DIN 54270-2-1977 Spinning & weaving products inspection; Determination of the ultimate viscosity of cellulose by the copper ethylene diammonia solution viscosity method "is a standard developed by the German Institute for Standardization, which specifies the method for determining the ultimate viscosity of cellulose by the copper ethylene diammonia solution method (Cuen method). This method is suitable for the viscosity analysis of cellulose in Spinning & weaving products. The ultimate viscosity is calculated by measuring the flow time of cellulose in a specific solvent. The ultimate viscosity is an important indicator of the molecular weight of cellulose and can be used to evaluate the mass and performance of cellulose fibers. This standard provides a scientific basis for the quality control of Spinning & weaving products, the performance analysis of cellulose fibers, and the research and development of related products.