Evaluating Storage Stability in EVA–PU Waterborne Systems

Storage stability is a defining requirement for industrial waterborne formulations. EVA–PU systems are particularly sensitive due to differences in stabilization mechanisms.

Initial visual inspection provides limited information. Many incompatible systems remain visually acceptable for several hours before showing signs of flocculation or viscosity drift. Time-based evaluation is therefore essential.

Recommended tests include 24-hour and 72-hour static storage, low-shear viscosity monitoring, and gentle agitation recovery. These tests simulate real warehouse conditions more accurately than short-term observations.

Temperature variation should also be considered. Moderate temperature changes can accelerate destabilization by increasing particle mobility and reducing steric barriers. Even if freeze–thaw resistance is not required, thermal cycling tests provide valuable insight.

Stable EVA–PU systems exhibit minimal viscosity change and no phase separation over time. Formulations that fail these criteria require further adjustment of pH alignment, ionic strength, or stabilization strategy.

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