Application of hydroxypropyl methylcellulose ether HPMC in mechanical spraying mortar

In ready-mixed spray mortar, the addition amount of hydroxypropyl methylcellulose ether HPMC is very low, but it can improve the performance of wet mortar and is a major additive that affects the construction performance of mortar. Reasonable selection of cellulose ethers of different varieties, different viscosities, different particle sizes, different viscosity degrees and added amounts will have an impact on the improvement of the performance of dry mortar.

At present, many masonry and plastering mortars have poor water retention properties, and the water slurry will separate after leaving it alone for a few minutes. Water retention is an important performance of HPMC. Factors that affect the water retention effect of dry mortar include the amount of HPMC added, the viscosity of HPMC, the fineness of the particles and the temperature of the use environment. Cellulose ether is a synthetic polymer made from natural cellulose through chemical modification.

The important role of water-soluble cellulose ether in mortar mainly lies in three aspects. One is excellent water retention capacity, the other is its influence on mortar consistency and thixotropy, and the third is interaction with cement.

The water retention effect of HPMC depends on the water absorption of the base layer, the composition of the mortar, the thickness of the mortar layer, the water demand of the mortar, and the setting time of the setting material. The water retention of cellulose ether itself comes from the solubility and dehydration of cellulose ether itself.

In ready-mixed spray mortar, hydroxypropyl methylcellulose ether HPMC plays the role of water retention, thickening, delaying cement hydration power, and improving construction performance. Good water retention capacity enables complete hydration of cement, which can improve the wet viscosity of wet mortar, increase the bonding strength of mortar, and adjust the time. Adding hydroxypropyl methylcellulose HPMC to mechanical spray mortar can improve the spraying or pumping performance of the mortar, as well as the structural strength. Therefore, cellulose ether is being widely used as an important additive in ready-mixed mortar.