【国外标准】 Standard Test Method for Determining the Liquid or Solid State of a Material by Rheometry

5.1 Shipping regulations often require the identification of a material as either a liquid or a solid. This test method may be used to make that determination for regulatory purposes. (See also Test Method D4359.)5.2 For liquid thermosetting resin, as cure progresses, the liquid resin becomes a solid. A thermosetting resin is more easily worked or shaped while in the liquid-like form and becomes more difficult to do so as the cure advances. The point at which the solid-like character becomes dominant is called the gel point and is considered to be the end of the period where the thermosetting resin is workable. Gel point is identified as that point where tan δ = 1 as determined in Test Method D4473.NOTE 1: Gel point at ambient temperature is seldom a useful parameter. Use of this test method at the more useful elevated temperatures requires capabilities readily available but outside of 7.2.6, 7.2.7, and Section 10.5.3 This test method may be used in research, development, and for regulatory compliance.1.1 Using rheometry, this test method determines, for regulatory purposes, whether a viscose viscous material is a liquid or a solid. Very small amounts of material (typically less than 3 g) may be used for this measurement.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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.