348 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS lOO PETROLATUM SOLID PARAFFIN LIQUID PARAFFIN AFTER 15 MINUTES i I I I 0 I 2 3 • 5 AM0JNT CF 0IL(MG/C ) lOO 50 PETROLATUM SOLID PARAFFIN LIQUID PARAFFIN AFTER 60 MINUTES 0 I 2 3 4 5 AM0JNT CF 0IL(MG/CM 2) Figure 1. Effect of coating amount of oils on occlusivity. same beyond 60 min after the application even if the coating amount of the oil increased. It was found that the physical forms of oils strongly influenced the extent of the occlusivity as shown in Figures 2 and 3. The occlusive effect was most evident immediately after the application and it decreased with time for both liquid paraffin and solid paraffin when applied to the skin in their solution form. Different occlusive patterns attributable to the difference in the nature of oils were observed in the neat and emulsion forms. Solid paraffin in the neat form had no significant occlusive effect at any time, but liquid paraffin in the neat form occluded water as efficiently as liquid paraffin in the solution form. In the case of the emulsion form, the occlusivity immediately after the application of the samples could not be determined because of the evaporation of water contained in the emulsion. It required more than 30 min to

lOO lOO I , I I , I 30 60 90 120 TIME(M•N) Figure 2. Effect of physical forms of solid paraffin on occlusivity. LIQUID PARAFFIN N• _ EMULSION . SOLUTION • i I 30 60 ! 120 TIME(MIN) Figure 3. Effect of physical forms of liquid paraffin on occlusivity.