How Is Corrugated Cardboard Made?

Making the Kraft Paper

Before you can make cardboard, you need kraft paper. Kraft paper is made from pine trees. The pine trees are cut down and turned into pulp at the factory. Once they are pulped, they are pressed into thin layers of kraft paper. From there, the kraft paper is put onto large rolls and sent to the cardboard plants to be turned into corrugated cardboard. Larger companies own their own pine tree groves and plant new seeds so they can grow more trees and start the process over again.

Making the Cardboard Layers

The next step is to take the kraft paper and put it into the corrugator machine, a large machine that can stretch up to 300 feet. The corrugator machine is responsible for creating the layers of cardboard and sticking them together. Dry corn starch is mixed with water and certain chemicals to create a special glue used to hold the layers of cardboard together. The machine then takes the rolls of kraft paper and presses them together to make a layer of cardboard. Liners are the flat pieces of cardboard you see on the outside, and the corrugated pieces are the zig-zagged cardboard sandwiched in between the liners.

Creating Corrugated Cardboard

The pieces that make up the corrugated cardboard are crimped inside the machine. The machine then takes the liners and glues them to either side of a piece of corrugated cardboard. After that, it presses them firmly together so that they stick and fuse into one piece of cardboard. Once the machine is finished, the corrugated cardboard sheets come out. Workers then cut the cardboard into different sizes and fold it to form cardboard boxes or leave it flat to ship out as sheets of corrugated cardboard. From there, it goes to stores and companies and arrives in our homes.