Polyvinyl Alcohol (PVA) the least common plastic, is a low temperature water-soluble thermoplastic. it’s most often used as a support material for dual-extruing printers. It has a melting point below PLA and a texture similar to ABS, so it is fairly easy to print. Dissolving PVA can be done easily with simple submersion. One drawback of this 3D printer filament is its sensitivity to water –even mild humidity can ruin any unsealed material. This means that it must be stored in a cool, dry location. In cool climates, a resealable plastic bag with desiccant might be enough, but in warmer humid weather, more caution must be taken.
*3dprinterhub http://3dprinterhub.com/3d-printing-materials