What are the effects of odor size on hydroxypropyl methylcellulose:
Synthesis of hydroxypropyl methylcellulose: Treat refined cotton cellulose with lye at 35-40°C for half an hour, press, crush the cellulose, and age properly at 35°C, so that the average degree of polymerization of the obtained alkali is within the required range fibers within. Put the alkali fiber into the etherification kettle, add propylene oxide and methyl chloride in sequence, and etherify at 50-80°C for 5 hours, the maximum pressure is about 1.8MPa. Then add an appropriate amount of hydrochloric acid and oxalic acid to the hot water at 90°C to wash the material to expand the volume. Dehydrate in a centrifuge. Wash with water until neutral. When the moisture content of the material is lower than 60%, dry it with a hot air stream at 130°C until the moisture content is lower than 5%.
The HPMC produced by the solvent method uses toluene and isopropanol as solvents. If the washing is not good, some faint smell will remain. At present, the quality of domestic hydroxypropyl methylcellulose HPMC varies greatly, and the price varies widely, making it difficult for customers to make the right choice. This is the problem of the washing process, it does not affect the use and there is no problem, pure HPMC should not smell ammonia, starch and alcohol; Adulterated HPMC can often smell all kinds of smells, even if it is tasteless, it will feel heavy. However, the hydroxypropyl methylcellulose produced by many manufacturers has a particularly strong smell and a pungent smell. The quality is certainly not up to par.
Hypromellose is obtained by impregnating refined cotton with rare liquid to obtain alkaline cellulose, then adding solvent, etherification agent, toluene, and isopropanol for etherification reaction, neutralizing washing, drying, crushing, etc. to obtain finished products. Well, there will be an odor, so users can use it with confidence.
Post time: Apr-25-2024