Humiseal 1A20R | Polyurethane Conformal Coating

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

Humiseal 1A20R | Polyurethane Conformal Coating

Main features

One-component
Fast-curing
Chemically-resistant

Product Description

HumiSeal® 1A20R is a single-component, fast-curing polyurethane conformal coating that provides exceptional protection for printed circuit boards (PCBs). This coating is known for its excellent chemical resistance in addition to its moisture resistance. It dries quickly to a durable, transparent finish and is easy to apply.

HumiSeal® 1A20R coating meets the following requirements:

MIL-I-4658C
IPC-CC-830
RoHS Directive 2002/95/EC Compliant
Recognized under UL File Number E105698

Product Key Feature

Urethane Chemistry - Offers a superior balance of physical and electrical properties, including excellent resistance to moisture, fungus, and chemicals.
Fast Curing - Dries to the touch in about an hour, allowing for quicker handling and processing. Full cure is achieved after 24 hours at room temperature or 3 hours at 76°C.
Fluorescent Tracer - Contains a UV indicator for easy inspection under a blacklight to ensure complete and uniform coverage.
Chemically Resistant - Provides a durable barrier against various corrosive agents.

Applications

For protecting a wide range of electronic assemblies from environmental and chemical stress. It is suitable for use in industries such as automotive and military electronics, renewable energy, and industrial controls.

Specifications
Additional Information

Technical Specifications

General Properties

Density (g)

1.02 g/cm3

Solids

50 %

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

100 mPa.s

Electrical Properties

Dielectric Constant

Dielectric Constant
Dielectric Constant (k), commonly known as relative permittivity, is a number relating the ability of a material to carry alternating current to the ability of vacuum to carry alternating current.

It determines the ability of an insulator to store electrical energy and is the ratio of electric permeability in vacuum against the electric permeability of a material.

The lower the dielectric constant (κ) and dissipation factor, the less energy is absorbed from an electric field, making it a much better insulator.

It is a dimensionless property that can be affected by various factors such as the thickness uniformity of a material, insufficient contact between the sample and electrodes, water adsorption and contact resistance.

Dielectric Constant @ 1000 kHz

3.5

Dissipation Factor

Dissipation Factor
Dissipation factor is commonly known as loss tangent or tan delta.

It is a ratio of the loss index and the relative permittivity and it measures the inefficiency of an insulating material to maintain energy (that otherwise dissipates in the form of heat). The lower the factor, the better the insulation.

It is the reciprocal of the quality factor and always refers to a specific temperature and frequency.

Dissipation Factor @ 25°C /1000 kHz

0.028

Mechanical Properties

Storage (DMA) Modulus
Storage (DMA) Modulus @ 25°C	89.6 N/mm2

Thermal Properties

Coefficient of Thermal Expansion (CTE)

Coefficient of Thermal Expansion (CTE)
CTE (Coefficient of thermal expansion) is a material property that is indicative of the extent to which a material expands with a change in temperature. This can be a change in length, area or volume, depending on the material.

Knowing the CTE of the layers is helpful in analyzing stresses that might occur when a
system consists of an adhesive plus some other solid component.

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.

515 ppm/°C

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.

71 °C

Operating Temperature

-65 - 125 °C

Curing Conditions

Curing Schedule

Curing Schedule
Curing schedule is the time and temperature required for a mixed material to fully cure. While this applies to materials that cure with heat, there are also other materials that can be cured with UV.

Even though some materials can cure on ambient temperatures, others will require elevated temperature conditions to properly cure.

There are various curing schedules depending on the material type and application. For heat curing, the most common ones are Snap cure, Low temperature cure, Step cure and Staged cure.

Recommended cure type, schedule, time and temperature can always be found on the Technical data sheets.

Full Cure Time

24 hours

Additional Information

Frequently Asked Questions About HumiSeal® 1A20R

What are typical applications for HumiSeal® 1A20R?

HumiSeal® 1A20R is a one-part, moisture-curing polyurethane conformal coating designed to protect printed circuit board assemblies (PCBs) in demanding environments. Its excellent moisture and chemical resistance, along with its wide operating temperature range, make it a reliable choice for a variety of industries, including:

Military and aerospace electronics (e.g., control modules, avionics)
Industrial electronics (e.g., motor drives, sensors, process controls)
Automotive electronics (e.g., electronic control units)
Instrumentation and monitoring equipment

This coating is particularly well-suited for applications where reliable environmental protection is required and where the use of a simple, one-part, moisture-curing system is preferred.

Why choose HumiSeal® 1A20R over other conformal coatings?

HumiSeal® 1A20R is a single-component, high-performance polyurethane formulation that cures at ambient temperature and humidity. It provides excellent chemical and moisture resistance. Unlike coatings that require specialized curing equipment, 1A20R cures simply by reacting with atmospheric moisture, making it a cost-effective and easy-to-implement solution. It is a flexible coating with high abrasion resistance, and its viscosity is optimized for spray, brush, or dip application. The coating is compliant with MIL-I-46058C and IPC-CC-830, and it meets the requirements of the RoHS Directive 2011/65/EC (and 2015/863/EU). You can learn how to select a conformal coating in our latest blog.

What is the shelf life of HumiSeal® 1A20R?

HumiSeal® 1A20R has a shelf life of 6 months from the date of manufacture when stored at 0 to 35°C in a tightly closed container, away from direct sunlight or excessive heat. As it is a moisture-curing material, it is crucial to protect the product from ambient humidity to prevent premature polymerization. Therefore, any open or partial containers should be tightly sealed after use, and ideally purged with a dry, inert gas (e.g., nitrogen or argon) before closure.

How should I clean tools after applying HumiSeal® 1A20R?

To flush equipment and clean uncured HumiSeal® 1A20R, non-alcohol based solvents like xylene or toluene are suitable. HumiSeal® Thinner 521 is an effective option. For coating removal during rework, the cured film can be difficult to remove. Thermal displacement, mechanical abrasion, and specialized chemical strippers (e.g., HumiSeal® Stripper 1072) are all suitable options for rework.

What happens to HumiSeal® 1A20R after its shelf life?

After the shelf life, the material's viscosity may increase, and its curing characteristics may degrade. This can lead to improper application, uneven coating, and a reduction in the protective performance of the cured film. The use of expired material is not recommended as it may compromise the quality and reliability of the coating. Due to its moisture-curing nature, proper storage is critical to maintaining product integrity.

How does HumiSeal® 1A20R cure, and why do curing times vary?

HumiSeal® 1A20R is a single-cure, moisture-curing coating that reacts with atmospheric humidity to form a durable film. The coating has a drying time to handle of 60 minutes and will require 24 hours at room temperature or 3 hours at 76°C to cure. A full cure with optimum properties is achieved within 7 days. Curing times can vary based on ambient conditions; higher temperature and humidity will accelerate the curing process, while lower temperature and humidity will slow it down. Ensuring a well-ventilated and controlled environment is key for a consistent and reliable cure.

What is the recommended thickness for HumiSeal® 1A20R?

The recommended coating thickness for HumiSeal® 1A20R is 25 to 75 microns (1-3 mils). This thickness range ensures optimal protective performance while maintaining flexibility and electrical properties. The final thickness can be adjusted based on the application method and specific project requirements.

What are the differences between application methods for HumiSeal® 1A20R?

HumiSeal® 1A20R can be applied by dipping, spraying, or brushing. Dipping is often used for high-volume, automated processes, providing uniform coverage for complex geometries. Spraying, using conventional spray equipment, is ideal for selective application and achieving a consistent film. Brushing is suitable for rework or small-scale applications, offering precise control in localized areas. For all methods, ensuring a dry, inert gas source for any spray equipment is crucial to prevent premature curing.

What is the maximum operating temperature for HumiSeal® 1A20R?

HumiSeal® 1A20R has a continuous use operating temperature range of –65°C to +125°C, providing consistent protection across a wide range of thermal conditions. It is capable of withstanding thermal shock within this range, as demonstrated by its compliance with MIL-I-46058C testing.

What safety precautions should I take when using HumiSeal® 1A20R?

HumiSeal® 1A20R contains flammable solvents, so it should be used in well-ventilated areas and kept away from open flames or sparks. Prevent skin and eye contact by wearing appropriate personal protective equipment, including safety glasses and solvent-resistant gloves. Avoid inhalation of vapors and spray mist. Always consult the product's Safety Data Sheet (SDS) for detailed handling, storage, and disposal information.

How can I ensure proper application of HumiSeal® 1A20R?

HumiSeal® 1A20R contains a UV fluorescent tracer, which makes it easy to inspect for proper coverage. Under a UV lamp, the coating will fluoresce, allowing visual confirmation of uniform application and film integrity. This feature is essential for quality control and process monitoring, ensuring all required areas of the PCB have been coated uniformly. Test coupons can be used to periodically check thickness and cure quality.

How does HumiSeal® 1A20R perform in harsh environments?

HumiSeal® 1A20R provides excellent protection against moisture, humidity, and chemical exposure. The cured polyurethane film is tough and flexible, ensuring long-term integrity against environmental stressors. This makes it an ideal solution for applications where PCBs are exposed to corrosive agents, moisture, or significant temperature fluctuations, such as in military or industrial settings.

Learn More About HumiSeal® 1A20R

HumiSeal® 1A20R is a high-performance, single-component, moisture-curing polyurethane conformal coating. Designed for superior protection, this coating offers a simple yet effective solution for safeguarding electronic assemblies in demanding environments. It provides a reliable defense against moisture, chemicals, and temperature extremes, making it an industry staple for protecting PCBs in sectors like military, aerospace, and industrial automation. An added UV fluorescent tracer assists with visual inspection for quality control.

Key Features at a Glance

✔ Single-component, moisture-curing system
✔ Excellent moisture and chemical resistance
✔ Good flexibility and abrasion resistance
✔ Wide operating temperature range
✔ UV fluorescent tracer for inspection
✔ Can be applied by spray, dip, or brush

Simple, Reliable Moisture Cure 💧

HumiSeal® 1A20R offers a straightforward and highly reliable curing system that doesn't require any special equipment. It cures at ambient temperature and humidity by reacting with moisture in the air. This eliminates the need for ovens or UV lamps, simplifying the production process and reducing energy costs. The tack-free time is just 1-3 hours, with a full cure typically achieved within 72 hours, depending on atmospheric conditions.

Curing Parameters:

Ambient Cure: Tack-free in 1-3 hours. Full cure in 72 hours at 25°C / 50% relative humidity.

This simple curing mechanism provides a robust and complete cure for even the most complex PCB assemblies without the need for specialized equipment or process steps.

Application and Compatibility

HumiSeal® 1A20R is a versatile coating formulated for various application methods, making it compatible with a wide range of manufacturing environments.

Compatible With:

✔ Spray, dip, or brush application methods
✔ High-reliability applications requiring excellent moisture resistance
✔ "No-clean" flux residues (users should confirm compatibility)
✔ Lead-free and RoHS-compliant manufacturing environments

Additionally, the coating is reworkable using thermal methods or chemical strippers, making it a practical choice for designs that may require servicing or component repair.

High-Performance Electrical and Physical Protection 🧪

HumiSeal® 1A20R delivers outstanding electrical insulation with a dielectric withstand voltage >1,500 volts and insulation resistance >1.0 × 10¹⁴ ohms. Its polyurethane chemistry provides excellent chemical resistance, flexibility, and abrasion resistance, ensuring long-term durability and protection against moisture, contaminants, and mechanical stress.

Inspection and Quality Control 🔎

HumiSeal® 1A20R contains a UV fluorescent tracer, allowing for easy and reliable inspection under UV light. Quality assurance can be achieved by carefully monitoring the application process to ensure all critical areas are coated to the recommended thickness. This feature is ideal for manufacturers who require a simple, visual method for verifying proper coverage and uniformity across the entire PCB.

Repairable and Reworkable 🔁

Although HumiSeal® 1A20R forms a robust, durable film, it is still reworkable. If component replacement or repair is needed, the cured coating can be selectively removed using thermal displacement (e.g., a soldering iron), mechanical abrasion, or a chemical stripper. This feature makes 1A20R suitable for applications that require field serviceability or prototype modification.

Reliable Across Environments 🌍

With a continuous operating temperature range of –65°C to +125°C, coupled with excellent moisture and chemical resistance, 1A20R ensures consistent performance across varied environmental conditions. Its robust polyurethane film is particularly well-suited for critical systems exposed to humidity, corrosive agents, and significant temperature cycling.