Containerboard, also referred to as
CCM or
corrugated case material, is a type of
paperboard specially manufactured for the production of
corrugated board. The term encompasses both
linerboard and
corrugating medium (or
fluting), the two types of paper that make up
corrugated board. Since containerboard is made mainly out of natural unbleached
wood fibers, it is generally brown, although its shade may vary depending on the type of
wood,
pulping process,
recycling rate and impurities content. For certain boxes that demand good presentation white bleached pulp or coating is used on the top ply of the linerboard that goes outside the box.