Redispersible polymer powder and other inorganic adhesives (such as cement, slaked lime, gypsum, clay, etc.), as well as various aggregates, fillers, other additives (such as hydroxypropyl methylcellulose, polysaccharide (starch ether), Cellulose fibers, etc.) are physically mixed to make dry-mixed mortar.
When the dry powder mortar is added to the water and stirred. Under the action of hydrophilic protective colloid and mechanical shear force. Latex powder particles can be quickly dispersed in water. And it is enough to make the Redispersible polymer powder fully film-forming.
The composition of the rubber powder is different. Which affects the rheology of the mortar and various construction properties: the affinity of the latex powder to water when it is redispersed. Different viscosities after dispersion of latex powder. The effect on the air content of mortar and the distribution of air bubbles. The interaction between rubber powder and other additives, etc. Different latex powders have the effects of increasing fluidity, increasing thixotropy, and increasing viscosity respectively.
It is generally believed that the mechanism of redispersible polymer powder to improve the workability of fresh mortar is: the affinity of latex powder, especially the protective colloid, to water when it is dispersed. And increased the viscosity of the slurry. Improve the cohesion of construction mortar.
After molding of fresh mortar containing latex powder dispersion. With the absorption of water by the base surface, the consumption of hydration reaction, and the volatilization to the air, the water gradually decreases, the resin particles gradually approach, the interface gradually blurs, the resin gradually fuses with each other, and finally polymerizes to form a film.
Mechanism of Redispersible Polymer Powder in Dry Mix Mortar (2)
Mechanism of Redispersible Polymer Powder in Dry Mix Mortar (3)