HPMC and HEMC have similar roles in construction materials. It can be used as dispersant, water retention agent, thickening agent and binder, etc. It is mainly used in cement mortar and molding of gypsum products. It is used in cement mortar to increase its adhesion, workability, reduce flocculation, improve viscosity and shrinkage, as well as to retain water, reduce water loss on concrete surface, improve strength, prevent cracks and weathering of water-soluble salts, etc. It is widely used in cement-based plaster, gypsum plaster, gypsum products, masonry mortar, sheet caulking, caulking agent, tile adhesive, self-leveling floor material, etc. It can be used as film-forming agent, thickener, emulsifier and stabilizer in emulsion coatings and water-soluble resin coatings, giving the film good abrasion resistance, uniformity and adhesion, and improving surface tension, stability to acids and bases and compatibility with metal pigments. Due to its good viscosity storage stability, it is particularly suitable as a dispersant in emulsified coatings. In a word, although the amount in the system is small, it is very useful and widely used.
The gel temperature of cellulose ether determines its thermal stability in applications. the gel temperature of HPMC usually ranges from 60°C to 75°C, depending on the type, group content, different production processes of different manufacturers, etc. Due to the characteristics of HEMC group, it has a high gel temperature, usually above 80°C. Therefore, its stability under high temperature conditions is higher than that of HPMC. In practice, under the very hot construction environment in summer, the water retention of HEMC in wet mix mortar with the same viscosity and dosing has a greater advantage than HPMC.
The mainstream cellulose ether in China’s construction industry is still mainly HPMC, as it has more types and lower prices, and can be freely chosen at a comprehensive cost. With the development of domestic construction market, especially the increase of mechanized construction and the improvement of construction quality requirements, the consumption of HPMC in the construction field will continue to increase.
Post time: May-20-2022