• • Blog
• April 1st 2026

Dosage, Viscosity, and Function of Hydroxypropyl Methylcellulose in Putty Powder

Putty powder is a type of building decoration material, primarily used as a base material for repairing or leveling wall surfaces. Hydroxypropyl methylcellulose in putty powder mainly functions to retain water, as well as providing lubrication and rapid adhesion. It prevents dehydration and cracking caused by excessive water loss. Simultaneously, it enhances the adhesion of the putty, thereby improving its application performance and extending its workability.

Hydroxypropyl methylcellulose, also known as HPMC, is an abbreviation for hydroxypropyl methylcellulose. The dosage of HPMC in wall putty powder varies considerably depending on the surrounding climate, relative temperature and humidity, the quality of local lime powder, the putty powder formula, and the user’s required product quality. Generally, it’s between 4 and 5 kg, with slight regional variations. For example, in Beijing, about 5 kg of HPMC is typically needed, while in Guizhou, 5 kg is used in summer and only about 4.5 kg in winter. In Yunnan, the dosage is relatively smaller, usually around 3 to 4 kg.

So, what viscosity is suitable for HPMC added to wall putty powder?

For ordinary putty powder, a viscosity of around 100,000 is usually sufficient. For mortar, a higher viscosity of 15 is required for optimal performance. The primary function of HPMC is water retention, followed by thickening properties. Therefore, in putty powder, as long as the water retention is good, a lower viscosity, such as 70,000 or 80,000, is acceptable. Of course, the higher the viscosity, the better the water retention. However, if the viscosity exceeds 100,000, its impact on water retention becomes negligible. Due to the product’s thermogelation properties, the viscosity gradually decreases with increasing temperature. When the temperature exceeds the product’s gelation temperature, HPMC will precipitate from the water, thus losing its applicable viscosity. Summer temperatures are generally above 30 degrees Celsius, a significant difference from winter temperatures, so the viscosity tends to be lower. Therefore, in summer, it’s advisable to choose HPMC with a higher viscosity, increase the amount of cellulose, or choose a product with a higher HPMC gelation temperature.

The main functions of hydroxypropyl methylcellulose (HPMC) in putty powder are water retention, thickening, and good workability. Its specific functions are as follows:

1. Good water retention: Its water-retention effect slows down the drying time of the putty powder and facilitates the reaction of lime with water.

2. Excellent thickening effect: Hydroxypropyl methylcellulose thickens and suspends the solution, keeping it uniform and preventing sagging.

3. Good workability: The fiber has a lubricating effect, enabling the putty powder to have good workability.

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