Patent ID: 8206814

Claim:
A film of a material comprising: a denatured clay and an additive, wherein the denatured clay comprises at least one clay selected from the group consisting of mica, vermiculite, montmorillonite, beidellite, saponite, hectorite, stevensite, magadiite, ilerite, kanemite, illite and sericite, the weight ratio of the denatured clay is not less than 70% relative to total solids, the denatured clay comprises a clay with lithium ions wherein the lithium ions are at least 50% within an interlayer of ionic substances of the clay, a silylated clay reacted with a silylating agent having a reactive end, and an organic cation present in an amount of less than 30 wt %, based on the total weight of the denatured clay, the additive is a lignin-based epoxy resin or a sucrose-based epoxy resin, the film has a 5% weight reduction temperature of 235° C. to 760° C. as measured by thermogravimetry, the water-vapor permeability of the film at 40° C. and 90% relative humidity is less than 6 gm −2 day −1 , the film has been subjected to at least one surface treatment selected from the group consisting of a water-repellency treatment, a water-proofing treatment, a reinforcement treatment, and a surface flattening treatment, and wherein the film has gas barrier properties, sufficient mechanical strength to be used as a self-supporting film, and water resistance obtained by a thermal treatment.