FIELD: packing of food products, for instance, bag for potato chips. SUBSTANCE: sheet has at least one pleated zone with fields fixed on ends, This zone is folded in two in direction square to direction of folds. At least one of ends is closed by moving the edges together and fixing them in position to form space for product which can be unfolded afterwards to provide complete or partial closing of bag. EFFECT: enlarged operating capabilities. 5 cl, 20 dwg
