Waxed cardboard boxes

Students at Portland State University have developed a new insulation material made from shredded waxed cardboard produce boxes. The insulation helps local grocery stores sustainably dispose of the boxes and could provide low-cost energy savings.

PSU assistant architecture professor Margarette Leite heard that many local grocery stores were looking for a way to sustainably dispose of their waxed cardboard produce boxes. The boxes have traditionally gone into the store’s compostable waste, but because of the wax coating it can take them up to 50 years to decompose. She brought the problem back to her architecture students and had them design several ways to reuse the boxes in the built environment.

Ideas included using the cardboard in building siding or shingles, but the one that caught Leite’s eye was the use of shredded cardboard as insulation. The material stream of waxed cardboard is almost endless, and free, as grocery stores need to get rid of them somehow.

“We’re getting a lot of support from the grocery stores, ” Leite said. “This is more about diverting material from a landfill and making a green product that way.”

Some cellulose insulation products are made with recycled cardboard, which is purchased. “Right now, the waxed cardboard has no value, so there’s really no competition right now for the resource, ” she said. “So that’s the biggest advantage over the cellulose.”

The waxed cardboard insulation has been tested at PSU’s Green Building Research Laboratory and shows great promise. The waxed coating actually acts as a thermal sink, holding the heat from the air, making it a better insulator. In order to get the material up to building code, it needs to be fire resistant. This can be done by adding a fire-retardant to the loose fill or wrapping it in fire resistant material.

The product competed in the Cleantech Challenge – part of the Oregon BEST FEST clean technology conference in Portland – and was one of seven finalists. It didn’t win any money, but Leite has been encouraged by the response from local grocery stores, and is looking to license the product with an insulation manufacturer or start a company to manufacturer it. The cost of manufacturing should be fairly low.

• Get rid of cardboard boxes
• Design cardboard boxes
• Kraft cardboard boxes
• Wax coated cardboard boxes