GB/T 4616-2008 specifies the determination method of acetone soluble matter (apparent Resin content of unmolded materials) in plastic phenolic molding plastics. The standard specifies the determination principle, standardizes the preparation requirements of instruments, equipment, reagents and samples, and details the operation steps of extraction, evaporation, weighing, etc. At the same time, the calculation method and precision regulations of the results are given, which provides a unified technical standard for the accurate determination of the relevant indicators of phenolic molding plastics, and helps to evaluate the mass and process characteristics of the product.