HPMC is available in a wide range of viscosity grades — from 4,000 mPa·s to 200,000 mPa·s (2% solution, 20°C; 1 mPa·s = 1 cP) — 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.
Technical specifications
| Parameter | Value |
|---|---|
| Chemical Name | Hydroxypropyl Methylcellulose |
| Viscosity grades | 400–200,000 mPa·s |
| Methoxyl content | 19–30% |
| Moisture content | ≤5% |
| pH (2% solution) | 5.0–8.0 |
| Appearance | White to off-white powder |
| CAS Number | 9004-65-3 |
| HS Code | 3912.39 |
| Purity | Multiple grades: 4,000–200,000 mPa·s (2% solution) |
Applications
- Tile Adhesive — Water retention prevents premature water loss into substrate; open time extension of 20–30 min enables large tile installation
- Wall Putty — Improves workability, reduces cracking, and provides a smooth finish on cement and gypsum substrates
- Cement Render — Anti-sagging properties allow thick renders to be applied in one coat; improves bond to substrate
- EIFS / ETICS — Critical in base coat mortars for external insulation systems; provides flexibility and weather resistance
- Self-Levelling — Controls flow time and prevents segregation; essential for pumpable floor levelling compounds
Usage and recommendations
Viscosity is 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.
| Viscosity Grade | Typical Application | Dosage | Key Effect |
|---|---|---|---|
| 4,000 mPa·s | Self-levelling compounds, grouts | 0.05–0.15% | Low thickening, fast flow |
| 15,000 mPa·s | Tile adhesive, plasters | 0.15–0.30% | Medium water retention |
| 60,000 mPa·s | Tile adhesive, wall putty | 0.20–0.35% | High water retention, good open time |
| 100,000 mPa·s | EIFS, textured coatings | 0.25–0.50% | Maximum water retention, sag resistance |
| 200,000 mPa·s | Heavy renders, thick mortars | 0.30–0.60% | Maximum anti-sag, extended open time |
HPMC grades are also differentiated by their methoxy and hydroxypropoxy substitution levels, which affect gelation temperature and solubility behaviour. The K, E and F designations follow the widely used METHOCEL-style nomenclature; grade naming varies between manufacturers:
- K Grade — High hydroxypropoxy content (7–12%). Lower gelation temperature (~60°C). Most widely used in construction dry-mix products. Best water retention.
- E Grade — Medium hydroxypropoxy (4–7.5%). Intermediate gelation temperature (~65°C). Used in coatings and pharmaceutical applications. Good film-forming properties.
- F Grade — Low hydroxypropoxy (1–3%). High gelation temperature (~85°C). Used where heat resistance of the gel is needed. Less common in standard dry-mix.
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
High temperatures (35–50°C in UAE and Saudi Arabia during summer) accelerate hydration and can reduce open time. Use a higher viscosity grade or increase dosage slightly in hot weather. Some HPMC grades are specifically formulated for hot-climate construction — ask Raykem for grade recommendations for GCC applications.
Packaging
- 25 kg paper bags
- 500 kg big bags
- 1,000 kg big bags