How Shrink Wrap Is Made

Shrink wrap plastic is typically made from a type of polymer called polyethylene. The manufacturing process involves the following steps:

1. Polymerization: Ethylene gas is polymerized using high heat and pressure, or catalysts, to create polyethylene. This process forms long chains of repeating ethylene units.

2. Extrusion: The polyethylene is melted and extruded through a die to form a continuous sheet or film. This film can be either a monolayer or a multilayer structure, depending on the desired properties of the shrink wrap.

3. Cooling: The extruded film is rapidly cooled to solidify it and maintain its desired thickness.

4. Orientation: The cooled film is then stretched in both the machine direction (MD) and transverse direction (TD) using a process called orientation. This stretching aligns the polymer chains, which improves the strength and clarity of the shrink wrap.

5. Heat setting: The oriented film is heated again to a specific temperature, and then cooled to “set” the molecular structure and lock in the orientation.

6. Slitting and winding: The wide sheet of shrink wrap film is slit into narrower rolls of the desired width. These rolls are then wound onto cores, creating individual rolls of shrink wrap plastic.

Once the shrink wrap plastic is produced, it can be used for various applications, such as packaging, bundling, and protecting products during transportation or storage.