(Equivalent Tests: IP 76, ISO 2207, and AFNOR T60-128)
EXPLANATION
Congealing point is a wax property of interest to many petroleum wax consumers. This procedure measures the temperature at which a sample being cooled develops a "set" or resistance to flow. At that temperature the wax may be at or close to the solid state, or it may be semisolid and quite unctuous, depending on the composition of the wax or petrolatum being tested. In the case of petrolatums, congealing property is associated with the formation of a gel structure as the sample cools.
TEST SUMMARY
A droplet of the melted wax sample is made to adhere to the bulb of a thermometer. Using a prewarmed flask as an air jacket, the droplet on the bulb is allowed to cool at a fixed rate until it congeals. The congealing point is observed as the temperature at which the droplet ceases to flow as the thermometer is turned.
TEST PRECISION
This test method has no bias.