How is PET strapping made?

PET (Polyethylene Terephthalate) strapping is made through a multi-step manufacturing process that involves polymerization, extrusion, and specific treatments to ensure the strapping has the desired properties, such as strength, durability, and flexibility. Here’s a breakdown of how PET strapping is typically made:

1. Polymerization:

The process starts with the polymerization of ethylene glycol (EG) and terephthalic acid (TPA), which are the two raw materials used to produce polyethylene terephthalate (PET).

The polymerization process creates long chains of PET molecules, resulting in a strong, durable plastic material.

2. Extrusion:

Once the PET polymer is formed, it is heated and melted before being passed through an extruder. The extruder shapes the molten PET into flat strands, which are cooled and solidified into a continuous extruded film.

3. Stretching (Orientation):

The extruded PET bands are then stretched longitudinally (lengthwise). This process, known as orientation, aligns the polymer chains in the direction of the stretch, which increases the tensile strength of the material.

4. Slitting:

After the stretching process, the PET film is slit into narrower strips, or straps, that can be used for different packaging applications. The width and thickness of these strips can vary based on the specifications required by the end user.

5. Coating (Optional):

In some cases, the PET straps are coated with a thin layer of adhesive or lubricant to improve their handling, prevent damage to the surface of the product being strapped, and enhance friction to maintain tension during use. This coating may also improve resistance to abrasion or UV damage.

6. Final Treatment:

Heat treatment is sometimes applied to ensure the straps maintain their strength and do not lose their properties under stress.

The straps are then wound onto rolls for easy application in packaging systems.

7. Quality Control:

Throughout the manufacturing process, PET strapping undergoes various quality control checks to ensure that the strapping meets the required standards. This includes testing for tensile strength, elongation, surface smoothness, and resistance to environmental factors.