This International Standard specifies three methods for the quantitative determination of the material extractable from raw rubbers, both natural and synthetic, and their unvulcanized and vulcanized compounds. - method A measures the mass of the solvent extract, after evaporation of the solvent, relative to the mass of the original test portion; - method B measures the difference in the mass of the test portion before and after extraction; - method C, which is for raw rubber only, measures the difference in the mass of the test portion before and after extraction using boiling solvent. NOTE 1 Depending on the test method used, the conditioning of the test portion and the solvent used, the test result will not necessarily be the same. NOTE 2 Method C generally gives results which are lower than those obtained with methods A and B due to the fact that an equilibrium is set up, particularly if large test portions are used, depending on the content and the nature of the extractable matter. Method C is, however, a quicker method than method A or method B. NOTE 3 Method C is not suitable if the test portion disintegrates during the extraction. Recommendations as to the solvent most appropriate to each type of rubber are given in Annex A.