4.1 This test method is used to evaluate the suitability of powdered rubber chemicals, particularly accelerators, for use in rubber compounds that require very small particle clusters to achieve a uniform cross-linked network. This test method is intended to be used to ensure that no excessively large particles are present that would result in network “flaws” and to determine that the powdered product follows a typical pattern of size distribution.

4.2 In view of the inherent variability in this type of method, it is recommended that the results be used only in a semi-quantitative sense; that is, comparisons within a laboratory or relative comparisons of samples against reference samples, or both.

1.1 This test method covers a procedure for the qualitative evaluation of aggregate size and aggregate size distribution of powdered rubber accelerators and other compounding materials which are insoluble in water.

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.

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.