Q: Why do transformer makers test the seal in the oil, not just on the rubber?

Hot transformer oil is a working dielectric, and utilities watch its loss factor (tan δ) as a fleet KPI. Every organic part inside the tank leaches something into that oil. A seal that reads "fine" on a bench can still raise the oil's tan δ past the acceptance limit. IOTA F3672 was compounded so the rubber changes as little as the oil does.

Q: What are the numbers?

That tan δ line is the headline: measured increment 0.2 against a ≤0.5 requirement — the seal stays close to invisible inside the dielectric.

Q: How is it processed?

Standard hot-air vulcanizing: add 1.5 phr bis(2,5-dimethyl-2,5-di-tert-butylperoxy)hexane type peroxide (40% content); first stage 170 °C × 15 min, post-cure 200 °C × 4 h. For compression and injection molded parts, 0.6–1.2 phr of the dipentadienyl peroxide is a common starting window — tune temperature and time to part thickness.

Q: Storage?

Original unopened packaging below 40 °C, 12 months from production date. Heat-resistant additives must be added when the application requires full heat-rating.

FAQ

1. Can F3672 be co-vulcanized with MVQ parts? — Fluorosilicone/VMQ co-cure is feasible with matched peroxide systems; ask for our co-vulcanization adhesion data before committing a joint design.

1. Why fluorosilicone instead of NBR for transformer service? — NBR swells and hardens faster in hot oil and does not hold 225 °C excursions; F3672 holds −60 °C brittle point as well.

1. Is the tan δ value factory-guaranteed? — Table values are typical performance, not factory standards; confirm against your acceptance test on production batches.

Related Product: IOTA F3672 Fluorosilicone rubber compound for transformer