Re-Dispersible polymer powders are spray-dried emulsions that, when mixed with water or water in a mortar, form the same stable dispersion as the original emulsion. The polymer forms a polymer network structure in the mortar, which is similar to the polymer emulsion properties and modifies the mortar. The characteristic of dispersible polymer powder is that this powder can only be dispersed once, and it will not be dispersed again when the mortar becomes wet again after hardening. The invention of redispersible polymer powder has significantly improved the performance of dry powder mortar. In the bonding mortar for decorative panels, there are more requirements for the amount of redispersible polymer latex powder. Its addition improves the flexural strength, crack resistance, adhesion strength, elasticity and toughness of the mortar, which can be avoided. Mortar shrinkage and cracking can also reduce the thickness of the bonding layer. The redispersible polymer latex powder can improve the above properties of mortar because it can form a polymer film on the surface of the mortar particles. There are pores on the surface of the film, and the surface of the pores is filled with mortar, which reduces the stress concentration and reduces the external force. Under the action will produce relaxation without damage. In addition, the mortar forms a rigid skeleton after cement hydration, and the film formed by the polymer can improve the elasticity and toughness of the rigid skeleton, and the redispersible polymer latex powder can also improve the tensile strength of the mortar.
The lubricating effect between the redispersible polymer powder particles enables the components of the mortar to flow independently. At the same time, it has an inductive effect on the air, giving the mortar compressibility, so it can improve the construction and workability of the mortar. The compressive strength of polymer mortar decreases with the increase of the content of rubber powder, the flexural strength increases with the increase of the content of rubber powder, and the compression-folding ratio shows a downward trend.
The test shows that the redispersible latex powder can modify the mortar and can obviously improve the flexibility of the mortar. Redispersible latex powder polymer resin can improve the flexural strength of mortar, especially the early flexural strength of mortar. The polymer aggregates in the capillary pores of the hardened mortar and acts as a reinforcement. The addition of dispersible polymer powders can significantly improve the bond strength of mortars, especially when combining different materials, such as for adhering ceramic tiles. With the increase in the amount of rubber powder, the flexural strength and adhesive strength are also increased.
Incorporating the redispersible polymer powder can significantly improve the inherent flexibility and deformation resistance of the material, so it contributes to the flexural strength and bonding strength of the material. After adding the polymer to the cement matrix, the tensile strength will be greatly improved. During the hardening process of cement, there will be many cavities inside. These cavities are filled with water at the beginning. When the cement is cured and dried, these parts become cavities. It is generally considered that these cavities are the weak points of the cement matrix. part. When the redispersible polymer powder is contained in the cement system, these powders will immediately disperse and concentrate in the water-rich area, that is, in these cavities. After the water dries up. The polymer forms a film around the cavities, thereby strengthening these weak points. That is, adding a small amount of redispersible latex powder can significantly improve the bond strength.