Hydroxypropyl methyl cellulose(HPMC)

Hydroxypropyl methylcellulose (HPMC) is a kind of non-ionic cellulose ether, which is made from natural high molecular material (cotton) cellulose through a series of chemical processes. It is a kind of odorless, tasteless and nontoxic white powder, which swells into a clear or slightly turbid colloidal solution in cold water. It has the characteristics of thickening, adhesion, dispersion, emulsification, film formation, suspension, adsorption, gel, surface activity, water retention and protective colloid.

Hydroxypropyl methylcellulose is mainly used in building materials, coating industry, synthetic resin, ceramic industry, medicine, food, textile, agriculture, daily chemical industry, etc.
 

Typical Properties

a) Appearance: White or similar to white powder, odorless.
b)   Graininess: More than 98.5% sieving rate for 100 mesh; Totally 100% sieving rate for 80 mesh.
c) Carbonization Temperature: 280-300 ℃
d) Apparent Density: 0.25 to 0.70 g/cm3
f) Color-change Temperature: 190-200 ℃
g)Surface Tension: 42-56 dyn/cm in 2% aqueous solution.
h) Solubility: HPMC is soluble in water and some organic solvents. Its aqueous solution has surface activity. The solubility changes with the viscosity. The higher viscosity, the better solubility. The performance is different for different HPMC. HPMC solubility is not affected by PH value.
i) Methoxyl content: With the reduction of methoxyl content, gel point raise up, water solubility reduce, surface activity decrease.
j) Inertness: No heat, chemical inertness, and not participate in the metabolism of human body.

For HPMC does not dissolve in hot water, first HPMC can be dispersed uniformly in the hot water, then dissolved quickly while cooling down. Two typical methods are described as follows:
a) Method One of Hydrothermal Solution
-Put needed amount of hot water in container and heat to about 70 ℃.
-Add gradually Hydroxyl Propyl Methyl Cellulose(HPMC) while slowly stirring.
-HPMC first floating on the surface of the water, then gradually formed a slurry and cooling down under stirring.
b) Method Two of Hydrothermal Solution
- Put 1/3 or 2/3 needed amount of water in container and heat to about 70℃.
-Following a) method, HPMC disperse and complete the preparation of hot water slurry.
- Put the remaining amount of cold water to the hot water slurry, stirring and cooling down the mixture.
Dry Powder Mixing Method:
-Blend HPMC powder into a lot of other powder material and fully mixed by the mixer.
-Dissolved in water, then HPMC can be dissolved without condensation. Each little HPMC powder at every corner will dissolve when wet.