Custom plastic bottle manufacturers
Few people realize what it takes to bring a bottle of juice to life. From the initial design to the final product, the design team in question works closely with plastic bottle manufacturers to ensure their idea stays as close as possible to their original vision. But the process in between remains somewhat of a mystery. Just what does it take to manufacture a plastic bottle?
What types of plastic bottles are there?
Before we dive into the logistics, let’s talk a little bit about what plastic bottles are made of. The material used to create plastic bottles is called polyethylene terephthalate, or PET for short. PET is a thermoplastic polymer, making it a perfect material for manufacturing plastic bottles because it is lightweight and robust. PET is made of petroleum hydrocarbons, the product of a chemical reaction between terephthalic acid and ethylene glycol. These reactions form long polymer chains, which are quite reliable when bundled together.
However, not all PET is created equal; it must go through a rigorous set of tests before it can be used in manufacturing. Several factors that are tested include transparency, gloss, shatter resistance, thickness, and pressure resistance. Two common impurities that appear during the polymerization process are diethylene glycol and acetaldehyde. While the former usually appears only in negligible, trace amounts, the latter can affect the taste of the bottle’s contents if too much is present. One last important test these bottles undergo is carbon dioxide permeability testing. This part tests the bottle to see if carbon dioxide leaks through–a crucial step when producing bottled soda.
How are plastic bottles made?
Now that we know a little about the stuff that goes into plastic bottle manufacturing, let’s take a look at how the bottles are made.
The first step in the plastic bottle-making process is the stretch blow molding. It’s a little like glassblowing, but with plastic instead. A long, thin mold of hot plastic is blown and stretched into a bottle mold. This long, thin mold of plastic has an unusual name, actually: parison. A long, thin rod known as a mandrel is then forced into the mold, creating a pocket of pressurized air. This pocket of air pressure forces the plastic in the first mold into a larger second mold–and that’s how you achieve the bottle shape.
This hot mold must be cooled very quickly, though. There are a couple of ways to achieve this. The mold can either be indirectly cooled by coursing cold water through the pipes surrounding the mold, or directly cooled by blowing pressurized air or carbon dioxide on the molds themselves. Once the bottles are set and cooled, they can be removed from their molds for packaging.
However, it is possible to produce custom plastic bottles, too. This customization changes the process a little bit and is often a collaboration between the manufacturers and the product’s design team.
While the design team might think the sky’s the limit when it comes to their dream bottle, it’s up to the engineers manufacturing the bottles to create a reliable product that is safe for commercial use. Often, this looks like a compromise between the two parties.
Design teams may also fail to consider some critical practicalities during the initial stages of the process. For example, the chemical composition of the liquid expected to fill the bottles may determine the shape and size of the bottle. It may also determine the type of closure used on the cap. How thick should the container be? Should it be transparent or opaque? All of these properties must be carefully selected, as design problems could pose problems and cost a lot of money in the future.
The devil is in the details when it comes to the closure, too. The molding process could change depending on whether the closure opening should face the same direction as the bottle label. Intended bottle decorations may also affect the molding process. This is why design teams ought to work closely with the engineering team in the beginning phases of the bottle-making process, as it will save a lot of headaches in the future.
Who knew so much thought went into making custom plastic bottles? It should come as no surprise, though, that the most mundane objects often require the most attention and detail in their production process. Their careful engineering and design are what make them such reliable staples in everyday life, so next time you take a swig from a soda bottle, thank the people behind it. Otherwise, you’d have carbon dioxide leaking all over you!