Hydroxypropyl methylcellulose is almost insoluble in absolute ethanol and acetone. The aqueous solution is very stable at room temperature and can gel at high temperature. Most of the hydroxypropyl methylcellulose on the market now belongs to the cold water (room temperature water, tap water) instant type. Cold water instant HPMC will be more convenient and safer to use. HPMC needs to be directly added to cold water solution after ten to ninety minutes to gradually thicken. If it is a special model, it needs to be stirred with hot water to disperse, and then poured into cold water to dissolve after cooling.
When HPMC products are directly added to water, they will coagulate and then dissolve, but this dissolution is very slow and difficult. The following three dissolution methods are recommended, and users can choose the most convenient method according to the usage situation (mainly for cold water instant HPMC).
Dissolving method and precautions of HPMC
1. Cold water method: When it needs to be directly added to the normal temperature aqueous solution, it is best to use the cold water dispersion type. After adding the viscosity, the consistency will gradually increase to the index requirement.
2. Powder mixing method: HPMC powder and the same amount or more of other powdery components are fully dispersed by dry mixing, and after adding water to dissolve, HPMC can be dissolved at this time and will no longer agglomerate. In fact, no matter what kind of hydroxypropyl methylcellulose. It can be dry blended directly into other materials.
3. Organic solvent wetting method: HPMC is pre-dispersed or wetted with organic solvents, such as ethanol, ethylene glycol or oil, and then dissolved in water, and HPMC can also be dissolved smoothly.
During the dissolution process, if there is agglomeration, it will be wrapped. This is the result of uneven stirring, so it is necessary to speed up the stirring speed. If there are bubbles in the dissolution, it is due to the air caused by uneven stirring, and the solution is allowed to stand for 2- 12 hours (the specific time depends on the consistency of the solution) or vacuuming, pressurization and other methods to remove, adding an appropriate amount of defoamer can also eliminate this situation. Adding an appropriate amount of defoamer can also eliminate this situation.
Since hydroxypropyl methylcellulose is used in various industries, it is of great significance to master the dissolution method of hydroxypropyl methylcellulose for its correct use. In addition, users are reminded to pay attention to sun protection, rain protection and moisture protection during use, avoid direct light, and store in a sealed and dry place. Avoid contact with ignition sources and avoid the formation of large amounts of dust in closed environments to prevent explosion hazards.
Post time: Jun-20-2023