Premium Cartridge Heaters and Barrier Film Extrusion

Who can resist a bit of cheese when confronted with a crusty loaf and a slab of butter? Well, according to UK cheese sale statistics as a nation we can’t get enough of the stuff, eating a total of nearly 400,000 tonnes across the country in 2009, with the majority of this being purchased pre-packed, rather than loose form.

It would also seem that our palates are developing ever more adventurous tastes. No longer is the block of mild cheddar or pack or triangular processed cheese a staple purchase for our fridges. Instead we are moving onwards and upwards to full blown, top of the taste Richter scale offerings such as extra mature cheddar, stilton and gorgonzola, and (for the really brave) a slice of Stinking Bishop perhaps!

But thankfully, cheese manufacturers have recognised that strong cheese really does pong and a smelly cheese odour is not something most shoppers want wafting from their refrigerators every time they reach inside for the milk carton. Hence, the majority of cheese sold in supermarkets is pre-packed in plastic wrap, ensuring a barrier between shoppers noses and the cheesy fragrance.

The process used to manufacture plastic barrier film for food products such as cheese is blown film extrusion. The process requires molten polymer (melted to a specific temperature using heating elements such as cartridge heaters), to be extruded through a (usually vertical) die where it is then blown up to a balloon like state using warm air. The balloon gradually cools as it rises upwards, until it passes through a set of rollers where it is flattened to create a ‘lay-flat’ tube of film. The process continues with the tube of film being sealed as required to make individual bags. The bags will later be printed and finished ready for packing with the delicious cheese. Anyone for Port?