Hydroxypropyl methyl cellulose in dry mortar, cellulose ether addition is very low, but can significantly improve the performance of wet mortar, mortar construction performance is one of the main additives. Now, hydroxypropyl methyl cellulose used in dry mortar cellulose ether is mainly hydroxypropyl methyl cellulose ether (HPMC). Hydroxypropyl methyl cellulose in dry mortar HPMC mainly plays a role in water retention, thickening, improving the performance of construction. Hydroxypropyl methylcellulose HPMC does not participate in any chemical reaction, only play an auxiliary role. Putty powder added water, on the wall, is a chemical reaction, because there is the generation of new material, putty powder on the wall down from the wall, ground into powder, and then used, it is no longer, because has formed a new material (calcium carbonate). The main components of grey calcium powder are: Ca(OH)2, CaO and a small amount of CaCO3 mixture, CaO+H2O=Ca(OH)2 – Ca(OH)2+CO2=CaCO3↓+H2O calcium ash in water and air under the action of CO2, the formation of calcium carbonate, and HPMC only water retention, auxiliary calcium ash better reaction, its own did not participate in any reaction.
High quality of hydroxypropyl methyl cellulose can uniformly and effectively disperse in cement mortar and plaster products, and package all solid particles, and form a layer of wetting film, the moisture in the base for a long time gradually released, and inorganic cementitious material hydration reaction, so as to ensure the bond strength and compressive strength of materials. Therefore, in the high temperature summer construction, in order to achieve water retention effect, need to add high quality HPMC products in accordance with the formula, otherwise, there will be dry too fast and caused by insufficient hydration, strength reduction, cracking, empty drum and fall off and other quality problems, but also increase the difficulty of workers construction. As the temperature decreases, the amount of water added by HPMC can be gradually reduced, and the same water retention effect can be achieved.