Production processes for manufacturing
polyester fibers and yarns, as explained in the following:
Production of ester building unit
In this process a chemical reaction is
carried out between monoethylene glycol and dimethyl terephthalate to produce
diglycol terephthalate.
Polymerization
In this process (for fiber
production) polymerization occurs to diglycol terephtalate to produce
polyester polymer.
Spinning
In this process, molten polyester
polymer is pumped to the spinnerettes and the filaments come out to meet a
stream of cold air and get solidified. The resulting filament tows collected
in
cans feed the next stage. The fineness of the resulting filaments depend on the
size of the spinneret holes.
Tensioning and crimping
In this operation, the large number of
tows are fed as a layer to a stage of tensioning and crimping, to adjust the
fiber fineness and crimp.
Cutting and pressing
The filament sheet is introduced in this
stage to a cutting machine which transforms the polyester filaments to fibers
with length similar to cotton length or similar to wool length. The resulting
fibers are pressed into bales and covered with polyethylene sheets.
Spinning
In this process (for filament
yarn) the number of filaments coming out of the spinneret is much less
than in the case of fiber production. The produced yarn in this process is
known as “poy” yarn which needs further processing to produce the required yarn
Ring-twisting
In this stage poy yarn is drawn, twisted
and wound to produce polyester filament yarn.
Texturing
In this process the polyester “poy” (preoriented yarn) is
passed in a texturing machine which induce crimp in the filaments, resulting
polyester textured yarn.
