Blown Film


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Index

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Introduction:

Some of the products formed by the blown film process are garbage bags, can liners, agricultural films, grocery bags, T-shirt bags, and thin film for paper and tissue products.

The typical range of film gauges encountered with this process is 0.0001-0.050 inch.

Process:

Plastic melt passes through a die that forms it into an annular shape, usually directed upward. Air is introduced into the tube to inflate it and around the outside of the "bubble" to cool and solidify the melt. The cooled bubble is closed in a set of rolls (nip rolls) placed at some distance above the die. After the bubble is cooled and collapsed into a flat shape, the product is rolled up on a high-speed winder.


Advantages

  • No trimming necessary to make the film edges uniform in dimensions
  • Disadvantages

  • Lower clarity than cast film counterparts

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