METHOD FOR CAP WITH HEAT-SHRINKABLE SKIRT PRODUCTION AND CAPS OBTAINED BY ABOVE METHOD Russian patent published in 2006 - IPC B65D41/62 B29C47/90 B29L31/56 B29K101/12 

FIELD: packing means, particularly caps to seal vessels or bottles or to reseal vessels or bottler previously closed with plugs.

SUBSTANCE: method involves forming tube by extrusion thereof of thermoplastic material selected from polyolefins and having D₁ diameter equal to 10-30 mm at extrusion machine outlet; exposing the tube having D₁ diameter to rays emitted by annular emitter surrounding above extruded tube to create structured polyolefin and to create cross-linked tube; heating the tube up to temperature less or equal to crystalline phase melting temperature; expanding the heated tube in radial direction to obtain expanded tube having D₂ diameter, wherein ratio D₂/D₁=1.5-4; cooling the tube up to temperature usually equal to room temperature; cutting the tube into sections having lengths substantially equal to cup heights; connecting tops to tube sections or shaping the tube sections to form cap tops, which results in cap provided with heat-shrinkable skirt production without connection lines.

EFFECT: possibility to produce caps of different materials, increased productivity.

10 cl, 9 dwg