Lightweight sound-absorbing and fire-resistant insulation panel using expanded graphite and swelling clay and method for manufacturing the same

A method for manufacturing a lightweight sound-absorbing and fire-resistant insulation panel, the method comprising the steps of:

• manufacturing expanded graphite by second expanding through thermal treatment after first expanding of graphite by acid;
• manufacturing swelling clays by crushing clays to a circular shape, heating the clays at a temperature of about 400 to 600° C., expanding the distance between the layers of clays as much as 20 times to 50 times, and comminuting the expanded clays to have particle sizes in the range of 50 to 20 μm;
• and
• mixing the expanded graphite with a binder and the swelling clays, said mixing comprising adding 10 to 200 parts by weight of a flame-retardant composition per 100 parts by weight of the expanded graphite and the swelling clays, the flame-retardant composition comprising one or more materials selected from the group consisting of water glass having alkali metal carbonates removed therefrom and silica sol;
• and
• molding the mixed material to form the lightweight sound-absorbing and fire-resistant insulation panel,
• wherein the swelling clays are formed of honeycomb-shaped layered clays containing water molecules in interlayers.