Hydroxypropyl methylcellulose is a non-ionic cellulose alkyl hydroxyalkyl mixed ether obtained by cellulose alkalization, etherification, neutralization and washing. Hydroxypropyl methylcellulose is a water-soluble non-ionic cellulose ether. It is a product obtained when some methoxy groups in methyl cellulose (MC) are replaced by hydroxypropoxy groups.
As a catalyst in the etherification reaction, its aqueous solution is the transfer carrier of the etherification agent. Because of the steric hindrance of the methyl group on the substitute group, it has a deactivation effect on the further etherification and makes the etherification reaction of hydroxypropyl methylcellulose. The speed slows down, as long as 1/4 of the hydroxypropyl methylcellulose, and the hydroxyl reaction activity on the substitute group is also low, so the distribution of the substitute group on the hydroxypropyl methylcellulose house chain is more uniform.
The aqueous solution of this product has surface activity, making it emulsifying, maintaining colloid and relative stability. Thermal gelation effect: when heated to a certain temperature, the aqueous solution of this product can become opaque, generate deposits, and make the solution lose its viscosity. However, after it gradually cooled, it changed the state of the solution. The temperature of condensation and deposition depends on the type of product, the concentration of the solution and the heating rate.