HPMC is one of cellulose ether, is abbreviation for hydroxypropyl methyl cellulose. It is white powder appearance, odorless and tasteless, soluble in water and most polar organic solvents. Its water solution has a surface activity, high transparency, stable performance. HPMC has a thermal gel properties, after heating, the product solution formed the gel precipitation, dissolving after cooling. Different specifications products have different gel temperature. Solubility changes with viscosity's difference. The lower viscosity, the higher solubility, different specifications HPMC have difference in properties, dissolving HPMC in water won't be affected by PH value.
HPMC mainly used in building materials, hydroxypropyl methyl cellulose can act as dispersing agents, thickeners and binders, and hydroxypropyl methyl cellulose is mainly used in the molding of the cement mortar and plaster products. It is used in the cement mortar to increase its adhesion, reduce flocculation, improve the viscosity, shrinkage, and water retention, reduce the water loss of concrete surface, enhance the strength, prevent the occurrence of cracks and weathering effects of water-soluble salts.
Type of SX HPMC:
Quick dissolving type: it is specially developed to prevent lumping in cold water for emulsion paint, detergent, glue, soap etc., put the HPMC powder into cold water directly and continuously stir till the viscosity fully developed.
Heat dissolving type: when it put into cold water directly, it is easy to form lumps due to the solubility with cold water. To prevent lumping, it needs put the powder into hot water (﹥85℃), then stir and cool down the solution to 20°C. When Heat dissolving type is used in dry mix mortars application, lumping is not a problem due to the dosage is very low and each particle of HPMC is distributed in the final product completely.
Main advantage of SX HPMC:
Water retention: Chemical reaction (hydration) between water and cement/gypsum will cause crystals to grow and wrap around the mix components. During the early stages of cure , there must be enough water to maintain the hydration process otherwise the cement/gypsum will harden promptly. SX HPMC can reduce the water loss, allow the crystal structure to keep growing and building strength during the critical early curing stage.
Lubrication effect: When the dry mix mortars are mixed with water, air are entrained and which gives easy handling, better workability.
Thickening effect: SX HPMC is used as a thickening agent in building applications as it can prevent segregation and improve the cohesion of the components.