Abstract: Method and apparatus for producing a multi-ply corrugated paperboard (105) by repeatedly laminating multi-ply corrugated mediums (102, 103) with different pitches and widths between top and bottom liners is disclosed. This invention thins the paperboard and improves the compressive strength of the paperboard so as to substantially reduce the package volume. In the process for producing the multi-ply corrugated paperboard, a first corrugated medium (102) is continuously laminated to a liner (101), thereby forming a single-ply paperboard. The first corrugated medium (102) has predetermined flute pitch and flute peak height. Thereafter, a second corrugated medium (103) is continuously laminated to the single-ply paperboard, thereby forming the multi-ply corrugated paperboard (105) having improved shock absorptivity and compressive strength against a vertical load. The second corrugated medium has optionally selected flute pitch and flute peak height.

Abstract: A high strength double-ply corrugated paperboard including upper (102) and lower (106) liners and multiple-ply corrugated mediums (101, 104) disposed between the liners (102, 106), thereby capable of exhibiting a high compressive strength while having a small thickness to minimize the packaging size, and effectively absorbing outside shock applied to the package to keep the packaged goods more safe.