The dissolution of polyvinyl alcohol is a very delicate operation. If the dissolution is not good, micelles or even hard blocks will appear, which directly affects the subsequent operation and product quality. First, the polyvinyl alcohol is dispersed into cold water. The dispersion means that the particles are scattered in the water, rather than a large group. In industrial production, bulk material cones are often placed at the feeding port and the feeding speed is controlled.
The second is to place for a period of time under slow stirring or static, so that the PVA swells in cold water. The swelling time is determined according to the specific type of PVA. Then slowly and uniformly heated to the specified temperature while stirring slowly to dissolve the PVA. The dissolution temperature ranges from 80 degrees to 90 degrees according to the specific model. The principle of slow stirring is to agitate the system without air bubbles.
The dissolved PVA is a transparent viscous liquid with a slight blue light.