Products of polyvinyl alcohol resins are dissolved in hot water at 95 ° c below, but due to differences in degree of polymerization, Alcoholysis of high and low, Alcoholysis, different dissolve has certain differences in the time, temperature, so when you use a different brand of Polyvinyl Alcohol resins, dissolving method and time need to be groping.c When dissolved, the stirring slowly add the product in cold water about 20 ℃ fully swollen, escapes decentralized and volatile materials ( not more than 40 ℃ water was added to dissolve the product directly to avoid packet shape and skin dissolved endogenous phenomenon ), and then heated to about 95 ℃ accelerated dissolution and heat 2 to 2.5 hours, until the solution no longer contains tiny particles, and then filtered through 28 mesh stainless steel impurities can spare.
Indirect heating with stirring speed of 70 to 100 rev / min, the temperature, can be jacketed water bath and so on, water vapor may also be heated directly. However, not directly heated with an open flame, and in order to avoid local overheating decomposed without mixer, available steam blown tangentially methods dissolved. Concentration of the aqueous solution of polyvinyl alcohol series resin is generally 12 to 14 % or less, low concentration of the resin Polyvinyl Alcohol aqueous solution of the product is generally about 20%.
How to test Polyvinyl Alcohol products are fully dissolved: A small amount of solution was added 1 to 2 drops of iodine solution, if there blue transparent body pellets that have yet to be completely dissolved, such as color can be evenly spread, indicating that it has completely dissolved.