Hydroxypropyl Methylcellulose Supplier

Frequently Asked Questions

• Q: What viscosity grade of HPMC should I use for tile adhesive?
• A: For standard cement-based tile adhesives (EN 12004 C1/C2), viscosity grades between 40,000 and 100,000 mPa·s are most commonly used. Higher-viscosity grades (100,000–200,000 mPa·s) improve slip resistance for vertical tile work and large-format tiles. Lower grades can be used in machine-applied systems where pump-ability is more important than static sag resistance. Our technical team can recommend the optimal grade based on your specific formulation and application method.

• Q: Why does HPMC gel when heated and dissolve when cooled?
• A: This reversible thermal gelation is caused by the hydrophobic methoxy groups. At low temperatures, water molecules form hydration shells around these groups, keeping the polymer chains dispersed. As temperature rises above the gelation point, the hydration shells collapse, the hydrophobic groups associate, and a gel network forms. On cooling, the hydration shells reform and the gel reverts to a viscous solution. This is a fully reversible, physical process with no chemical change.

• Q: How do I choose between standard and surface-treated HPMC grades?
• A: Standard grades dissolve readily in cold water and are suitable for wet mixing applications (mixing on site with water). Surface-treated (delayed-dissolve) grades are designed for dry-mix mortar factories: the surface treatment prevents premature hydration during blending and bagging, but the coating dissolves quickly once the end user adds water on site. If you produce bagged dry-mix mortars, surface-treated grades are strongly recommended to prevent caking and flow problems during production.

• Q: Can HPMC be combined with RDP (redispersible polymer powder) in mortar formulations?
• A: Yes — in fact, HPMC and RDP are highly complementary in modern dry mix mortar formulations. HPMC provides water retention, workability, and open time, while RDP improves flexibility, adhesion, and impact resistance of the hardened mortar. The combination is standard in premium tile adhesives, renders, and EIFS adhesive coats. Yisheng supplies both HPMC and RDP, enabling customers to source both ingredients from a single supplier with consistent quality.

• Q: Is pharmaceutical-grade HPMC available and what documentation is provided?
• A: Yes. Pharmaceutical-grade HPMC is available tested against USP, EP, and JP monographs. Documentation includes COA with all pharmacopoeial parameters, DMF (Drug Master File) reference number for US FDA submissions, CEP (Certificate of Suitability) for European submissions, and TSE/BSE freedom declaration. GMP compliance documentation and audit support are available for registered pharmaceutical customers.

• Q: What is the typical lead time for HPMC orders?
• A: For standard grades held in stock, lead time is typically 7–14 business days from order confirmation to ex-works dispatch. Custom grades or large-volume orders (full container loads) may require 2–4 weeks. Sea freight transit time to major European ports is approximately 25–30 days; to the US East Coast, 28–35 days; to Southeast Asia, 5–12 days. We can arrange DHL or air freight for urgent sample shipments.