Fiber production

The production of synthetic man-made fibers is carried out in two sub-steps:

1) Synthesis of reactive precursors. These consist of individual small molecules, the monomers. Petroleum is the main raw material for their production.

2) Linking thousands of small molecules to form macromolecules. Because macromolecules are formed from many individual molecules, they are called polymers. Three different chemical reactions are distinguished in the polymer formation of synthetic man-made fibers: Polymerization, polyaddition and polycondensation.

3) The spinning mass is produced from the polymers, e.g. in the form of granules or powder.

The spinning mass coming out of the nozzle solidifies to the fiber inside of which the molecular chains are still disordered. Drawing, which is possible during spinning or in a separate process, makes the man-made fibers thinner and aligns the chain molecules in the longitudinal direction of the fiber. In addition to the amorphous areas, crystalline areas are also formed, as well as cross bridges between the individual molecular chains, which provide the necessary strength.

A distinction is made between three different spinning processes to produce man-made fibers: Wet and dry spinning processes – where the starting materials are liquefied by dissolving the spinning mass, and the melt spinning process, where the starting materials are melted. After the filaments have left the spinneret and solidified, drawing takes place by drawing at higher speeds or in a downstream process. The size of the nozzle hole as well as the drawing influence the fineness of the fiber.