Method for producing free-flow interlocking foamed packing material

Abstract

An improved method for the manufacture of free-flow packing material particularly characterized by its ability to isolate packed items and to absorb the energy of potentially destructive shocks and impacts. The method produces individual units of the packing material which are structurally in the form of elongate flat 'bows,' wherein two self-adhered layers of foamed expanded plastic material form a central portion of the 'bow' and curved outward extensions of these layers form two oppositely extending flat loops. The flat bow-shaped units are individually of a size and shape to provide a desired free-flowing characteristic, and are formed of a foamed expanded crushable plastic material which inherently possesses a shock absorbing characteristic. The method can be carried out, alternatively, by squeezing a single heat-softened tube to effect internal contact and adherence, or by bringing two adjacent heat-softened tubes into engagement to effect external contact and adherence, followed successively by cooling and slicing through the walls of the tube to form relatively shallow bow-shaped units. The resulting aligned flat loops and centrally adhered midsection of the bows cooperate to provide unusually shape stable packing units without detracting from the shock absorbing characteristics of a mass of such packing units.