Hydroxypropyl methylcellulose mainly plays the role of water retention and thickening in cement mortar and gypsum based slurry, and can effectively improve the adhesion and sag resistance of slurry.
Air temperature, temperature and wind pressure speed will affect the volatilization rate of water in cement mortar and gypsum based products. Therefore, there are some differences in the water retention effect of products with the same amount of hydroxypropyl methylcellulose in different seasons. In the specific construction, the water retention effect of the slurry can be adjusted by increasing or decreasing the amount of HPMC. The water retention of methyl cellulose ether at high temperature is an important index to distinguish the quality of methyl cellulose ether.
Excellent hydroxypropyl methylcellulose series products can effectively solve the problem of water retention at high temperature. In high temperature season, especially in hot and dry areas and thin-layer construction on sunny surface, high-quality HPMC is required to improve the water retention of slurry;
High quality hydroxypropyl methylcellulose can be evenly and effectively dispersed in cement mortar and gypsum based products, wrap all solid particles, and form a layer of wetting film. The water in the base is gradually released for a long time, and hydration reaction occurs with inorganic cementitious materials, so as to ensure the bonding strength and compressive strength of the materials.
During construction, in order to achieve the water retention effect, high-quality HPMC products shall be added in sufficient quantity according to the formula, otherwise there will be quality problems such as insufficient hydration, strength reduction, cracking, hollowing and falling off caused by too fast drying, which will also increase the construction difficulty of workers. With the decrease of temperature, the addition of water HPMC can be gradually reduced, and the same water retention effect can be achieved.