The smell of HPMC powder

How is HPMC powder synthesized?

HPMC powder is to treat the refined cotton cellulose with alkaline solution at 35-40℃ for half an hour, press, crush the cellulose, and properly age it at 35℃, so that the average degree of polymerization of the alkali fiber obtained is within the required range. Put the alkali fiber into the etherification kettle, add propylene oxide and methyl chloride successively, and etherify at 50-80℃ for 5h, the maximum pressure is about 1.8MPa. Then add appropriate amount of hydrochloric acid and oxalic acid to wash the material in hot water at 90°C to increase the volume. Dehydrate with a centrifuge. Wash to neutral. When the water content in the material is less than 60%, dry it with a stream of hot air at 130°C until the water content is below 5%.

The HPMC powder  produced by the solvent method uses toluene and isopropanol as solvents. If the washing is not good, there will be some faint residual odor. This is a problem of the washing process, which does not affect the use or any problem, but in reality The hydroxypropyl methyl cellulose produced by many manufacturers has a particularly serious smell and a pungent smell. This quality is definitely not good.