Softening Point Drop Method

Mettler softening point method — ASTM D 3461-76. This is the most recent method. This automatic method measures the temperature at which the resin flows out of a sample cup under its own weight. The temperature is recorded when the first drop crosses the light path of a photocell (Fig. 21). This method is quite accurate and reproducible. 

Although not widely used, there are other methods to determine the softening point, such as the capillary method, the flow point, the drop point, and the Kofier method. The different methods provide different values of the softening point. In general, the Ring and Ball method provides the highest softening point while the... 

The dropping point corresponds to a solid fat content of about 5% (Papalois et al., 1996), and corresponds closely to the softening point determined by the method of Barnicoat (1944) (Timms, 1978 deMan etal., 1983 Papalois et al., 1996). Barnicoat s method was developed for application to milk fat fractions as an alternative to the tedious Wiley melting point technique (Mertens, 1973). In Barnicoat s method, the softening point is taken as the temperature at which a steel ball bearing, initially on the surface of a column of the fat, sinks halfway through the column. In the Wiley method, historically favored in the US, but now an AOCS surplus official method (Firestone, 1998), the melting point is taken as the temperature at which a disc of initially solid fat located at the interface between a layer of water and an (upper) layer of 95% ethanol, becomes spherical. The Barnicoat method is still used in the chocolate industry (Minifie, 1999). 

Drop Softening Point Determine as directed in the Drop Method under Softening Point, Appendix IX, using a bath temperature of 100°. 

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