HumiSeal 1A33LOS Urethane Conformal Coating

Harmonization Code : 3906909090 | Acrylic polymers in primary form Others>Others

Main features

Fluoresces under UV light for easy inspection
Low moisture vapor permeability
No free isocyanates

Product Description

HumiSeal 1A33LOS is a high-performance, single-component polyurethane coating that eliminates the safety risks associated with traditional isocyanates. Ideal for high-reliability PCBs, it provides a tough, chemical-resistant shield while remaining low-odor and low-toxicity. With UV fluorescence for inspection and full RoHS compliance, it offers a "no-compromise" transition from standard 1A33 to a safer, more sustainable production process.

Product Key Features

Single-component polyurethane conformal coating
Reduced odor formulation with lower toxicity solvents
Comparable cured performance to HumiSeal 1A33
Fluoresces under UV light for easy inspection
No free isocyanates
Low moisture vapor permeability
Available in ready-to-use pre-blended viscosities
RoHS Directive 2015/863/EU and China RoHS 2 compliant

Applications

Printed circuit board (PCB) protection
Consumer electronics assemblies
Industrial electronics
Telecommunications equipment
Automotive electronic modules
Power supply assemblies
Electronic assemblies requiring low-odor coatings

Specifications
Additional Information

Technical Specifications

General Properties

Density (g)

0.92 g/cm3

Film Thickness

Film Thickness
Film thickness is the thickness of a backing film without taking into account any coatings or adhesive layers. It is measured in micron and the conversion factor to mil is 0.039.

25 - 75 µm

Solids

44 %

Physical Properties

Viscosity

Viscosity
Viscosity is a measurement of a fluid’s resistance to flow.

Viscosity is commonly measured in centiPoise (cP). One cP is defined as
the viscosity of water and all other viscosities are derived from this base. MPa is another common unit with a 1:1 conversion to cP.

A product like honey would have a much higher viscosity -around 10,000 cPs-
compared to water. As a result, honey would flow much slower out of a tipped glass than
water would.

The viscosity of a material can be decreased with an increase in temperature in
order to better suit an application

195 mPa.s

Thermal Properties

Glass Transition Temperature (Tg)

Glass Transition Temperature (Tg)
The glass transition temperature for organic adhesives is a temperature region where the polymers change from glassy and brittle to soft and rubbery. Increasing the temperature further continues the softening process as the viscosity drops too. Temperatures between the glass transition temperature and below the decomposition point of the adhesive are the best region for bonding.

The glass-transition temperature Tg of a material characterizes the range of temperatures over which this glass transition occurs.

26 °C

Operating Temperature

-65 - 125 °C

Coefficient of Thermal Expansion (CTE)
Coefficient of Thermal Expansion (CTE), α1 Coefficient of Thermal Expansion (CTE), α1 CTE α1 (alpha 1) is the slope of the Coefficient of thermal expansion in a temperature range below the Glass transition temperature (Tg). It explains how much a material will expand until it reaches Tg.	193 ppm/°C

Mechanical Properties

Storage (DMA) Modulus
Storage (DMA) Modulus @ 25°C	27.2 N/mm2

Additional Information

Learn More About HumiSeal® 1A33LOS

Application Methods

HumiSeal® 1A33LOS is available in pre-blended viscosities for immediate use, supporting multiple application techniques.

Dipping: Apply using a controlled immersion and withdrawal rate of 5–15 cm/min to ensure uniform coating thickness. Monitor viscosity regularly and adjust with approved thinner as needed.
Spraying: Pre-blended grades can be sprayed using conventional spray equipment. Adequate ventilation is required to remove solvent vapors and mist.
Brushing: Suitable pre-blends may be applied by brush. Film uniformity depends on viscosity selection and operator technique.

Important Notes:

Substrate cleanliness is critical for coating performance.
Perform compatibility testing prior to production use.
Consult HumiSeal® Technical Support for pre-blend selection.

Application Compatibility

HumiSeal® 1A33LOS is compatible with a wide range of materials used in electronic assemblies.

Compatible With:
✔ FR-4 and common PCB substrates
✔ Metals and plated finishes
✔ Most electronic components
✔ Automated coating equipment

Not Recommended For:
✖ Contaminated or moisture-laden substrates
✖ Application near open flames or ignition sources

Additional Guidance:
Always verify material compatibility and cleanliness prior to coating. UV fluorescence allows easy inspection and repair after application.

Safety and Handling Precautions ⚠️

Use only in well-ventilated areas
Avoid inhalation of vapors or spray mist
Avoid contact with skin and eyes
Keep away from sparks, heat, and open flames
Follow local and national health and safety regulations

Always consult the Safety Data Sheet (SDS) before use.

Storage Recommendations 📦

Store HumiSeal® 1A33LOS and its pre-blends in tightly closed containers away from excessive heat or cold. Recommended storage temperature is 0–35°C. Allow material to equilibrate for 24 hours at 18–32°C before use.