Published: 2026-10-16 · Category: Selection guide
An oil filter has to survive oil temperature swings, system pressure fluctuation and a steadily growing contaminant load. The paper must hold its pleat shape throughout - no collapse, no cracking at the crease, no delamination.
Three stresses the paper sees
- Temperature: a long soak in hot oil changes the fibre-to-resin bond. Insufficient heat resistance shows up as softening, embrittlement or strength loss.
- Pressure pulses: cold starts hit hardest. Without enough stiffness and tensile strength, the paper cracks along the crease.
- Contaminant build-up: as the filter cake forms, pressure drop rises and the mechanical load on the paper grows, so holding capacity and strength have to match.
What each property is for
| Property | Role |
|---|---|
| Tensile strength | Resists tearing at creases and edges under pressure pulses |
| Stiffness | Keeps pleat geometry; prevents crushing and uneven spacing |
| Resin content | Raises strength and oil resistance; affects permeability and brittleness |
| Burst strength | Resists local damage from sharp particles |
| Holding capacity | Determines the service interval within the allowed pressure drop |
More resin is not automatically better
Impregnation raises strength, stiffness and oil resistance, but a high resin level makes the paper brittle, so it cracks when pleated, and it consumes pore volume, raising restriction. The practical approach is to establish the minimum strength and stiffness the element needs, then keep as much open structure as that minimum allows. Control points are covered in resin impregnation and curing.
Suggested sequence
- Fix element size, pleat height and available media area from the filter design;
- Set holding capacity from the target service interval and oil cleanliness requirement, then infer weight and thickness;
- Confirm the stiffness requirement (assembly method, centre tube, pressure pulse);
- Check permeability and initial pressure drop with stiffness already satisfied;
- Confirm temperature and oil resistance, and select the resin system and cure level;
- Sample, assemble and inspect for damage before releasing the grade.
In short: meet strength and stiffness first, then optimise flow. Give us the element design, oil type and service interval and we can narrow the family.