[C₆H₇O₂(OH)₃,_x(OCH₃)_x]_n, a methyl ether of cellulose. The type most widely used in industry is water-soluble methyl cellulose (degree of substitution γ, 140–200;—OCH₃ group content, 23.5–33.0 percent); an odorless and tasteless white solid. Density, 1.29–1.31 g/cm³; melting point, 290°−305°C .

Methyl cellulose is prepared commercially by reacting alkali cellulose with methyl chloride, CH₃C1. It is used mainly in the manufacture of adhesives for foam plastic (expanded plastic), leather, and wallpaper, as well as in the production of water-soluble packing film and emulsion paints; it serves as a stabilizer in aqueous-fatty emulsions in cosmetics manufacture, as a preservative in ice cream, and as a thickening agent in juices. Methyl cellulose is also used in medicine for the preparation of capsules, as a fat-free base for eye drops and ointments, and as an ingredient in laxatives.