What is Corrugated?
Corrugated board is a combination of at least three sheets of paper, collectively called containerboard. The paper layers on the outside are known as the liners, or linerboard, while the fluted or wave-shaped material in the middle layer is called corrugating medium.
Corrugated board comes in different thicknesses, depending on the height of the flutes, and number of flutes per foot, as follows:
Source: Association of Independent Corrugated Converters,
Buyer's Guide to Corrugated Packaging
In industry terms, this three-layer corrugated material is called singlewall corrugated board. Two or three layers of corrugated board can also be combined for stronger packaging requirements. These are called doublewall or triplewall corrugated.
Where's Corrugated made?
There are nearly 1,500 corrugated packaging plants in the United States and Canada. There are basically three kinds of corrugated packaging plants.
- Corrugator Plants: Plants that combine containerboard into corrugated board are called corrugator plants. Typically, these plants also have equipment that converts the corrugated board into finished corrugated products: boxes, shipping containers, point-of-purchase displays and other kinds of protective and distribution packaging. There are approximately 600 corrugator plants in the United States and Canada.
- Sheet Plants: Plants that purchase already-combined corrugated board, called sheets in corrugated industry terms, and convert these into boxes, shipping containers and displays are called sheet plants. In physical terms, these plants are usually smaller than corrugator plants, but they can also be highly specialized in their product mix - high-end graphics, inner-packing and other items to serve customer needs. There are more than 800 sheet plants in the U. S. and Canada.
- Sheet Suppliers: There's a third kind of corrugated plant called a sheet supplier. These plants' specialty is combining corrugated board into corrugated sheets exclusively for purchase by sheet plants. They have no other converting equipment to make finished boxes, shipping containers, point-of-purchase displays or other corrugated product. There are approximately 50-60 sheet suppliers in the United States and Canada.
Corrugated is the largest segment of all paperboard packaging products.