How to Judge the Quality of Hydroxypropyl Methylcellulose

Hydroxypropyl methylcellulose has the characteristics of thickening, bonding, dispersion, emulsification, film formation, suspension, adsorption, gelation, surface activity, moisture retention and protective colloid. Wide range of applications. Judge the quality through the following aspects：

1) Fineness: The fineness of hydroxypropyl methylcellulose is generally 80 mesh and 100 mesh. The finer the fineness, the faster the dissolution, which is generally better. Under normal circumstances, vertical reactors produce smaller products than horizontal reactors.
2) Transmittance: Dissolve hydroxypropyl methylcellulose (HPMC) in water to form a transparent liquid. Look at its transmittance. The greater the transmittance, the better, indicating that there are fewer insolubles inside.
3) Specific gravity: A moderate specific gravity is better. If the specific gravity is too large or too small, it may be the result of not having a good control during the production process.
4) Appearance: The pure hydroxypropyl methylcellulose has a fluffy visual state, and the bulk density is small. The range is: 0.3-0.4g/ml; the adulterated HPMC has better fluidity and feels heavier, which is obviously different from the original appearance difference. The appearance of some special-purpose cellulose and common specifications of cellulose are also very different, and specific products are analyzed in detail.

5) Aqueous solution: The pure HPMC aqueous solution is clear, has high light transmittance, and the water retention rate is ≥90%; the adulterated HPMC water solution is turbid, and the water retention rate is difficult to reach 70%
6) Whiteness: Although whiteness cannot determine whether HPMC is easy to use, and if a brightener is added in the production process, it will affect its quality. However, most of the good products have good whiteness.