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- Humiseal 1A33 GEL | Thixotropic Polyurethane Paste
Humiseal 1A33 GEL | Thixotropic Polyurethane Paste
- Thixotropic Gel Consistency
- Solvent-Free and No Free Isocyanates
- UV Fluorescence for Inspection
Product Description
HumiSeal® 1A33 GEL is a single-component, thixotropic gel based on polyurethane chemistry, specifically formulated to protect printed circuit board (PCB) assemblies. This solvent-free, non-flammable gel offers superior edge coverage and exceptional moisture protection for demanding applications. Its unique gel consistency allows for precise application without the mess of traditional coatings, and it fluoresces under UV light for easy inspection and quality control.
HumiSeal® 1A33 GEL can be applied by a variety of methods including dispensing, brushing, or syringe. Unlike liquid coatings, its viscosity is not adjustable with thinners. It cures through a moisture-cure mechanism, where ambient humidity initiates the curing process. While it will skin over in approximately 30-40 minutes at room temperature, it achieves optimum properties after 30 days at RT, or optionally, through accelerated curing at 30 hours @ 76°C or 20 hours @ 88°C.
HumiSeal® 1A33 GEL is engineered to meet stringent industry specifications, including MIL-I-46058C and RoHS Directive 2011/65/EU.
Target Applications
- General printed circuit board applications
- Automotive electronic applications, including in-cabin and exterior use.
- Military equipment requiring durable performance.
- Renewable energy systems needing robust electronic reliability.
- Industrial controls exposed to high humidity, salt-spray, and corrosive environments.
Technical Specifications
| General Properties | |
| Solids | 44 % |
| Electrical Properties | |
| Dielectric Strength Dielectric Strength Dielectric strength is measured in kV per mm and is calculated by the Breakdown voltage divided by the thickness of the tested material. Those two properties go hand in hand and while Breakdown voltage is always thickness dependent, dielectric strength is a general material property. As an example, the dielectric strength of Polyimide is 236 kV/mm. If we place 1mm of Polyimide between two electrodes, it will act as an insulator until the voltage between the electrodes reaches 236 kV. At this point it will start acting as a good conductor, causing sparks, potential punctures and current flow. | 42 kV/mm |
Additional Information
Frequently Asked Questions About HumiSeal® 1A33 GEL
What are typical applications for HumiSeal® 1A33 GEL?
HumiSeal® 1A33 GEL is ideal for protecting printed circuit board assemblies (PCBs) or spot coating applications. Its non-sagging thixotropic consistency makes it suitable for:
- Military and aerospace electronics (e.g., modules, sensors)
- Industrial electronics (e.g., ruggedized controls, connectors)
- Automotive electronics (e.g., control units, sensitive components)
Its robust chemical resistance and moisture protection make it perfect for protecting sensitive components, especially where a thick or precise coating is required.
Why choose HumiSeal® 1A33 GEL over other conformal coatings?
HumiSeal® 1A33 GEL is a single-component, urethane-based gel that provides excellent chemical and environmental resistance. It offers a thixotropic (non-flowing) consistency for applications like dam-and-fill, encapsulating components, or creating a specific high-build protective layer. It is compliant with MIL-I-46058C and RoHS 2011/65/EU directive. The gel fluoresces under UV light to enable easy inspection of coverage. It is applied by dispensing, syringe, or hand-applied methods, offering flexibility for various production processes. Its curing process allows for efficient manufacturing cycles, and it's a great choice for targeted protection.
What happens to HumiSeal® 1A33 GEL after its shelf life?
After the shelf life, viscosity and curing characteristics may degrade, potentially leading to inconsistent dispensing or reduced protective performance. Use of expired material is not recommended as it may compromise coating quality.
How do curing times vary for HumiSeal® 1A33 GEL?
Curing times depend on temperature and humidity. A full cure can be achieved in 30 days at room temperature (25°C, 50% RH). Curing can be accelerated by heating, which may require specific temperature profiles for thicker applications to ensure a full and uniform cure.
What is the recommended thickness for HumiSeal® 1A33 GEL?
Due to its thixotropic nature, HumiSeal® 1A33 GEL is designed for applications where high-build or encapsulated thicknesses are required, typically ranging from 20 to 100 mils (500 to 2500 microns). This is significantly thicker than standard conformal coatings and allows for dam-and-fill applications and glob topping.
What are the differences between application methods for HumiSeal® 1A33 GEL?
HumiSeal® 1A33 GEL is applied by dispensing, syringe, or hand-applied methods due to its gel-like consistency. These methods are preferred for precise, high-build applications or for coating around components. Unlike liquid coatings, it is not suitable for spraying or dipping.
What is the maximum operating temperature for HumiSeal® 1A33 GEL?
HumiSeal® 1A33 GEL is an evolution of the 1A33 chemistry, and it withstands thermal shock from –65°C to +125°C as per MIL-I-46058C testing. Continuous operation above 125°C is not recommended as it may degrade coating integrity.
What safety precautions should I take when using HumiSeal® 1A33 GEL?
Use in well-ventilated areas and avoid open flames due to flammable solvents. Prevent skin and eye contact by wearing appropriate protective equipment. Consult the Safety Data Sheet (SDS) for detailed handling and disposal instructions.
How can I ensure proper application of HumiSeal® 1A33 GEL?
The gel fluoresces under UV light, allowing easy inspection of coverage and uniformity, which is critical for high-reliability electronics manufacturing, especially for ensuring full component coating.
How does HumiSeal® 1A33 GEL perform in harsh environments?
HumiSeal® 1A33 GEL provides exceptional protection against moisture, chemicals, salt spray, and fungus. Its unique thixotropic consistency allows for a thick, non-flowing barrier, making it particularly effective in maintaining performance in humid, corrosive, and mechanically stressful environments. It is well-suited for military, aerospace, automotive, and industrial applications.
Learn More About HumiSeal® 1A33 GEL
HumiSeal® 1A33 GEL is a proven solution for engineers needing to protect specific, high-risk components on electronic assemblies. This urethane gel offers a unique combination of a non-flowing gel consistency, excellent electrical insulation, and mechanical resilience—making it an industry favorite for glob top, dam and fill, and spot coating applications on PCBs in sectors such as automotive, aerospace, consumer electronics, and industrial automation.
Key Features at a Glance
- ✔ Thixotropic gel for targeted application
- ✔ Cures at room temperature in 30 days
Targeted Application Methods 🧰
HumiSeal® 1A33 GEL is specifically designed for applications requiring precise, high-build coverage. Its thixotropic nature prevents it from running or sagging, making it ideal for spot coating. It is not designed for spraying, brushing, or dipping. Instead, it is applied using automated or manual dispensing equipment. Unlike a liquid coating, no dilution is needed.
Application Methods:
- Automated Dispensing: For high-volume, repeatable processes.
- Syringe/Hand Application: For low-volume or rework.
Cure the gel at room temperature (7 days) for convenience, or explore accelerated curing options (data is available on the product's TDS) to match fast-paced production cycles.
Application Compatibility
Its gel consistency is compatible with various component types and PCB layouts, providing reliable protection for complex assemblies.
Compatible With:
- ✔ Dam-and-fill applications
- ✔ Spot coating for specific areas
- ✔ High-reliability applications requiring a thick, protective barrier
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 🧪
1A33 GEL protects even the most sensitive circuit designs from moisture, contaminants, and voltage-induced failure.
Fluorescent for Inspection 💡
To simplify quality assurance, HumiSeal® 1A33 GEL 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® 1A33 GEL is easily repairable. Should rework or component replacement be required, the coating can be selectively removed using HumiSeal® Stripper 1063, making it ideal for prototyping, low-volume builds, or field serviceability.
Reliable Across Environments 🌍
With a wide thermal shock range of –65°C to +125°C and resistance to fungus (ASTM G21) and moisture, 1A33 GEL ensures consistent performance across varied environmental conditions. It’s particularly well-suited for mission-critical systems exposed to humidity, mechanical stress, or temperature cycling, where its thick, non-flowing barrier provides enhanced protection.
Compliance You Can Trust ✅
HumiSeal® 1A33 GEL meets stringent industry standards, ensuring reliability and regulatory adherence for OEMs and contract manufacturers:
- MIL-I-46058C Qualified
- RoHS 2011/65/EU Compliant