HUMISEAL 1A33/521PB25
Harmonization Code : 3404.90.00.00 | Artificial waxes and prepared waxes : Other
Main features
- Ready for Automated Spray Processing
- Environmental Protection with Inspectability
- UL 94 V-0 Classification
Product Description
HumiSeal® 1A33/521 PB25 Urethane Conformal Coating is a single-component polyurethane conformal coating pre-blended to 25 cP for immediate use in automated spray equipment without additional thinning. Designed for general printed circuit board applications, it provides protection against moisture, salt and corrosive environments, dirt, and other supported environmental exposure. The flexible coating dries to handle in 15 minutes, fluoresces under UV light for inspection, and is readily repairable. Recommended dry-film thickness is 25–75 microns, with optional cure schedules of 30 days at room temperature, 30 hours at 76°C, or 20 hours at 88°C to reach optimum properties.
Key features
- Ready-to-spray 25 cP pre-blend: Formulated for automated spray equipment without additional thinning.
- Single-component polyurethane: Provides a flexible cured conformal coating for general printed circuit board applications.
- Fast handling: Typical drying time to handle is 15 minutes.
- UV inspection and repair: Fluoresces under UV light for coverage inspection and is readily repairable.
- Environmental protection: Supports protection against moisture, salt and corrosive environments, and dirt.
- Qualified 1A33 coating system: The 1A33 system meets multiple military, IPC, IEC, UL, REACH, RoHS, and salt-spray requirements.
Applications / Suitable for
- Automated spray coating of printed circuit board assemblies
- Protection of electronics from moisture, salt, corrosive environments, and dirt
- UV-inspectable conformal coating processes
- Repairable polyurethane coating for general PCB applications
TDS, SDS & Technical Documents
Technical Specifications
Other Properties
Thermal Properties
Electrical Properties
Additional Information
HumiSeal® 1A33/521 PB25 Urethane Conformal Coating
HumiSeal 1A33/521 PB25 is a single-component polyurethane conformal coating pre-blended for automated spray application without additional thinning. It combines fast handling, flexible environmental protection, UV-fluorescent inspection, repairability, and documented electrical and thermal performance.
As-Supplied Properties
Typical exact-product liquid-coating data. Values are representative and are not specifications.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Product type | Single-component polyurethane conformal coating | — | Pre-blended for automated spray |
| Viscosity | 25 ± 3 | cP | Fed-Std-141, Method 4287 |
| Solids content | 36 ± 1 | % by weight | Fed-Std-141, Method 4044 |
| Density | 0.93 ± 0.02 | g/cm³ | ASTM D1475 |
| Volatile organic compounds | 569 | g/L | Exact-product HumiSeal TDS |
| Drying time to handle | 15 | min | Fed-Std-141, Method 4061 |
| Shelf life | 24 | months | At room temperature from date of manufacture |
Surface Preparation, Spraying, and Cure
Cleanliness is critical to conformal-coating performance. Surfaces must be free of moisture, dirt, wax, grease, flux residues, and other contaminants. Confirm compatibility with the actual assembly materials, process conditions, and cleanliness level before production use.
Conformal Coating Sequence
Cured Coating Properties
Typical properties of fully cured HumiSeal 1A33 and its pre-blends. Values are representative and should not be used as design allowables.
| Property | Value | Unit | Method / condition |
|---|---|---|---|
| Recommended dry-film thickness | 25–75 | µm | Documented application range |
| Thermal shock | -65 to 125 | °C | 50 cycles per MIL-I-46058C |
| Coefficient of thermal expansion | 193 | ppm/°C | TMA |
| Glass transition temperature | 26 | °C | DSC |
| Modulus | 27.2 | MPa | DMA at 40°C |
| Flammability | V-0 | — | UL 94 |
| Dielectric withstand voltage | >1,500 | V | MIL-I-46058C |
| Dielectric breakdown voltage | 7,500 | V | ASTM D149 |
| Dielectric constant | 3.6 | — | 1 MHz and 25°C; ASTM D150-98 |
| Dissipation factor | 0.03 | — | 1 MHz and 25°C; ASTM D150-98 |
| Insulation resistance | 2.0 × 1014 | Ω | MIL-I-46058C |
| Moisture insulation resistance | 1.6 × 1010 | Ω | MIL-I-46058C |
| Comparative tracking index | PLC 0 | — | UL746E at 600 V |
| Fungus resistance | Passes | — | ASTM G21 |
Store HumiSeal 1A33/521 PB25 away from excessive heat or cold in tightly closed containers at 0–35°C. Before use, allow the product to equilibrate for 24 hours at 18–32°C. The solvent system is flammable: keep the material away from open flames, sparks, heat, and other ignition sources, control static electricity, and use adequate ventilation to carry vapors and spray mist away from operators. Consult the current SDS before handling, application, storage, transport, spill response, or disposal.
Qualifications and Compliance
| Requirement | Product status | Scope note |
|---|---|---|
| MIL-I-46058C | Meets | HumiSeal 1A33 coating requirement; fully cured pre-blends are documented as equivalent. |
| IPC-CC-830B | Meets | HumiSeal 1A33 coating requirement. |
| IEC60664-3 | Meets | HumiSeal 1A33 coating requirement. |
| UL746E and UL94 V-0 | Meets | UL recognition is listed under file number E105698. |
| REACH and RoHS Directive EU 2015/863 | Compliant | Confirm current regional obligations and customer-specific declaration requirements. |
| IEC61086 / IEC60068-2-11 salt spray | Passes | HumiSeal 1A33 coating-system test statement. |
Inspection, Compatibility, and Rework
Applications
HumiSeal 1A33/521 PB25 supports printed circuit board coating processes where the assembly materials, cleanliness, spray equipment, coating thickness, cure schedule, inspection method, and service environment have been validated.
Technical Support
Work with Krayden to evaluate HumiSeal 1A33/521 PB25 against your PCB materials, flux and cleanliness condition, masking plan, automated spray equipment, target thickness, cure schedule, UV inspection criteria, repair process, and service environment. Our team can help review compatibility, process trials, packaging, and implementation requirements.
