How many types of HPMC?
There are several types of hydroxypropyl methylcellulose (HPMC), what are the differences between them?
HPMC can be divided into two types: instant and hot melt.
Instant products will quickly disperse and disappear in water when they meet cold water, and the liquid is not viscous at this time. Because hydroxypropyl methylcellulose is only dispersed in water and has not been truly dissolved. After about two minutes, the viscosity of the liquid gradually increased and a transparent gel was formed.
The hot-melt product can be quickly dissolved in hot water when it encounters cold water, and the viscosity will gradually appear after the temperature drops to a certain level until it forms a transparent viscous colloid.
The heat-dissolving type is only suitable for putty powder and mortar, and it will be bonded in liquid glue and paint, so it cannot be used. The fast-dissolving type has a wide range of applications, and can be used in putty powder, mortar, liquid glue, and paint, without contraindications.
In the production process, what is the difference between the cold-water instant type and the hot-soluble type of hydroxypropyl methylcellulose?
The cold-water instant HPMC is surface-treated with glyoxal, then put into cold water to disperse quickly, but it does not really dissolve, and the viscosity rises to dissolve. The hot-melt type has not been treated with glyoxal. If the amount of glyoxal is large, the dispersion will be rapid, but the viscosity is low and the amount is small. The opposite is true.