The role of HPMC in coatings goes beyond thickening
In modern architectural coating systems, HPMC (hydroxypropyl methylcellulose) has become an indispensable key additive. Many people still view it solely as a “thickening agent,” but in reality, HPMC’s functions extend far beyond this.
Thickening — The “Scaffolding” for Stabilizing Coating Systems
HPMC’s most well-known function is thickening. By forming a network structure, it significantly enhances the viscosity and thixotropy of coatings, preventing sedimentation and layer separation, and improving control over application thickness.
Water Retention — Enhancing Flow Leveling and Open Time
During coating application, rapid water evaporation can lead to brush marks, sagging, or even cracking.
HPMC forms a water-retaining film on the substrate surface, prolonging drying time, expanding the application window, and improving the final film formation.
Stabilization — The “Coordinator” Between Emulsions and Pigments
In water-based coatings such as latex paints, HPMC also serves as an emulsion stabilizer. It improves pigment dispersion, suppresses color floating and blooming, enhances coating storage stability, and prevents separation and water phase separation.
Crack control—the “guardian” that enhances film flexibility
In wall putty or base coats, if moisture is lost too quickly or the film is uneven, fine cracks are likely to appear. HPMC effectively reduces stress concentration and microcracking by improving water retention and extending the drying cycle.
