Hot-water dissolution method: Since HPMC does not dissolve in hot water, initially HPMC can be evenly dispersed throughout the hot water and then rapidly dissolves upon cooling. The two typical methods are described below:

(1) Place the required amount of hot water into a container and heat it to approximately 70℃. While slowly stirring, gradually add hydroxypropyl methylcellulose. Initially, the HPMC will float on the surface of the water; then, it will gradually form a slurry. Allow this slurry to cool down while continuing to stir.

(2) Add 1/3 or 2/3 of the required amount of water into the container, heat it to 70℃, and disperse HPMC using the method described in (1) to prepare a hot-water slurry. Then, add the remaining amount of cold water to the hot-water slurry, stir thoroughly, and allow the mixture to cool.

Powder Mixing Method: First, thoroughly mix HPMC powder with a large quantity of other powdered ingredients using a mixer. Then, add water to dissolve the mixture. At this point, the HPMC will dissolve without clumping or aggregating, because each tiny corner contains only a minuscule amount of HPMC powder, which will immediately dissolve upon contact with water. This method is precisely what putty and mortar manufacturers employ. [Hydroxypropyl methylcellulose (HPMC) is used as a thickener and water-retaining agent in putty and mortar formulations.]