How is polyester made?
• Polymerization: The two raw material- ethylene glycol and terephthalic acid are mixed in a reaction chamber at high temperature and under vacuum. Catalysts are used to speed up the reaction. This leads to the formation of polyethylene terephthalate (PET) by the process of condensation polymerization. The end product of polymerization is molten chips which are pumped out, dried and cut into the chip.
• Spinning: Melt spinning is carried out to produce polyester. The chips produced by the process of polymerization are then fed into the hopper which is heated which converts chips into molten liquid. The molten liquid is allowed to pass through the grid that is attached to the base. The extrusion is done through a spinneret vertically followed by solidification.
• Drawing: This step involves stretching of the extruded filament which imparts strength to polyester filaments. In order to obtain staple fibers, the filaments prepared are cut and broken.