Humiseal 1B51NSLU | Synthetic Rubber Conformal Coating

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

Humiseal 1B51NSLU | Synthetic Rubber Conformal Coating

Main features

Fast-drying
Low moisture vapor permeability
Environmentally friendly

Product Description

HumiSeal 1B51NSLU is a fast-drying, single-component synthetic rubber conformal coating made with methylcyclohexane solvent that is more environmentally friendly than traditional solvents. This coating has extremely low moisture vapor permeability, low stress, and excellent flexibility. For easier inspection, HumiSeal 1B51NSLU coating fluoresces under UV light. It is also in full compliance with the RoHS Directive 2002/95/EC.

Product Key Features

Fast-drying
Single-component formula — No mixing required.
Excellent flexibility — Prevents cracking under stress.
Fluoresces under UV light for easy inspection.

Applications

Suitable printed circuit assemblies.

Specifications
Additional Information

Technical Specifications

General Properties

Density (g)

0.81 g/cm3

Solids

15 %

Electrical Properties

Breakdown Voltage

Breakdown Voltage
Breakdown voltage is the minimum voltage necessary to force an insulator to conduct some amount of electricity.
It is the point at which a material ceases to be an insulator and becomes a resistor that conducts electricity at some proportion of the total current.

After dielectric breakdown, the material may or may not behave as an insulator any more because of the molecular structure alteration. The current flow tend to create a localised puncture that totally alters the dielectric properties of the material.

This electrical property is thickness dependent and is the maximum amount of voltage that a dielectric material can withstand before breaking down. The breakdown voltage is calculated by multiplying the dielectric strength of the material times the thickness of the film.

4900 V

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

2.5

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

0.07

Mechanical Properties

Storage (DMA) Modulus
Storage (DMA) Modulus @ 25°C	35.3 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.

55 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.

14 °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® 1B51NSLU

What are typical applications for HumiSeal® 1B51NSLU?

HumiSeal® 1B51NSLU is a fast-drying, single-component synthetic rubber conformal coating. Due to its unique polymer base, it provides an exceptionally low moisture vapor permeability, making it an excellent choice for protecting printed circuit board assemblies (PCBs) in high-humidity and demanding environments. Its flexibility and low stress on components make it a reliable choice for a variety of industries, including:

Automotive electronics (e.g., in-cabin and under-the-hood)
Industrial control systems
Military electronics
Renewable energy systems

This coating is particularly well-suited for applications that require superior protection against moisture and environmental stressors, where a simple and flexible coating system is preferred.

Why choose HumiSeal® 1B51NSLU over other conformal coatings?

HumiSeal® 1B51NSLU is a high-performance synthetic rubber formulation that dries quickly at ambient temperature. It stands out due to its extremely low moisture vapor permeability, superior flexibility, and low stress on components. Unlike some coatings, it includes a UV fluorescent tracer for easy inspection, and it is easily repaired. It leverages an environmentally friendly solvent blend, making it a more sustainable choice. The coating's viscosity is optimized for spray, brush, or dip application. It meets the requirements of the RoHS Directive 2011/65/EC (and 2015/863/EU).

What is the shelf life of HumiSeal® 1B51NSLU?

HumiSeal® 1B51NSLU has a shelf life of 12 months from the date of manufacture when stored at room temperature in a tightly closed container, away from excessive heat or cold. As a fast-drying solvent-based material, it is crucial to protect the product from ambient air to prevent premature polymerization and solvent evaporation. Therefore, any open or partial containers should be tightly sealed after use.

How should I clean and rework HumiSeal® 1B51NSLU?

For coating removal during rework, the cured film can be selectively removed using thermal displacement (e.g., a soldering iron), mechanical abrasion, or a chemical stripper. HumiSeal® Stripper 1080 is a suitable option for stripping the cured film.

What happens to HumiSeal® 1B51NSLU after its shelf life?

After the shelf life, the material's viscosity may increase, and its application 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 solvent-based nature, proper storage is critical to maintaining product integrity.

How does HumiSeal® 1B51NSLU cure, and why do drying times vary?

HumiSeal® 1B51NSLU is a single-component, fast-drying coating. It is dry to the touch in approximately 10 minutes and will be ready for handling. A full cure is achieved after 24 hours at room temperature (25°C) or within 30 minutes at an elevated temperature of 76°C. The time required to reach optimum protective properties is approximately 7 days. Drying times can vary based on ambient conditions; higher temperature and lower humidity will accelerate the drying process.

What is the recommended thickness for HumiSeal® 1B51NSLU?

The recommended coating thickness for HumiSeal® 1B51NSLU 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® 1B51NSLU?

HumiSeal® 1B51NSLU 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 adequate ventilation is crucial to prevent the build-up of flammable solvent vapors.

What is the maximum operating temperature for HumiSeal® 1B51NSLU?

HumiSeal® 1B51NSLU 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® 1B51NSLU?

HumiSeal® 1B51NSLU 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® 1B51NSLU?

HumiSeal® 1B51NSLU contains a UV fluorescent tracer, which makes it easy to inspect under a blacklight. This allows for quick and efficient quality control to ensure proper coverage and uniformity. Visual inspection under UV light is the primary method for ensuring proper application and can reveal areas that were missed or have an inconsistent thickness.

How does HumiSeal® 1B51NSLU perform in harsh environments?

HumiSeal® 1B51NSLU provides excellent protection against moisture, humidity, and chemical exposure. The cured synthetic rubber film is tough and flexible, ensuring long-term integrity against environmental stressors. Due to its extremely low moisture vapor permeability, this coating is an ideal solution for applications where PCBs are exposed to high humidity and corrosive agents.

Learn More About HumiSeal® 1B51NSLU

HumiSeal® 1B51NSLU is a high-performance, single-component, synthetic rubber conformal coating. Designed for superior protection, this coating offers a fast-drying 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 automotive, military, and industrial automation.

Key Features at a Glance

✔ Fast-drying, single-component system
✔ Extremely low moisture vapor permeability
✔ Excellent flexibility and low stress on components
✔ Wide operating temperature range (-65°C to +125°C)
✔ Contains a UV fluorescent tracer for easy inspection

Fast Drying with an Environmental Focus 🌱

Application Method

HumiSeal® 1B51NSLU offers a fast and reliable drying system that doesn't require any special curing equipment. It is ready to handle in just 10 minutes. The coating contains a methylcyclohexane solvent, which is a more environmentally friendly alternative to traditional solvents, helping manufacturers reduce their environmental footprint while maintaining high performance.

Drying Parameters:

Time to Handle: 10 minutes
Full Cure: 24 hours at room temperature or 30 minutes at 76°C

This fast-drying mechanism helps streamline the production process and is ideal for high-volume manufacturing environments.

Application and Compatibility

HumiSeal® 1B51NSLU 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® 1B51NSLU delivers outstanding electrical insulation with a dielectric withstand voltage >1,500 volts and insulation resistance >2.0 × 10¹⁴ ohms. Its synthetic rubber 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®1B51NSLU contains a UV fluorescent tracer, allowing for quick and easy inspection under UV light. This feature enables manufacturers to rapidly confirm uniform coverage and identify any areas that may have been missed. The fluorescent glow provides a clear visual signal, simplifying the quality assurance process and ensuring consistent application.

Repairable and Reworkable 🛠️

Although HumiSeal® 1B51NSLU 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 1B51NSLU 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, 1B51NSLU ensures consistent performance across varied environmental conditions. Its robust synthetic rubber film is particularly well-suited for critical systems exposed to humidity, corrosive agents, and significant temperature cycling.