HPMC (Hydroxypropyl Methylcellulose) | CAS 9004-65-3 | UAE & GCC

Hydroxypropyl Methylcellulose (HPMC, CAS 9004-65-3) is a non-ionic cellulose ether that is the most important additive in construction dry-mix mortars. It provides water retention, workability, open time extension, and anti-sagging properties in tile adhesives, wall putty, cement renders, and repair mortars. HPMC is available in a wide range of viscosity grades — from 15,000 cps to 200,000 cps (2% solution, 20°C) — and the correct grade selection is critical for achieving target performance in each formulation. Raykem supplies HPMC across the UAE, Saudi Arabia, and the GCC for construction chemical manufacturers.

HPMC Viscosity Grades & Selection

HPMC is available in a wide range of viscosity grades, measured as a 2% aqueous solution at 20°C. The viscosity grade is the single most important selection parameter — it determines water retention, open time, and sag resistance in your formulation.

Substitution Types — K, E and F Grades

HPMC grades are also differentiated by their methoxy and hydroxypropoxy substitution levels, which affect gelation temperature and solubility behaviour:

Interaction with RDP and Calcium Formate

In a complete dry-mix tile adhesive system, HPMC works alongside RDP (redispersible polymer powder) and calcium formate:

• HPMC controls water retention and open time — keeps the mortar workable
• RDP provides flexibility and tensile adhesion after curing
• Calcium formate accelerates early strength without chloride risk
• Increasing HPMC dosage extends open time but may delay set — balance with calcium formate dosage for your target setting speed

Technical Specifications

Common Uses & Applications

• Tile adhesive (C1, C2 grade formulations)
• Wall putty and skim coat
• Cement-based renders and plasters
• Exterior Insulation Finishing System (EIFS/ETICS)
• Self-levelling underlayment
• Repair mortars and patching compounds
• Joint filling compounds
• Gypsum-based products