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US 6,149,972 AGranted
Expandable graphite and method
AssigneeUCAR Graph-Tech Inc.
InventorRonald Alfred Greinke
Life of this patent
Estimating the term…
Abstract
Intercalated graphite flake which has enhanced exfoliation volume characteristics at relatively low exfoliation temperatures e.g. 600.degree. C. is made by heating a blend of intercalated particles and an organic reducing agent in the temperature range of 25.degree. to 110.degree. C.
Claims13
Method for providing intercalated graphite flake with increased exfoliation volume at exfoliation temperatures as low as 600.degree. C. which comprises:
- (i) treating of graphite flake with an oxidizing intercalant solution to provide intercalated graphite flake having a surface film of oxidizing intercalant solution;
- (ii) blending said intercalated graphite flake which has a surface coating film of the oxidizing intercalant solution with an organic agent reactive with the oxidizing intercalant solution at temperatures of from 25.degree. C. to 110.degree. C., selected from sugars, alcohols, aldehydes and esters in an amount of from 0.75 to 4% by weight of the graphite flake;
- and (iii) heating the blend of step (ii) to a temperature in the range of 25.degree. C. to 110.degree. C. to promote reaction of the organic agent with the coating of oxidizing intercalant solution.
Dependencies are inferred from the claim text.