HumiSeal 1A27 Urethane Conformal Coating
Properties of HumiSeal® 1A27
Density, per ASTM D1475 0.96 ± 0.02 g/cm³
Solids Content, % by weight per Fed-Std-141, Meth. 4044 50 ± 3 %
Viscosity, per Fed-Std-141, Meth. 4287 3000 ± 1000 centipoise VOC 480 grams/litre Recommended Coating Thickness 25 - 75 microns
Drying Time to Handle per Fed-Std-141, Meth. 4061 30 minutes
Optional Curing Conditions to Reach Optimum Properties 30 days at RT
30 hours @ 76°C
20 hours @ 88°C Recommended Thinner HumiSeal® Thinner 521
Recommended Stripper HumiSeal® Stripper 1063
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 170 ppm/°C Glass Transition Temperature - DSC 28°C
Modulus - DMA 18.1 MPa
Flammability, per UL 94 V-0
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 3.6
Dissipation Factor, at 1MHz and 25°C per ASTM D150-98 0.02
Insulation Resistance, per MIL-I-46058C 2.0 x 1014 ohms (200TΩ) Moisture Insulation Resistance, per MIL-I-46058C 1.2 x 1010 ohms (12GΩ)
Application of HumiSeal® 1A27
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® 1A27 with HumiSeal® Thinner 521 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. Viscosity in the dip tank should be checked regularly, using a simple measuring device such as a Zahn or Ford viscosity cup.
HumiSeal® 1A27 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® 1A27 to HumiSeal® Thinner 521 is 1:1 by volume; however the ratio may need to be adjusted to obtain a uniform coating.
HumiSeal® 1A27 may be applied by brush with a small addition of HumiSeal Thinner 521. Uniformity of the film depends on component density and operator's technique.
HumiSeal® 1A27 should be stored away from excessive heat or cold, in tightly closed containers. HumiSeal® products may be stored at temperatures of 0 to 35°C. Prior to use, allow the product to equilibrate for 24 hours at a room temperature of 18 to 32°C.
Application of HumiSeal® Conformal Coatings should be carried out in accordance with local and National Health and Safety regulations.
The solvents in HumiSeal® Conformal Coatings are flammable. Material should not be used in presence of open flame or sparks. Use only in well-ventilated areas to avoid inhalation of vapours or spray. Avoid contact with skin and eyes.
Consult MSDS/SDS prior to use.