Lesson 15 F

15.21 Retortable Pouches

  • A typical laminate for retortable pouch is 0.0005 polyester / 0.00035 foil / 0.003 polypropylene, with the outer ply designated first as is customary for pouch material.
  • Filled pouches are sterilized at 115-1210 C, with overriding air pressure of ~ 2 kg/cm2 to prevent bursting.
  • Pouch material that will not delaminate at these temperatures must be selected, and the seals should withstand a tensile test of 0.08 kg/m of width, internal pressure of 1 kg/cm2 for 30 s, pinhole strength of 0.6 kg and a drop test of 1.22 m.
15.22 Multilayer Collaspsible Tubes (MLCT)

  • The collapsible tube has traditionally been made of soft metal, tin, lead, tin-lead and in recent years aluminum.
  • One end of the tube is a threaded dispensing nozzle which can be closed by a screw cap closure.
  • The entire tube is formed by impact extrusion from a slug of metal, and then it is trimmed, threaded and annealed.
  • Exteriors are decorated by roller coating and offset printing.
  • Interiors may be lined by dipping, flushing or spraying prior to exterior coatings.
  • Linings may be waxes or vinlys, phenolic or epoxy resins.
  • Product is filled through the open bottom which is then crimped or sealed shut.
  • In use, the closure is removed, the interior seal (if present) is punctured and product is dispensed through the nozzle by squeezing the tube.
  • Tubes are marketed on cards, in blister packs or in folded cartons.
  • Blow-molded plastic tubes are now being used for some products. Their main disadvantage is lack of dead - fold. They tend to spring back when squeezed making total dispensing of the product difficult.
  • Tubes are best for packaging thick liquids or thin pasty solids.
  • It is used for packaging of process cheese spread/ fruit jams, fat spread and ketch-ups.
Last modified: Thursday, 11 October 2012, 9:51 AM