WATER-IN-OIL EMULSIFIERS 7 3 5 Table I Typical Properties of Polygylcerol Esters Acid SAP Hydroxyl HLB Viscosity* Value Value Value (calc) (25øC) Triglycerol diisostearate 4.0 maximum 140-160 205-235 4.7 Triglycer ol triisostearate 2.9 168.6 86.7 2.6 Hexaglycerol triisostearate 3.4 142.9 199.7 5.3 Hexaglycerol hexaisostearate 3.6 170.7 50.8 2.4 Octaglycerol pentaisostearate 4.7 157.6 134.1 3.8 900-1000 cst 500-600 cst 5500cst 590 cst 2100cst *Kinematic viscosity--ASTM D445. Table II Nessler Tube Test Emulsion Wt % Mineral oil, 70 visc. 65.0 Emulsifier 10.0 Water 25.0 mixed with the mineral oil. The mixture was then agitated at 250 rpms with a Lightnin '© type of mixer* attached to a Powerstat © Variable Auto Transformer.? The water is then quickly added, and the emulsion formed is mixed for precisely 20 min. The emulsion is quickly transferred to a Nessler tube of 100 ml capacity (30 mm diameter, 20 cm high), placed on a rack, and observed for 3 weeks. Being a relatively unstable system, separation of a clear oily layer on the top of the emulsion occurs quite rapidly. The height of this separation is measured daily and recorded. After calculating a per cent separation based on emulsion heights, a graph is plotted represented by Fig. 1. Six emulsifiers were tested in this manner--Triglycerol Diisostearate, Octaglycerol Pentaisostearate, Octaglycerol Pentaoleate, Hexaglycerol Triisostearate, a 50/50 blend of Triglycerol Diisostearate-Glycerol Trioleate, and as a control--Sorbitan Sesquioleate. At least one supplier (2) advocates the use of Sorbitan Sesquioleate as an effective w/o emulsifier and its use as a control in this experiment seemed to provide a good basis on which to judge the performance ofpolyglycerol esters. RESULTS: The ideal HLB range for w/o emulsifiers falls in the range 3 to 6. As shown in Table I, the polyglycerol esters tested here all meet this requirement. As shown in Fig. 1, all the polyglycerol esters, except the Octaglycerol Pentaoleate, had slower separation rates than the control. A comparison between the Octaglycerol Pentaisostearate and the Octaglycerol Pentaoleate demonstrates the superior effective- ness ofisostearate ester versus the oleate ester. A more extensive study is currently un- derway to study this phenomenon of isostearate versus oleate esters. The branched *Mixing Equipment Co. Inc., 138 Mount Read Blvd., Rochester, NY. ?Superior Electric Co., Bristol, CT.

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