Technical Information
AQUEOUS SOLUTION OF PVA

Generally, PVA is used by dissolving into water.

1.How to dissolve "KURARAY POVAL" (Dissolving procedure)

The solubility of PVA depends on degree of polymerization and percent hydrolysis. PVA is charged into cold water and heat it up to get its solution. Direct injection or indirect jacketed heating by steam is the heat source for the dissolution. It is completed if the particle of PVA disappear in the aqueous solution.
Please note that the dissolving method of completely hydrolyzed grades and partially hydrolyzed grades has a slight difference. Please refer to the following indication.

  1. COMPLETELY HYDROLYZED GRADES

    PVA should must be charged into water within the dissolution vessel at the room temperature, about 15 - 25, with continuous stirring. Since completely hydrolyzed grades of "KURARAY POVAL" hardly dissolve at this temperature, no lumps will be formed, and become slurry in cold water. After charging PVA into the vessel, heating should be started and when the slurry temperature reaches 97 - 98, just before boiling, "KURARAY POVAL" is completely dissolved. If the capacity of the agitator is low, continued stirring at this temperature is required until the particles of PVA disappear.

  2. PARTIALLY HYDROLYZED GRADES

    Partially hydrolyzed grades can be easily dissolve in cold water, so it should be cared that large and hard lumps are likely to be formed when charging PVA into the water. Please refer to the following ' MAJOR NOTICES '.

    >>MAJOR NOTICE

    1. The water temperature should be lower than 25, when charging PVA.
    2. The charging speed of PVA should be as slow as possible.
    3. After the charging, the slurry should be continuously stirred for about 10 - 15 minutes without raising the temperature immediately, in order to disperse the particles efficiently.
    4. The water temperature should be raised to about 95, to shorten the dissolving time. The lower degree of polymerization is, the lower water temperature is acceptable for making solution.
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