From Hosfelt, under "relays"
180 Second Delay $US 5.95
Mfg. - MIDTEX
Mfg.# - 711-180B115
115 VAC input, SPST
1-1/4" dia. x 2-1/8" H metal enclosure
5 amp @30 VDC/120 VAC contacts
Superior replacement for plug in timer.
Normally Closed
PN 45-598
and they probably have others suited to your app.
or else, if the timing need is not precise, get a relay with a high coil resistance and use a transistor and a 1000 µF capacitor to simulate a really large capacitor (apparent C = β[actual C]). A 12v relay drops out at ~9v.
This circuitry could get tricky.