1, a total of 55% of water and polyvinyl alcohol were added to the reaction kettle and heated to about 90 degrees C. The PVA was completely dissolved in I and then cooled to 80.
2, add the essence, stirring even. At this time the solution is slightly turbid.
3, add the formaldehyde, stirring for 15 minutes.
4. Spillage at 75-80 C and 10% hydrochloric acid.
5, the polycondensation reaction at this temperature, the viscosity changes observed at any time of the reactant and the foaming phenomenon, about 40~60 minutes later, when the bubble appears in the reaction system and the viscosity rises sharply, immediately joined with a good city of hydrogen sodium solution is neutralized, book pH 8-9, then add the remaining 45% of the water. Stir well.
6, cooling out of the material, that is, the finished product.