Film containing alginate membrane layer and method for preparing same

Disclosed are a film containing an alginate membrane layer and a method for preparing the same. The method is as follows: using a thin layer carrier capable of absorbing liquid, the carrier being made of non-woven fabrics, textures, porous spongy films or plastic films, etc. formed from at least one synthetic or natural fiber; then using at least two coating procedures, which are separate but continuous in succession, to uniformly coat at least one surface of the thin layer carrier with a layer of aqueous alginate solution containing a proper weight percent of sodium alginate or potassium alginate and a layer of salt compound aqueous solution containing a proper weight percent of divalent metal ions such as calcium ions, respectively; rendering the divalent metal ions in the alginates and salt compound cross-linked, so as to form a colloid complex membrane layer, which has a net structure and is water insoluble, on the surface of the thin layer carrier, including on the surface or penetrating more deeply into the inner layer of the surface; thereby producing a film with a membrane layer of alginates such as sodium alginate and with a film carrier in a continuous, fast way in a large amount. When the thin layer carrier has a coarse surface, the formed alginate membrane layer is combined with the thin layer carrier together; and when the thin layer carrier has a smooth surface, the formed alginate membrane layer is easy to separate from the thin layer carrier, so as to enlarge the application range of the film.