250 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 150 100 Clay concentration, % 0 0.5 1.0 Sodium concentrotion, me g-• Figure 12 Effect of clay and electrolyte concentration on pure water systems liquids, the plastic viscosities of all the dispersions made were also measured. The results in Tables III -- V show that in all cases the plastic viscosity greatly increases with increasing clay concentration, but is less affected by variations of electrolyte or organic content. Table III Effect of clay concentration on plastic viscosity (cP) System 40 •o Methanol 25 •o Methanol 40 •o Ethanol 25 •o Ethanol 40 % isoPropanol 25 % isoPropanol 40 •o Acetone 50 •o Ethylene glycol 60 •o Glycerol 50 •o Sorbitol Water 1.6 1.2 4.3 13.9 17.5 0.8 Clay concentration 3.7 3.0 5.1 4.6 6.3 4.4 4.3 6.6 16.1 24.4 2.3 5.4 4.8 7.0 6.3 8.7 7.8 5.8 8.6 18.5 30.2 5.1 7.0 10.3 -- -- -- -- __ 10.2 8.8 10.2 29.0 41.7 5.9

LA PONITE CLAY--A SYNTHETIC INORGANIC GELLING AGENT 251 Table IV Effect of organic concentration on plastic viscosity (cP) at 2 •o clay concentration Compound Methanol Ethanol isoPropanol Acetone Ethylene G. Glycerol Concentration 10 20 25 30 40 50 60 70 2.2 2.4 3.4 14.6 $.0 5.1 s.$1 I 2.3 3.8 4.4 5.5 6.3 4.0 1.9 4.3 4.5 4.7 4.7 3.5 5.8 6.6 6.4 4.1 7.3 10.8 16.1 Sorbitol Concentration % W/W 14 28 42 56 70 6.3 10.6 5:4 lO.8 Table V Effect of electrolyte concentration on plastic viscosity (cP) at 2 • clay concentration System 40 % Methanol 25 % Methanol 40 % Ethanol 25 % Ethanol 40 •o isoPropanol 25 •o isoPropanol 40 % Acetone 50 •o Ethylene glycol 60 •o Glycerol 56 • Sorbitol Water 0 0.1 3.7 3.7 3.0 3.5 5.l 5.2 4.6 4.7 6.3 6.4 4.4 5.7 4.3 4.6 6.6 7.2 16.1 15.7 24.4 24.2 2.3 2.5 NaC1 me g-1 0.2 0.4 S S 3.8 3.8 5.7 S 4.9 5.0 S S 6.1 5.7 4.8 4.3* 7.1 7.1 16.2 14.8 18.1 23.4 2.9 3.4 Notes: * indicates that visible flocculation occurred S indicates gross flocculation and some settlement. 0.8 S 4.0 S 4.1' S 5.4* S 7.2 16.2 3.1' DISCUSSION The three properties studied, yield value, plastic viscosity and clarity, react differently to changes in the conditions, but are, of course, inter- related. Certain general trends can be observed in the results. 1. In all systems the yield value and plastic viscosity increase greatly with clay concentration, while the clarity, indicating a low degree of flocculation, does not alter significantly.