【国外标准】 Standard Test Method for Softening Point of Pitches (Mettler Softening Point Method)

4.1 Pitch does not go through a solid-liquid phase change when heated, and therefore does not have a true melting point. As the temperature is raised pitch gradually softens or becomes less viscous. For this reason, the determination of the softening point must be made by an arbitrary, but closely defined, method if the test values are to be reproducible.4.2 This test method is useful in determining the consistency of pitches as one element in establishing the uniformity of shipments or sources of supply.1.1 This test method covers the determination of the softening point of pitches having softening points in the range from 50 °C to 180 °C by this test method, and gives results comparable to those obtained by Test Method D2319 above 80 °C (176 °F).1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.