How standard beta phthalocyanine blue compares to the non-flocculating beta variant for waterborne paints, automotive coatings, and process inks.
PB15:3 and PB15:4 are the same chemistry (copper phthalocyanine, beta crystal form) but with different stabilization. PB15:4 is non-flocculating: it stays dispersed under shear and through long shelf life. The price premium is real; whether it’s justified depends on your application.
| Property | PB15:3 | PB15:4 |
|---|---|---|
| Chemistry | Copper phthalocyanine, beta crystal | Copper phthalocyanine, beta crystal (non-flocculating treated) |
| CI Code | CI Pigment Blue 15:3 | CI Pigment Blue 15:4 |
| CAS Number | 147-14-8 | 147-14-8 (same) |
| Shade | Greenish blue (process cyan) | Greenish blue, virtually identical to PB15:3 |
| Lightfastness | 8/8 Blue Wool | 8/8 Blue Wool |
| Heat stability | 300°C+ | 300°C+ |
| Flocculation tendency | Can flocculate in waterborne and high-shear systems | Resistant to flocculation |
| Stability under shear | Moderate | Excellent |
| Storage stability in waterborne paint | Variable; may need rework over time | Stable for full paint shelf life |
| Cost tier | Standard | Premium (10-25% higher) |
| Primary use | Process cyan inks, solvent-borne paints, plastics | Automotive basecoat, premium waterborne paints |
Choose PB15:3 for the vast majority of applications, including process cyan inks, solvent-borne architectural and industrial paints, plastic masterbatch (PVC, HDPE, PP), powder coatings, textile printing, and construction. Industry-standard, cost-effective, well-understood. The default blue.
Choose PB15:4 specifically for: premium waterborne paints (where flocculation is a real risk), automotive basecoat (especially waterborne basecoat under high-shear pumping), high-shelf-life waterborne coatings, premium powder coatings where shade stability through cure matters most. The price premium is justified only when flocculation would actually be a problem.
No. PB15:4 costs 10-25% more and provides flocculation resistance. If your application doesn't have a flocculation problem (most solvent-borne systems, dry powder coatings, plastics), PB15:3 gives identical color performance at lower cost. Pay the premium only when flocculation is actually causing shade drift in your system.
Yes. PB15:3 and PB15:4 have virtually identical shade and lightfastness; the difference is dispersion stability, not color. You can substitute without recalibrating your formulation, just expect to pay more for PB15:4.
Standard beta-form phthalocyanine has surface chemistry optimized for solvent-borne systems. In waterborne emulsions, the surface charges interact with the binder differently, allowing particles to slowly aggregate (flocculate) over shelf life. PB15:4 has surface treatment that prevents this. Some PB15:3 grades are also surface-treated for waterborne use, so ask your supplier.
Share your binder system, processing temperature, and required performance, and we'll recommend the right grade and ship a free 50-100g sample for qualification.