Potting a populated board or a filtration cartridge is a thermal and mechanical problem before it is a chemical one. A system that exotherms hard will damage components; one that shrinks will pull on solder joints and open a moisture path at the interface.
MCP 3335 was developed for exactly this envelope: low-exotherm, low-shrink encapsulation qualified in Fortune-500 filtration assemblies.
What this application has to hit
- Low peak exotherm at production pour volumes
- Minimal cure shrinkage and low stress on components
- Dielectric performance and insulation resistance
- Adhesion to housing materials with moisture-tight sealing
- Thermal cycling and humidity resistance over service life
How MCPU formulates for it
Tightly controlled equivalent-weight polyethers keep the reaction exotherm inside the window that sensitive components tolerate, even at larger pour volumes.
Formulation targets low shrink so the cured mass does not load solder joints or peel from the housing wall as it cools.
Hydrophobic network design keeps water out of the encapsulant, protecting insulation resistance under humid service.
Formulation levers we adjust
| Lever | What it controls |
|---|---|
| Exotherm | Equivalent weight and catalyst set peak temperature at pour volume. |
| Shrink | Network design and filler loading minimize cured-part stress. |
| Viscosity | Mixed viscosity tuned for flow around components and full wet-out. |
| Moisture resistance | Hydrophobic segments protect dielectric performance. |
Products used here
- Specialty Polyurethane Systems — Custom polyol systems, encapsulants, fluid-applied roof coatings, and rubber-crumb binders.
- Custom Formulation Development — Bench-to-plant formulation development, reverse engineering, and toll-blended production.