Scoured Wool Testing

Our scoured wool measurement services include certified tests for:

• Conditioned mass – wool absorbs up to 20 percent of its weight as moisture so invoicing is based on an agreed moisture content or regain (known as the conditioned mass)
• Yield – determining the amounts of clean wool (woolbase), and vegetable matter contamination in a sample
• Mean fiber diameter – the average fineness of the wool (fiber thickness), which is a primary determinant of wool value 
• Color – measured as tristimulus values, and normally used to assess clean color brightness (Y value) and yellowness (Y-Z value)

In addition, we certify a large proportion of scoured wool for Length After Carding (LAC). To do this, we use a standardized method of simulating semi-worsted processing to estimate mean fiber length after processing. We also test for:

• Residuals – the amount of mineral matter and residual grease left on the fibers after scouring, indicating scouring efficiency
• pH – the acidity or alkalinity of the wool after scouring affects the dyeing process, so it is important for processors to know the pH value
• Alkali solubility and extent of bleaching – solubility is used to assess fiber damage, while the extent of bleaching is important in some processes
• Medullation – refers to the hollow fibers in wool and other animal fibers, which causes uneven dye uptake and adversely affects appearance in apparel wools (but may be desirable for some carpet types)
• Bulk – this measures the fibers’ ability to fill space and also relates to resilience, which are important properties for applications such as carpets, futons and insulation
• Fiber curvature – relates to bulk, compressibility and crimp and is cited as an influence on processing
• Fiber diameter distribution – information about aspects of the diameter distribution may affect assessments of comfort and processing performance
• Detergent residuals – wools intended for certain markets must be scoured with detergents that do not contain nonyl phenol ethoxylate (NPEO)
• Mothproofing treatments – these must comply with the appropriate regulations
• Sanitary reports – shipments to certain destinations require an inspection report confirming that any residual vegetable matter is non-viable, while other places may require sanitization procedures to be verified
• Exports to Iran – these shipments require conformity assessment involving specialized testing to Iranian Standards

To verify the quality and quantity of scoured wool across a range of criteria, contact SGS now to ask about our independent testing services.