Synthetic Rubber 1B51 NSLU
Model No: 1B51 NSLU

HumiSeal® 1B51NSLU is an air drying, single component, synthetic rubber conformal coating that contains methylcyclohexane solvent that is more environmentally friendly than traditional solvents. Because of its unique base polymer, HumiSeal® 1B51NSLU has extremely low moisture vapour permeability. The coating demonstrates excellent flexibility, low stress on components, fluoresces under UV for ease of inspection and is easily repaired.

 Product Enquiry

HumiSeal® 1B51 NSLU conformal coating is:

  • a fast drying
  • single component
  • synthetic rubber
  • environmentally friendly solvent blend


HumiSeal® 1B51 NSLUconformal coating has:

  • excellent moisture and environmental protection for printed circuit assemblies
  • extremely low moisture vapor permeability
  • excellent flexibility, enabling low stress on components
  • full compliance with the RoHS Directive 2015/863/EU
  • UV additive for fluorescence


Application of HumiSeal® 1B51 NSLU

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.  


Product Specification

Density, per ASTM D1475

0.79 ± 0.02 g/cm3

Solids Content, % by weight per Fed-Std-141, Meth. 4044

18.5 ± 1.5 %

Viscosity, per Fed-Std-141, Meth. 4287

210 ± 70 centipoise


648 grams/litre

Drying Time to Handle per Fed-Std-141, Meth. 4061

6-10 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

Thinner 903 or 904

Recommended Stripper

Stripper 1080

Shelf Life at Room Temperature, DOM

12 months

Thermal Shock, 50 cycles per MIL-I-46058C

-65°C to 125°C

Coefficient of Thermal Expansion – TMA

55 ppm/°C

Glass Transition Temperature – DSC


Modulus – DMA

93.1 MPa @ -20°C73.5 MPa @ 0°C35.3 MPa @ 20°C

Moisture Vapour Transmission, per ASTM E398-03

<1 g/m2·day·mil

Dielectric Withstand Voltage, per MIL-I-46058C

>1500 volts

Dielectric Breakdown Voltage, per ASTM D149

4900 volts

Dielectric Constant, at 1MHz and 25°C per ASTM D150-98


Dissipation Factor, at 1MHz and 25°C per ASTM D150-98


Insulation Resistance, per MIL-I-46058C

8.4 x 1012 ohms (200TΩ)

Moisture Insulation Resistance, per MIL-I-46058C

1.8 x 1010 ohms (10GΩ)

Fungus Resistance, per ASTM G21