Multi-layer printing substrate with hidden information

A multilayer substrate comprising

• at least one first paper ply,
• at least one second paper ply and
• a plastic layer arranged between the paper plies and directly bonded to the paper plies on both sides of said plastic layer, which plastic layer is made of at least one thermoplastic polymeric material;
• wherein between the paper plies on an inside of the second paper ply and at least partially embedded in the plastic layer a strip-shaped tear film is embedded;
• wherein hidden information is arranged on at least one of
• an inside of the first paper ply and perpendicular to and, viewed from a side of the second paper ply, covered by the strip-shaped tear film
• and a surface of the strip-shaped tear film facing the first paper ply and covered at least by the first paper ply;
• wherein the hidden information can be exposed by irreversibly tearing the strip-shaped tear film out of the multilayer substrate together with a strip of the second paper ply;
• and
• wherein a cover layer is arranged on the inside of the first paper ply at least in a region of the hidden information and the hidden information is arranged facing the strip-shaped tear film on this cover layer, so that the hidden information cannot be read from a side of the first paper ply.

A multilayer substrate comprising

• at least one first paper ply,
• at least one second paper ply and
• a plastic layer arranged between the paper plies and directly bonded to the paper plies on both sides of said plastic layer, which plastic layer is made of at least one thermoplastic polymeric material,
• wherein between the paper plies on an inside of the second paper ply and at least partially embedded in the plastic layer a strip-shaped tear film is embedded,
• wherein hidden information is arranged on at least one of
• an inside of the first paper ply and perpendicular to and, viewed from a side of the second paper ply, covered by the strip-shaped tear film
• and a surface of the strip-shaped tear film facing the first paper ply and covered at least by the first paper ply;
• wherein the hidden information can be exposed by irreversibly tearing the strip-shaped tear film out of the multilayer substrate together with a strip of the second paper ply;
• and
• wherein the first paper ply comprises at least two or at least three window-shaped cutouts along an extension direction of the strip-shaped tear film.