Electrical Insulating Varnish

With the achievement of high-density mounting, higher quality and performance are required for insulation materials used for mounting circuit boards, compared with general insulation materials. MELQUID V985 is a coating agent for moisture-proof insulation especially developed to enhance the environmental durability of the mount board, to achieve the highest performance level.

Product name

MELQUID V985(-45K、-30K、-15E、-SE)


  • Extremely low water-vapor permeability and excellent water resistance.
  • Excellent adhesive property with parts of the mount board.
  • Substances subject to RoHS regulation are not used.
  • An environmentally-friendly solvent that is not subject to PRTR regulation is used.
  • The E type offers fluorescence that allows a visual film check with black light irradiation.


  • Moisture-proof coating of high-density mounting printed wiring board
  • Environment-resistant insulation protection coating of various electronic parts


  • There are four types, with viscosity adjusted according to application.

High-viscosity type for thick film (V985-45K)

This is suitable for conducting a thick film coating to the required section with one application.

General type (V985-30K)

Its viscosity is suitable for dip coating and brush coating.

Low-viscosity type for thin film (V985-15E)

Minute pore spaces can be also sealed with low viscosity.
It offers fluorescence that allows a visual film check with black light irradiation.

Spray type (V985-SE)

Environment-resistant insulation protection coating is possible by jetting the necessary amount to the required point.
It offers fluorescence that allows a visual film check with black light irradiation.

General characteristics

Item Condition Unit V985-45K V985-30K V985-15E V985-SE
Feature For thick film For general film For thin film Spray
Composition Polyurethane
Viscosity 25℃/B type mPa・s 6000 350 16 Spray
Non-volatile component 135℃/3h % 45 30 15
Drying time 25℃/set to touch min 50 35 15
Attached film thickness Center mm 0.15 0.043 0.01
Lower part % 122 121 100
Fluorescence Black light No Yes
Incombustibility?*) UL94 V-0 (FileNo.E120504)
Water-vapor permeability 150μm g/m2/24h 30
Dielectric constant Normal state 3.8
Dielectric loss tangent Normal state % 2.1
Breakdown voltage Normal state kV/0.1mm 5.3
Volume resistivity Normal state Ω・cm 2.8×1015
Cross cut adhesive property
Cu 100/100
Resist 100/100
Paper phenol 100/100

*) Incombustibility; Achieved when double-sided coating is applied on FR-4 (plate thickness of 0.85 mm or more) certified in QMTS2 with thickness of 0.03 to 0.05 mm. Cure condition; 80℃/2.0hr+r.t./48h
*The values in the table above are measured values, not certified values.

  • Coating
  • Black light irradiation after coating
    <Black light irradiation after coating>
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