Solvent Extraction Methods for NonFibrous Additives in Spun Yarns
Solvent extraction isolates spin finishes and waxes from spun yarns, preventing excess processing aids from inflating commercial mass and landed duty costs.
Clean Yarn Yield
Production Metric
Quantitative ratio of clean scoured fibre mass to the original grease weight of the raw material. Raw material enters the mill with impurities like grease and vegetable matter that are removed during early processing to determine the clean yarn yield. This value accounts for moisture regain and non-fibrous content to establish a basis for commercial pricing.
Buyers use the figure to adjust invoices from the nominal weight to the actual fibre content delivered.
Calculation Procedure
Assessment begins with a representative sample of grease wool or raw fibre being subjected to a standard scouring process. After drying and conditioning the sample to a standard moisture level, the clean yarn yield is calculated by dividing the final mass by the initial mass. This percentage informs the spinning plan by indicating the expected output volume from a specific bale of raw material.
Corrections are applied for residual vegetable matter that survives the scour but disappears during carding. Analysts must also account for any remaining alcohol extractable matter to ensure the result is not artificially inflated by residual oils.
Economic Consequence
Small percentage shifts in the reported value change the profitability of a contract because the raw material is purchased on a grease basis. High clean yarn yield indicates a more efficient purchase where less waste is transported and processed per kilogram of finished yarn. Mill managers monitor this data to evaluate the efficiency of scouring lines and the honesty of supplier claims.
Measurement Boundary
Results depend on the conditioning environment and the intensity of the scouring cycle used. The clean yarn yield stops being an accurate predictor if the fibre contains high levels of inorganic sand. Differences in testing methods between regional labs can lead to disputes over the final settlement weight.