Function of hydroxypropyl methylcellulose (HPMC) in wall putty

1. What are the main technical indicators of hydroxypropyl methylcellulose (HPMC)?

Hydroxypropyl content and viscosity, most users are concerned about these two indicators. Those with high hydroxypropyl content generally have better water retention. The one with high viscosity has better water retention, relatively (not absolutely), and the one with high viscosity is better used in cement mortar.

2. What is the main function of the application of HPMC in putty powder?
In putty powder, HPMC has three functions of thickening, water retention and construction.
Thickening: Cellulose can be thickened to suspend and keep the solution uniform up and down, and resist sagging. Water retention: make the putty powder dry slowly, and assist the ash calcium to react under the action of water. Construction: Cellulose has a lubricating effect, which can make the putty powder have good construction.

3. Is there any relationship between the drop of putty powder and HPMC?
The powder loss of putty powder is mainly related to the quality of ash calcium, and has little to do with HPMC. The calcium content of gray calcium and the ratio of CaO and Ca(OH)2 in gray calcium are not suitable, which will cause powder loss. If it has something to do with HPMC, then the poor water retention of HPMC will also cause powder loss.

4. What is the amount of hydroxypropyl methylcellulose (HPMC) in wall putty powder?
The amount of HPMC used in practical applications varies depending on the climate, temperature, quality of local ash calcium, formula of putty powder and “quality required by customers”. Generally speaking, between 4 kg and 5 kg. For example: most of the putty powder in Beijing is 5 kg; most of the putty powder in Guizhou is 5 kg in summer and 4.5 kg in winter; the amount of putty in Yunnan is relatively small, generally 3 kg to 4 kg, etc.

5. What is the appropriate viscosity of hydroxypropyl methylcellulose (HPMC)?
Generally, 100,000 yuan of putty powder is enough, and the requirements for mortar are higher, and 150,000 yuan is required for easy use. Moreover, the most important function of HPMC is water retention, followed by thickening. In putty powder, as long as the water retention is good and the viscosity is low (70,000-80,000), it is also possible. Of course, the higher the viscosity, the better the relative water retention. When the viscosity exceeds 100,000, the viscosity has no effect on water retention. big.

6. How to choose the appropriate hydroxypropyl methylcellulose (HPMC) for different purposes?
Application of putty powder: the requirements are low, the viscosity is 100,000, it is enough, the important thing is to keep water well. Mortar application: high requirements, high viscosity, 150,000 is better, glue application: instant products are required, high viscosity.

7. The application of HPMC in putty powder, what is the reason for the bubbles in the putty powder?
In putty powder, HPMC plays three roles of thickening, water retention and construction. Do not participate in any reactions. Causes of bubbles:
(1) Put too much water.
(2) The bottom layer is not dry, and another layer is scraped on top, and it is easy to foam.