UV curable UV 40-250
Model No: UV-40-250

HumiSeal® UV40-250 is a single component, high solids, UV curable, acrylated polyurethane conformal coating that possesses excellent chemical resistance, surface hardness, flexibility and moisture resistance. The material is tack-free after exposure to UV light. A secondary moisture cure mechanism will cure unexposed areas of the coating within 2-3 days at ambient conditions. The coating fluoresces under UV light to allow for coating inspection and can be applied by all selective coating equipment.

 Product Enquiry

HumiSeal® UV40-250 conformal coating is:

  • single component
  • high solids
  • UV curable
  • acrylated polyurethane


HumiSeal® UV40-250 conformal coating has:

  • excellent chemical resistance, surface hardness, flexibility, and moisture resistance.
  • secondary moisture cure mechanism for curing in the non-UV exposed shadowed areas
  • fluoresces under UV light to allow for coating inspection
  • can be applied by selective coating equipment.
  • recognized under UL File Number E105698
  • MIL-I-46058C qualified
  • IPC-CC-830 and RoHS Directive 2015/863/EU compliant


Application of HumiSeal® UV40-250 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” assembly 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


1.06 g/cm3

Minimum Solids Content

95 %

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

300 ± 50 centipoise

Recommended Coating Thickness

25 – 125 microns

Recommended UV Dose*

see curing section above

Shelf Life at Room Temperature, DOM

6 months

Recommended Stripper**

HumiSeal® Stripper 1100

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

-65°C to 125°C

Glass Transition Temperature – DSC


Coefficient of Thermal Expansion

112 ppm/°C Below Tg
283 ppm/°C Above Tg

Modulus – DMA

1060 MPa -60°C

Flammability, per UL-94


Dielectric Withstand Voltage, per MIL-I-46058C

>1500 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

8.0 x 1014 ohms (800TΩ)

Moisture Insulation Resistance, per MIL-I-46058C

4.7 x 1010 ohms (47GΩ)

Fungus Resistance, per ASTM G21


Resistance to Chemicals


*Microwave UV cure ovens equipped with “H” style bulbs recommended
**Stripper 1100 is not available in the EU