We have so many things that we want to talk about! We just sent this response to a person asking about our Paper Backpack. We'll edit and polish it over time!
The paper backpack is really neat. Kraft paper is a different grade of paper that is very durable (as it is used industrially), recyclable, and doesn't break down when wet (unlike like copy paper).
At the end of the paper bag's life, the Kraft paper and Tyvek would have to be cut away from each other as both can separately be recycled. Also the vegan leather and any metal bits would have to be cut away as well and are not recyclable (at some point, I'm hoping to have any metal bits made out of recycled materials as well).
We used Tyvek as a lining because it is a water barrier and allows the Kraft Paper backpack to be used in the rain. While Tyvek is a plastic, it is recyclable and it is very thin which means we're using a very small amount of plastic that allows that bag to be used in rain as well. I wouldn't use the Kraft Paper backpack in heavy rain for an extended period of time because the paper will eventually absorb water and become heavier and take a little time to dry out.
This all said, I just saw someone who has been wearing our Kraft Paper backpack everyday for 4 months. The bag is a little dirty (it is white) but the material looks perfectly fine. =) And this is my long term goal with the company. Make products that last a long time and then at some point in the future, you can recycle/compost the materials.