What is the main role of HPMC in putty powder?

What is the main role of HPMC in putty powder?
In the putty powder, HPMC plays three roles of thickening, water retention and construction.

Thickening: Cellulose can thicken to suspend and keep the solution evenly up and down, and resist sagging.

Water retention: Make the putty powder dry slower, and help the gray calcium react under the action of water.

Construction: cellulose has a lubricating effect, which can make the putty powder have good construction.

HPMC does not participate in any chemical reaction, only plays an auxiliary role. Adding water to the putty powder and putting it on the wall is a chemical reaction. Because new substances are generated, remove the putty powder from the wall and grind it into a powder and use it 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 produced, and HPMC only retains water, and assists in the better reaction of gray calcium, which itself does not participate in any reaction.