Elastane fiber manufacturing process
The manufacturing process of Elastane fiber:
Spandex is a polyurethane that has a polymer of a urethane group (-NH-COO-). It can be produced from the synthesis of polyurethane urea. Organic isocyanide (R-N=C=O) alcoholic compound (R-OH) reacts and makes urethane. The reaction is as below :
C2H5-OH+CH3-NCO.....CH3-NH-COOC2H5
Spandex fiber preparation process:
Spandex fiber is at least 85% segmented long-chain polymer that is made by the artificial process of polyurethane.
1. Pre polymer production
2. Reaction with isocyanide and pre-polymer (polymerization)
3. Segmented polyurethane structure
1. Pre polymer production: Segmented polyurethane can be in two classes.
a) Polyester type
b) Polyether type
In the polyester type ethylene glycol and adipic acid make a reaction and make polyester and after that it produces polyurethane.
In the case of polyether type rings are broken and produce polyether. This soft segmented polyether is used to produce segmented polyurethane.
2. Reaction with isocyanide and pre-polymer (polymerization): Produced soft segmented polyester or polyether reacts with two molecules of Di-isocyanide and makes polyurethane. And the reaction is completed in the presence of tertiary amine or amine salt. As a result, complete the polymerization process.
3. Segmented polyurethane structure formation: To make a long-chain polymer needs a reaction with glycol, di-amine, hydrazine, and water and complete full polymerization. In this way, pre-polymer be hard segmented polyurethane which is ready for spinning.
Spinning process: Spandex fiber is generally produced by the dry spinning or solvent spinning process and produces filament. Sometimes need reaction spinning to produce spandex fiber. The solvent spinning process need to use de-lusturing agent whiteners, and lubricants. We can produce spandex as we need the finer or coarser count and when polymers are not dissolved then we need reaction spinning. The dry spinning process needs Di-methyl chloride formic acid and tri-chloromethane as solvents.