Chemical Analysis
Quantitative determination of the non-polymeric residues and finishes on synthetic fibers by solvent washing and subsequent weighing of the dried residue ensures correct coating levels. This analytical procedure is called gravimetric melt extraction, which identifies the quantity of lubricants and spin finishes present on the yarn surface.
Process Control
Excessive spin finish on the yarn causes slippage during high-speed drawing and generates residue buildup on the heater plates of texturizing machines. By performing gravimetric melt extraction, the mill ensures that the applied finish falls within the narrow band required for downstream processing. The process involves boiling a weighed sample of fiber in a solvent like petroleum ether, evaporating the solvent, and weighing the remaining finish.
If the extraction results deviate from the specified range, the finishing nozzles on the extrusion line must be recalibrated.
Quality Assay
Textile laboratories use the test to verify that the yarn is clean enough for subsequent dyeing or bonding processes. Running a gravimetric melt extraction before dyeing prevents dye unevenness caused by oil residues that block the penetration of dye molecules.
Material Boundary
Synthetic polymer resistance determines the suitability of the solvent used for this test. High-performance fibers with high solvent resistance are particularly suited to this method of analysis.
