Hydroxypropyl methylcellulose (HPMC) is a nonionic cellulose ether with excellent performance. It has been widely used in the construction industry, especially in cement mortar systems.
1. Basic characteristics of HPMC
HPMC is a nonionic cellulose ether obtained by a series of chemical modification reactions using natural polymer cellulose as raw material. It has good water retention, thickening, film-forming, dispersibility and anti-slip properties. As a water-soluble polymer, HPMC can be quickly dispersed and dissolved in cold water to form a stable colloidal solution.
2. The main role of HPMC in cement mortar
2.1. Water retention
If cement mortar loses water too quickly after construction, it may lead to incomplete cement hydration, cracking or insufficient bonding. HPMC has excellent water retention performance, which can significantly prolong the water evaporation time of mortar, maintain a moist environment, promote full hydration of cement, and improve mortar strength.
2.2. Thickening effect
HPMC can improve the viscosity of the mortar system, making it more workable and operable. By increasing the consistency, the mortar is not easy to delaminate or bleed, which is convenient for construction tools to operate, thus ensuring the construction quality.
2.3. Improve construction performance
Mortar with HPMC has better lubricity and pumpability, making it easier and smoother during construction, reducing the difficulty of construction, and is particularly suitable for processes such as mechanical spraying and plastering.
2.4. Anti-sagging performance
Mortar is prone to sagging or falling off during vertical or top surface construction. The bonding properties of HPMC can effectively improve the anti-sagging properties of mortar, making it more stable and less likely to slide down during vertical surface construction such as walls.
2.5. Enhanced bonding strength
HPMC can improve the interfacial bonding properties of mortar and substrate, especially suitable for products such as tile adhesives, plaster mortar, and floor mortar, to improve bonding strength and durability.
2.6. Extended open time
In hot and dry environments, mortar tends to lose water quickly and dry out. HPMC can extend the construction time, improve construction flexibility, avoid rework, and improve work efficiency.
3. Specific application of HPMC in different types of mortar
3.1. Masonry mortar
HPMC can improve the water retention rate of mortar, prevent the blocks from absorbing water too quickly and causing hollowing, and improve the strength of masonry.
3.2. Plastering mortar
During the plastering process, HPMC can improve the construction fluidity, enhance the adhesion of mortar, prevent cracking and shelling, and improve the surface quality.
3.3. Tile adhesive
HPMC increases the open time and adjustable time of tile adhesive, ensures firm adhesion, and reduces the risk of hollowing and falling off.
3.4. Self-leveling mortar
In self-leveling products, HPMC controls the rheological properties of mortar, enhances the flatness of construction and the surface density after hardening.
3.5. External insulation mortar
External wall insulation mortar needs to have good bonding and water retention properties. HPMC can improve its comprehensive performance and adapt to various insulation systems.
4. Recommended dosage and usage suggestions
The dosage of HPMC varies according to the product type, required performance and formulation system. The general reference range is as follows:
Ordinary cement mortar: 0.1%~0.3% (by dry powder weight)
Plaster mortar: 0.2%~0.4%
Tile adhesive: 0.3%~0.5%
Self-leveling mortar: 0.1%~0.2%
Usage suggestions:
Choose a suitable viscosity model (such as 40,000~100,000 mPa·s). The higher the viscosity, the stronger the water retention, but the construction performance may be reduced;
It is recommended to use instant HPMC, which can be quickly dissolved in cold water to improve production efficiency;
In the actual formula, it needs to be optimized in coordination with other additives (such as polymer powder, water retaining agent, etc.).
HPMC is an indispensable functional additive in cement mortar, which can effectively improve the construction performance, water retention, adhesion and comprehensive mechanical properties of mortar. Reasonable selection and application of HPMC can not only improve the construction process, but also significantly improve the quality and service life of the final product. With the development of construction industrialization, the requirements for mortar performance are increasing. As a key material, HPMC's market demand and application prospects will continue to expand.
Post time: Jul-15-2025