A flexible cellulosic fiber-based material including: a core portion having a geometrically patterned structure defining two spaced-apart substantially planar faces and providing air space therebetween, the core portion including cellulosic fiber-based walls having a core grammage; and at least one cellulosic fiber-based liner bonded to a respective one of the planar faces of the core portion and having a liner grammage lower than the core grammage, the material being flexible along a plane defined by the at least one liner.

A flexible cellulosic fiber-based material including: a core portion having a geometrically patterned structure defining two spaced-apart substantially planar faces and providing air space therebetween, the core portion including cellulosic fiber-based walls having a core grammage; and at least one cellulosic fiber-based liner bonded to a respective one of the planar faces of the core portion and having a liner grammage lower than the core grammage, the material being flexible along a plane defined by the at least one liner.

A flexible packaging material including: a core portion having a geometrically patterned structure defining two spaced-apart substantially planar faces and providing air space therebetween, the core portion including cellulosic fiber-based walls having a core grammage; and at least one cellulosic fiber-based liner bonded to a respective one of the planar faces of the core portion and having a liner grammage lower than the core grammage, the material being flexible along a plane defined by the at least one liner.

A flexible packaging material including: a core portion having a geometrically patterned structure defining two spaced-apart substantially planar faces and providing air space therebetween, the core portion including cellulosic fiber-based walls having a core grammage; and at least one cellulosic fiber-based liner bonded to a respective one of the planar faces of the core portion and having a liner grammage lower than the core grammage, the material being flexible along a plane defined by the at least one liner.