SYMPOSIA PAPER Published: 01 January 1960

Calcium-45-Tagged Clay as Detergency Test Soil


Lack of progress in reaching any general agreement on standard laboratory tests for laundry detergency performance may be related to the general use of carbon blacks as standard soils and limitations on measurement methods. Availability of radioisotopes and sensitive methods of measurement facilitate investigations with other soil materials more similar to those encountered in practice.

Some investigations have been carried out with a test soil consisting of calcium-45-tagged clay dispersed in lubricating oil and applied to cotton swatches. This soil has been employed in a miniature laboratory wash apparatus to evaluate soil removal and redeposition properties of detergents. Data are given on precision of the test method and effects on evaluations of certain test variables. Employing various detergent compositions as well as commercial laundry products, comparisons have been made between evaluations with the oily tagged clay and a conventional carbon black soil. Pronounced contradictions were found in relative evaluations with the two methods, particularly with regard to the effect of alkalies as builders, the effectiveness of unbuilt nonionic surfactant, and the action of NaCMC in promoting whiteness retention of a built anionic surfactant. Evaluations with the tagged clay soil appear to be in better general accord with practical observations than those with carbon black soil.

Author Information

Hensley, JW
Wyandotte Chemicals Corp., Wyandotte, Mich.
Inks, CG
Wyandotte Chemicals Corp., Wyandotte, Mich.
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Developed by Committee: E10
Pages: 27–39
DOI: 10.1520/STP39371S
ISBN-EB: 978-0-8031-5666-1
ISBN-13: 978-0-8031-5665-4