How much is HPMC hydroxypropyl methylcellulose in putty powder?
The amount of HPMC used in practical applications is affected by the climate, temperature, local ash calcium quality, the formula of putty powder and the quality required by customers, but there are differences in different regions, generally speaking, it is between 4-5 kg.
Hydroxypropyl methylcellulose is used in different amounts due to the weather
Factors such as air temperature, temperature and wind pressure will affect the volatilization rate of moisture in cement mortar and gypsum-based products. Therefore, in different seasons, the water retention effect of the same amount of HPMC is different.
In the specific construction, the water retention effect of the slurry can be adjusted by increasing or decreasing the amount of HPMC added. The water retention of hydroxypropyl methyl cellulose ether under high-temperature conditions is an important indicator to distinguish the quality of hydroxypropyl methyl cellulose ether. Excellent HPMC series products can effectively solve the problem of water retention at high temperatures.
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 has 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 the free water becomes bound water, thereby effectively controlling the evaporation of water caused by high temperature weather, and achieving high water retention.
High-quality cellulose HPMC can be uniformly and effectively dispersed in cement mortar and gypsum-based products, and wrap all solid particles, and form a wetting film. The water in the base is gradually released over a long period of time. The condensed material undergoes hydration reaction to ensure the bonding strength and compressive strength of the material. Therefore, in high-temperature summer construction, in order to achieve the effect of water retention, high-quality HPMC products must be added in sufficient quantities according to the formula, otherwise, insufficient hydration, reduced strength, cracking, hollowing and falling off caused by excessive drying will occur. It also increases the difficulty of construction for workers. As the temperature decreases, the amount of HPMC added can be gradually reduced, and the same water retention effect can be achieved.
What are the dissolution methods of HPMC hydroxypropyl methylcellulose?
1) All models can be added to the material by dry mixing;
2) When it needs to be directly added to the aqueous solution at room temperature, it is better to use the cold water dispersion type, and the thickening is generally 10 to 90 minutes after adding (stirring and stirring) 3) For ordinary models, first stir and disperse with hot water, then add cold water to stir and cool to dissolve;
4) If agglomeration and wrapping occurs during dissolution, it is due to insufficient stirring or the normal type is directly added to cold water. At this time, stir quickly.
5) If bubbles are generated during dissolution, they can be left to stand for 2-12 hours (the specific time is determined by the consistency of the solution) or removed by vacuum, pressure, etc., or an appropriate amount of defoamer can be added.
