The advanges of HPMC & MHEC in dry mix mortar products
November 22nd 2024
Hydroxypropyl Methyl Cellulose is a non-ionic cellulose ether made from refined cotton and processed through a series of chemical reactions. It is an odorless, non-toxic white powdery substance that dissolves in water and presents clear or slightly cloudy colloidal solution. It has the characteristics of thickening, water retention and easy construction. HPMC aqueous solution is relatively stable in the range of pH3.0-10.0, and when it is less than 3 or more than 10, the viscosity will be greatly reduced.
water retention
The main function of Hydroxypropyl Methyl Cellulose in cement mortar and putty powder is to retain water and thicken, which can effectively improve the adhesion and sag resistance of the material.
Factors such as temperature and wind speed will affect the volatilization rate of water in products such as mortar and putty, so in different seasons, the water retention effect of products with the same dosage of cellulose ether will also have some differences. In the specific construction, the water retention effect of mortar can be adjusted by increasing or decreasing the dosage of HPMC.
The water retention of HPMC at high temperature is an important indicator to distinguish the quality of HPMC. Excellent HPMC can effectively solve the problem of water retention under high temperature conditions. In dry seasons and areas with high temperature and high wind speed, it is necessary to use high-quality HPMC to improve water retention performance of mortar.
Therefore, in high-temperature summer construction, in order to achieve water retention effect, it is necessary to add high-quality HPMC according to the formula, otherwise there will be quality problems such as insufficient hydration caused by too fast drying, strength reduction, cracking, hollowing and falling off. It also increases the difficulty of construction for workers. As the temperature decreases, the dosage of HPMC can be gradually reduced, and the same water retention effect can be achieved.
In the production of building materials, Hydroxypropyl Methyl Cellulose is an indispensable additive. After adding HPMC, the following properties can be improved:
1. Water retention: Improve water retention, protect cement mortar and gypsum mortar against poor hardening and cracking due to speedy drying and insufficient hydration.
2. Workability: The plasticity of the mortar is increased, improve workability, and the work efficiency is improved.
3. Adhesion: Due to the improved plasticity of the mortar, it can better bond the substrate and the adherend.
4. Slipping resistance: Due to its thickening effect, it can prevent the slippage of mortar and adherends during construction.
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