The storage time of sodium carboxymethylcellulose (CMC) solutions depends on several factors, including the concentration of the solution, storage conditions and required quality.

Generally speaking, under appropriate storage conditions, CMC solutions can be stored in a temperature-stable, light-shielded environment for several months to several years.

Please note that CMC solutions may undergo some quality changes over time, such as changes in viscosity or separation. Before use, please check the appearance and performance of the solution. If there are any abnormalities, use is not recommended.

Additionally, if you are using a specific type of CMC solution, it is recommended to refer to the storage guidelines and shelf life recommendations provided by the CMC manufacturer for more specific information.