Dispersible polymer powder and other inorganic binders (such as cement, slaked lime, gypsum, etc.) and various aggregates, fillers and other additives (such as methyl hydroxypropyl cellulose ether, starch ether, lignocellulose, hydrophobic Agents, etc.) are physically mixed to make dry-mixed mortar. When the dry-mixed mortar is mixed with water, under the action of hydrophilic protective colloid and mechanical shearing, the latex powder particles will disperse into the water.

Due to the different characteristics and modification of each subdivided latex powder, this effect is also different, some have the effect of promoting flow, while some have the effect of increasing thixotropy. The mechanism of its influence comes from many aspects, including the influence of the latex powder on the affinity of water during dispersion, the influence of the different viscosity of the latex powder after dispersion, the influence of the protective colloid, and the influence of the cement and water belt. The influence of the following factors includes the influence on the increase of the air content of the mortar and the distribution of air bubbles, as well as the influence of its own additives and the interaction with other additives. Therefore, customized and subdivided selection of redispersible polymer powder is an important means to affect product quality. Among them, the more common point of view is that the redispersible polymer powder usually increases the air content of the mortar, thereby lubricating the construction of the mortar, and the affinity and viscosity of the polymer powder, especially when the protective colloid is dispersed, to water. The increase of α contributes to the improvement of the cohesion of the construction mortar, thereby improving the workability of the mortar. Subsequently, the wet mortar containing the latex powder dispersion is applied to the work surface. With the reduction of moisture on three levels – the absorption of the base layer, the consumption of the cement hydration reaction, and the volatilization of the surface moisture into the air, the resin particles gradually approach the , the interface gradually merges with each other, and finally becomes a continuous polymer film. This process mainly occurs in the pores of the mortar and the surface of the solid.

It should be emphasized that, in order to make this process irreversible, that is, when the polymer film is not redispersed when it encounters water again, the protective colloid of the redispersible polymer powder must be separated from the polymer film system. This is not a problem in an alkaline cement mortar system, because it will be saponified by the alkali generated by the hydration of cement, and at the same time, the adsorption of quartz materials will gradually separate it from the system without hydrophilic protection. Colloid, a film that is insoluble in water and formed by one-time dispersion of redispersible latex powder, can function not only under dry conditions, but also under conditions of long-term immersion in water. In non-alkaline systems, such as gypsum systems or systems with only fillers, protective colloids are still partially present in the final polymer film for some reason, affecting the water resistance of the film, but since these systems are not used for In the case of long-term immersion in water, and the polymer still has its unique mechanical properties, it does not affect the application of dispersible polymer powder in these systems.

With the formation of the final polymer film, a framework system composed of inorganic and organic binders is formed in the cured mortar, that is, the hydraulic material forms the brittle and hard skeleton, and the redispersible polymer powder forms a film in the gap and the solid surface. Flexible connection. This connection can be imagined as many small springs connected to a rigid skeleton. Since the tensile strength of the polymer resin film formed by the latex powder is usually an order of magnitude higher than that of the hydraulic material, the strength of the mortar itself is enhanced, that is, the cohesive force. be improved. Since the flexibility and deformability of the polymer are much higher than those of rigid structures such as cement, the deformability of the mortar is improved, and the effect of dispersing stress is greatly improved, thereby improving the crack resistance of the mortar.