Application knowledge of hydroxypropyl methylcellulose in putty powder

Application knowledge of hydroxypropyl methylcellulose in putty powder

What is the viscosity of hydroxypropyl methyl cellulose (HPMC) for putty powder production?

Putty powder is generally 100,000 yuan, but the mortar is more demanding, and it takes 150,000 yuan to work. Moreover, the most important role of HPMC is water retention, followed by thickening. In putty powder, as long as the water retention is good and the viscosity is lower (70,000-80,000), it is also possible. Of course, the viscosity is higher, and the relative water retention is better. When the viscosity exceeds 100,000, the effect of viscosity on water retention is Not big anymore.

What is the main function of the application of HPMC in putty powder?

HPMC plays three roles in the putty powder: thickening, water retention and construction. Thickening: Cellulose can be thickened to suspend, keep the solution uniform, and resist sagging. Water retention: make the putty powder dry slowly, and assist the gray calcium to react under the action of water. Construction: Cellulose has a lubricating effect, which can make the putty powder have good workability. HPMC does not participate in any chemical reaction, only plays a supporting role. Putty powder is added with water and applied to the wall. It is a chemical reaction. Because of the formation of new substances, the putty powder on the wall is removed from the wall and ground into powder. Then it will not work, because a new substance (calcium carbonate) ) Again. The main components of gray calcium powder are: a mixture of Ca(OH)2, CaO and a small amount of CaCO3, CaO+H2O=Ca(OH)2-Ca(OH)2+CO2=CaCO3↓+H2O gray calcium in water and air Under the action of CO2, calcium carbonate is formed, while HPMC only retains water and assists the better reaction of gray calcium, and it does not participate in any reaction.