Stack-sealable, heat-shrinkable multilayer packaging film

A heat-shrinkable multilayer film comprises (A) a first layer, which is an outer layer, and which comprises polyolefin; (B) a second layer comprising at least one member selected from the group consisting of polyolefin, polystyrene, and polyurethane, wherein the second layer has a thickness of from about 10 to 50 percent, based on a total film thickness; (C) a third layer comprising a polyamide having a melting point of 160° C. and below; and (D) a fourth layer, which is an outer layer, the fourth layer comprising polyester. The first layer preferably serves as a seal layer in a heat-shrinkable bag. The third layer provides enhanced orientability of the tape from which the film is formed, thereby providing improved total free shrink and lower shrink temperature. The third layer also provides greater optical clarity and permits the presence of a thicker polyamide layer, thereby increasing impact strength and improving the O<SUB>2</SUB>-barrier of the film. The high melting polyester of the fourth layer permits at least two bags, having product therein, to be stacked on top of one another and sealed simultaneously, without sticking to one another, thereby doubling the output of a vacuum chamber machine. A bag and a process of making a packaged product are also disclosed.