642 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table III Esters of Oleic Acid CHa(CH2)7CH•CH(CH,•)7COOH C•s Acid Mol Wt 276 Polyol Monoesters: Approx Mol wt Polyol Viscosity Carbons (Lotion)(cps) Glyceryl monooleate 350 3 4580 PEG 200 monooleate 506 85= 7810 Triglyceryl monooleatc 498 9 8290 PEG 600 monooleate 863 26-4- 182 PEG 1540 monooleate 1753 69 5= 30 PPG 2000 monooleate 2244 1025= 2560 Polyol Polyesters: Diglyceryl dioleate 682 6 2092 PEG 400 dioleate 916 17 5= 2688 Decaglyceryl tetraoleate 1791 30 7940 Decaglyceryl octaoleate 2822 30 2300 Decaglyceryl decaoleate 3339 30 2180 Fatty Alcohol Esters: (% Branching) n-Decyl oleate Isodecyl oleate Hexadecyl oleate Oleyl oleate Isostearyl oleate Polyol Monoester Skin Feels: Polyol Polyester Skin Feels: Fatty Alcohol Ester Skin Feels: 410 10 5320 ... 410 10 6180 3.6 500 16 5300 17.0 526 18 6860 528 18 5780 2.8 Initial Slip (Scale 1-5) Total End Feel (Scale 4-20) PEG 1540 PEG 600 Glyccryl Triglyceryl PEG 200 PPG 2000 PEG 400 di- Decaglyceryl octa- Decaglyceryl deca- Decaglyceryl tetra- Diglyceryl di- Isostearyl Isodecyl Oleyl Hexadecyl n-Decyl 1.3 PEG 1540 2.2 Triglyceryl 3.5 Glyceryl 3.7 PEG 600 4.0 PPG 2000 4.0 PEG 200 3.5 Decaglyceryl tetra- 4.0 Decaglyceryl octa- 4.0 Diglyceryl di- 4.3 Decaglyceryl deca- 4.8 PEG 400 di- 3.0 Hexadecyl 3.5 Isostearyl 4.0 n-Decyl 4.0 Isodecyl 4.5 Oleyl 73 77 83 87 11 3 15 7 8.5 9.3 11.3 11.5 14.5 13.0 15.0 17.0 17.0 18.5

EMOLLIENCY AND CHEMICAL STRUCTURE 643 all the polyol esters of oleic acid tested. Within this subgroup, there seems to be no correlation between End Feel and molecular weight, nor with per cent branching. The best End Feel was obtained from oleyl oleate, but we do not think that this richer skin feel is due to the addi- tional unsaturation. As a gToup, all these fatty alcohol esters of oleic acid gave rich Initial Feel and slip, as well as rich End Feel. For the ESTERS OF STEARIC ACID (Table IV), it should be noted that the End Feel score for PEG 1000 monostearate is less than half that of the fatty alcohol monostearates. The best End Feel score was obtained from butyl stearate, where stearic acid represents ahnost 83% of the molecule. Branching, in this series, did not seem to improve End Feel substantially. The poor performance of PEG 1000 monostearate may be due in some measure to the almost watery viscosity lotion which it pro- duced. Table IV Esters of Stearic Acid XXX 55% C,.6 acid--CH•(CH,•)•4COOH• Commercial 45% C•8 acid--CH.¾CH2)•.6COOH•Stearic (Mol Wt 270) Approx Carbons on Viscosity Mol Wt Alcohol (Lotion) (cps) Branching Butyl stearate Isodecy] stearate Hexadecyl stearate PEG 1000 monostearate Initial Slip (Scale 1-5) PEG 1000 3.0 Butyl 3.5 Hexa decyl 4.0 Isod½cyl 4.5 326 4 2144 ... 410 10 5230 3.7 494 16 2322 17.2 1247 44+ 39 ... End Feel (Scale 4-20) PEG 1000 6.5 Isodecyl 16.3 Hexadecyl 17.0 Butyl 17.0 Unfortunately, we were not able to obtain the same ESTERS OF 1SOSTEARIC ACID (Table V) as were available to us for stearic acid. Therefore, it is difficult to compare the two series. The only ester com- mon to both acids, that of isodecyl alcohol, shows the isostearic ester to be somewhat better, as would be expected. Note again that the two polyol esters gave substantially worse End Feels than the fatty alcohol esters in this series. ESTERS OF LINOLEIC ACID are shown in Table VI. Linoleic is another C•s acid, structurally identical to oleic acid except for an addi- tional double bond. Table VI shows that such extra unsaturation appears