redispersible latex powder RDP for tile adhesivesDecember 7th 2023
HPMC mainly plays the role of water retention and thickening in cement mortar and gypsum-based slurry, which can effectively improve the cohesion and sag resistance of the slurry.
Factors such as air temperature, temperature and wind pressure will affect the evaporation rate of water in cement mortar and gypsum-based products. Therefore, in different seasons, adding the same amount of HPMC, the water retention effect of the products have some differences. The water retention of methyl cellulose ether at high temperature is an important indicator to distinguish the quality of methyl cellulose ether. Excellent HPMC can effectively solve the problem of water retention under high temperature. In high temperature seasons, especially in hot and dry areas and thin-layer construction on the sunny side, high-quality HPMC is required to improve the water retention of the slurry. High-quality HPMC, with very good uniformity, its methoxy and hydroxypropoxy groups are evenly distributed along the cellulose molecular chain, which can improve the ability of the oxygen atoms on the hydroxyl and ether bonds to associate with water to form hydrogen bonds, so that free water becomes bound water, so as to effectively control the evaporation of water caused by high temperature weather and achieve high water retention.
High-quality cellulose HPMC can be uniformly and effectively dispersed in cement mortar and gypsum-based products, and encapsulates all solid particles, and forms a wetting film, and the moisture in the base is gradually released over a long period of time. The hydration reaction of the coagulating material occurs, thereby ensuring the bonding strength and compressive strength of the material. Therefore, in high temperature summer construction, in order to achieve the effect of water retention, it is necessary to add high-quality HPMC products according to the formula, otherwise, there will be insufficient hydration, strength reduction, cracking, hollowing and falling off caused by too fast drying. It also increases the difficulty of construction for workers. As the temperature decreases, the addition amount of HPMC can be gradually reduced, and the same water retention effect can be achieved.