In accordance with a broad embodiment of the invention, a novel paper product is comprised of two or more slit sheet packing material layers, each layer having its own slit pattern design to create interlocking layers of expansion sheet packaging materials. Each layer expands to create a three dimensional open netting of cells of hexagons, and the like, and is designed to have limited nesting with its opposing layer, thereby maximizing the thickness of the combined layers as compared to nested layers. Adjacent layers have differing slit patterns and can be expanded through expander type machinery such that the expansion rates of the differing slit pattern layers can be varied to deliver the same width of exiting expanded material from each layer. Preferably the differing slit patterns produce when expanded, inclined land area that have the same number of rows per inch, but different angles of inclination of the land areas, such that adjacent layers can interlock, that is, have a restricted amount of nesting.

A honeycomb for curved surface lightweight components includes a plurality of elongate ribbons and connecting regions. The connecting regions are provided, respectively, between opposing ribbons to connect the ribbons together in a portion-wise manner in a firmly bonded relationship in a transverse direction. The connecting regions are arranged at regular spacings along the longitudinal direction of a ribbon. Honeycomb-like cells form cavities between the ribbons. With respect to three successive ribbons, a displacement of the connecting regions between first and second ribbons relative to the connecting regions between second and third ribbons toward a first side of the longitudinal direction is lesser than toward a second side of the longitudinal direction. Consequently, at least a part of the cells in cross-section in the longitudinal direction/transverse direction plane have at least one longer limb corresponding to the greater displacement and at least one shorter limb corresponding to the lesser displacement.

An apparatus for the fabrication of mechanically stable, planar rectangular or quadratic plates or bent plates from comigated cardboard at an industrial scale with minimum waste and dust. generation.

The present invention discloses a method of producing at least a pair of interlocking adjacent layers of a paper packaging product, the pair of interlocking adjacent layers being formed of a sheet of slit paper having a slit pattern, the slit pattern upon expansion, forming cells that include land regions that are inclined with respect to a plane of an unexpanded sheet. The method comprises slitting the sheet of slit paper with beveled blades that have a first wedge angle on one side of the blades and a second wedge angle on the other side of the blades, wherein the first wedge angle is wider than the second wedge angle to produce slits that upon expansion, produce the lands regions that have angles of inclination in a range for 50 to 85 degrees.

A unified corrugator and die-cutting system is disclosed. The system comprises: (a) a corrugator configured to produce an elongated and multi-layer moving strip of corrugated board; (b) and a die-cutting machine configured to receive said strip of corrugated cardboard and repeatedly cut it to a plurality of shaped boards.