redispersible latex powder RDP for tile adhesivesDecember 7th 2023
construction hpmc-What raw materials are needed for the production of gypsum-based self-leveling mortar?
Gypsum-based self-leveling mortar is mainly composed of base material, mixed material, admixture and other parts.
The base material mainly refers to α-type hemihydrate gypsum made by autoclaving or hydrothermal synthesis, or β-type hemihydrate gypsum calcined with first-grade dihydrate gypsum with a purity of more than 90%.
Mixed materials: Fly ash, slag powder, etc. are used as mixed materials to add to the self-leveling mortar. Their function is mainly to make the particle size distribution of the material, improve the performance of the hardened material, and improve the compactness and later strength of the material structure.
Early-strength cementing material: gypsum-based self-leveling mortar mainly uses sulphoaluminate cement as early-strength cementing material, which can meet the requirements of early strength of the material and shorten the effective construction time.
The main types of gypsum-based self-leveling mortar admixtures are as follows:
Alkaline activator: Quicklime and 5 cement are generally used to adjust the pH value to provide an alkaline environment for the hydration of the cementitious material, so that the strength of the gypsum composite cementitious material will increase under moderately alkaline conditions.
Coagulation accelerator: The main function of the coagulation accelerator is to stimulate the activity of gypsum, accelerate the supersaturated crystallization speed of dihydrate gypsum, shorten the setting time, and keep the setting and hardening time of self-leveling materials within a reasonable range.
Water-reducing agent: Naphthalene-based water-reducing agents are generally used. The water-reducing mechanism is that the sulfonate groups in the naphthalene-based water-reducing agent molecules and water molecules are associated with hydrogen bonds, forming a stable water film on the surface of the gelled material, so that Sliding is easy to occur between material particles, thereby reducing the amount of mixing water required, making the structure of the material hardened, and improving the compactness and strength of the self-leveling material.
Water retention agent: SLEOCHEM hydroxypropyl methylcellulose (HPMC) is recommended for gypsum-based self-leveling mortar as a water retention agent. Hydroxypropyl methylcellulose has good wettability, water retention and film-forming properties, making self-leveling materials Non-bleeding and fully hydrated.
Redispersible latex powder: SLEOCHEM redispersible latex powder can improve the elastic modulus of self-leveling mortar, improve the crack resistance, bond strength and water resistance of self-leveling mortar.
Defoamer: The main function of the defoamer is to improve the apparent performance of the gypsum-based self-leveling mortar, reduce the air bubbles during the mortar molding, and help to improve the strength of the self-leveling mortar.