Determining Fibre Commercial Mass under International Regain Standards
Determine commercial mass by calculating clean oven-dry mass from certified core samples and adding standard international commercial regain allowances to settle invoices.
Polyester Staple Regain
Synthetic Moisture
Moisture holding capacity of polyester staple fibres calculated as a percentage of their dry mass is low compared to natural fibres. In shipment evaluation, polyester staple regain represents the small amount of water that adheres to the hydrophobic polymer surface under standard conditions. This standard value is officially set at zero point four percent for trade purposes.
Yarn Spinning
Spinners monitor this moisture level before blending polyester with cotton or wool to ensure consistent blend weights. If the polyester staple regain deviates from the standard, the blend ratio of the yarn will be incorrect. This impacts both dye uptake and final fabric performance.
Drying Method
Polyester polymer consists of tightly packed crystalline structures with very few polar sites to bind water molecules. To measure the regain, a specimen of the staple fibre is weighed, dried in a ventilated oven at one hundred and five degrees Celsius, and then reweighed. The weight difference is minimal, reflecting the hydrophobic nature of the material.
This procedure must be performed with high-precision balances because of the very low mass differences involved. It ensures that the calculated moisture level is free from environmental interference.
Weight Correction
Shipping weights are adjusted using this percentage to establish the clean, dry mass of the polymer. It prevents disputes between fibre manufacturers and spinning mills. Maintaining this control is standard practice in international trade.