Sheet packaging material for producing sealed packages of pourable food products

There is described a sheet packaging material (M) for producing a sealed package (1) of a pourable food product; the packaging material (M) comprises one base layer (11) for imparting stiffness, a number of lamination layers (12) covering both sides of the base layer (11), and a removable portion (10, 10', 10", 10"', 10"", 10""') which, in use, can be detached partly from the rest of the packaging material (M) along at least one arc-shaped cutting line (20, 20""') and folded at a folding zone (21, 81) extending between the opposite ends of the cutting line (20, 20""') so as to free a pour opening (9) by which to pour the food product from the package (1); the removable portion (10, 10', 10", 10"', 10"", 10""') comprises a central area (25) made of whole packaging material and which, in use, in any case, remains attached to the rest of the packaging material (M) through a permanent bridge (26) defined by the folding zone (21, 81), and a peripheral area (27, 27', 27", 27"', 27"", 27""') for cutting interaction, extending around part of the central area (25).