HumiSeal® 1A20 conformal coating is:
- Urethane chemistry
- fast curing, chemically resistant
- single component
- used in combination with Thinner 521
- RoHS Directive 2002/95/EC compliant
- recognized under UL File Number E105698.
HumiSeal 1A20 conformal coating has:
- excellent moisture and environmental protection for printed circuit assemblies
- fluorescence under UV light for ease of inspection
- MIL-I-46058C qualified
- IPC-CC-830 compliance
- RoHS Directive 2002/95/EC compliance
Although its formulation allows HumiSeal® 1A20 to be applied using a wide variety of methods, care should be taken to ensure that it is only applied in an environment where the ambient relative humidity is at 60% or less. Application of the coating when the RH is higher than 60% can cause acceleration of the cure reaction, resulting in bubbles in the dried film.
Application of 1A20 Conformal Coating
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. Please contact a HumiSeal representative for additional information.
Depending on the complexity, density and configuration of components on the assembly, it may be necessary to reduce the viscosity of HumiSeal 1A20 with HumiSeal Thinner 521 in order to obtain a uniform film. Once optimum viscosity is determined, a controlled rate of immersion and withdrawal (typically, 5 to 15 cm/min) will further ensure even deposition of the coating and provide a uniform film. During application, evaporation of solvent causes an increase in viscosity that should be adjusted by adding small amounts of HumiSeal® Thinner 521. Viscosity in the dip tank should be checked regularly using a simple measuring device, such as a Zahn or Ford viscosity cup.
HumiSeal 1A20 can be sprayed using conventional spraying equipment. Spraying should be done in an environment with adequate ventilation so that vapor and mist are carried away from the operator. The addition of HumiSeal® Thinner 521 is necessary to ensure a uniform spray pattern resulting in a pinhole-free film. The amount of thinner and spray pressure will depend on the specific type of spray equipment and operator technique. The recommended ratio of HumiSeal 1A20 to HumiSeal Thinner 521 is 1:1 by volume; however, the ratio may need to be adjusted to obtain a uniform coating.
HumiSeal 1A20 may be brushed with a small addition of HumiSeal Thinner 521. Uniformity of the film depends on the component density and operator technique.
|Density, per ASTM D1475||1.02 ± 0.02 g/cm3|
|Solids Content, % by weight per Fed-Std-141, Meth. 4044||50 ± 3 %|
|Viscosity, per Fed-Std-141, Meth. 4287||100 ± 30 centipoise|
|Recommended Coating Thickness||25 -75 microns|
|Drying Time to Handle per Fed-Std-141, Meth. 4061||60 minutes|
|Recommended Curing Conditions||24 hrs @ RT or 3 hrs @ 76°C|
|Time Required to Reach Optimum Properties||7 days|
|Thinner, if needed (dipping, brushing, spraying)||HumiSeal® Thinner 521, 521EU|
|Recommended Stripper||HumiSeal® Stripper 1072|
|Shelf Life at Room Temperature, DOM||6 months|
|Thermal Shock, per MIL-I-46058C||-65°C to 125°C|
|Coefficient of Thermal Expansion – TMA||515 ppm/°C|
|Glass Transition Temperature – DSC||71°C|
|Modulus – DMA||89.6 MPa|
|Flammability, per UL94||V-0|
|Dielectric Withstand Voltage, per MIL-I-46058C||>1500 volts|
|Dielectric Constant, at 1MHz and 25°C per ASTM D150-98||3.5|
|Dissipation Factor, at 1MHz and 25°C per ASTM D150-98||0.028|
|Insulation Resistance, per MIL-I-46058C||3.0 x 1014 ohms (300TΩ)|
|Moisture Insulation Resistance, per MIL-I-46058C||4.8 x 1010 ohms (48GΩ)|
|Fungus Resistance, per ASTM G21||Passes|
|Resistance to Chemicals||Excellent|