PTMATECH Additive Water Repellent in Dry Mixed Mortar V

PTMATECH Additive Water Repellent in Dry Mixed Mortar

The water-proof or water-repellent function of the plastering mortar, tile grout, decorative color mortar and dry-mixed mortar for external wall surface of thin plaster insulation system is indispensable, which requires the addition of powdery water repellent , But it should have the following characteristics: ① make the mortar hydrophobic as a whole and maintain long-term effects; ② have no negative impact on the bonding strength of the surface; ③ some water-repellent agents commonly used in the market, such as calcium stearate, are difficult to It is mixed quickly and evenly with cement mortar. It is not a suitable hydrophobic additive for dry-mixed mortar, especially for mechanically constructed plastering materials.

Recently, a silane-based powder water-repellent agent has been developed, which is a powdery silane-based product obtained by spray-drying the silane with a protective colloid and an anti-caking agent that is easily soluble in water. When the mortar is mixed with water, the protective colloid shell of the water-repellent agent is quickly dissolved in the water, and the encapsulated silane is released and dispersed into the mixing water. In the highly alkaline environment after cement hydration, the hydrophilic organic functional groups in silane are hydrolyzed to form highly reactive silanol groups, and the silanol groups continue to irreversibly react with the hydroxyl groups in the cement hydration products to form chemical bonds , So that the silane connected together by cross-linking is firmly fixed on the surface of the hole wall in the cement mortar. Since the hydrophobic organic functional groups face the outside of the pore wall, the surface of the pores is hydrophobic, thereby bringing the overall hydrophobic effect to the mortar.