How to make the surface treated HPMC？

How to make the surface treated HPMC？

Compared with ordinary HPMC, the production of surface-treated HPMC has one more process. We use a cross-linking agent (usually use glyoxal) to treat its surface. The purpose of this step is to enable HPMC to disperse quickly in cold water, rather than dissolving at the beginning. If the added amount of glyoxal is large, the dispersion will be fast, but the viscosity will rise slowly. If the added amount is small, then the situation will be the opposite. It is this extra process that makes the price of surface-treated HPMC higher than the non-surface treated type.