Polyvinyl alcohol powder
Polyvinyl alcohol (PVA) is made from vinyl acetate (VAM) through alcoholysis polymerization. It is a water-soluble and environmentally friendly polymer.
Appearance: White powder, odorless, odorless, and fluid.
Solubility: Polyvinyl alcohol powder (PVA) 17-88 and 24-88 are partial alcoholysis type PVA, which can be dissolved in room temperature water.
Thermal stability: Polyvinyl alcohol softens when heated. There is no significant change below 40 ° C, and it will gradually color when heated at 160 ° C for a long time. It decomposes above 220 ° C to generate water, acetic acid, acetaldehyde and butenal.
Chemical resistance: It is hardly affected by weak acids, alkalis or organic solvents, and has high oil resistance.
Storage stability: PVA is a low viscosity polymer, and its aqueous solution is very stable at normal temperature. The PVA aqueous solution does not deteriorate during storage.
Film-forming property: Due to the high adhesion between PVA molecules, PVA is easy to form a film. The formed film is colorless and transparent, has good mechanical strength, has a smooth surface without stickiness, and good solubility. PVA film has good light transmittance, high moisture permeability, no charge, no dust absorption, and good printability.
2. Chemical properties
PVA can be regarded as a linear polymer with secondary hydroxyl groups. The hydroxyl group in the molecule of PVA has higher activity, can carry out the typical chemical reactions of low alcohols, such as esterification, etherification, acetalization, etc., and can also react with many inorganic compounds or organic compounds. Note: The difference in PVA properties is mainly determined by its degree of polymerization and alcoholysis.
3.PVA dissolution method
Powder mixing method: PVA powder particles and equivalent or larger amounts of other powdery ingredients are fully dispersed by dry mixing, and then dissolved by adding water. At this time, PVA can be dissolved without agglomeration.
4. Product use
Polyvinyl alcohol powder (PVA) is used in various dry powder putties in powder chemical building materials, additives in dry powder mortar, tile adhesives, plaster plaster adhesives, etc., which can effectively increase the adhesion and flow of cement and mortar. And slow down the drying time of the cement surface, increase the adaptability of the coating, and prevent cracking of the cement coating. It is suitable for wall, ceiling whitewashing and tile bonding. It is easy to use and has excellent results.
5. Packaging, transportation and storage
Polyvinyl alcohol powder products are packed in paper-plastic composite bags, lined with high-density polyethylene plastic bags, 25 kg / bag. When transporting PVA products, use clean and sturdy means of transport to prevent moisture, rain, and sun. Handle them with care to prevent scratching or breaking the packaging. PVA powder should be stored in a dry, well-ventilated room at room temperature 5-30 ° C. Keep away from heat sources, prevent moisture, and avoid direct sunlight. It is strictly forbidden to store with volatile chemicals to prevent adsorption and deterioration.