Humiseal 1C63 | UV/RTV Curing, Oxime-Type Cure Silicone Conformal Coating

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

Humiseal 1C63 | UV/RTV Curing, Oxime-Type Cure Silicone Conformal Coating

Main features

UV/RTV curing
Non-corrosive
Excellent weather resistance

Product Description

HumiSeal® 1C63 is a silicone conformal coating that provides superior moisture and environmental protection for printed circuit assemblies. This single-component, non-corrosive coating cures through exposure to either UV light or atmospheric moisture, making it highly versatile. After UV exposure, the coating is tack-free, and any unexposed areas will fully cure within 24 hours at ambient temperature and 50% relative humidity. HumiSeal® 1C63 is recognized under UL File Number E105698 and RoHS
Directive 2011/65/EC compliant.

Product Key Features

Cures when exposed to UV light or atmospheric moisture for flexible application.
A single-component formula that will not corrode sensitive electronic components.
Self-Leveling - Applies smoothly and evenly, ensuring complete coverage.
Provides long-lasting protection against environmental factors.

Applications

PCB applications requiring UV/RTV cure.

Specifications
Additional Information

Technical Specifications

General Properties

Density (g)

1.04 g/cm3

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.

-90 °C

Operating Temperature

-65 - 200 °C

UL 94 Rating

UL 94 Rating
Flammability rating classification.
It determines how fast a material burns or extinguishes once it is ignited.

HB: slow burning on a horizontal specimen; burning rate less than 76 mm/min for thickness less than 3 mm or burning stops before 100 mm
V-2: burning stops within 30 seconds on a vertical specimen; drips of flaming particles are allowed.
V-1: burning stops within 30 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed.
V-0: burning stops within 10 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed.
5VB: burning stops within 60 seconds on a vertical specimen; no drips allowed; plaque specimens may develop a hole.
5VA: burning stops within 60 seconds on a vertical specimen; no drips allowed; plaque specimens may not develop a hole

V-1

Mechanical Properties

Elongation

Elongation
Elongation is the process of lengthening something.

It is a percentage that measures the initial, unstressed, length compared to the length of the material right before it breaks.

It is commonly referred to as Ultimate Elongation or Tensile Elongation at break.

100 %

Tensile Modulus
Tensile Modulus @25°C	0.69 N/mm2

Hardness
Durometer (Shore A)	15

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

3500 mPa.s

Additional Information

Frequently Asked Questions About HumiSeal® 1C63

What are typical applications for HumiSeal® 1C63?

HumiSeal® 1C63 is a UV/RTV curing, oxime-type cure silicone conformal coating used for protecting printed circuit board assemblies (PCBs) in various industries, including:

Aerospace systems (e.g., avionics, control modules)
Automotive electronics (e.g., engine control units, sensors)
Industrial automation (e.g., motor drives, PLCs)
Consumer electronics (e.g., smartphones, gaming devices)

Why choose HumiSeal® 1C63 over other conformal coatings?

HumiSeal® 1C63 is a non-corrosive, single-component coating that cures with both UV light and atmospheric moisture, providing a fast, tack-free surface and excellent protection in hard-to-reach areas. It provides excellent electrical insulation, fluoresces under UV for easy inspection, and is easily reworkable. It is also recognized under UL File Number E105698 and is RoHS Directive 2011/65/EC compliant, making it a trusted choice for demanding applications. You can learn how to select a conformal coating in our blog.

What is the shelf life of HumiSeal® 1C63?

HumiSeal® 1C63 has a shelf life of 6 months from the date of manufacture when stored at or below 27°C in tightly closed containers. Prior to use, allow the product to equilibrate for 24 hours at room temperature to ensure optimal performance. The product also has a long pot life, typically exceeding 30 days.

How should I clean tools after applying HumiSeal® 1C63?

Tools and equipment used for applying HumiSeal® 1C63 can be cleaned with a suitable solvent, such as a mineral spirit or acetone, before the coating cures. Thinner is not required or recommended for this product. Always use a lint-free cloth and ensure proper ventilation during cleaning. The recommended stripper for this product is Humiseal Stripper 1090.

What happens to HumiSeal® 1C63 after its shelf life?

Past its 6-month shelf life, HumiSeal® 1C63 may experience changes in viscosity, which could affect application consistency and coating uniformity. Using expired product may lead to suboptimal performance, and the manufacturer will not be liable for quality or performance issues if expired material is used. If the product has cured in the container, it cannot be recovered.

Why do curing times vary for HumiSeal® 1C63?

HumiSeal® 1C63 is a dual-curing coating. Its tack-free surface is achieved in seconds under UV light, while a secondary moisture cure ensures that shadowed or unexposed areas fully cure within 24 hours at ambient temperature and 50% relative humidity. This dual-cure mechanism makes it suitable for high-volume production while ensuring complete protection.

What is the recommended thickness for HumiSeal® 1C63?

The recommended coating thickness for HumiSeal® 1C63 is 50 to 200 microns. This range ensures optimal protection without compromising flexibility or electrical performance. The thickness is controlled primarily by the application method and withdrawal rate, as the coating is not designed to be thinned.

What are the differences between application methods for HumiSeal® 1C63?

HumiSeal® 1C63 can be applied via spraying, dipping, or brushing. Spraying and dipping are ideal for large-scale production, while brushing is suited for small repairs. This product has a low viscosity and does not require thinning for any of these methods. Each method should be controlled to achieve a uniform coating, especially the withdrawal rate for dipping, which should be between 5–15 cm/min.

What is the maximum operating temperature for HumiSeal® 1C63?

HumiSeal® 1C63 can withstand a wide thermal range, making it suitable for high-temperature applications where its protective properties must be maintained under constant thermal stress.

What safety precautions should I take when using HumiSeal® 1C63?

HumiSeal® 1C63 is VOC-free and solvent-free, reducing flammability risks. However, proper ventilation is still crucial to prevent inhalation of vapors or spray mist, especially during the curing process. Avoid skin and eye contact. Always consult the Safety Data Sheet (SDS) prior to use for detailed safety guidelines.

How can I ensure proper application of HumiSeal® 1C63?

HumiSeal® 1C63 fluoresces under UV light, allowing for easy inspection of coating coverage. After application, use a UV light source to check for a uniform, void-free coating, which is critical for high-reliability electronics manufacturing.

How does HumiSeal® 1C63 perform in harsh environments?

HumiSeal® 1C63 is designed for harsh conditions, with excellent fungus resistance per ASTM G21 and exceptional moisture insulation resistance. It maintains performance in humid, mechanically stressful, or temperature-cycling environments, making it ideal for mission-critical systems.

Learn More About HumiSeal® 1C63

HumiSeal® 1C63 is a proven solution for long-term protection of electronic assemblies in demanding environments. This silicone conformal coating offers a unique combination of ease of use, excellent electrical insulation, and exceptional flexibility—making it an industry favorite for protecting PCBs in sectors such as automotive, aerospace, consumer electronics, and industrial automation.

Key Features at a Glance

✔ Tack-free cure in seconds with UV light
✔ Cures fully with atmospheric moisture
✔ Non-corrosive and self-leveling

Versatile Application Methods 🧰

Application methods

Whether you’re using spraying, dipping, or brushing, 1C63 offers flexibility in manufacturing workflows. It is a 100% solids coating and should not be diluted. The dual UV/moisture cure mechanism allows for rapid integration into high-volume inline processes while ensuring full cure even in shadowed areas.

Application Methods:

Spray: Apply without thinning
Dip: 5–15 cm/min withdrawal rate
Brush: For touch-up applications

The quick UV cure (tack-free in seconds) allows for high-speed production, while the secondary moisture cure ensures stability for dipping applications and complete curing.

Application Compatibility

It integrates well with lead-free processes, supports standard cleaning practices, and offers strong performance even on flux-contaminated surfaces.

Compatible With:

✔ Compatible with “no-clean” flux residues
✔ Common PCB finishes including ENIG, HASL, and OSP
✔ High-reliability applications requiring low ionic content
✔ Lead-free and RoHS-compliant manufacturing environments
✔ Fast tack-free time under UV light

Additionally, its UV fluorescence ensures easy inspection, and the coating is reworkable using standard HumiSeal strippers—ideal for repairable designs and serviceable assemblies.

High-Performance Electrical Protection 🧪

1C63 delivers an insulation resistance exceeding 1.0 x 10¹² ohms, protecting even the most sensitive circuit designs from moisture, contaminants, and voltage-induced failure. It is rated for a dielectric withstand voltage of >1,500 volts.

Fluorescent for Inspection 💡

To simplify quality assurance, HumiSeal® 1C63 fluoresces under UV light, making it easy to confirm proper coating coverage during post-application inspection—an essential feature for high-reliability electronics manufacturers.

Repairable and Reworkable 🔁

Unlike many conformal coatings, HumiSeal® 1C63 is easily repairable. Should rework or component replacement be required, the coating can be selectively removed. This makes it ideal for prototyping, low-volume builds, or field serviceability.

Reliable Across Environments 🌍

With its wide thermal range and resistance to fungus (ASTM G21) and moisture, 1C63 ensures consistent performance across varied environmental conditions. It’s particularly well-suited for mission-critical systems exposed to humidity, mechanical stress, or temperature cycling.