Blown and Cast stretch film – Best one to use?
Stretch film comes in varying gauges, colors and can be used in numerous applications. The main variable and starting point for stretch films is blown versus cast.
Blown stretch film, or blown stretch wrap as it's also known, is created by blowing heated resin out vertically into a bubble. The bubble is then transformed into rolls while it is cooled by the surrounding air.
Cast stretch film, or cast stretch wrap as it's also known, is created by feeding a sheet of heated resin along a rolling path with chilled rollers. The cooling solidifies the film, and it is made into large rolls.
Features and Benefits:
Blown film is tougher and has less of a chance to puncture than cast. This occurs due to the slower cooling process, which allows the molecules in blown film to spread out as opposed to aligning in long lines like in cast. Blown film also has a higher level of cling than cast, making it stick to itself easier.
So, why would anyone use cast film? Cast stretch wrap has a clear, glossy finish allowing RFID and other scanning technology to be used with it while blown is hazy and dull. Cast stretch film unwinds much quieter than blown. It is also easier to stretch and control the gauge with cast film.
Both films have their benefits:
So, which stretch film fits your application? Factors to keep in mind include:
What type of machine is being used, if not applied by hand?
What kind of load is being wrapped?
Where does your skid go after leaving your dock?
How many variants of load does your facility wrap?
Now let’s get down to work and figure out what is the best film for you.