The purpose of this standard is to specify a method for the determination of the pH value of polypropylene (PP) acid slurries for Spinning & weaving sizing. It is suitable for the determination of the pH value of polypropylene (PP) acid slurries for Spinning & weaving sizing. This includes references to normative reference documents such as GB/T 8170 and FZ/T 10016, which ensure accuracy and conformity. The determination principle is simple, and the pH Meter is used to measure the pH value of the specimen. Equipment and utensils required include Balance, Plugged Triangle flask, Magnetic Therstatic Stirrer and pH Meter. In terms of sample preparation, the non-volatile-matter content of the sample is determined according to the test method in FZ/T 10016, and the results are revised according to the revision rules of GB/T 8170.