Application of self-leveling HPMC

1. Overview of self-leveling HPMC

Hydroxypropyl Methylcellulose (HPMC) is a non-ionic cellulose ether, which is widely used in building materials, coatings, medicine, food and other industries. In building materials, HPMC is mainly used in dry-mixed mortar systems, such as tile adhesive, putty powder, self-leveling mortar, etc. Among them, self-leveling mortar is a highly fluid floor leveling material, in which HPMC plays a role in thickening, water retention, enhancing adhesion and improving construction performance.

2. The role of HPMC in self-leveling mortar

2.1 Thickening effect

HPMC can significantly increase the viscosity of self-leveling mortar, improve its rheological properties, keep the mortar in a good suspension state during construction, and prevent material stratification or water seepage. At the same time, appropriate viscosity helps to control the fluidity of the mortar and ensure that it has good self-leveling performance during construction.

2.2 Water retention effect

HPMC has excellent water retention performance, which can slow down the volatilization rate of water in mortar and ensure the full hydration of cement. This feature not only improves the early strength development of self-leveling mortar, but also reduces cracks and shrinkage problems caused by too fast water loss.

2.3 Improve adhesion

HPMC can enhance the adhesion between self-leveling mortar and the base layer, making it more firmly attached to the ground. This is crucial to reduce problems such as hollowing and cracking of the mortar layer. At the same time, HPMC can also improve the construction adaptability of mortar, making it easier to spread and level.

2.4 Influence on the open time of mortar

HPMC can effectively extend the construction time of self-leveling mortar by adjusting the evaporation rate of water, so that construction personnel have enough time to adjust and trim, and avoid affecting the construction quality due to too fast solidification of mortar.

3. Selection and influencing factors of HPMC

3.1 Effect of viscosity on self-leveling performance

The viscosity of HPMC is an important parameter that determines its role in the mortar system. Generally speaking, low-viscosity HPMC is more suitable for self-leveling mortar, because high viscosity may reduce fluidity and affect the leveling effect. The common HPMC viscosity range is 400-2000mPa·s, and the specific selection needs to be adjusted according to the mortar formula.

3.2 Effect of substitution degree on performance

The hydroxypropyl and methyl substitution degrees of HPMC directly affect its solubility, water retention and thickening ability. HPMC with a high degree of substitution has better water solubility and water retention, but the thickening effect may be slightly reduced. In self-leveling mortar, it is necessary to select a suitable degree of substitution according to the characteristics of the cement substrate to ensure the best construction performance.

3.3 Solubility and dosage control

The solubility of HPMC determines its uniformity of dispersion in the mortar, which directly affects the final construction effect. High-quality HPMC is easily soluble in cold water and can form a uniform solution in a short time. In addition, the dosage of HPMC is usually low, generally between 0.1%-0.5%. Excessive addition may affect fluidity and mechanical properties after hardening.

The application of HPMC in self-leveling mortar greatly improves the construction performance and final quality of the material. By reasonably selecting the viscosity, substitution degree and dosage of HPMC, the fluidity, water retention and adhesion of the self-leveling mortar can be optimized to ensure construction quality and durability. In practical applications, reasonable adjustments should be made according to different construction environments and material formulas to achieve the best results.