The important role of hydroxypropyl methylcellulose in ready-mixed mortar
In ready-mixed mortar, the amount of cellulose ether added 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 addition amounts will have a positive impact on the improvement of dry powder mortar performance. At present, many masonry and plastering mortars have poor water retention properties, and the water slurry will separate after a few minutes of standing.
Water retention is an important property of methyl cellulose ether, and it is also a property that many domestic dry powder mortar manufacturers pay attention to, especially those in areas with high temperatures in the south. The factors that affect the water retention effect of dry mortar include the amount of MC added, the viscosity of MC, the fineness of the particles and the temperature of the use environment.
Cellulose ether is a synthetic high molecular polymer obtained by chemical modification of cellulose as raw material. Cellulose ether is a derivative of cellulose. The production of cellulose ether is different from synthetic polymers. Its basic material is cellulose, a polymer compound. Due to the particularity of cellulose structure, cellulose itself has no ability to react with etherifying agents. However, after the treatment of the swelling agent, the strong hydrogen bonds between the molecular chains and within the chain are destroyed, and the huo of the hydroxyl group is released into a reactive alkali cellulose, and the -OH group is converted into -OR through the etherification agent base to obtain cellulose ethers.
Water retention of cellulose ether: In the production of building materials, especially dry powder mortar, cellulose ether plays an irreplaceable role, especially in the production of special mortar (modified mortar), it is an indispensable part. . The important role of water-soluble cellulose ether in mortar is mainly manifested in three aspects, one is the excellent water retention capacity, the other is the effect on the consistency and thixotropy of the mortar, and the third is the interaction with the cement. The water retention effect of cellulose ether depends on the water absorption of the base layer, the composition of the mortar, the thickness of the mortar, the water demand of the mortar and the setting time of the coagulating material. The water retention of cellulose ether itself comes from its solubility and dehydration.