The dropping point describes the temperature at which a substance begins to flow under standardized test conditions. The substance is heated in a controlled manner until it changes from a solid to a liquid state. During the measurement, the temperature at which the first drop is released from the material sample is recorded. The dropping point indicates the meltability of solid substances such as bitumen , fats , pitch , lubricants, petroleum jelly , etc.
No dropping point can be determined for greases with solid lubricants or gel thickeners. The dropping point is an important figure for lubricants and greases , but it is also determined for other substances such as wax and asphalt . It is regulated according to DIN ISO 2176 (or according to Ubbelohde DIN 12785).
However, the dropping point is not to be confused with the heat resistance .
Apparatus for determination
An apparatus for determining the dropping point is given in the literature.
- European Pharmacopoeia , Deutscher Apotheker Verlag Stuttgart, 6th edition, 2008, pp. 42–43, ISBN 978-3-7692-3962-1 .
- Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 6: T-Z. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1988, ISBN 3-440-04516-1 , p. 4378.
- dr-tillwich.com: Test methods - dropping point , accessed on April 16, 2013.
- florin-ag.ch: Lexika - Tropfpunkt , accessed on April 16, 2013.