Intumescent sheet material.

摘要

Flexible intumescent sheet materials particularly useful for mounting automotive catalytic converter monoliths, said sheets having greatly decreased negative expansion characteristics in the range of 200 to 400°C, and which are thermally resistant and resilient after expansion, are disclosed. The flexible intumescent sheets may be formed by standard paper-making techniques from a furnish comprising from 40% to 65% by weight of NH<Sup>+</Sup><Sub>4</Sub>-exchanged unexpanded vermiculite, from 25% to 50% by weight of inorganic fibrous material and from 5 to 15% of binder.