A Brief Introduction to Hydroxypropyl Methylcellulose (HPMC)

I. Product Details:

1. Chemical Name: Hydroxypropyl Methylcellulose

2. Full English Name: Hydroxypropyl Methyl Cellulose

3. Abbreviation: HPMC

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II. Physical and Chemical Properties:

1. Appearance: White or off-white powder.

2. Particle Size: Over 98.5% pass through 100 mesh; over 100% pass through 80 mesh.

3. Char Temperature: 280-300°C

4. Bulk Density: 0.25-0.70/cm³ (usually around 0.5g/cm³), specific gravity 1.26-1.31.

5. Discoloration Temperature: 190-200°C

6. Surface Tension: 42-56 dyn/cm for 2% aqueous solution.

7. Solubility: Soluble in water and some solvents (e.g., ethanol/water, propanol/water, trichloroethylene).

8. HPMC Characteristics: Vary with methoxy content, gel point, water solubility, and surface activity.

III. Characteristics of HPMC:

HPMC integrates various physical and chemical properties, making it versatile for different applications:

1. Water Retention: Maintains moisture on porous surfaces like cement boards and bricks.

2. Film Formation: Forms a clear, tough, and flexible film with excellent grease resistance.

3. Organic Solubility: Dissolves in organic solvents like ethanol, ethylene glycol, and binary solvent systems.

4. Thermal Gelation: Forms a gel upon heating, reverting to a solution upon cooling.

5. Surface Activity: Provides surface activity in solutions for emulsification, colloid protection, and stabilization.

6. Suspension: Prevents solid particle precipitation, inhibiting the formation of sediment.

7. Colloid Protection: Protects against droplet and particle agglomeration or coalescence.

8. Adhesion: Acts as a binder in pigments, tobacco products, and paper items with excellent functionality.

9. Water Solubility: Dissolves in varying concentrations in water, limited only by viscosity.

10. Nonionic Inertness: A nonionic cellulose ether that does not form insoluble precipitates with metal salts or other ions.

11. pH Stability: Suitable for use in the pH range of 3.0-11.0.

12. Odorless and Tasteless: Used as an additive in food and pharmaceuticals without affecting taste or metabolism.

IV. HPMC Dissolution Methods:

HPMC dissolves slowly in water. Recommended dissolution methods include:

1. Hot Water Method: Disperse HPMC in hot water and cool under stirring.

2. Powder Mixing Method: Mix HPMC powder with equal or larger amounts of other powders, then dissolve in water.

3. Organic Solvent Wetting Method: Pre-disperse or wet HPMC with organic solvents like ethanol, ethylene glycol, or oil, then dissolve in water.

V. Main Applications of HPMC:

HPMC serves as a thickening, dispersing, emulsifying, and film-forming agent. Industrial-grade HPMC finds applications in daily chemicals, electronics, synthetic resins, construction, and coatings.

1. Suspension Polymerization: Stabilizes hydrophobic monomers in the production of synthetic resins like PVC.

2. Construction Material Formulations: Used in adhesives and fillers for gypsum-based tapes, cement bricks, mortar for gypsum board bases, structural plaster, and paint formulations.

3. Overall Functionality: HPMC enhances product properties, providing improved adhesion, viscosity, and stability.

In conclusion, this brief overview aims to aid in understanding the diverse applications and properties of Hydroxypropyl Methylcellulose (HPMC).