The Working Mechanism of RDP in Mortar
December 9th 2024With the advancement of ceramic tile technology, the body of the ceramic tile is getting denser and larger, and the size is getting larger and larger, which brings great challenges to the paving of the ceramic tile. How to make large-size tiles stick more firmly and ensure long-term paving reliability has become a new focus in the field of modern decoration.
The bonding material (such as high molecular polymer) is wetted on the surface of the tile, and a wetting state is formed between the two, so that the molecular distance between the two is very small, and finally a huge intermolecular force is formed at the bonding interface, which will bond the bonding material. The material is tightly integrated with the tiles. As tile technology advances, denser and denser tiles make it difficult to provide more voids for mechanical interlocks to form anchors. Intermolecular adhesion is becoming more and more important.
SLEOCHEM dispersible polymer powder (RDP) forms a polymer network in the mortar product, connecting the tiles and the mortar together through intermolecular forces, and even if the tiles are denser, they can be firmly attached to the mortar.
Dispersible polymer powders are polymerized from two or more polymers, with different hardnesses based on different ratios of polymer composition. When in a high temperature state, the rubber powder will show varying degrees of softening due to its own hardness. The harder the rubber powder, the lower the softening degree at the same temperature, and the stronger the ability to resist external force at high temperature. Therefore, for the rubber powder used in the tile adhesive, the rubber powder with high hardness is preferred, which can effectively ensure the long-term bonding in the high temperature environment.
When using the thin-layer construction method for tile paving construction, in order to facilitate the construction, workers will choose a large area of sizing before tiling. In this process, the tile adhesive will form a crust on the exposed surface due to the environmental wind speed, the water absorption of the base layer, and the dissolution and movement of its own internal cellulose ether. Since wetting is the key to the tight bonding of materials, when the crust is difficult to be destroyed, it will be difficult for the tile adhesive to wet the tile surface, which will ultimately affect the bonding strength.
The choice of redispersible polymer powder, on the one hand, because of its structure can play a certain role in water retention, delaying the rate of hydration and skinning. On the other hand, the adhesive force per unit area can be improved, and the overall adhesive force can be guaranteed even if the wetted area is reduced. At the same time, the rational selection of cellulose ether is also very important. As the size of the tiles increases, hollowing is more and more likely to occur after laying, and even the accident of the tiles falling off occurs. This problem has a lot to do with the flexibility of the bonding material.
The ceramic tile has high density and low deformation, and the base layer will have a large deformation due to various external and own factors. The tile adhesive as an adhesive layer must be able to absorb the stresses caused by deformation. If the tile adhesive does not contain glue powder, or the content of glue powder is low, it will be difficult to absorb the stress caused by deformation, so that the entire paving system will gradually fall off at the weak point, forming an empty drum.
Redispersible latex powder can provide tile adhesive with the ability to adapt to stress and deformation, that is, improve the flexibility of tile adhesive. In this system, the rigidity of tile adhesive is mainly provided by inorganic materials such as cement and sand, and the flexibility is provided by rubber powder. The polymer is interspersed in the pores of the cement stone to form a polymer network, which becomes the elastic link between the rigid components, making it flexible. When deformation occurs, the polymer network absorbs the stress, ensuring that the rigid components are not cracked and damaged. Therefore, improving the flexibility of the bonding material is very important to reduce hollowing. Appropriate amount of glue powder can improve the state of the network structure formed by the polymer inside the tile glue.
Tags: