Blown or Cast Stretchfilm

various stretchfilms

Stretch film comes in varying gauges, colours and can be used in numerous applications. The main variable and starting point for stretch films is blown versus cast.

While I won’t bore you too much with the details behind how they are manufactured, here are the basics. 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.

So, now that you know how stretch wrap is produced, what do the difference in films provide you, the end user, in terms of features and benefits? I thought you would never ask.

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 (think Reynolds Wrap) 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.

As you can see, both films have their benefits and hindrances.

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?

Does your distributor ask you these types of questions and provide solutions based off of your answers?

If you answered no, it’s time for a free needs analysis from the industrial packaging experts at Lynx Polythene. Our solutions providers will ask you the above questions and more and perform tests to determine just how much film you are using and how much it is costing you per application. Having troubles with punctures or products getting damaged? That means it’s time to reevaluate your film type and usage.

If you are purchasing films based on the one with the cheapest price per roll, you may be surprised what kind of information and insight can be gained by going through our process.

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