HumiSeal® 1A34 is a single component, fast curing polyurethane conformal coating. HumiSeal® 1A34 offers easy application and handling and fluoresces under UV light for ease of inspection. HumiSeal® 1A34 coating is MIL-I-46058C qualified, IPC-CC-830 and RoHS Directive 2002/95/EC compliant.

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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® 1A34 with HumiSeal® Thinner 521 or 521EU 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 521 or 521EU. Viscosity in the dip tank should be checked regularly using a simple measuring device such as a Zahn or Ford viscosity cup.

HumiSeal® 1A34 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 or 521EU 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® 1A34 to HumiSeal® Thinner 521 or 521EU is 1:1 by volume; however the ratio may need to be adjusted to obtain a uniform coating.

HumiSeal® 1A34 may be brushed with a small addition of HumiSeal® Thinner 521 or 521EU. Uniformity of the film depends on component density and operator’s technique.

Product Specification

Product Specification
Density, per ASTM D1475 0.95 ± 0.02 g/cm3
Solids Content, % by weight per Fed-Std-141, Meth. 4044 39 ± 2 %
Viscosity, per Fed-Std-141, Meth. 4287 125 ± 75 centipoise
VOC 576 grams/litre
Recommended Coating Thickness 25 -75 microns
Drying Time to Handle per Fed-Std-141, Meth. 4061 120 ± 30 minutes
Recommended Curing Conditions 24 hrs @ RT or 4 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 260 ppm/°C
Glass Transition Temperature – DSC  18°C
Modulus – DMA  51.3 MPa
Flammability, per MIL-I-46058C  Self-Extinguishing
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 1.7 x 1014 ohms (170TΩ)
Moisture Insulation Resistance, per MIL-I-46058C  6.3 x 1010 ohms (63GΩ)
Fungus Resistance, per ASTM G21 Passes