【国外标准】 Standard Test Method for Gel Time and Peak Exothermic Temperature of Reacting Thermosetting Resins (Withdrawn 2008)

Since the gel time and the peak exothermic temperature of a reacting thermosetting plastic composition vary with the volume of material mixed at one time, it is essential that the volume be specified in any determination. By selection of an appropriate volume, gel time and peak exothermic data may be obtained in sufficiently precise and reproducible form or application evaluation, quality control, and material characterization of a thermosetting plastic composition. For most meaningful results, the cross sectional area of the material being examined, as well as other conditions of testing, should approximate as closely as possible the conditions of use of the material. This test method is operator-dependent since it is simple to perform. It is of value for determining conditions required to produce an end product.1.1 This test method covers the determination of the time from the initial mixing of the reactants of a thermosetting plastic composition to the time when solidification commences, under conditions approximating the conditions of use. This test method also provides a means for measuring the maximum temperature reached by a reacting thermosetting plastic composition, as well as the time from initial mixing to the time when this peak exothermic temperature is reached. This test method is limited to reacting mixtures exhibiting gel times greater than 5 min. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 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 and health practices and determine the applicability of regulatory limitations prior to use. Note 1-There is no similar or equivalent ISO standard.