Patent ID: 7083758

Claim:
A free flowing dry back-up insulating material having a thermal conductivity ranging between about 0.8 and about 1.8 BTU·in/ft 2 ·hr.·° F. and a setting temperature lower than 400° F., wherein said material consists essentially of: a) from 67 to 96% by weight of fly-ash comprising cenospheres, b) from 2 to 15% by weight of a heat sensitive binder selected from the group consisting of boric acid and anhydrous boron oxide; c) from 2 to 7% by weight of a non-wetting agent selected from the group consisting of calcium fluoride, magnesium fluoride and barium sulphate; d) from 0 to 10% by weight of a heat expandable material selected from the group consisting of vermiculite and graphite; and e) from 0 to 1% by weight of a dust suppressant.