Water soluble films for packaging are films made by evaporation of a solution of alginate or by extrusion of an alginate solution into a non-solvent which mixes with water, such as acetone or ethanol. Water soluble films provide a convenient, safe and economical means of packaging a wide range of products. They also help to reduce the freight costs. By shipping highly concentrated liquid and dry formulations in water-soluble films, it is easier and safe for consumers to purchase and use the products.

Materials
The film is made of polyvinyl alcohol or cellulose nitrate nitrite. Films made of cellulose nitrate nitrite are cold water soluble films. They are prepared by dissolving bleached sulfite pulp in a solution of nitrogen dioxide in dimethylformamide at room temperature and heating the solution at 70 degree C for about 3 hours. They have higher crystallinity, lower moisture absorption, and lower permeability.

The other film could be cast from cyanoethylated polyvinyl alcohol with a degree of cyanoethylation between 5 and 10 mole % which were readily soluble in cold water.

Features

• Good tensile strength and elasticity
• Good barrier characteristics
• Free from static electricity
• Non-hazardous
• Readily accepts specified print processing
• Has user controllable solubility
• Options of both hot and cold water solubility is possible
• After it is dissolved, its residues proves to be non-toxic
• Strong resistance to hydrocarbons, organic solvents, oils, gases
• It is transparent
• It is biodegradable
• Great property of being printed and decorated
• Can be easily sealed

Applications: Water-soluble-films and Packaging
Water-soluble films are used for packaging of washing powder, detergents, dyestuff, pesticides, fertilizers, toxicant, embroidery, needlework, stitchwork, and backlayer of brede. Water soluble film is used for hazardous chemical packaging, agriculture packaging, dye stuff packaging, and dry cell battery separator. They can be used as food packages, garment packages, inside bag of pesticides and chemical products, and as artificial mold releasing film. They are also used for water transfer printing.