PVA MANUFACTURER---LIWEI CHEMICAL CO. LTD

Storage

PVA can be storaged for a long period without denaturalization unless it contacts water directly. During the storage, volatilization matter may slightly cause both moisture and weight loss but that will not affect the quality of PVA. Then, when the volatilization matter gets low, PVA absorbs easily moisture and adds weight to it.
If it is not contaminated, PVA solution does not rot or deteriorate easily which makes it easier for storage than any other macromolecular solution.
PVA 24-99, 18-99, 17-99 13-99 series are high viscosity and complete alcoholysis types. If they are made into a paste with a concentration higher than 8%, they can be stored at the ambient temperature lower than 20℃ with increased viscosity, forming gel due to molecule crystallization without any change in nature. Their fluidity can be restored to the original after heated and stirred. To avoid such happenings, in winter the frost resistance type PVA can be selected, or similar products with alcoholysis degrees of 88-97(mol/mol)%, which perform slightly poor in PVA water resistance, or by combination of complete and partial alcoholysis types for freeze resistance.
For the PVA with a degree of alcoholysis smaller than 99 (mol/mol)%, its viscosity is consistent with few possibilities to gel at low temperatures.
Stainless steel tanks are suitable for storage of PVA paste. If only iron or carbon steel containers are available, 0.05% sodium nitrate or sodium benzoate can be added into the PVA paste to avoid rusting.
Given a long period of storage, the untreated PVA solution in water mildew and rot easily, when some 0.01%-0.05% antiseptic can be added, e.g. salicylic acid.