Questions about You Should Know about HPMCMarch 23rd 2023
The redispersible polymer powder RDP can be quickly redispersed into an emulsion after contacting with water, and has the same properties as the initial emulsion, that is, a film can be formed after the water evaporates. This film has high flexibility, high weather resistance and resistance to various High adhesion to various substrates. In addition, the latex powder with hydrophobicity can make the mortar have good water resistance.
Redispersible polymer powder is mainly used in:
Inner and outer wall putty powder, tile adhesive, tile grout, dry powder interface agent, external wall thermal insulation mortar, self-leveling mortar, repair mortar, decorative mortar, waterproof mortar and external thermal insulation dry-mixed mortar. In the mortar, it is to improve the weakness of traditional cement mortar such as brittleness and high elastic modulus, and to give cement mortar better flexibility and tensile bond strength to resist and delay the generation of cement mortar cracks. Since the polymer and the mortar form an interpenetrating network structure, a continuous polymer film is formed in the pores, which strengthens the bond between the aggregates and blocks some of the pores in the mortar. Therefore, the modified mortar after hardening has better performance than cement mortar. Great improvement.
The role of redispersible polymer powder in mortar is mainly in the following aspects:
1 Improve the compressive strength and flexural strength of mortar.
2 The addition of latex powder increases the elongation of the mortar, thereby improving the impact toughness of the mortar, and at the same time giving the mortar a good stress dispersion effect.
3 Improve the bonding properties of mortar. The bonding mechanism relies on the adsorption and diffusion of macromolecules on the sticky surface. At the same time, the rubber powder has a certain permeability and fully infiltrates the surface of the base material together with cellulose ether, so that the surface properties of the base layer and the new plaster are close, thereby improving the performance of the base material. Adsorption, its performance is greatly increased.
4 Reduce the elastic modulus of the mortar, improve the deformation ability, and reduce the cracking phenomenon.
5 Improve the abrasion resistance of mortar. The improvement of wear resistance is mainly due to the existence of a certain number of rubber ridges on the surface of the mortar, the rubber powder plays a bonding role, and the mesh structure formed by the rubber powder can pass through the holes and cracks in the cement mortar. Improves the adhesion of the binder to the cement hydration product, thereby increasing the wear resistance.
6 Give the mortar excellent alkali resistance.
7 Improve the cohesion of the putty, excellent resistance, alkali resistance, abrasion resistance, and enhance the flexural strength.
8. Improve the waterproofness and permeability of putty.
9 Improve the water retention of the putty, increase the open time, and improve the workability.
10 Improve the impact resistance of the putty and enhance the durability of the putty.
Redispersible latex powder is made of polymer emulsion by spray drying. After mixing with water in mortar, it is emulsified and dispersed in water to form a stable polymer emulsion. After redispersible latex powder is emulsified and dispersed in water, the water evaporates. The polymer film is formed in the mortar to improve the properties of the mortar. Different redispersible polymer powders have different effects on the dry powder mortar.
Product properties of dispersible polymer powder
──Improve the flexural strength and flexural strength of mortar
The polymer film formed by Zhaojia dispersible polymer powder has good flexibility. A film is formed in the gaps and surfaces of the cement mortar particles to form a flexible connection. Heavy and brittle cement mortar becomes elastic. The mortar added with dispersible polymer powder is several times higher in tensile and flexural resistance than ordinary mortar.
── Improve the adhesive strength and cohesion of mortar
The redispersible polymer powder as an organic binder can form a film with high tensile strength and bond strength on different substrates. It plays an important role in the adhesion between mortar and organic materials (EPS, extruded foam board) and substrates with smooth surfaces. The film-forming polymer powder is distributed throughout the mortar system as a reinforcing material to increase the cohesion of the mortar.
──Improve the impact resistance, durability and wear resistance of mortar
The rubber powder particles fill the cavities of the mortar, the density of the mortar increases, and the wear resistance is improved. Under the action of external force, it will relax without being damaged. The polymer film can exist permanently in the mortar system.
──Improve the weather resistance and freeze-thaw resistance of the mortar and prevent the mortar from cracking
Redispersible latex powder is a thermoplastic resin with good flexibility, which can make the mortar respond to changes in the external hot and cold environment, and effectively prevent the mortar from cracking due to changes in temperature difference.
── Improve the water repellency of the mortar and reduce the water absorption rate
The redispersible latex powder forms a film in the cavity and surface of the mortar, and the polymer film will not be dispersed twice after meeting water, which prevents the intrusion of water and improves the impermeability. Special dispersible polymer powder with hydrophobic effect, better hydrophobic effect.
── Improve the workability of mortar construction &
The polymer rubber powder has a lubricating effect between the particles, so that the mortar components can flow independently. At the same time, the rubber powder has an inductive effect on the air, giving the mortar compressibility and improving the construction and workability of the mortar.