Chemistry of Redispersible Polymer Powder
October 30th 2024
HPMC solubility in water has two types: surface-treated HPMC and non-surfaced treated HPMC.
When surface-treated HPMC is added to cold water, it disperses into the water without exhibiting any viscosity. After stirring and waiting for approximately 2 minutes, the solution thickens and becomes viscous. This is attributed to the presence of a crosslinking agent on the surface of instant HPMC. Commonly, Glyoxal is employed as a crosslinking agent, aiding the dispersion in cold water initially. As a result, surface-treated HPMC tends to be more expensive than its non-surface-treated counterpart.
Hot melt products may condense upon contact with cold water due to the outer layer of non-surface-treated HPMC reacting with the cold water. This reaction leads to the solution becoming viscous and thickening. The HPMC powder becomes enveloped in a transparent gel, with only the outer layer dissolving. This process significantly slows down the dissolution rate of HPMC inside. Generally, non-surface-treated HPMC is dissolved more efficiently by dissolving in hot water.
Tags:
