HPMC (hydroxypropyl methylcellulose) is a common functional additive widely used in putty powder.
Wall putty (Skim Coat) is a decorative material that makes the wall surface smooth and can be used for interior and exterior wall decoration. Cellulose HPMC plays a vital role in wall putty (putty layer) to improve the key properties such as water retention, open time, crack resistance, workability, etc. Dingao HPMC for wall putty is characterized by high water retention, dispersion, good fineness, good workability and easy dissolution. It is suitable for dry mortar construction, internal and external wall putty powder (paste), putty powder)
The following are several main applications of HPMC for putty powder:
1. Increase viscosity: HPMC can increase the viscosity of putty powder, making it easier to apply and apply. By adjusting the amount of HPMC added, the fluidity of the putty powder can be controlled to keep it in the desired position on vertical or inclined surfaces.
2. Improve adhesion: HPMC has good adhesion and can enhance the bonding force between the putty powder and the base surface. It can form a uniform adhesive film so that the putty powder can firmly adhere to the wall or other base surface.
3. Adjust drying time: HPMC can meet different construction requirements by adjusting the drying speed of putty powder. It can delay the drying time of putty powder, giving construction workers enough time for trimming and polishing.
4. Improve weather resistance: HPMC can improve the weather resistance of putty powder and make it stable under different environmental conditions. It can reduce the possibility of putty powder getting wet, cracking and falling off, and improve its service life and appearance quality.
5. Control contractility: HPMC can control the shrinkage of putty powder and reduce volume changes during drying. This helps reduce the risk of the putty powder cracking or deforming after it dries.
Hydroxypropyl Methyl Cellulose (HPMC) does not participate in any chemical reaction except as an auxiliary molecule. The process of puttingty powder with water is put on the wall as a chemical reaction. In this process, a new substance (calcium carbonate) is formed.
The main components of gray calcium powder are: a mixture of Ca(OH)2, CaO, and a small amount of CaCO3. the reaction equation is as follows:
CaO + H2O = Ca(OH)2 - Ca(OH)2 + CO2 = CaCO3↓ + H2O.
In this process, gray calcium will be converted to calcium carbonate under the action of CO2 and water, while HPMC just plays the role of water retainer, assisting the reaction under better conditions, and does not participate in the reaction.
According to different specifications, the formula of putty can be different. Therefore, the viscosity and dosage of hydroxypropyl methyl cellulose (HPMC) are also different. In practice, it is recommended to use HPMC products with lower viscosity in winter, which is more favorable for construction. Otherwise, when the temperature is lower, the viscosity will increase and cause trouble for further application.
It should be noted that the specific HPMC dosage and application method may vary due to different putty powder formulas and construction requirements. Before using HPMC or any other additives, it is recommended to refer to the product instructions or consult relevant professionals to ensure the correct usage method and ratio.
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