NOT LONG AGO, upcycling became ultra hip. It's now common in consumer soft goods to find apparel, umbrella bags plastic, backpacks, and laptop sleeves made of material that was used for something entirely different in a previous life. You can get shoulder bags made of discarded sailcloth and pillows sewn from Japanese shibori remnants.

But one of the first brands to stoke the upcycling craze was Freitag. The Swiss company has been making backpacks and messenger bags out of recycled truck tarpaulins since the early 1990s. In fact, those rubbery and rugged truck tarps—weatherproof polyvinyl sheets used by shipping companies to secure their clients' inventory on a truck bed and keep it from getting blown all over the freeway—have come to define the brand.

Now Freitag is bringing a new design to market: a line of biodegradable bags that are made partially of truck tarp, and partially of material spun from recycled plastic bottles. For the new line, Freitag has partnered with a Swedish company called We aRe SpinDye, one of several companies making synthetic yarns out of broken-down PET plastic bottles. SpinDye's plastic yarn is woven into a textile which Freitag uses to build the inner lining and the more flexible parts of the bag. Truck tarps make up the rest of the piece.

The first bag from this "Tarp on PET" collection, a drawstring-closure backpack/tote combo named Cinnamon, was released on February 14. Now, exactly one month later, Freitag is adding three new designs. There's a commuter backpack called Carter, a sling/fanny-pack piece called Phelps, and a roll-top shoulder rigid handle bag named Rollin.

The most noticeable advantage of this new design is a big reduction in weight. The truck tarp material is insanely durable—just yesterday I met somebody who's been using the same Freitag truck-tarp laptop sleeve for 20 years—but it's also thick and rather stiff. Make a whole backpack out of truck tarp, and weight starts to become an issue. These new Tarp on PE plastic bag, however, are mostly constructed from that new plastic-bottle fabric, so they're much lighter and more pliable. The brightly colored tarp sections are incorporated sparingly, giving the bag structure and adding durability where it's needed the most: in the straps, along the bottom, and on the seams that see the most stress.