Partially dehydrated vermiculite flakes and method of making same
AssigneeMinnesota Mining and Manufacturing Company
InventorsRoger L. Langer, Richard P. Merry
Life of this patent
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Abstract
Intumescent vermiculite flakes useful in mountings of catalytic converters are prepared by partially dehydrating vermiculite ore to afford a uniform content of chemically bound water from about 1.0 to 3.2% by weight and a uniform bulk density from about 0.2 to 0.9 g/cm.sup.3. Such a mounting affords good support to the monolith at warm-up temperatures, exerts adequate holding forces at operating temperatures without danger of cracking the monolith, and does not incur gradual reduction in holding forces at operating temperatures. The mounting layer can be applied as either a mat or a paste.
Claims17
Intumescent vermiculite flakes having
- a) from about 1.0 to 3.2% by weight of chemically bound water, and
- b) a uniform bulk density from about 0.2 to 0.9 g/cm.sup.3.
Method of producing intumescent vermiculite flakes having a low initial expansion temperature and little or no negative expansion at moderately elevated temperatures, said method comprising the step of partially dehydrating vermiculite ore to produce a batch of intumescent vermiculite flakes having
- a) from about 1 to 3.2% by weight of chemically bound water, and
- b) a uniform bulk density from about 0.2 to 0.9 g/cm.sup.3.
Dependencies are inferred from the claim text.