Polyester is a thread made by a synthetic polymer that is well known to be associated with polyester fabric, this type of fabric is recognized worldwide because it is resistant to wrinkles, has enough elasticity and part of being used for sportswear, it is also used in the automotive sectors, aeronautics and technical applications that require more specific properties.
Polyester is only one class of polymer, it is categorized as an elastomer class with a functional ester group. The best-known thermoplastic polyester from petroleum is PET.
It is formed by ethylene glycol and more terephthalic acid, transforming it into polymer or poltericoletane. Thanks to the union of these two compounds, called polymerization, the polyester filament or fiber is obtained. Once this polymer is obtained, the yarns can be created with other natural or synthetic compounds.
The best polyester fibres on the market are manufactured using the fusion method, which consists of the following steps:
- Prepare the melt
- Extrusion of the melt through the holes of the row
- The extent of the polymer linings that will exert from the holes
- The winding of filaments already solidified in a coil.
Preparation of the melt
First the small pieces of the polymer will be introduced into a fusion grid or grill, by means of a stainless steel spiral coil which will be heated electrically, now the polymer will begin to pass under the grill.
Extrusion and spinning
The entire melt goes from the melting tank to metering gear pumps and then to a filtration equipment which will consist of numerous fine metal sieves.
After this the polymer will pass to the row, the rows consist of several 5mm steel discs with holes of a size and distribution that are efficient to give maximum regularity and uniform cooling for a better finish.
The polymer jet will solidify immediately as soon as it comes into contact with the atmosphere, after which it will solidify and pass into the silo area and then be passed through a collection mechanism.
This consists of passing the filaments through rollers that will rotate at different speeds, the speeds will determine the stretch, which will vary between 3 and 6 for the different types of fibers and threads, when it is a continuous thread the stretch ratio will be between 3 and 5, but everything will always depend on the properties of the thread.
That is an old but effective method, today is used a method known as spinning stretched which is much faster, this is used in large factories, because it gives greater productivity to it and decreases the handling of the product giving it a better finish.