Sheet packaging material for producing a sealed package containing a pourable food product and a sealed package obtained from a sheet packaging material

A sheet packaging material for producing a sealed package with a pourable food product; the packaging material has a quadrangular configuration with two boundary edges parallel to a longitudinal direction and two other boundary edges parallel to a transversal direction orthogonal to the longitudinal direction; the packaging material comprises two transversal crease lines extending transversally to the longitudinal direction and dividing the packaging material into: a bottom region containing a bottom crease pattern and configured to form a bottom portion of the package; a top region containing a top crease pattern and configured to form a top portion of the package; and an intermediate region contained between the transversal crease lines and designed to form a main portion of the package having a plurality of side wall portions; the intermediate region further comprises a plurality of V-shaped crease lines having respective vertices located on or adjacent to the transversal crease lines and at given points thereof destined to define the opposite ends of respective lateral edges delimiting the side wall portions of the package; each V-shaped crease line extending in proximity of the respective transversal crease lines.