Vermiculite composition with improved thermal expansion properties
AssigneeW.R. Grace & Co.-Conn.
InventorsSemyon D. Friedman, Robert W. McKinney, Chia-Chih Ou, Robert M. Spotnitz, Shaohai Wu
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Abstract
A vermiculite composition capable of exhibiting a high degree of volume increase upon subjection to thermal exfoliation composed of vermiculite mineralogical species having specific gravity of from 2.5 g/cm.sup.3 to 2.9 g/cm.sup.3. Further, intumescent sheets formed with said vermiculite composition exhibit low initial expansion temperature and very high maximum expansion properties.
Claims15
A vermiculite composition having the capability of exhibiting enhanced volume increase upon subjection to thermal exfoliation consisting essentially of a vermiculite ore concentrate material having at least 90% of at least one unexpanded vermiculite mineralogical specie or mixtures thereof having a specific density in the range of from 2.5 g/cm.sup.3 to 2.9 g/cm.sup.3.
A process of forming a vermiculite composition capable of exhibiting enhanced volume increase upon subjection to thermal exfoliation comprising:
- i. beneficiating vermiculite ore to form vermiculite ore concentrate having a substantial portion of gangue material removed therefrom;
- ii. treating the ore concentrate to density classification to separate out a vermiculite ore concentrate composition composed of at least 90 weight percent of vermiculite mineralogical species having specific density in the range of from 2.5 g/cm.sup.3 to 2.9 g/cm.sup.3 ;
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- iii. recovering the vermiculite composition.
A flexible intumescent sheet product comprising from about 25% to 50% by weight of inorganic fibrous material, from about 5% to 15% of a binder and from about 40% to 65% by weight of at least one vermiculite mineralogical species having a specific density of from 2.5 g/cm.sup.3 to 2.9 g/cm.sup.3.
Dependencies are inferred from the claim text.