7. Storage

PVA aqueous solution does not make a chemical change even stored for a long term, however, sometimes it will be putrid, or gather mold or rust, due to the invade of microorganism or mold, water quality, or the material of the storage container. Moreover, the viscosity of solution sometimes rises or it will be gelled as the change on standing. As a countermeasure for these problems, we introduce the following method.

1. For putridity and mold
   aPlease prevent from the invasion of microorganism or mold, or please add antisepsis or anti-mold agent.
   
   
2. For rust
   aPlease avoid using container, which is susceptible to rust. When using this kind of container, please add anti-rust agent. (100 - 1,000 ppm / PVA solution)
   
   
3. For viscosity increasing
   aIn case of using PVA solution, which is apt to increase the viscosity such as high concentration solution of completely hydrolyzed PVA, please consume it as soon as possible or please dilute the solution. It is recommendable to preserve the temperature within the range of 50 - 70, in case of storage of high concentration aqueous solution. And the PVA solution once gelled can be used as well as before, if the fluidity recovers by heating and churning.

8. Foaming and anti-foaming for the aqueous solution

If foaming occurs during dissolving or using PVA solution due to the viscosity or churning velocity, please add anti-foaming agent. (500 - 5,000 ppm / PVA) Further, we are ready to supply Anti-foaming / Defoaming type of "KURARAY POVAL" grades.