HPMC in putty powder
HPMC plays three roles in water retention, thickening and construction in putty powder.
1. Thickening: cellulose can thicken and keep the solution uniform up and down, and resist hanging.
2. Water retention: It makes the putty powder dry slower and assists the reaction of calcium ash under the action of water.
3、Construction: Cellulose has lubricating effect, which can make the putty powder have good construction.
HPMC does not have any chemical reaction, but only plays an auxiliary role. Putty powder with water on the wall is a chemical reaction, because there is a new substance generated.
The viscosity of HPMC is inversely proportional to the temperature, the viscosity increases as the temperature decreases. We usually refer to the viscosity of a product as a 2% aqueous solution tested at a temperature of 20 degrees Celsius. In practical application, the temperature difference between summer and winter areas, should pay attention to the recommended use of relatively low viscosity products in the winter time, which is more conducive to construction. Otherwise, the viscosity of cellulose will increase when the temperature is low, and the feel will be heavy when scraping. 75000-100000 medium viscosity is mainly used for putty, the reason: good water retention; high viscosity: 150000-200000 mainly used for polyphenylene particles insulation mortar rubber powder material and glass beads insulation mortar, the reason: high viscosity, mortar is not easy to fall, will not flow hanging, improve the construction.