SMOOTHLY BENDING CARDBOARD Russian patent published in 2016 - IPC B32B3/28 B32B29/08 B32B37/28 

FIELD: textiles, paper.

SUBSTANCE: cardboard comprises a middle layer, a first outer layer attached to the middle layer, and a second outer layer attached to the middle layer. The middle layer is a corrugated layer comprising the corrugations. The bending stiffness of the second outer layer is selected according to the mathematical equation. The second outer layer has a lower bending stiffness according to ISO 5628 than the first outer layer, so that smoothly bending cardboard is bent outwardly only in the direction which the second layer faces, where the said direction is substantially perpendicular to the corrugations of the middle layer so that the first outer layer of the smoothly bending cardboard becomes convex after bending.

EFFECT: creation of cardboard which is resistant to deformation.

13 cl, 5 dwg, 1 tbl