What viscosity is suitable for hydroxypropyl methyl cellulose in putty powder

What viscosity is suitable for hydroxypropyl methyl cellulose in putty powder

Hydroxypropyl methyl cellulose plays three roles in the putty powder: thickening, water retention and construction:
1. Thickening: Cellulose can be thickened to suspend and keep the solution uniform and consistent, and anti-sagging
2. Water retention: make the putty powder dry slowly, and assist the gray calcium to react under the action of water.
3. Construction: Cellulose has a lubricating effect, which can make the putty powder have good workability.
In the role of putty powder, hydroxypropyl methyl cellulose only plays an auxiliary role and does not participate in any chemical reaction. Adding water to the putty powder on the wall 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 to form a new substance, calcium carbonate. Hydroxypropyl methylcellulose just retains water and assists the better reaction of gray calcium, and it does not participate in any reaction.
Hydroxypropyl methyl cellulose HPMC does not participate in any chemical reaction, only plays an auxiliary 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. It does not participate in any reaction itself.
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 hydroxypropyl methylcellulose 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.