redispersible latex powder RDP for tile adhesivesDecember 7th 2023
1.the Similar Performances Between HPMC and HEMC in Construction Chemicals:
Used as thickener, dispersant, water retention agent and air-entraining agent etc. Mainly used in cement and gypsum based dry mix mortar to increase bond strength, workability, and water retention. Reduce water loss on concrete surface, preventing cracks and increase scrape area. It is widely used in wall plaster and tile adhesive products
In paints, as a protective colloid, HPMC and HEMC can be used in the polymerization of vinyl acetate emulsion to improve the stability of the polymerization system in a wide pH range. Use pigments, fillers and other additives in finished product manufacturing to evenly disperse, stabilize and provide thickening effect.
In general, the gel temperature of HPMC is around 60-75 centigrade depending on its group content and different production technique. Due to the characteristics of HEMC group, it has a higher gel temperature, usually more than 80centigrade . Therefore its stability under high temperature is better that HPMC. In practical construction, in the hot construction environment in summer, the water holding capacity of HEMC with the same viscosity and dosage is better than that of HPMC. Especially in the Southeast Asian countries and India, mortar will sometimes be constructed at high temperature. Cellulose ether with low gel temperature will lose its thickening and water retention at high temperature, thereby accelerating the hardening of mortar, and affects the construction.
On the other hand, because there are more hydrophilic groups in the structure of HEMC, it has better hydrophilicity. The water retention rate of HEMC in mortar is a little higher than HPMC at the same dosage of products with the same viscosity.