PET | Extrusion
PET Full form:
What is PET?
The most widely used thermoplastic polymer in the world is polyethylene terephthalate (PETE or PET), which is more often referred to as "polyester" in the textile sector. It is a naturally translucent and semi-crystalline plastic that is widely used as a fiber for clothing, as a moisture barrier that is widely applicable in bottling and packaging (in which case it is referred to as PET or "PET resin"), and as an engineering plastic when it is combined with other materials to significantly increase the material's strength, such as glass fiber or carbon nanotubes. It is a naturally crystalline, colorless substance.
How is PET made?
The two essential elements of PET are ethylene glycol and terephthalic acid, which are combined to form PET pellets. The resin pellets are then heated to the point where they are a molten liquid that may be extruded or molded into almost any shape of item. PET is created by combining terephthalic acid and ethylene glycol, resulting in pellets of the PET polymer.
More specifically, when the two PET fundamental components are combined at high temperatures and low vacuum pressure, long chains of the polymer are formed. As the mixture becomes denser, the chains get longer. Once the appropriate chain length has been obtained, the reaction is over. The PET spaghetti-like strands are quickly cooled, and then they are extruded into tiny pellets.
When the resin pellets are heated to that temperature, the polymer chains can be stretched in two directions (for fibers) or just one direction (for molten liquid) (for bottles and films). If the polymer is suddenly cold while being stretched, the chains are frozen with their orientation preserved. When the material is stretched out into a form, it is tremendously strong.
If PET is held in the stretched form at high temperatures, it eventually starts to crystallize and start to become opaque, more rigid, and less flexible. This crystalline kind of PET is widely used in take-home and prepared food trays and containers that can be reheated in the oven or microwave.
PET is used for making food packaging as well as in the form of clothing as well. Here are some great examples of PET-
Types of PET
1. PET resin (Used for food and beverage packaging)
2. PET-P (Used in a form of a fabric)
The high-performance, crystal-clear thermoplastic known as polyethylene terephthalate (PET) is made from the combination of ethylene glycol and dimethyl terephthalate (DMT). In comparison to other widely used plastic films, PET film offers a higher tensile strength, excellent dimensional stability, less moisture absorption, and superior physical property retention across a reasonably large temperature range. It also boasts excellent electrical properties, exceptional UV resistance, superb optical clarity, high gloss, and decent gas barrier properties, but only passable moisture barrier properties. The ideal material for high-quality printing and laminating, it is a fantastic alternative for high-performance plastic films and sheets. It can be utilized in applications that require high-temperature sterilization because of its comparatively high melting point.
- Blow Molding
The PET bottle blow molding technique involves heating a pre-molded PET preform that is then automatically positioned into a mould. After that, food-grade, high-pressure compressed air is introduced into the preform, causing it to expand and take on the shape of the mould. After the plastic has cooled, the bottle is taken out, and the process is repeated. This technology is suitable for creating a wide selection of bottles up to 1 liter in capacity and has a number of standard necks available.
Benefits of PET
The strength of PET is strong even when it is light in weight
It is chemically resistant