Process difference between quick-dissolving and slow-dissolving hydroxypropyl methyl cellulose:
Hydroxypropyl methylcellulose HPMC cold water (instant type): It is surface treated with glyoxal and quickly dispersed in cold water, but it is not really dissolved, the viscosity comes up, and the aqueous solution becomes clear and transparent. Really dissolved.
Hydroxypropyl methylcellulose HPMC hot-melt type (slow-melting type): no surface treatment with glyoxal. A large amount of glyoxal will disperse quickly, but the viscosity will come up slowly, and a small amount will be the opposite.
The difference between the application areas of fast-dissolving and slow-dissolving hydroxypropyl methylcellulose:
The characteristic of slow-dissolving hydroxypropyl methyl cellulose ether (HPMC) is that it will clump when it encounters cold water, but it will quickly diffuse into the water in hot water until it completely disappears in the water. The viscosity slowly increases until a transparent viscous liquid is formed. The clumping phenomenon is similar to the dissolution of high-viscosity sodium carboxymethylcellulose, which is when the cellulose powder outside the water is dissolved, the viscosity is obtained, and then the cellulose inside that has not been exposed to the water is wrapped, but This situation will also slowly dissolve, but it takes a relatively long time. It has an extremely wide range of uses in commercial mortars, with large amounts used as water retention agents, thickeners and adhesives. In ordinary dry powder mortar, external wall external insulation mortar, self-leveling mortar, tile bonding mortar, high-performance building putty, crack-resistant internal and external wall putty, waterproof mortar, gypsum-based mortar, joint filler and other materials, cellulose ether plays a role Important role.
The characteristic of instant soluble hydroxypropyl methylcellulose (HPMC) is that when it encounters cold water, it will diffuse rapidly in cold water, but its viscosity will take time to rise, because in the early stage it only diffused in water, not in essence. Its viscosity reaches the maximum value of about forty minutes, which has the advantage that it is used in a specific industry and will not be mixed with dry powder, or when it needs to be dissolved and cannot be used with hot water because of equipment conditions and other reasons. Hydroxypropyl methylcellulose solves this problem. Used in cement-based mortar, water-based paint, building glue and other fields to play the role of water retention, thickening and adhesion