Grease dropping point

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

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. 

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

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. 

Figure 178. Changes in the dropping points (the temperature required for suppositories to melt and fall from a grease cup orifice) of suppositories following storage at 15 C ( ) or 25 C ( ) and 75% RFL (Reproduced from Ref. 710 with permission.)...

It is interesting to point out that stable CNT greases can stiU be made without an appropriate chemical surfactant. The dropping point still remains high (>271 °C). 

Dropping Point. Dropping point is the temperature at which the first drop of oil falls from a sample of grease under test conditions. Generally it is not advisable to use a grease at temperatures higher than 125 to 150°F (69 to 85°C) below its dropping point. 

The penetration number, dropping point, metallic base, and the thickening agents used are ah elements that are used to grade grease. 

A continuous process for the production of high dropping point lithium complex greases has been developed (13). Here, the conventional dibasic acid salt or the dibasic ester component is no longer used. These conventional components are substituted with a borated additive fed into the reactor downstream of the thickener formation zone. This substitution and process modification results in a significantly less problematic process and a substantial increase in production throughput (13). 

ASTM D566 Drop point of lubricating greases (12)... 

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