Blue Green Phosphorescent Pigment, Strontium Aluminate, 65–75μm – KT-GBG02

Blue Green Phosphorescent Pigment, Strontium Aluminate, 65–75μm – KT-GBG02

Special Effect Pigments › Glow in Dark Pigment Series

KT-GBG02 is a Blue Green strontium aluminate phosphorescent pigment in the coarse 65–75μm particle size range — a glow-in-the-dark pigment that absorbs ambient light (sunlight, fluorescent, LED) during exposure and releases it as a sustained blue-green glow after the light source is removed. The 65–75μm particle size places it at the coarser end of the Kolortek glow-in-the-dark range, making it appropriate for applications where individual luminescent particles contribute to visible sparkle-glow in thick films, resin castings, and decorative surfaces. Strontium aluminate chemistry delivers significantly longer afterglow duration and higher initial glow brightness than older zinc sulfide formulations — the current industry standard for performance glow-in-the-dark applications.

How Phosphorescent Pigments Work — and Why Strontium Aluminate Matters

Phosphorescent pigments store light energy in the crystal lattice of the host material during exposure and release it gradually as visible light emission after the light source is removed. The duration and brightness of the afterglow depends on the host crystal chemistry and the rare earth dopant used — strontium aluminate activated with europium and dysprosium is the current benchmark for long-duration afterglow in glow-in-the-dark pigments, producing significantly longer and brighter afterglow than older zinc sulfide (ZnS) based materials.

Key distinction from fluorescent pigments: Phosphorescent (glow-in-the-dark) pigments like KT-GBG02 store energy and emit light in darkness — they continue to glow after the light source is removed. Fluorescent (neon) pigments require continuous incident light and stop immediately when it is removed. These are fundamentally different materials serving different application needs. Kolortek's fluorescent neon pigment range is a separate product family.

Kolortek Glow in Dark Series — Product Overview

Water-based compatible series (KT-GYG-05, KT-GPO-07, KT-GVP-03, KT-GOY-01, KT-GOR-03, KT-GFG-05, KT-GBR-02, KT-GBB-04) available at 30–50μm in multiple glow colors. Zinc Sulfide series available for cost-sensitive applications. Contact Kolortek for the complete glow-in-the-dark range.

Technical Specifications — KT-GBG02

Key Technical Characteristics

Strontium aluminate vs. zinc sulfide — why chemistry matters: Zinc sulfide (ZnS) phosphorescent pigments were the industry standard for decades but have two significant limitations: relatively short afterglow duration (typically 1–2 hours at useful brightness) and lower initial glow intensity. Strontium aluminate activated with rare earth dopants (europium, dysprosium) stores energy more efficiently and releases it over a substantially longer period — typically 8–12+ hours of measurable glow following adequate light exposure, with much higher initial brightness immediately after the light source is removed. For applications where sustained overnight glow is a functional requirement, strontium aluminate is the appropriate specification. For cost-sensitive applications where a shorter, dimmer glow is acceptable, Kolortek's zinc sulfide grades (KT-GYG03DSA series) are available.

65–75μm — coarse grade rationale: At this particle size, individual luminescent particles are clearly visible to the naked eye. In epoxy resin castings, thick decorative coatings, and craft applications, the coarse particles contribute both a visible sparkle texture in daylight (the particles have a slight translucent appearance) and distinctly visible individual glow points in the dark. This gives finished surfaces a more dynamic, multi-point luminescent appearance compared to fine-grade glow pigments, which produce a more diffuse, uniform glow across the surface.

Critical formulation constraint — moisture sensitivity: Strontium aluminate is sensitive to water — direct contact with liquid water or high-humidity waterborne binder systems causes hydrolytic degradation of the crystal lattice, reducing afterglow performance and potentially causing color shifts or particle breakdown. KT-GBG02 at 65–75μm is intended for use in anhydrous systems: solvent-based coatings, epoxy resin, UV-curable formulations, wax, and oil-based applications. For water-based systems, specify the dedicated water-based compatible grades (KT-GBG02-2, KT-GYG-10, or the 30–50μm water-based series) which use a protective surface treatment to manage moisture exposure.

Charging time and light source: Strontium aluminate charges efficiently under both UV and visible light — sunlight, fluorescent, and LED sources all provide adequate charging. Shorter exposure to higher-intensity UV light charges the pigment faster; longer exposure to ambient indoor light produces similar results over a longer period. UV black light (365nm range) provides the fastest charging in controlled conditions. The blue-green glow color of KT-GBG02 is characteristic of the specific europium/dysprosium dopant configuration in this grade.

Application Range

Formulation Notes

Moisture exclusion is the primary processing concern: Keep KT-GBG02 sealed and dry during storage and processing. In epoxy systems, add the pigment to the resin component and mix before adding the hardener — this minimizes moisture exposure time during the open pot life. Ensure mixing equipment and containers are dry. Even brief exposure to significant moisture during processing can initiate hydrolytic degradation, which reduces afterglow performance in the cured product.

Loading levels in epoxy resin: For epoxy flooring and resin art, typical loading levels run 10–30% by weight of the total resin system depending on the desired glow intensity. Higher loading produces more intense and longer-lasting glow due to higher photon storage capacity. At 65–75μm, the coarse particles settle in low-viscosity uncured resin — incorporate into the mixed system shortly before application or use a thixotropic epoxy formulation to maintain particle suspension.

Film thickness for coatings: Glow intensity in coatings is proportional to pigment loading and film thickness. For functional safety marking applications requiring adequate dark-visibility, a minimum dry film thickness should be established during application trials — contact Kolortek for guidance on loading levels and film thickness targets for specific use cases.

Kolortek has produced strontium aluminate glow-in-the-dark pigments alongside its broader effect pigment range for over 20 years, with consistent phosphor crystal quality and particle size distribution across production batches — both parameters that directly affect afterglow brightness reproducibility in production-scale manufacturing. TDS and SDS are available on request for KT-GBG02.

Frequently Asked Questions

Q: How long does KT-GBG02 glow after charging?
A: Strontium aluminate phosphorescent pigments like KT-GBG02 provide measurable glow for 8–12+ hours following adequate light exposure under standard conditions. Initial brightness immediately after the light source is removed is highest, then decreases gradually over the afterglow period. The exact duration and brightness visible to the eye depends on the darkness of the environment, the film thickness and loading level in the application, and the intensity and duration of the prior light exposure. For specific afterglow performance data, contact Kolortek for the TDS.

Q: Can KT-GBG02 be used in water-based coatings or waterborne epoxy systems?
A: Standard strontium aluminate at 65–75μm (KT-GBG02) is moisture-sensitive and is not recommended for direct incorporation into waterborne systems. For water-based compatible applications, specify KT-GBG02-2 SC (Blue Green, 15–25μm, water-based grade) or KT-GYG-10 (water-resistant surface-treated yellow green, 20–38μm). The water-based series (30–50μm grades, multiple colors) is also available for waterborne formulations.

Q: What is the difference between KT-GBG02 (65–75μm) and KT-GBG02-2 SC (15–25μm)?
A: Both are blue-green strontium aluminate grades. KT-GBG02 at 65–75μm is the coarse-format grade — individual particles are visible in the finished application, contributing both a sparkle texture in daylight and visible individual glow points in the dark. It suits epoxy resin art, thick film coatings, and applications where particle texture is acceptable or desirable. KT-GBG02-2 at 15–25μm produces a smoother, more diffuse glow suitable for thinner films and waterborne-compatible applications. Fine-grade grades also suit printing inks and applications with strict surface finish requirements.

Q: Is strontium aluminate safe for cosmetic or skin-contact applications?
A: Strontium aluminate glow pigments are not currently listed as approved cosmetic colorants under FDA or EU Cosmetics Regulation frameworks for direct skin application. For cosmetic glow-in-the-dark applications (nail art, body products), verify regulatory compliance in your target market before specifying. Contact Kolortek to discuss which grades, if any, may be appropriate for cosmetic-adjacent use cases.

Request Samples or Technical Data

Glow performance is best evaluated in your specific application system — epoxy type, film thickness, and ambient light conditions all affect how KT-GBG02 performs in practice. Contact Kolortek to request a sample of KT-GBG02 alongside fine-grade blue-green alternatives, download the TDS with afterglow performance data, or discuss grade selection across the full glow-in-the-dark range.