How To Use Polyvinyl Alcohol Resin

Polyvinyl alcohol resin series products can be dissolved in hot water below 95 ℃, but due to the difference in the degree of polymerization, alcoholysis degree, and alcoholysis methods, there are certain differences in dissolution time and temperature, so the use of different polyvinyl alcohol resins When branded polyvinyl alcohol resin, the dissolution method and time need to be explored. When dissolving, this product can be slowly added to cold water at about 20℃ while stirring to fully swell, disperse and escape of volatile substances (do not add this product to water above 40℃ for direct dissolution to avoid the appearance of clumps. Then the temperature is raised to about 95°C to accelerate the dissolution, and the temperature is kept for 2 to 2.5 hours until the solution no longer contains tiny particles. After filtering impurities through 28-mesh stainless steel, it is ready for use.

The stirring speed is 70-100 rpm. When heating up, indirect heating methods such as jacket and water bath can be used, or direct heating with water vapor can be used; however, direct heating cannot be used with an open flame to avoid local overheating and decomposition. If there is no mixer, it can be used Dissolution is carried out by blowing steam in a tangential direction.

The aqueous solution concentration of polyvinyl alcohol resin series products is generally below 12 to 14%; the aqueous solution concentration of low alcoholysis degree polyvinyl alcohol resin products can generally be around 20%.

How to check whether this product is completely dissolved: take out a small amount of solution, add 1 to 2 drops of iodine solution, if there is a blue clump transparent body, it means that it has not been completely dissolved, if the color can spread evenly, it means it has been completely dissolved.

Storage of the solution: Preservative: If stored for a long time, the water in the aqueous solution will be corrupt, but it will not affect the performance of this product. At this time, 0.01-0.05% (based on PVA) formaldehyde, salicylic acid or other preservatives should be added. Anti-rust: When storing with iron, a small amount of weak alkali should be added, and when using copper, 0.02-0.05% (based on PVA) sodium nitrite should be added, preferably stainless steel or plastic containers.

Addition of defoaming agent: When preparing aqueous solution, this product is not easy to foam, but when the solution concentration is high and the rotation speed is fast, a small amount of foam will also be generated. Benchmark) octanol, tributyl phosphate or 0.2-0.5% (based on PVA) silicone emulsion.