Pigment Blue 15:3 — often abbreviated PB15:3 — is a greenish-shade copper phthalocyanine blue and one of the most widely used blue pigments in industrial color formulation. It owes its popularity to a combination that's hard to find elsewhere in the blue color space: strong tinting strength, excellent lightfastness, and a crystal structure that stays put under heat and solvent exposure instead of drifting in shade over time. This guide covers what PB15:3 is, how its key properties compare to related phthalocyanine grades, and where it performs best across inks, plastics, and coatings.

What Is Pigment Blue 15:3?

PB15:3 (Colour Index Pigment Blue 15:3, C.I. 74160) is a copper phthalocyanine pigment identified by CAS number 147-14-8, with the chemical formula C32H16CuN8. Like all phthalocyanine blues, it's built around a copper atom coordinated at the center of a phthalocyanine ring — a structure that gives the whole pigment family its signature intensity and stability.

What sets PB15:3 apart from some of its closest relatives (PB15:0, PB15:1, and PB15:2) is its crystal form. Those earlier grades are produced in the alpha crystal modification, which leans toward a redder shade but can undergo a partial crystal transformation — known as "flushing" or crystal growth — when exposed to certain solvents or heat over time, causing the color to shift or lose strength. PB15:3 (along with PB15:4) is produced in the beta crystal modification, which is thermodynamically stable: it doesn't convert to another crystal form under normal processing or storage conditions. That stability is the main reason PB15:3 is the default choice for applications where long-term, consistent color matters more than achieving the reddest possible blue shade.

Key Properties

Color Shade and Crystal Stability

PB15:3 produces a clean, greenish-blue shade with high color strength and comparatively low viscosity in paste and ink systems, which supports good flow and easier dispersion during manufacturing. Because its beta crystal form resists flocculation and crystal growth, formulations made with PB15:3 tend to hold their shade and gloss consistently through storage, reprocessing, and solvent exposure — a meaningful advantage over alpha-form phthalocyanines in solvent-based systems.

Lightfastness

PB15:3 is one of the strongest performers in the entire organic pigment range for lightfastness, commonly rated at the top of the Blue Wool Scale (ISO 105-B02). This puts it in the same class as premium pigment families and makes it a reliable choice for outdoor coatings, automotive finishes, and any application with sustained UV exposure — without the cost premium of specialty pigment chemistries.

Heat Resistance

PB15:3 holds up well through the temperature ranges typical of plastics processing and coil or powder coating cure cycles, which is part of why it's a standard choice for masterbatch and engineering plastic coloration. As with any pigment, heat tolerance can vary somewhat between suppliers' specific grades and particle treatments, so it's worth confirming the heat-resistance data on the technical data sheet for your particular processing temperature and dwell time, especially for high-temperature engineering plastics or repeated-pass extrusion.

Chemical and Solvent Resistance

PB15:3 offers excellent resistance across a broad range of solvents — including alcohols, esters, ketones, aromatics, and mineral spirits — along with strong resistance to both acids and alkalis. This broad chemical resistance is one of the pigment's defining strengths and is a major reason it performs reliably across such a wide span of ink, coating, and plastic systems without special formulation workarounds.

Migration and Bleed Resistance

PB15:3 is insoluble in water and shows good resistance to migration and bleeding in plastic substrates, which supports its use in packaging films, masterbatch, and multi-layer plastic articles. As with any pigment used near food-contact or sensitive end uses, migration performance should still be verified on the actual production formulation rather than assumed from general pigment behavior.

Applications by Industry

Printing Inks

PB15:3 is a workhorse in flexographic water-based inks, offset inks, corrugated packaging inks, and publication and packaging gravure, where its strong tinting strength, low viscosity, and excellent lightfastness deliver consistent, cost-effective results across high-volume print runs.

Plastics and Masterbatches

In polyolefins (LDPE, HDPE, PP), PVC, and rubber, PB15:3's crystal stability is especially valuable — it resists the shade drift that can occur with alpha-form blues when plastic is repeatedly melted and reprocessed, making it a dependable choice for masterbatch producers supplying color-critical end markets.

Coatings

PB15:3's combination of lightfastness, weatherability, and chemical resistance makes it well suited to automotive OEM and refinish coatings, industrial coatings, and decorative water-based architectural paints, where long-term outdoor performance is a core requirement.

A Regulatory Note on Sensitive End Uses

PB15:3 (along with Pigment Green 7) has come under regulatory review in the EU regarding its use specifically in tattoo inks, due to data-adequacy concerns under REACH rather than any finding specific to its established industrial uses. For buyers supplying tattoo ink or other direct skin-contact formulations, it's worth checking the current regulatory status in your target market before specifying this pigment for that use; for its core markets — inks, plastics, and coatings — this review has no bearing on compliance.

Common Mistakes to Avoid

PB15:3 remains the benchmark greenish-shade blue pigment for formulators who need strong color, excellent lightfastness, and dependable long-term stability across inks, plastics, and coatings.

TRESAI Chemical supplies Pigment Blue 15:3 along with technical data sheets and free samples for qualification testing. Contact our technical team to find the right grade for your formulation.