Hydroxypropyl cellulose (HPC), also known as hydroxypropyl cellulose or cellulose hydroxypropyl ether, is an organic compound with a molecular formula of (C15H28O8)n, a molecular weight of 50000~1250000, and n=3.0. It is usually a white or off-white, odorless, tasteless powder with strong hydrophilicity, large swelling in cold water, and slightly soluble in cold water. It can be dissolved in water, ethanol, methanol, isopropanol, and vinyl chloride at room temperature, and is difficult to dissolve in ether or benzene. The heat-resistant temperature is 195~210℃ (the temperature at which it starts to change color). The softening temperature is 130℃, and the pH of the aqueous solution is 5~8.5. It can disintegrate in the stomach and in the intestine. The viscosity of its 10% alkaline solution at 20±0.2℃ is 0.02~0.08Pa·s.

Hydroxypropyl cellulose can be produced by the reaction of alkaline cellulose and propylene oxide under high temperature and pressure, and can also be produced by the reaction of propylene oxide and cellulose under the action of alkali. It has good thickening effect, as well as emulsification, stabilization, coating and protective colloid properties. It is mainly used in the production of pharmaceuticals (adhesives, film adhesives), cosmetics (dispersants, stabilizers), colloid protective agents, and is used as a dispersant for vinyl chloride suspension polymerization, ink, printing dye, water-based coatings, etc.

Hydroxypropyl cellulose is non-toxic and relatively safe, with LD50>15.0g/kg, but it is incompatible with parahydroxybenzoates and high concentrations of electrolytes. It needs to be sealed and placed in a dry and cool place to prevent moisture. In addition, the US FDA lists hydroxypropyl cellulose as a GRAS substance.