To ensure that the plastic is appropriate for use, numerous tests are done post-manufacturing to check that the bottles are impermeable by carbon dioxide (which is important for bottles that carry soda). Once the plastic itself has been manufactured, the PET bottle manufacturing process can begin. A large amount of acetaldehyde in PET used for bottle manufacturing can give the beverage inside an odd taste. Although diethylene glycol is generally not produced in high enough amounts to affect PET, acetaldehyde can not only be produced during polymerization but also during the bottle manufacturing process. Typically, two kinds of impurities are produced during polymerization: diethylene glycol and acetaldehyde. Polymerization itself can be a complicated process and accounts for many of the inconsistencies between one batch of manufactured PET and another. The PET is polymerized to create long molecular chains, which allows it to produce PET bottles later on. As with most plastics, PET is produced from petroleum hydrocarbons, through a reaction between ethylene glycol and terephthalic acid. Polyethylene Terephthalate is a thermoplastic polymer that can be either opaque or transparent, depending on the exact material composition. We'll be examining how each material affects the bottle manufacturing process below. PE is often referred to as LDPE (Low-Density Polyethylene) or HDPE (High-Density Polyethylene). What are Plastic Bottles Made of?Īs mentioned above, plastic bottles are commonly made of PET, PP, PC, and PE. You can also learn more about how glass bottles are made and types of glass bottles in our other guides. To understand the manufacturing process, it is helpful to first examine the compositions of the materials they're made from. Polycarbonate (PC) is used for refillable water bottles and similar reusable containers.
![water bottle preform water bottle preform](http://www.technopackpet.com/preforms/wp-content/uploads/2018/10/05.jpg)
Polypropylene (PP) is used for pill bottles and the like. Polyethylene (PE) in its high-density form is used for making rigid plastic bottles such as detergent bottles and in its low-density form for making squeeze bottles. Typically, the plastic bottles used to hold potable water and other drinks are made from polyethylene terephthalate (PET), because the material is both strong and light.
![water bottle preform water bottle preform](https://www.bottledwater-dispenser.com/photo/pl20784923-20liter_clear_blue_water_bottle_preform_for_5_gallon_3_gallon_pet_bottle.jpg)
Plastic bottle manufacturers generally use one of four types of plastic to create bottles. Plastic bottle manufacturing takes place in stages.