Look at the clothes you wear, they might be made of polyester. It is a very popular material used to make clothes, like shirts, bed sheets, and curtains. But do you know what polyester is made of? Let’s explore and find out what makes up this material.
What is Polyester?
Polyester is a well-known synthetic fiber that is a kind of plastic widely used in clothing industries. It’s derived from petroleum and belongs to the ester functional group from which it got its name “Polyester.”
There are different types of polyester, some polyesters are natural biodegradable resources, but most of them are non-biodegradable, like Polyethylene terephthalate (PET), which contributes to world pollution. Polyester in apparel is first blended with cotton and then used, reducing the cost, making it more durable, and also reduces comfortability.
Around the 1930s, British scientist W.H. Caruthers found that he could produce fiber by mixing alcohol and carboxylic acids. He named this fiber Terylene. Later other British scientists were interested in it and started working on it. In 1941 during World War II, British scientists created a better and more credible form of polyester that attracted American investors toward it.
After 1940, many other forms of polyester were created, like Dacron and Kodel. Its main usage expanded in the 70s when demand increased as it was used in different suits and fashion atrocities. At that time, people didn’t know about polyester plastic or not and its toxic effects on the environment, which have been enlightened from the last decade.
What is Polyester Made Of?
Polyester is a combination of two words. Poly means many, and ester which is an organic functional group. Mainly it is manufactured from ethylene that is derived from petroleum. The process through which it is manufactured is called polymerization.
It’s also defined as polyester is fiber in which substance that forms fiber is a long-chain synthetic polymer that is 85% ester by weight. The most commonly and widely used polyester is Polyethylene Terephthalate (PET).
Types Of Polyester
Before talking about the manufacturing process, it’s essential to know about the different types of polyester. Three major types of polyester are;
Ethylene polyester is a world-famous and widely used polyester that is most durable and inexpensive. It’s also known as PET (polyethylene terephthalate). It is called PET resin when used for containers or other applications, while it’s called polyester when used as a fiber.
PCDT polyester is manufactured the same as PET and is more durable, yet it’s still not famous. This polyester is more elastic; that’s why it is widely used for heavy applications.
This polyester was derived from naturally occurring elements which make it biodegradable and eco-friendly. But this polyester is a bit more costly than the other two polyesters.
Process of Manufacturing
Depending upon its form, polyester production is carried out in several ways. All the methods have different end products, so manufacturers use the particular method to get their required fiber. Here are the four widely used methods for manufacturing polyester.
These processes start with the reaction of ethylene glycol and dimethyl terephthalate at high temperatures. Then another process carries on until polyester filament forms. After this, they are reacted with different chemicals depending on the method you use for that particular polyester. Among all these methods, filament and staple are frequently used. Let’s discuss them more deeply.
1.Polyester Filament Yarn (PFY)
At first, in the presence of a catalyst, dimethyl terephthalate reacts with ethylene glycol at a high temperature ranging from 302°F to 410°F ( 150-210° C). Then the resulting chemical, monomer alcohol, is mixed with terephthalic acid at a higher temperature of 472°F (280°C). Then the new molten and clear polyester is removed through a slot.
After completion of the polymerization step, the clear and molten ribbons are left for some time, so they’ll cool down, forming the brittles. Then those ribbons are cut into small chips and again allow them to dry completely to avoid irregularities in the consistency.
When the small polymer chips are dried, then again it’s melted at a high temperature of 500-518°F (260-270°C). This is done to change it into a syrup-like solution which is added to the spinneret, which is a metal container. There are numerous tiny holes in the spinneret through which this syrup, like the suspension, is passed.
The number and size of the hole in it determine the yarn’s size; their shape may be different, like a pentagon or any other, depending on the need. Fivers coming from the holes are brought together to form a single string.
During the spinning stage, manufacturers add different chemicals in solution to change their properties. These chemicals might make them antistatic, flame retardant, or easy to dye.
Drawing The Fiber
Polyesters are too soft when released from spinnerets; even they can be stretched five times longer than their original strength. They are stretched to align polyester molecules in parallel formation, which increases their resilience, strength, and tenacity. Again they are allowed to cool, after which they become more durable, solid, and long-lasting.
Drawn fibers differ from each other depending on the size and shape. The final product can be made duller or soft by stretching it.
At last, drawn fibers or polyester yarn is collected and coiled on a big bobbin. Now your final desirable product is ready; you can use it in your clothes.
2.Polyester Staple Fiber (PSF)
In the production of Polyester Staple Fiber, the first few steps are the same as polymerization and drying. But in the next step in melt spinning, the number of holes spinneret increases, and the rope released from it is called tow. Let’s talk about the further steps that occur after the melt spinning.
When the new town emerges from the spinneret, it is cooled and gathered. All the collected two are stretched, making them three to four times longer in length than the original one.
Then the final drawn tow is inserted in the compression box where force is applied on it and fold the fiber-like accordion. This is done just to keep them together in the next step.
Crimping is done to hold the fiber together in this heating process. Here the crimped tow is heated at 212-302°F (100-150°C) to dry the fiber completely.
After drying the tow in the heat setting process, now the tow is cut into different pieces of different sizes. Here its size depends on the material with which it will be blended for cotton 1.25-1.50 inches of polyester is cut.
3.Polyester Tow Fiber
The polyester tow fiber method is not much used as other methods. This process resembles the polyester filament method, but the filaments are not arranged tightly here.
In this method, continuous polyester filaments are produced that are mostly used to produce bulky products. This polyester is ideal for stuffing as it is soft, comfortable, and breathable.
Manufacturing of Other Polyesters
PCDT polyester is manufactured by following the same steps as PET polyester; the only thing that makes it different is its chemical structure. In its manufacturing process, ethylene glycol reacts with dimethyl terephthalate, but the end product is different.
This polyester is also manufactured by the reaction of ethylene glycol with dimethyl terephthalate, but the source of ethylene glycol is sugar cane. It is a natural resource of polyester that is sustainable and less toxic than other types of polyester.
Research on the production of polyester isn’t finished yet. Scientists are still trying to find sustainable types of polyester that are less toxic. Research being conducted by North Carolina State University in which they are finding a method to manufacture polyester with Kevlar.