This International Standard specifies a gravimetric method for the determination of the amount of matter that can be extracted by acetone, at a temperature near its boiling point, from a sample of finely divided phenolic moulding material. The method applies only to moulding materials based upon novolak resins and not to those based upon resols, as the latter type of resin may not be completely soluble in acetone. In this International Standard, the amount of acetone-soluble matter is reported as the apparent resin content because, although the extract consists mainly of phenolic resin and hexamine, other acetone-soluble components such as lubricants and colorants or natural resins from the filler are normally also present and will therefore be reported as resin.