Humiseal 1B51NSLU D40 | Synthetic Rubber Conformal Coating

Harmonization Code : 3208.20.90 | Paints and varnishes that are dispersed or dissolved in a non aqueous medium

Humiseal 1B51NSLU D40 | Synthetic Rubber Conformal Coating

Main features

  • 10-Minute Handling-Dry Coating
  • Below 1 g/m^2 day mil MVTR
  • Flexible UV-Fluorescent Reworkable Coating

Product Description

HumiSeal® 1B51NSLU Synthetic Rubber Conformal Coating is a fast-drying, single-component coating for printed circuit board protection. The methylcyclohexane-based formulation combines a flexible synthetic rubber polymer with very low documented moisture-vapor transmission and UV fluorescence for inspection. It can be applied by dipping, spraying, or brushing and is recommended at 25–75 µm dry coating thickness. Typical handling dry time is 10 minutes, with recommended cure conditions of 24 hours at room temperature or 30 minutes at 76°C. The coating is also reworkable using the recommended HumiSeal stripper.

Key features

  • Single-component synthetic rubber coating for printed circuit board protection.
  • Fast handling dry: 10 minutes by Fed-Std-141, Method 4061.
  • Recommended coating thickness: 25–75 µm.
  • UV fluorescent to support coating inspection.
  • Very low moisture-vapor transmission: less than 1 g/m²·day·mil by ASTM E398-03.
  • Reworkable with HumiSeal® Stripper 1080 or 1080EU.

Applications / Suitable for

  • Protective conformal coating of printed circuit boards.
  • Assemblies requiring dip, spray, or brush application.
  • Coated assemblies requiring UV-assisted inspection and practical rework.
Product Family

HUMISEAL 1B51NSLU D40

Catalog Product

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TDS, SDS & Technical Documents

Technical Specifications

General Properties
Density (g)Density (g)
0.81 g/cm3
SolidsSolids
22 %
Physical Properties
ViscosityViscosity
185 mPa.s
Other Properties
Coating ThicknessCoating Thickness
25-75 nm
Thermal Properties
Glass Transition Temperature (Tg)Glass Transition Temperature (Tg)
14 °C
Electrical Properties
Breakdown VoltageBreakdown Voltage
4900 V

Additional Information

Synthetic rubber conformal coating

HumiSeal® 1B51NSLU Synthetic Rubber Conformal Coating

A fast-drying, single-component protective coating for printed circuit boards. The methylcyclohexane-based formulation combines flexibility, UV fluorescence for inspection, very low documented moisture-vapor transmission, and practical reworkability.

Single component 185 ± 30 cP 25–75 µm coating 10-minute handling dry UV fluorescent

As supplied

As-supplied properties

Typical product-selection data; values are not specification limits.

Property Value Method / context
Product form Single-component liquid Synthetic rubber conformal coating
Density 0.81 ± 0.02 g/cm³ ASTM D1475
Solids content 22 ± 2 wt% Fed-Std-141, Method 4044
Viscosity 185 ± 30 cP Fed-Std-141, Method 4287
VOC 632 g/L As reported
Handling dry time 10 minutes Fed-Std-141, Method 4061
Processing

Application and cure

Surfaces should be free of moisture, dirt, wax, grease, flux residues, and other contaminants. Assemblies using “no-clean” materials require compatibility and reliability testing before coating.

Dipping: Adjust viscosity with HumiSeal® Thinner 903, 905, or 521EU when required. Use controlled immersion and withdrawal at 5–15 cm/min and check dip-tank viscosity regularly.
Spraying: Use conventional spray equipment with adequate ventilation. A 1:1 volume ratio of coating to approved thinner is recommended as a starting point, then adjust for the equipment and required spray pattern.
Brushing: Apply with a small addition of an approved thinner as needed. Film uniformity depends on component density and operator technique.
Thickness and cure: Apply at 25–75 µm. Recommended cure is 24 hours at room temperature or 30 minutes at 76°C. Allow 7 days for optimum properties.

Storage and handling

Store in tightly closed containers away from excessive heat or cold at 0–35°C. Before use, allow the product to equilibrate for 24 hours at 18–32°C. Shelf life is 18 months from the date of manufacture when stored at room temperature. The solvent system is highly flammable; use only with suitable ventilation and away from ignition sources, following the current SDS and local regulations.

Final coating

Final coating properties

Typical values apply to the stated methods and conditions and are not guaranteed specifications.

Property Result Method / condition
Thermal shock 50 cycles, -65°C to 125°C MIL-I-46058C
Coefficient of thermal expansion 55 ppm/°C TMA
Glass transition temperature 14°C DSC
Modulus 93.1 MPa at -20°C; 73.5 MPa at 0°C; 35.3 MPa at 20°C DMA
Moisture-vapor transmission <1 g/m²·day·mil ASTM E398-03
Dielectric withstand voltage >1500 V MIL-I-46058C
Dielectric breakdown voltage 4900 V ASTM D149
Dielectric constant 2.5 ASTM D150-98, 1 MHz and 25°C
Dissipation factor 0.07 ASTM D150-98, 1 MHz and 25°C
Insulation resistance 2.0 × 10¹⁴ Ω MIL-I-46058C
Moisture insulation resistance 1.0 × 10¹⁰ Ω MIL-I-46058C
Fungus resistance Passes ASTM G21
Use contexts

Applications

HumiSeal® 1B51NSLU is intended as a protective conformal coating for printed circuit boards. Final suitability depends on substrate cleanliness, assembly materials, coating process, thickness, cure, and end-use conditions.

Printed circuit board protection
Protective coating for printed circuit boards where a flexible synthetic rubber film and low moisture-vapor transmission are relevant selection factors.
UV-assisted inspection
The coating fluoresces under UV light, supporting visual inspection of coating presence and coverage within the limits of the inspection process.
Reworkable coated assemblies
The coating can be repaired and removed using the recommended HumiSeal® stripper, supporting assemblies that may require localized rework.
Next steps

Evaluate HumiSeal® 1B51NSLU for your PCB coating process

Contact Krayden to discuss substrate preparation, no-clean material compatibility, dip or spray viscosity control, coating thickness, cure conditions, inspection, rework, and qualification testing for your printed circuit board assembly.

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