Effect of Modified Rinsing Conditions on the Whiteness of Laboratory Scoured Wool

Abstract

The effect of detergent distribution and the influence of various additives to the penultimate rinse bowl on the whiteness of laboratory scouted wool was investigated. With different distributions of scouring reagents (nonionic detergent plus alkali) between bowls 1 to 3 and a rinse in bowl 4, the whitest samples of both high yielding and low yielding merino fleece wools were obtained with the following bowl compositions: bowl 1, a large amount of detergent plus alkali; bowl 2, rinse; bowl 3, a small amount of detergent plus alkali; bowl 4, rinse. The lowest whiteness resulted when all the detergent was added to the first bowl. Intermediate whitenesses were obtained when a small amount of detergent plus alkali was followed by a large amount in the later bowls.

In a more conventional scouring system with constant scouring conditions in bowls 1 and 2, the addition of various builders to bowl 3 increased the whiteness in the order sodium carbonate < trisodium citrate < trisodium ethylenediamine tetraacetate (EDTA-3) < trisodium nitrilotriacetate. Analyses of the level of residual contaminantes gave a statistically significant negative linear correlation between whiteness and residual iron content for both high and low yielding wool. For the low yielding wool, statistically significant correlations aiso existed between whiteness and residual solvent extractables, residual calcium, and ash content.

The improved whiteness obtained using EDTA-3 compared with no additive was also observed initially in simulated continuous scouring, but the overall whiteness decreased rapidly thereafter because of the rapid build-up of contaminants in the liquor.

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References

Anderson, C.A. , A. New Picture of the Raw Wool Fibre, J. Textile Inst. 73(6), 289-292 (1982).

Anderson, C.A. , Mechanisms of Raw Wool Scouring- The Role of the Protein Contaminant Layer, Textile Res. J. 53(12), 741-750 (1983).

Anderson, C.A. , The Protein

Contaminant Layer in Raw Wool and its Role in Processing Technology, Australasian

Textiles 2(5), 28, 29, 32 (1982).

Anderson, C.A. , Bateup, B.O. , and Warner, J.J. , An Assessment of the Wool Characteristics and Liquor System Performance of an Optimized Lo-flo Scouring Plant, Textile Res. J. (in press).

Anderson, C.A. , and Wood, G.F. , The Function of the Individual Bowls in Raw-Wool Scouring, J. Textile Inst. 74(3), 148-149 (1983).

ASTM Designation D584-72, Wool Content of Raw Wool—Laboratory Scale.

Bateup, B.O. , Relationship Between the Whiteness of Scoured Wool and the Level of Residual Nitrogen-Containing Contaminants, Textile Res. J. 54, 299-307 (1984).

Billmeyer, F.W. , Jr. , and Saltzman , M. , "Principles of Color Technology," 2nd ed., Wiley Interscience , N.Y., 1981.

Christoe, J.R. , The Scouring of Protein Contaminants from Raw Wool, Part I: Single-Bowl Laboratory Studies, Textile Res. J. (in press).

10.

Klevens, H.B. , Alcohol-Soap Micelles: "Solubilization, J. Am. Chem. Soc. 72, 3581-3586 (1950 ).

11.

Morgenthaler, W.W. , Sequestration, in "Detergency, Theory and Test Methods, Part II," ch. 11, W. G. Cutler and R. C. Davis , Eds., Marcel Dekker, Inc., N.Y., 1975.

12.

Parker, C.R. , "Water Analysis by Atomic Absorption Spectroscopy," Varian Techtron, Australia, 1972.

13.

Rutkowski, B.J. , Recent Changes in Laundry Detergents, in "Detergency, Theory and Test Methods, Part III," ch. 23, W. G. Cutler and R. C. David , Eds., Marcel Dekker, Inc., N.Y., 1981.

14.

Snyman, J.G. , and Veldsman, D.P. , The Rinsing of Scoured Wool, SAWTRI Technical Report No. 41 1965.

15.

Standards Association of Australia , The Objective Measurement of the Colour of Raw Wool, Draft Standard DR80031, 1980.

16.

Stewart, R.G. , Observations on the Effect of Scouring Systems on the Colour of Scoured Wool, J. Textile Inst. 73(1), 39-41 (1982).

17.

Turpie, D.W.F. , Scouring Conditions, Part II: The Effect of Rinsing at Different Liquor pH Values During Scouring on the Subsequent Combing Performance of Wool, SAWTRI Technical Report No. 193, 1973.