Method for improving water retention effect of hydroxypropyl methylcellulose

Hydroxypropyl methyl cellulose in dry mortar (mortar), the addition of cellulose ether is very low, but it can significantly improve the performance of wet mortar. Mortar is the main additive that affects construction performance. The redispersible latex powder product is a water-soluble white or almost white flowable powder, a copolymer of ethylene and vinyl acetate, and polyvinyl alcohol as a protective colloid. At present, the cellulose ether used in dry mortar of hydroxypropyl methyl cellulose is mainly hydroxypropyl methyl cellulose ether (HPMC). Hydroxypropyl methyl cellulose mainly plays a role in water retention, thickening and improving construction performance in dry mortar. Hydroxypropyl methylcellulose HPMC does not participate in any chemical reaction and is only used as a supplement. Putty powder can add water to the wall. This is a chemical reaction. Due to the formation of a new substance, the putty powder is spread from the wall on the wall, ground into powder, and then used because it has formed a new substance (carbon (C) calcium (Ca)). The main components of gray calcium powder are: Ca (OH) 2, CaO and a small amount of CaCO 3 in water and air, CaO + H 2 O = Ca (OH) 2-Ca (OH) 2 + CO 2 = CaCO 3 + The mixture of H 2 O gray calcium in CO 2 forms calcium carbonate, while HPMC only retains water to help the reaction of gray calcium, gray calcium itself does not participate in any reaction. High-quality hydroxypropyl methylcellulose can be evenly and effectively dispersed in cement (Material: powdery hydraulic inorganic cementitious material) mortar and gypsum-based products (Product), and seal all solid particles, and form a Layer wetting film. Hypromellose As a food additive, hypromellose can play the following roles: emulsifier, thickener, suspending agent and substitute for animal gelatin. Redispersible latex powders. Because redispersible latex powders have high bonding ability and unique properties, such as water resistance, construction and heat insulation, etc., their application range is extremely wide. The water in the matrix is ​​gradually released over a long period of time and hydrates with the inorganic cementing material. Ensure the material’s bond strength (strength) and compressive strength. Therefore, in high-temperature summer construction, in order to achieve the water retention effect, a sufficient amount of high-quality HPMC products must be added according to the formula. Otherwise, excessive drying will result in insufficient hydration, reduced strength, cracking, hollowing and shedding. The problem (Emerson) also increases the difficulty of the construction staff (difficulty). As the temperature decreases, the amount of HPMC added can be minimized gradually, and the same water retention effect can be achieved.

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