• • Blog
• January 26th 2023

Production Process of Hydroxypropyl Methyl Cellulose

Hydroxypropyl Methyl Cellulose (HPMC) is a non-ionic cellulose ether whose solubility, surface activity, thermal gelation, and compatibility vary with substitution, broadening its applications.

HPMC is a white or off-white powder used in petrochemicals, coatings, building materials, paint removers, agriculture, inks, textiles, ceramics, and papermaking as a thickener, stabilizer, emulsifier, excipient, water-retaining agent, or film-forming agent.

Ultra-low viscosity Hydroxypropyl Methyl Cellulose (HPMC) (below 100 mPa·s) is a white powder with good fluidity and solubility. Its aqueous solution is transparent, colorless, and stable.

This production process overcomes existing limitations by using refined cotton, propylene oxide, and methyl chloride to prepare ultra-low viscosity HPMC, reducing costs, increasing output, and expanding applications.

Preparation steps:

1. Mixing: Add solvent, water, and sodium hydroxide to the reactor. Heat to 70°C and maintain for 30 minutes.

2. Alkalization: Cool to 30°C, add refined cotton, and stir for 1 hour at 25–40°C. Evacuate to 0.05–0.07 MPa, add propylene oxide and methyl chloride, and react for 30 minutes.

3. Etherification: Heat to 55±3°C for 1.5 hours, then to 85±3°C for 1.5 hours.

4. Neutralization & Washing: Cool below 40°C, add glacial acetic acid, and wash to remove impurities.

5. Centrifugal Drying: Dry in a horizontal spiral centrifuge, crush the dried material, and package.

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