mortar additive hpmcMay 11th 2023
HPMC manufacturer-The influence of the smell of hydroxypropyl methylcellulose on the quality
The synthesis of hydroxypropyl methylcellulose: the refined cotton cellulose is treated with lye at 35-40℃ for half an hour, squeezed, the cellulose is crushed, and properly aged at 35℃, so that the obtained alkali fiber has an average degree of polymerization 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 proper amount of hydrochloric acid and oxalic acid to wash the materials 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 to less than 5%.
The HPMC 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.
Hypromellose is refined cotton that is rarely impregnated with liquid to obtain alkaline cellulose, then add solvent, etherification agent, toluene, isopropanol for etherification reaction, neutralization, washing, drying, pulverization, etc. to obtain the finished product, washing It’s not good, it’s smelly, so users can use it with confidence