The advanges of HPMC & MHEC in dry mix mortar products
November 22nd 2024
Hydroxypropyl methyl cellulose（HPMC）is selected from highly pure cotton cellulose as raw material, treated with lye at 35-40 ° C for half an hour, pressed, The cellulose was pulverized and appropriately aged at 35 ° C so that the average degree of polymerization of the obtained alkali fibers was within a desired range.
The alkali fiber was charged into an etherification kettle, and propylene oxide and methyl chloride were sequentially added thereto, and etherified at 50 to 80 ° C for 5 hours, and the maximum pressure was about 1.8 MPa. Then, an appropriate amount of hydrochloric acid and oxalic acid are added to the hot water at 90 ° C to wash the material, and the volume is expanded, and then dehydrated by a centrifuge, and finally washed repeatedly until neutral.
HPMC has sufficient time in the mortar to promote continuous hydration of the cement and improve the adhesion of the mortar to the substrate.
The water retention capacity of the mortar is largely controlled by the dissolution time. The finer cellulose dissolves faster and the water retention performance is faster.
For mechanized construction, due to time constraints, the choice of cellulose must be finer powder.
The solubility and temperature of hydroxypropyl methyl cellulose in water depend on the degree of etherification, the outside temperature rises, and the water retention decreases.
The higher the degree of etherification, the better the water retention of cellulose ether.
The consistency and slip resistance of the mortar is a very important indicator. For thick layer construction and tile adhesives, proper consistency and slip resistance are required.
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