Most common disposable paper cups use paperboard to form the structure of the cup and have a lining of polyethylene. This lining in most common paper cups presents a problem for recycling since it is difficult to separate the two materials. This means that specialized recycling processes are required for these cups that make it more expensive and inconvenient to recycle.
To make a cup easily recyclable by established regular recycling practices the paper cup would have to be easily separable. The Duo Cup is a two-part cup, an outer paperboard cup that would feel and look like a conventional paper cup, and a separate plastic liner that nests inside the outer cup. The inner liner would be thicker than traditional cups and would not be held in with an adhesive, just friction fit. When the cup has been used the two parts could easily be separated and recycled separately.