3. How many types of hydroxypropyl methylcellulose (HPMC) are there? What is the difference between them?
HPMC can be divided into instant and hot soluble. Instantly soluble products, dissipate quickly and disappear into the water in cold water. At this point, the liquid has no viscosity as the HPMC is simply dispersed in the water and does not dissolve. After about 2 minutes, the viscosity of the liquid gradually increases, forming a clear viscous gel. The hot soluble product can disperse rapidly in hot water and disappears in the hot water. As the temperature drops to a certain temperature, the viscosity gradually appears until a clear viscous gel is formed.

In the paper industry, MHEC functions as a surface-sizing agent, enhancing the printability, water resistance, and strength of paper products. It also serves as a coating binder, promoting the adhesion of pigments and additives in paper coatings. Within the textile industry, MHEC assumes the role of a thickener and stabilizer in dyeing and printing processes, ensuring uniform color distribution and improved wash fastness.