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Nov. 21, 2025
As modern construction materials continue to evolve, Hydroxypropyl Methylcellulose (HPMC) has become an essential functional additive in dry-mix mortars.
Known for its excellent water retention, thickening ability, film formation, and workability improvement, HPMC plays a critical role in tile adhesives, wall putties,
gypsum-based products, EIFS mortars, and self-leveling compounds.
However, to fully achieve its intended performance, HPMC must be used correctly. Recent industry analyses highlight several important precautions that manufacturers
and contractors should follow to ensure consistent product quality and optimal construction results.
1. Avoid Direct Addition to Hot Water — Ensure Proper Dispersion
One of the most common issues in mortar production is improper dispersion of HPMC. If added directly to hot water or mixed unevenly,
HPMC may form lumps, resulting in poor viscosity development and inconsistent performance.
To ensure proper dispersion:
Dry blend first: Mix HPMC with all dry powders before adding water. Avoid adding HPMC to water above 60°C, which may cause gelation and clumping. In liquid formulations, HPMC
should be sprinkled slowly into vigorously stirred water to avoid agglomeration.Correct dispersion is the foundation for HPMC to deliver its full water-retention and thickening effects.
2. Control Dosage to Prevent Excessive Thickening or Poor Workability
Although HPMC greatly improves mortar performance, excessive dosage can cause:
Mortar becoming too thick or sticky. Difficulty in troweling and finishing. Excessively long open time. Increased material cost
Typical recommended dosages include: Wall Putty: 0.2%–0.4%. Tile Adhesive: 0.2%–0.45%. Gypsum-Based Plasters: 0.1%–0.3%.
Choosing the right viscosity and substitution level is crucial to achieving balanced performance.
3. Check Compatibility with Cement, Gypsum, and Other Additives
HPMC performance can vary depending on the components in the mortar system. Factors influencing compatibility include:
Cement mineral composition. Gypsum retarders or accelerators. Redispersible polymer powder (RDP). Plasticizers, defoamers, air-entraining agents.
Incompatibility may cause: Abnormal viscosity increase. Bleeding or segregation. Reduced early bonding strength. Unstable mortar behavior.
A full compatibility test is essential before launching new formulations.
4. Ensure Proper Storage — Moisture Protection is Critical
HPMC is hygroscopic and can easily absorb moisture, leading to: Caking. Reduced viscosity. Poor dispersibility.
To maintain product quality during storage: Store HPMC in a cool, dry, and well-ventilated place. Keep packages sealed tightly. Avoid direct sunlight or high-temperature environments.
Keep away from strong acids or alkali chemicals. Proper storage ensures long-term stability and consistent performance.
5. Adjust Formulation Based on Climate and Job-Site Conditions
Environmental factors have a significant impact on HPMC behavior:
Hot or Dry Weather. Mortar dries too quickly. Cracking risk increases. Higher water-retention grade HPMC is recommended.
Cold or Humid Conditions. Excessively long open time. Slower strength development. Medium-viscosity or lower water-retention grades may be more suitable.
Highly Absorbent Substrates (AAC blocks, lightweight bricks). Improve water retention. Increase bonding strength. Use higher viscosity or modified HPMC.
A flexible formulation strategy ensures consistent results across varying conditions.
6. Environmental & Safety Considerations — Focus on Low-VOC & Dust Control
As sustainability becomes a key priority in global construction, manufacturers must consider: Compliance with low-VOC requirements. Dust reduction during mixing.
Use of HPMC grades with environmentally friendly production processes. Worker safety during handling and batching.
Eco-friendly cellulose ethers not only protect the environment but also enhance company brand value.
Name: Cecilia.Wang
E-Mail:cecilia.wang@jtdf-rdp.com
Mobile:+86 190 3451 3486（Whatsapp）
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