PVOH gives films with glass-like transparency which biodegrade like cellulose and are therefore fully compostable. The packaging film used PVOH as the middle layer of a sandwich with PLA as the outer layers. There were problems with adhesion and these had been solved using a special tie resin. The 3-layer film could also be ground and recycled as PLA; the PVOH being water soluble could be washed away. A typical construction would be 20 microns of G-Polymer inside 30micron layers of PLA each bonded to the G-Polymer with 10microns of adhesive to give an oxygen transmission rate of 0.02 ccs/square metre/day at 23C and 50%RH.
Nippon Gohsei make 70,000 tonnes/year of PVOH in Japan. Nichigo G-Polymer™ is the world’s first amorphous PVOH and combines the strengths of regular PVOH and EVOH.