1B31 EPA Preblends

HumiSeal® 1B31 EPA conformal coating is:

  • an acrylic chemistry
  • fast drying
  • single component

HumiSeal 1B31 EPA conformal coating has:

  • excellent moisture and environmental protection for printed circuit assemblies
  • fluorescence under UV light for ease of inspection
  • reworkability with ease
  • MIL-I-46058C qualification
  • IPC-CC-830 compliance
  • RoHS directive 2015/863/EU

Application of 1B31 EPA 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 1B31 EPA with HumiSeal Thinner 600 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 600 or 604. Viscosity in the dip tank should be checked regularly using a simple measuring device, such as a Zahn or Ford viscosity cup.

HumiSeal 1B31 EPA 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 600 or 604 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 1B31 EPA to HumiSeal Thinner 600 or 604 is 1:1 by volume; however, the ratio may need to be adjusted to obtain a uniform coating.

HumiSeal 1B31 EPA may be brushed with a small addition of HumiSeal Thinner 600 or 604. Uniformity of the film depends on the component density and operator technique.

Product Specification:

Product Viscosity, CPS Solids Content, % Density, g/cm³ VOC, g/L
1B31EPA 265.0 – 385.0 25.00 – 31.00 0.95 ± 0.03 684
1B31EPA/600 PB65 60.0 – 70.0 18.00 – 20.00 0.94 ± 0.01 761
1B31EPA/604 PB35 30.0 – 40.0 14.00 – 16.00 0.93 ± 0.01 786
Product Specification
Density, per ASTM, Meth. D1475 0.95 ± 0.03 g/cm³
Solids Content, % by weight per Fed-Std-141, Meth. 4044 28 ± 3 %
Viscosity, per Fed-Std-141, Meth. 4287 325 ± 60 centipoise
VOC 684 grams/litre
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 30 min @ 76°C
Time Required to Reach Optimum Properties 7 days
Recommended Thinner (dipping, brushing) HumiSeal Thinner 604
Recommended Thinner (spraying) HumiSeal Thinner 600
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 170 ppm/°C below Tg
340 ppm/°C above Tg
Glass Transition Temperature – DSC 14°C
Modulus – DMA 2000 MPa@ -40°C
1050 MPa@ 20°C
8.5 MPa@ 60°C
Flammability, per MIL-I-46058C Self-Extinguishing
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 1012 ohms (550TΩ)
Moisture Insulation Resistance, per MIL-I-46058C 7.0 x 1010 ohms (70GΩ)
Fungus Resistance, per ASTM G21 Passes