The advantage of cast stretch film and blown stretch wrap

September 23, 2019

The following are the classifications of the two most commonly used stretch film extrusion processes. Extrusion produces stretch film and a variety of other flexible plastic products. Please visit our blog for more details on the extrusion process.

Cast stretch wrap - also known as cast stretch wrap - are manufactured using a cast extrusion process. The casting extrusion process is a continuous process by which a thermoplastic material is melted and extruded through a flat die onto a chill roll where it is quenched and resolidified. This process allows the cast stretch film to have excellent clarity, less force required for stretching, increased tear resistance, quiet release from the machine, and excellent adhesion. Mechanical grade and manual grade cast stretch film are available.

The advantage of cast stretch film - generally lower than the blown stretch wrap due to reduced manufacturing costs. The increased clarity allows the user to see the packaged product. The cast elastic wrap is quietly spread out compared to the blown stretch wrap. The cast stretch film provides adhesion on both sides to allow the wrap to be securely wrapped.

Disadvantages of cast stretch film - do not provide the load/holding force provided by the blown stretch wrap. The cast stretch film has less memory and tear resistance than the blown stretch wrap.

Blow stretch stretch wrap, also known as blow stretch wrap, is manufactured using a blow molding process. The plastic melt is typically extruded through a circular slot die in a vertical direction to form a thin walled tube. Air is introduced through the hole in the center of the mold, causing the balloon to blow up like a balloon. At the top of the tube, an air ring is blown onto the film to cool it. This process makes the blown film tougher and more flexible than cast film. The higher mechanical properties of the blown film generally allow for greater load holding forces.

The advantage of blown film winding - provides higher load and stretchability. Blown film is a higher quality film. The blown stretched film has a higher memory once stretched, so that the load can be better fixed. Higher tear resistance is an advantage when ensuring loads with sharp edges.

Disadvantages of blown stretch wrap - high cost due to manufacturing processes. The blown stretch wrap has poor transparency due to crystallization during the manufacturing process. The film that was blown off when unwinding from the roll was also noisy.

Author:

Ms. Lisa Lu

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