An Improved Method for the Rapid Determination of the Residual Grease on Scoured Wool

Abstract

In an investigation of the W.I.R.A. rapid grease-extraction apparatus, it was found that up to 20% of the methylene chloride extract of scoured wool could evaporate away at the heater mantle. This loss and others contributed to the low, and erratic results usually obtained when using the W.I.R.A. apparatus with scoured wool. An improved instrument (R5) has been devised with features which reduce or eliminate the main faults of the W.I.R.A. apparatus. The experimental investigations consisted of the extraction (with methylene chloride) of residual wool grease from scoured wool. Using four types of wool having residual wool-grease contents in the range 0.3-7%, the percent extrac tion from the Soxhlet, R5, and W.I.R.A. instruments have been compared. Highly significant linear relationships were found between the extract amounts from the R5 and Soxhlet apparatuses. The R5 instrument is sufficiently sensitive to distinguish between small discrepancies in residual wool grease found on different sections of a tuft of scoured wool.