Cardboard

/ˈkärdbôrd/ a material made from cellulose fiber (such as wood pulp) like paper but thicker

Cardboard is made through a process called corrugation. Corrugation involves sandwiching a piece of crimped paper, called a flute, between top and bottom liners using an adhesive. The top and bottom liners are made by gluing many layers of sheets of paper to increase their thickness and durability. If you haven’t already reviewed “Pulp & Paper” Info sheet – go there now.

To recycle cardboard, materials recovery facilities will sort it out of the single stream materials, make bales of OCC (old corrugated cardboard), and ship the bales to paper mills. Mills will shred the OCC and combine it with hot water in a machine that mixes and turns the cardboard back into pulp.

Just like the process for making paper, this pulp will be spread in a thin layer on a moving conveyer belt, pressed together using rollers which remove excess water, and dried out with heat. The sheets are then further processed according to end use.

If the quality is intact, most recovered OCC is used to make more cardboard for shipping and packaging. It can also be downgraded into paperboard (cereal boxes), chipboard (show boxes), or other fiber-based products.

According to the EPA’s 2015 Advancing Sustainable Materials Management Fact Sheet, OCC has one of the highest recycling rates of all recycled products at 92.3%. However, since 2015, the drastic increase in the use of OCC by online retailers, China’s ban on mixed paper imports, and a relatively small domestic collection infrastructure and end markets, result in an increasing amount of valuable OCC being landfilled in the U.S.

Despite that, OCC remains a top commodity for recycling in terms of value. As a consumer or business owner, it is important to support this market by recycling cardboard correctly. First, it’s important to flatten all boxes – this helps ensure recycling containers are not presumed full when they are really full of empty space. It also helps saves valuable space in recycling trucks and on the tipping floor of materials recovery facilities. While mills are equipped to deal with certain common contaminants, you can help out by removing the shipping tape from cardboard as well. Grease or food stained cardboard should never be recycled as it creates issues with fiber connectivity during the cardboard-making process. Lastly, since mills pay for cardboard based on weight, it’s important that both business operators and residents not store cardboard outside where it can get wet with snow and rain.

Resources

Sustainable Forestry Initiative

American Forest & Paper Association

Corrugated Packaging Alliance

Cardboard Recycling Process

How Cardboard is Recycled Video