Humiseal UV40SOLAR | Low-Viscosity, High Solids Conformal Coating

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

Humiseal UV40SOLAR | Low-Viscosity, High Solids Conformal Coating

Main features

For applications with prolonged sunlight exposure
Fluoresces under UV light
RoHS Directive 2011/65/EU compliant

Product Description

HumiSeal® UV40-SOLAR is a single-component, low-viscosity, high-solids conformal coating engineered for exceptional durability under direct sunlight. It is formulated to prevent discoloration or degradation during prolonged solar exposure and features a robust secondary moisture cure for shadowed areas.

Product Key Features

Formulated to resist discoloration and degradation under prolonged sunlight exposure.
Primary UV cure is tack-free immediately; secondary moisture cure fully cures shadowed areas within 2–3 days at ambient conditions.
Fully compliant with SAE-J-1960 & RoHS Directive 2011/65/EU.

Applications

Suitable printed circuit board assemblies that require additional resistance against consistent sunlight exposure.

Specifications
Additional Information

Technical Specifications

General Properties

Density (g)

1.06 g/cm3

Solids

95 %

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.

45 °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.	85 ppm/°C
Coefficient of Thermal Expansion (CTE), α2 Coefficient of Thermal Expansion (CTE), α2 CTE α2 (alpha 2) is the slope of the Coefficient of thermal expansion in a temperature range above the Glass transition temperature (Tg). It explains the extent to which a material will expand after it passes Tg.	197 ppm/°C

Electrical Properties

Dissipation Factor
Dissipation Factor @ 25°C /100 kHz	0.01

Dielectric Constant
Dielectric Constant @ 1000 kHz	2.5

Mechanical Properties

Storage (DMA) Modulus
Storage (DMA) Modulus @ 25°C	4283 N/mm2

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

650 mPa.s

Additional Information

Frequently Asked Questions About HumiSeal® UV40-SOLAR

What are typical applications for HumiSeal® UV40-SOLAR?

HumiSeal® UV40-SOLAR is a single-component, low-viscosity, high-solids UV curable conformal coating specifically formulated to withstand prolonged exposure to sunlight without yellowing or degradation. It is ideal for protecting printed circuit board assemblies (PCBs) used in:

Solar and Renewable Energy (e.g., inverters, charge controllers)
Exterior/Outdoor Electronics (e.g., lighting, signage, sensors)
Automotive (e.g., exterior electronic modules, cameras)
Industrial and Telecommunications equipment in harsh environments

Its excellent chemical resistance, surface hardness, flexibility, and moisture resistance, combined with proven UV stability, make it ideal for exterior and mission-critical applications where reliable long-term protection is essential.

Why choose HumiSeal® UV40-SOLAR over other conformal coatings?

HumiSeal® UV40-SOLAR is a single-component, low-viscosity, high-solids, acrylated polyurethane formulation that provides excellent chemical and environmental resistance. It is uniquely engineered to prevent discoloration or degradation under prolonged sunlight, meeting the rigorous SAE-J-1960 standard (QUV accelerated age testing). It offers rapid tack-free curing under UV light for high-efficiency production. Its unique secondary moisture cure mechanism ensures full curing of any unexposed "shadow areas" of the coating within 2-3 days at ambient conditions. The coating fluoresces under UV light to enable easy inspection of coverage and uniformity. It is compliant with the RoHS Directive 2011/65/EU. UV40-SOLAR is a low-viscosity material formulated for selective coating equipment application flexibility.

What is the shelf life of HumiSeal® UV40-SOLAR?

HumiSeal® UV40-SOLAR has a shelf life of 12 months from the date of manufacture when stored sealed in tightly closed opaque containers at 0 to 25°C, away from excessive heat and direct sunlight or full spectrum fluorescent lighting. Before use, allow the product to equilibrate for 24 hours at room temperature for optimal application performance. As UV40-SOLAR is a moisture curing material, care should be taken to protect process vessels and partial containers from moisture by purging with a dry, inert gas (e.g., dry air, nitrogen, or argon) before closure.

How should I clean tools after applying HumiSeal® UV40-SOLAR?

To flush equipment and clean uncured HumiSeal® UV40-SOLAR, non-alcohol based solvents should be used. HumiSeal® Thinner 521/521EU is recommended. For coating removal during rework, HumiSeal® UV40-SOLAR is a highly cross-linked UV cured coating and is more difficult to remove than traditional coatings. Thermal displacement, mechanical abrasion and, where available, HumiSeal® Stripper 1100 are suitable options for rework of HumiSeal® UV40-SOLAR.

What happens to HumiSeal® UV40-SOLAR after its shelf life?

After the shelf life, viscosity and curing characteristics may degrade, potentially leading to uneven coating, reduced protective performance, or improper curing. Use of expired material is not recommended as it may compromise coating quality. Given its photosensitive and moisture-curing nature, proper storage is crucial to maintaining product integrity.

How does HumiSeal® UV40-SOLAR cure, and why do curing times vary?

HumiSeal® UV40-SOLAR is a dual-cure coating. The primary cure is achieved rapidly through exposure to UV light, making the coating tack-free almost instantly. The required UV dose and irradiance will depend on the specific UV system. A secondary moisture cure mechanism is designed to fully cure any unexposed "shadow areas" within 2-3 days at ambient conditions. Due to variations in curing equipment and process conditions, it is strongly recommended to consult us for technical support.

What is the recommended thickness for HumiSeal® UV40-SOLAR?

The recommended coating thickness for HumiSeal® UV40-SOLAR is 25 to 125 microns (1-5 mils) to ensure optimal protection without compromising flexibility or electrical performance. The actual thickness will vary based on application equipment and process settings.

What are the differences between application methods for HumiSeal® UV40-SOLAR?

HumiSeal® UV40-SOLAR's low viscosity is suitable for selective coating equipment and may also be applied by conventional hand spray. When using selective coating equipment or spraying, the source air must be dry (a dry inert gas is highly recommended) to prevent premature curing of the secondary cure mechanism. Brushing may be used for touch-up or rework.

What is the maximum operating temperature for HumiSeal® UV40-SOLAR?

HumiSeal® UV40-SOLAR withstands thermal shock from –65°C to +125°C as per MIL-I-46058C testing. It has a continuous use operating range of -65°C to +125°C. Continuous operation at or above 125°C is generally the upper limit, as prolonged exposure to higher temperatures may degrade coating integrity.

What safety precautions should I take when using HumiSeal® UV40-SOLAR?

Use in well-ventilated areas and avoid inhalation of vapors or spray. Prevent skin and eye contact by wearing appropriate protective equipment, including opaque gloves and UV-protective eyewear due to its photosensitive nature. The product contains flammable solvents, so avoid open flames or sparks. Consult the Safety Data Sheet (SDS) for detailed handling, storage, and disposal instructions. Ensure that product containers are tightly closed and opaque, and purge partial containers with dry inert gas to prevent premature polymerization.

How can I ensure proper application of HumiSeal® UV40-SOLAR?

HumiSeal® UV40-SOLAR fluoresces brightly under UV light, allowing for quick and easy visual inspection of coating coverage and uniformity. This feature is critical for ensuring proper application and quality control in high-reliability electronics manufacturing, making it simple to identify any missed areas or defects.

How does HumiSeal® UV40-SOLAR perform in harsh environments?

HumiSeal® UV40-SOLAR provides excellent protection against moisture, chemicals, salt spray, and fungus (passes ASTM G21). Its highly cross-linked UV-cured film, combined with the secondary moisture cure and its unique UV/weathering resistance (SAE-J-1960), ensures robust long-term performance and maintains integrity in humid, corrosive, and mechanically stressful environments, making it highly suitable for exterior and solar applications.

Learn More About HumiSeal® UV40-SOLAR

HumiSeal® UV40-SOLAR is a single-component, low-viscosity UV curable conformal coating designed for rapid processing and superior, non-yellowing protection of electronic assemblies in outdoor and solar environments. This acrylated polyurethane coating offers a unique dual-cure mechanism and a combination of fast processing, excellent chemical resistance, high surface hardness, flexibility, and robust long-term UV stability—making it the ideal choice for protecting PCBs in sectors such as renewable energy, automotive, and industrial outdoor automation.

Key Features at a Glance

✔ UV & Weathering Stable: Specifically formulated not to yellow or degrade under prolonged sunlight.
✔ SAE-J-1960 Compliant: Meets rigorous QUV accelerated age testing standards.
✔ Rapid UV curing for high throughput.
✔ Secondary moisture cure for shadowed areas.
✔ Excellent chemical resistance and surface hardness.
✔ Fluoresces under UV light for easy inspection.
✔ Low viscosity for selective coating equipment application.

Advanced Dual-Cure Technology

HumiSeal® UV40-SOLAR leverages a dual-cure system to ensure complete protection. Its primary cure occurs almost instantly under UV light, allowing for immediate handling and significantly boosting production line speed. This makes it ideal for high-volume manufacturing. For areas that UV light cannot reach (known as "shadow areas" under components), a secondary moisture cure mechanism ensures full cross-linking within 2-3 days at ambient conditions.

Curing Parameters:

Primary UV Cure: Tack-free after exposure to UV light. Specific dose and irradiance will depend on the UV system.
Secondary Moisture Cure (for shadow areas): 2-3 days at ambient conditions.

This dual-cure capability provides robust and complete protection, even for complex geometries.

Application and Compatibility

UV40-SOLAR's low viscosity is formulated for efficient application and broad compatibility, fitting seamlessly into modern manufacturing environments.

Compatible With:

✔ Automated selective coating equipment (e.g., dispensing and spraying)
✔ High-reliability applications requiring excellent chemical and moisture resistance.
✔ Long-term outdoor and solar exposure without degradation.
✔ Lead-free and RoHS-compliant manufacturing environments.

Additionally, its UV fluorescence ensures easy inspection, and the coating is reworkable using thermal methods or mechanical abrasion—ideal for repairable designs and serviceable assemblies.

High-Performance Electrical and Physical Protection 🧪

HumiSeal® UV40-SOLAR delivers exceptional electrical insulation with a dielectric withstand voltage >1,500 volts and insulation resistance of 8.0 × 10¹⁴ ohms. Its acrylated polyurethane chemistry provides excellent chemical resistance, surface hardness, and flexibility, ensuring durability and protection against moisture, contaminants, and mechanical stress. It's also rated UL 94 V-0 for flame retardancy, ensuring safety in critical applications.

Fluorescent for Inspection 💡

To simplify quality assurance, HumiSeal® UV40-SOLAR fluoresces under UV light, making it easy to confirm proper coating coverage and uniformity during post-application inspection—an essential feature for high-reliability electronics manufacturers seeking efficient and reliable quality control.

Repairable and Reworkable 🔁

While HumiSeal® UV40-SOLAR forms a highly cross-linked, durable film, it is still reworkable. Should component replacement or repair be required, the cured coating can be selectively removed using thermal displacement (e.g., a hot soldering iron), mechanical abrasion, or Humiseal Stripper 1100. This feature makes UV40-SOLAR suitable for applications where field serviceability or prototyping may be necessary.

Reliable Across Environments 🌍

With a wide thermal shock range of –65°C to +125°C, coupled with excellent resistance to fungus (ASTM G21), moisture, and accelerated weathering (SAE-J-1960), UV40-SOLAR ensures consistent long-term performance across varied environmental conditions, making it particularly well-suited for exterior-facing and solar applications.