Verpackungsmaterial und Verfahren zu dessen Herstellung

摘要

924,285. Packaging material. DOW CHEMICAL CO. Nov. 13, 1961 [Nov. 15, 1960; March 13, 1961], No. 40482/61. Drawings to Specification. Class 94(1). A packaging material comprises a multiplicity of elongated pieces of expanded synthetic organic polymers which are preferably curled or bent to form an entangled mass. A process and apparatus for making such pieces is also described in which a thermoplastic polymer is mixed under pressure with an expanding agent above the plastifying temperature of the polymer, cooling the mixture to below the plastifying temperature and then extruding it through an orifice having an area of 0À05 to 20 sq. mm. The pieces are then preferably annealed and then expanded by heat treatment at a temperature above the boiling point of the expanding agent, above the softening point of the thermoplastic and below the temperature of heat plastification of the thermoplastic materials.