The dosage, viscosity and function of hydroxypropyl methylcellulose in putty powder
Putty powder belongs to a class of building decoration materials. Its main function is to repair or level the wall as a basic material, and hydroxypropyl methylcellulose can mainly play a role in water retention in putty powder, and also It has the functions of lubricating and fast bonding, which can avoid dehydration and cracks caused by excessive water loss. sex.
So what is the appropriate viscosity for the hydroxypropyl methylcellulose added to the putty powder? For ordinary putty powder, the viscosity is usually about 100,000. For mortar, the requirements need to be higher, and it needs a viscosity of 15 degrees to be easy to use. And the main function of hydroxypropyl methylcellulose is water retention, followed by thickening performance. Therefore, in the putty powder, as long as the water retention performance is good, even if the viscosity is lower, such as the viscosity of 70,000 or 80,000, it is still possible. Of course, if the viscosity is larger, the relative water retention performance will be better. If the viscosity exceeds 100,000, the influence of the viscosity on the water retention performance will not be large. Because of the thermal gel properties of the product, it also determines that the viscosity of the product will gradually decrease as the temperature increases. When the temperature exceeds the gel temperature of the product, HPMC will be precipitated from the water, thus losing its application. viscosity. The temperature in summer is relatively high, generally above 30 degrees, and the temperature difference in winter is large, so it feels that the viscosity is low, so try to choose HPMC with a higher viscosity in summer, or increase the amount of cellulose, and the other is Choose a product with a high HPMC gel temperature.
The main functions of hydroxypropyl methylcellulose HPMC in putty powder are water retention, thickening, and good construction performance. Its specific functions are as follows:
1. Good water retention effect, its water retention effect can slow down the drying time of putty powder, and assist ash calcium to react under the action of water.
2. Better thickening effect, hydroxypropyl methyl cellulose can thicken and suspend, keep the solution uniform and consistent, and resist sagging at the same time.
3. Good construction performance, fiber has lubricating effect, which can make putty powder have good construction performance.