GB/T 21992-2008 stipulates the determination method of the number of impurities and foreign particles in polyvinyl chloride (PVC) Resin for paste. The standard clarifies the test principle, standardizes the preparation process of instruments and samples, specifies the sampling, scattered observation and counting steps, and puts forward requirements for the calculation and precision of the results. It provides a unified technical standard for the accurate determination of the number of impurities and foreign particles in polyvinyl chloride (PVC) Resin for paste, and helps to control the mass of the product and ensure its stable performance in processing applications.