Polyethylene terephthalate, or PET, is a material often used in water bottles and in the creation of polyester textiles. The reason PET plastic is a preferred option is because it’s considered safe for use in regards to holding food and beverages intended for human consumption, as well as safe against the skin. But beyond the safety, there are numerous other reasons why PET plastics are a good choice for certain tasks.
History of PET
In 1941, PET plastic was patented by John Rex Whinfield and James Tennant Dickson, along with their employer the Calico Printers’ Association. It wasn’t until 1951 that the film known as Mylar was trademarked, and is still one of the most recognized product names associated with PET plastic material. It wasn’t until 1973 that the PET plastic bottle was patented.
Manufacturing Benefits of PET Plastics
PET plastics provide various benefits over certain other forms of plastic. First, it is very resistant to wear. This makes it an excellent choice for situations where durability is required. Plastic water bottles and polyester clothing must endure regular handling and, in some cases, washing. Less durable options may not hold up to the level of use PET is designed to manage.
The material is also highly flexible. With textiles, having a level of flexibility that prevents the material from being overly stiff. This not only makes it more comfortable to wear but also allows it to hang and drape naturally over the body.
Its flexibility allows a water bottle to be squeezed, and even crushed (to a degree), without compromising the structural integrity. For example, when you crinkle a water bottle, the material doesn’t crack immediately. The flexibility of PET plastic helps ensure that minor impacts or aggressive handling don’t necessarily result in the liquid contents spilling out through a split in the material.
When it comes to use as food and beverage containers, the chemicals in PET plastic do not leach into the fluid or foods with which it sustains contact. Since the materials do not commingle, it reduces the chance of an adverse reaction when people consume items previously stored in PET plastic containers.
PET plastic is also colorless in its natural state. This provides numerous options for manufacturers to help determine the final look of items created using the material. It also provides a more economical alternative to glass when then end goal is to allow consumers to see the contents of the container without having to open it.
The addition of other certain chemicals or materials can also change the color of the end product. For example, when the material is exposed to chloroform or other chemicals, it turns from clear to white. Other options can result in the container turning black, which will be appealing to some companies.
Consumer Benefits of PET Plastics
Containers made from PET plastic are incredibly lightweight in regards to their durability. They are also shatter-resistant, meaning they are unlikely to be damaged during typical household use-related accidents. For example, dropping a PET plastic jar of peanut butter off a counter and onto the floor does not generally result in the container breaking. This prevents wastage.
Most containers made of PET plastics are re-sealable. For example, you can remove the lid on a water bottle, and then screw it back on to close the container again. Essentially, this makes the container easy to reuse in the future.
Environmental Benefits of PET Plastics
Aside from the containers being reusable, PET plastics are also recyclable. Often, the plastic from used water bottles and be recycled for the creation of new water bottles. Some other uses for recycled PET includes the creation of carpet fibers, clothing fabric, and fiberfill for items like winter coats, sleeping bags, and even dog beds. Some industrial strapping and certain retail item packages are made of recycled PET plastic, as well as a variety of automotive parts.
Most recycling centers in the United States accept PET plastic containers for recycling. The recycling process is quite complex, with various different types of equipment required to ensure that the process happens smoothly. Recycling centers often have to partner up with a baler machine manufacturer to obtain the right machines for plastic recycling. From collecting, sorting, and categorizing the plastic, to washing, shredding, separation and extruding, this takes quite some manpower and machinery to accomplish.
To determine if an item is made of PET plastic, simply look for the number “1” in the recycling symbol on the bottle or container. Then, check with your local recycling facility to confirm that they recycle products with the number “1” recycling code.
Another environmental benefit involves the low amount of energy required to produce the packaging or container made of the material. This helps by using less electricity and other resources during the process of making the plastic material and when having it conform to a mold.
How PET Bottles are Made
PET is a product of ethylene glycol and terephthalic acid or dimethyl terephthalate. The process results in an esterification reaction or transesterification reaction respectively.
The flexibility and durability of PET plastic helps create strong and versatile products. The process of taking the raw material and using it to create a specific container shape is fairly simple. One of the key steps involves the use of a PET compressor and a mold.
The mold is used to determine the final shape of the product, while the PET compressor generates the necessary force to make the material conform to the mold. To begin, the PET plastic is heated to the necessary temperature to allow it to be shaped. Then, the material is placed into the mold, and the necessary force is applied.
Often, for plastic containers, this involves the use of a PET compressor to create enough pressurized air to force the plastic to expand into the shape of the mold. This ensures the inside remains hollow and the outside is shaped in the desired manner.
Common Products Featuring PET Plastic
Any plastic container featuring recycling code “1” may contain PET plastic. For example, certain popular vacuum freezer bags feature PET plastic. The majority of plastic soda bottles also use the material. Mylar balloons feature biaxially oriented PET film, as well as various food packages created with thermal insulation properties. “Space blankets” also contain PET along with certain kinds of tape.