| abstract |
A sealing material which comprises a water-resistant sheet that is formed from a layered clay mineral having a thickness of from 0.5 nm to 800 nm. A sealing material which comprises a sheet that is formed from a modified layered clay mineral wherein at least some of first cations, which are present between layers of a swellable layered clay mineral, are ion exchanged by second cations, and wherein the first cations are one or more kinds of cations selected from among Na+ and Li+. A sealing material which comprises a sheet that is formed from a layered clay mineral wherein one or more kinds of cations selected from among K+, Ba2 + and Pb2+ are present at least partially between the layers, said layered clay mineral having a thickness of from 0.5 nm to 800 nm. |