Containerboard, also referred to as CCM (corrugated case material), is a type of paperboard

Paperboard

Paperboard is a thick paper based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker than paper. According to ISO standards, paperboard is a paper with a basis weight above 224 g/m2, but there are exceptions. Paperboard can be single...

 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

Pulp (paper)

Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibres from wood, fibre crops or waste paper. Wood pulp is the most common raw material in papermaking.-History:...

, it is generally brown, although its shade can vary depending on the type of wood

Wood

Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

, pulping process, recycling

Recycling

Recycling is processing used materials into new products to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, reduce energy usage, reduce air pollution and water pollution by reducing the need for "conventional" waste disposal, and lower greenhouse...

 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.

Manufacture

Containerboard is made on modified paper machines that can handle higher grammages.

The production of containerboard is the highest of all kinds of paper in the world. More than 100 million tons are produced annually. It is made in specialized paper machines out of virgin as well as recycled fibers. Linerboard made of virgin pulp is called kraftliner, whereas recycled linerboard is known as testliner. Corrugating medium may be recycled medium, called wellenstoff in Europe, or virgin, which is called semichemical medium for the type of pulp used in its production. The borders of these categories become a little blurred, however, when both virgin and recycled fibers are used in making one product.

At the end of the manufacturing process containerboard is cut in to rolls comprising a continuous sheet of paper, which will later be unwound in the corrugator machine while making the corrugated board. A typical roll has a width of 2.5 mt and a diameter of 1.45 mt, and weighs around 3 tons.