The challenge of the current paper cup is that recyclability of the cup is extremely difficult. The plastic lining on the cup is bonded with the paper cupboard and to separate the two would require tremendous effort -- effort that has rarely been put forth by recycling and trash facilities.
X Cup has assembled the plastic liner and cupboard together at the upper rims through mechanical force. Traditionally, paper cups have used virgin paper board for hygienic concerns. One of the few exceptions to this FDA rule is when the cup board does not come in contact with the liquid at all. X Cup is designed with the cupboard and the plastic liner as two separate components and thus allows the use of 100% recycled paper. Not only are we extending the life of these materials, but we also reduce the number of trees that need to be felled, which has many impacts on its own.
While designing the cup, it was very important that the cup be leak proof. When a leak occurs, it is most often due to the seams of the paper cup. With using recycled paper, this issue is more common because of its less qualified shorter fibers not being able to withstand the mechanical bending force during production. By creating a seamless plastic liner, we were able to ensure that the cup remains leakproof and that the recycled cupboard serves as only a cup-shaped holder.
The separable plastic liner is made of polypropylene, due to its thermal stability and rigidity. The plastic liner was developed using thermoforming technique, that allows us to keep costs low and is easily replicable. Although a compostable bioplastic such as PLA is also optional, the current solutions are unable to meet our requirements of thermal stability. We anticipate switching to CPLA, a compostable bioplastic with higher melting point, in the near future when it is more available.
We tested the thermal performance of X Cup against a single-walled paper cup with a sleeve. The results between the two solutions were similar. Even without a sleeve, X Cup’s exterior was cool enough to hold the cup containing hot beverages for prolonged periods of time, reducing possible accidents and ultimately lawsuits. With X Cup, we believe that we can not only create a more recyclable paper cup, but also reduce the need for a sleeve required for hot drinks.