At present, hydroxypropyl methylcellulose is mainly classified into a slow-dissolving type (also called a hot-dissolved type) and a fast-dissolving type in the domestic market. The slow-dissolving type is the most common and frequently used cellulose ether. We will briefly introduce the characteristics of these two different types of methyl cellulose ethers so as to help customer choose in the practical production.
Slow-dissolving hydroxypropyl methyl cellulose, which is characterized by respective coagulation in cold water, but rapidly diffuses in hot water until it completely disappears into the water, and its viscosity increasing with the temperature gradually decreases. Slowly increase until a clear, viscous liquid is formed. The coagulation phenomenon of hydroxypropyl methyl cellulose is similar to the dissolution of the high-viscosity carboxymethyl cellulose. The cellulose powder wrapped in the outer surface dissolves in water, produces viscosity, and then the cellulose wrapped inside dissolves slowly, just takes a long time. One point to note here is that many users think that hot-dissolved type must rely on hot water, while that is one-sided view. Take the putty powder as example, both of them are dry powder, the cellulose will be dispersed during the mixing. In this way, the coagulation phenomenon of cellulose will not happen in cold water.
The fast dissolving type of hydroxypropyl methylcellulose is characterized by rapid diffusion in cold water, but it takes time to increase its viscosity because it only diffuses in water in the early stage, not dissolved in the substantial sense. Its viscosity reaches a maximum about forty minutes. The advantage is that it can be used in a specific industry without mixing dry powder, or it needs to be dissolved while hot water not available because of equipment conditions and other reasons.
In summary, in the production process, we should select the appropriate hydroxypropyl methylcellulose products according to different products and different production processes to maximize production efficiency and enterprise benefits.
Post time: Mar-21-2019