Corrugated fiberboard

The corrugated medium sheet and the linerboard(s) are made of kraft containerboard, a paperboard material usually over 0.25 millimetres (0.01 in) thick.

The patent was issued to Albert Jones of New York City for single-sided (single-face) corrugated board.

Applying this idea to corrugated boxboard was a straightforward development when the material became available in the early 20th century.

For example, edge crush, bending stiffness, tensile, and surface characteristics are different, depending on the orientation to the flutes and the machine direction of manufacture.

These machines, over time, have become very complex with the objective of avoiding some common problems in corrugated board production, such as warp and washboarding.

This is joined to a flat linerboard with a starch based adhesive to form single face board.

At the double-backer, a second flat linerboard is adhered to the other side of the fluted medium to form single wall corrugated board.

Double and triple-wall corrugated board is also produced for high stacking strength and puncture resistance.

The size of a box can be measured for either internal (for product fit) or external (for handling machinery or palletizing) dimensions.

A limitation of common corrugated material has been the difficulty in applying fine graphic print for informative and marketing purposes.

The reasons for this stem from the fact that prefabricated corrugated sheets are relatively thick and spongy, compared to the thin and incompressible nature of solid fibre paper such as paperboard.

Due to these characteristics of corrugated, it has been mainly printed using a flexographic process, which is by nature a coarse application with loose registration properties.

A more recent development popular in usage is a hybrid product featuring the structural benefits of corrugated combined with the high-graphics print of lithography previously restricted to paperboard folding cartons.

This application, generally referred to as "Single-Face Laminate" (SFL), begins its process as a traditional fluted medium adhered to a single linerboard (single-face), but in place of a second long-fibered liner, a pre-printed sheet of paperboard such as SBS (solid bleached sulfate) is laminated to the outer facing.

Specialized equipment is necessary for the material construction of SFL, so users may expect to pay a premium for these products.

However, this cost is often offset by the savings over a separate paperboard sleeve and the labor necessary to assemble the completed package.

The baled boxes are put in a hydropulper, which is a large vat of warm water for cleaning and processing.

Film-backed pressure-sensitive tape stays intact: the PSA adhesive and the backing are both removed together.