Basic Introduction
For mortar applications, polyvinyl alcohol (PVA) powder with a fineness of 80-120 mesh can be used, while for putty applications, a uniform powder with a fineness of 120 mesh or higher is required. 2488 has a higher viscosity but is relatively expensive; generally, the 1788 model is sufficient.
Detailed Description of Polyvinyl Alcohol Powder
Polyvinyl alcohol (PVA) is produced by the alcoholysis and polymerization of vinyl acetate. It is a white, powdery, stable, non-toxic, water-soluble polymer that dissolves quickly in room temperature water to form a stable colloid. Water is an excellent solvent for PVA. PVA has good film-forming properties; the film formed has excellent adhesion, solvent resistance, abrasion resistance, tensile strength, and oxygen barrier properties. PVA possesses both hydrophilic and hydrophobic functional groups, making it an interfacially active substance. Therefore, PVA can be used as a protective colloid during polymer emulsification and suspension polymerization reactions.
Physicochemical Properties
Physical Properties
A. Solubility: Polyvinyl alcohol powder dissolves in water at room temperature.
B. Thermal Stability: Polyvinyl alcohol softens when heated. Below 40℃, there is no significant change. Above 160℃, prolonged heating will gradually cause color change. Above 220℃, it decomposes, producing water, acetic acid, acetaldehyde, and butenal.
C. Chemical Resistance: PVA is almost unaffected by weak acids, weak bases, or organic solvents, and has high oil resistance.
D. Film-Forming Properties: PVA easily forms films; the resulting films are colorless and transparent, possessing good mechanical strength.
Chemical Properties
PVA can be considered a linear polymer with secondary hydroxyl groups.
Technical Indicators
| Items | 17-88 Type Index Range |
|---|---|
| Viscosity（mpa・s） | 20.0～26.5 / 44～50 |
| Degree of Alcoholysis[%(mol/mol)] | 86.0～90.0 |
| Volatile Matter (%) | ≤7.0 / ＜5.0 |
| Sodium Acetate (%) | ≤2.8 |
| Ash (%) | ≤1.0 / ＜0.5 |
| pH Value | 5～7 |
| Degree of Aggregation | 1650～1850 / 2400～2500 |
| Molecular Weight | 72600～81400 / 118000～124000 |
Main Functions
PVA polymer powder is particularly suitable as an additive in building mortars. When used in conjunction with methylcellulose ether-based water-retaining agents, it can improve the flexibility, water retention, and adhesion of cement mortar. Additionally, it reduces mortar friction, thereby enhancing work efficiency and quality.
Main Uses
Insulating mortar, interior and exterior wall putty powder, tile adhesive, thin-layer adhesive, flexible adhesive, cement additive, PVC latex, wet adhesive, office paste, cosmetics, screen printing photosensitive film, coated paper coating agent, long-fiber yarn sizing agent, zinc plate printing photosensitive film.
Recommended Dosage
0.2-1.2% of the total mixture.
Dissolution Method
Disperse the polyvinyl alcohol powder with other powdered ingredients by dry mixing, then dissolve in water.
Packaging, Transportation, and Storage
25 kg/bag, paper-plastic composite bag packaging. Store in a dry, well-ventilated indoor environment at 5-30℃.
Website: www.china-pva.net
Whatsapp: 0086-15380400285
E-mail: sales2@china-pva.net
