91 ± .02 g/cm3|
|Solids Content, % by weight per Fed-Std-141, Meth. 4044||35 ± 3 %|
|Viscosity, per Fed-Std-141, Meth. 4287||200 ± 15 centipoise|
|Drying Time to Handle per Fed-Std-141, Meth. 4061||10 minutes|
|Recommended Coating Thickness||25 – 75 microns|
|Recommended Curing Conditions||24hrs @ RT or 30min @ 76°C|
|Time Required to Reach Optimum Properties||7 days|
|Recommended Thinner (dipping & brushing)||HumiSeal Thinner 503|
|Recommended Thinner (spraying)||HumiSeal Thinner 521|
|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||175 ppm/°C below Tg |
345 ppm/°C above Tg
|Glass Transition Temperature – DSC||14°C|
|Modulus – DMA||850 MPa @ 40°C|
|Dielectric Withstand Voltage, per MIL-I-46058C||>1500 volts|
|Dielectric Breakdown Voltage, per ASTM D149||7500 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||8.0 x 1012 ohms (800TΩ)|
|Moisture Insulation Resistance, per MIL-I-46058C||6.0 x 1010 ohms (60GΩ)|
|Fungus Resistance, per ASTM G21||Passes|