Bio-degradable balloons?

One of the little news pieces was about a small business that makes balloons. For example, one popular design is a white bird that people release at weddings. The news piece was talking about this being a small business that the owner has set up in a small town, and his dream of small businesses re-invigorating the small towns here in Japan.

Along the way, he showed what he considers one of the best points about his balloons. They disintegrate in water! He took a piece of the material they use and swished it around in a bowl of water. Moments later, it was gone. He says the material is completely bio-degradable. So that flock of balloons released today will disappear in the next heavy rain, rather than trashing the countryside.