Dropping point

The dropping point is useful (1) in establishing benchmarks for quality control, (2) as an aid in identifying the type of thickener used in a grease, and (3) as an indication of the maximum temperature to which a grease can be exposed without complete liquefaction or excessive oil separation. 

These test methods do not give identical results, and the dropping point should be quoted in terms of the method used (ASTM D-566, ASTM D-2265, IP 31, IP 132). The tests consist of heating a sample of grease (contained in a cup suspended in a test tube) in an oil bath at a prescribed rate. The temperature at which the material falls from the hole in the bottom of the cup is averaged with the temperature of the oil bath and recorded as the dropping point. 

One test method (ASTM D-566, IP 132) is not recommended for temperatures above 288°C. In those cases, the alternate test method (ASTM D-2265) should be used. 

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Dropping point for greases NFT 60-102 ISO 2176 ASTM D 566 Heating up to the fail of the first droplet... 

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 drop point of grease is an indication of change from a soft solid to a viscous fluid its value depends completely on the conditions of test, particularly the rate of heating. The grease sample, which is held in a small metal cup with an orifice, is heated at a predetermined rate. The drop point is the temperature at which a drop of the sample falls from the cup. 

They have a characteristic smooth texture, thermal stability, good water resistance and are relatively inexpensive. The softer grades are easily applied, pump well and give low starting torque. Their application is limited by their relatively low drop points, which are around 100°C (212°F). This means that, in practice, the highest operating temperature is about 50°C (122°F). 

With 29Si NMR spectroscopy we can show that the chlorosilanol-intermediates of the partial hydrolysis of silicon tetrachloride are stable in solution for more than one houn After fast mixing of diluent water to prevent fast reactions at the dropping point we can see with 29Si NMR Cl3SiOH, Cl2Si(OH)2, and ClSi(OH)3 (table 1). 

Metropolis Monte Carlo (MMC) method, 26 1035-1036 Met-spar, 4 577 Metsulfuron-methyl, 13 322 Mettler dropping point, 10 827 Mevacor, 5 142... 

Gas Ignition Point. Discussion of relationships between ignition point (autoigoitian) and drop ignition point (spontaneous ignition). Derivation of a formula for calcg drop point temps... 

Hoechst Wax E Ester type wax. Drop point 175F Hoechst... 

Dropping point the temperature at which grease passes from a semi-solid to a liquid state under prescribed conditions. 

Figure 8.1. Example of a 3-step fractionation process for milk fat, with optional recycling of some fractions. AMF — Anhydrous milk fat DP = Dropping point of the fraction O — Olein or soft fraction of given step S = Stearin or hard fraction of given step (Gibon and Tirtiaux, personal communication).

Figure 8.4. Changes in triglyceride composition of top olein (OOO) with a dropping point of 7°C compared to the original anhydrous milk fat. M = myristic acid P = palmitic acid S = stearic acid (Gibon and Tirtiaux, personal communication).

When a 1,3-specific lipase is used for interesterification, the enzymatically-modified product has some different properties compared to those of a chemically-interesterified product. For example, the dropping point of butterfat was increased slightly by chemical interesterification whereas interesterification by a 1,3-lipase from Rhizopus arrhizus led to a 2-4°C decrease in dropping point. Although both methods of interesterification reduced hardness, the magnitude of the effect was greater for the enzymatically-interesterified fat (Marangoni and Rousseau, 1998). 

The melting point (determined as slip point or drop point) of the fat. 

The dropping point, commonly called the Mettler dropping point, is defined as the temperature at which a fat becomes sufficiently fluid to flow... 

As the dropping point method can be applied to fat fractions and fat-based ingredients, as well as to finished products made from them, it provides a means of studying the influence of manufacturing conditions (Mertens, 1973). 

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). 

BSI 1976a. British Standard Methods of Analysis of Fats and Fatty Oils, Part 1. Physical Methods, Section 1.4. Determination of flow and drop points. British Standards Institution, London. 

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