KT-7511 Bronze Metallic Pigment — Synthetic Mica Fluorphlogopite Iron Oxide

KT-7511 belongs to Kolortek's KT-7500 Metal Luster Series — a line of iron oxide-coated fluorphlogopite pigments engineered for warm metallic effects. The bronze color results from a controlled iron oxide coating thickness on the synthetic mica substrate. Vary that thickness, and the reflected color shifts — a straightforward mechanism that underpins the entire KT-75xx color family.

The fluorphlogopite base is the key differentiator here. Unlike natural mica, it carries virtually no dark inclusions, which directly translates to cleaner visual output — particularly relevant in high-gloss or transparent carrier systems where contamination reads immediately. Thermal stability is also meaningfully higher, making it a practical choice for systems processed at elevated temperatures.

Particle size for KT-sits at 10–60μm, which positions it in the fine-to-mid range — appropriate for most coating and cosmetic applications where smoothness and printability are priorities.

KT-7500 Series — Models at a Glance

KT-7511 is part of a broader series spanning four particle size ranges and three core colors. All grades share the same fluorphlogopite + iron oxide composition. Selection typically comes down to the visual effect target — fine for print and cosmetics, coarser for decorative and craft applications.

Applications

KT-7511's 10–60μm range makes it versatile across both surface-finish and body-incorporation applications. In practice, the most common deployment scenarios are:

• Cosmetics: Eyeshadows, bronzers, highlight powders, and body products. The high purity of the fluorphlogopite base keeps the formula visually clean, and the warm bronze tone works well in pressed and loose powder formats.
• Nail products: Gel systems, nail lacquers, and nail powders. The metallic luster reads well in thin film layers, and the particle size allows smooth brush application without drag.
• Decorative and functional coatings: Water-based and solvent-based architectural coatings, epoxy floors, and industrial decorative finishes. The concealing property is useful where opacity and metallic sheen are both required.
• Printing inks: At the finer end of the 10–60μm range, KT-7511 is compatible with offset and screen printing systems. Pigment loading and ink viscosity will need adjustment depending on the press setup.
• Soaps and craft: Melt-and-pour soap, handmade cosmetics, and resin craft applications where a clean bronze metallic powder disperses readily into the base.

Key Characteristics

A few properties that directly affect formulation decisions:

• Warm metallic luster: Iron oxide coating produces a bronze tone with reflective depth — not a flat pigment color, but an optically active metallic effect that changes slightly with viewing angle.
• Strong concealing property: Higher opacity compared to standard pearlescent grades. Useful when coverage is needed alongside the metallic effect, rather than a translucent shimmer.
• High purity / low black spot: Synthetic mica production eliminates the natural mineral inclusions that cause dark speckling in natural mica-based pigments. This matters most in light-colored or transparent bases.
• Thermal stability: Fluorphlogopite handles high processing temperatures better than natural mica, relevant for thermoplastic applications or coatings baked at elevated cure temperatures.
• Chemical and physical stability: Resistant to moisture, common solvents, and dilute acids/bases encountered in typical formulation environments. The iron oxide coating is durable under normal processing conditions.
• Better chroma and luster: The synthetic substrate's optical cleanliness contributes to a noticeably brighter, more saturated metallic output compared to natural mica equivalents at similar particle sizes.

Practical Formulation Considerations

Dispersion technique matters with platelet pigments. KT-7511 should be dispersed with low-shear mixing — high-shear equipment can fracture the flake structure, reducing particle size and degrading both luster and coverage. Pre-wetting with a small amount of the carrier solvent or binder before adding to the bulk is a reliable approach in coating and ink systems.

Typical loading rates vary by application: 1–5% in coatings and inks, up to 10–15% in cosmetic pressed powders or nail products, and higher in some craft or soap applications depending on the desired intensity. That said, over-loading in thin film systems tends to reduce luster rather than increase it — the flakes need adequate orientation to reflect properly.

Compatibility is generally broad. KT-7511 is compatible with water-based, solvent-based, and UV-curable systems. In aqueous systems, pH should be within a reasonable neutral-to-mildly alkaline range; strongly acidic environments can affect the iron oxide coating over time.

Worth noting: in epoxy floor and resin applications, particle orientation during cure significantly influences the final visual output. Slower cure rates or self-leveling formulations allow better flake alignment, producing a more uniform metallic appearance across the surface.

For cosmetic applications, KT-7511 is based on ingredients (Fluorphlogopite, Iron Oxide) that are well-established in the cosmetic INCI system. Confirm compliance with the specific regulatory requirements of your target market before finalizing formulations.

Synthetic Mica vs. Natural Mica — What Changes in Practice

This comparison comes up regularly among formulators switching from natural mica-based metallic grades. The differences are measurable, not just theoretical.

For applications where visual consistency across batches is critical — cosmetic production, branded coatings, or any high-volume run — the synthetic base provides a more predictable foundation.

Frequently Asked Questions

Q: Is KT-7511 suitable for use in cosmetics, including leave-on products?
KT-7511 is composed of Fluorphlogopite and Iron Oxide — both are established cosmetic-grade materials with INCI designations. For regulated markets (EU, US FDA, etc.), confirm that the specific batch meets relevant purity and safety requirements for your intended use. TDS, MSDS, and COA documentation are available to support registration and compliance review.

Q: How does KT-7511 differ from other grades in the KT-7500 series?
KT-7511 is the standard bronze in the 10–60μm size range, offering a smooth metallic finish suited to cosmetics, coatings, and fine-particle printing. The Flash (20–100μm), Shimmer (40–200μm), Sparkle (60–300μm), and Super (200–700μm) variants in the bronze color progressively increase in particle size, producing more visible sparkle and a coarser visual texture. The base composition and color chemistry remain the same across all bronze grades.

Q: Can KT-7511 be used in UV-curable ink or coating systems?
Yes. The pigment is chemically stable and compatible with UV-curable binder systems. Standard precautions apply: ensure the pigment doesn't significantly attenuate UV at the photoinitiator absorption wavelength, particularly at higher loading rates, as this can affect cure depth and speed. Testing at intended use concentrations is recommended before production runs.

Q: What is the recommended mixing method to preserve luster in liquid systems?
Low-shear dispersion is the standard approach — cowles blades at moderate speed, or simple paddle mixing for lower-viscosity systems. Avoid ball mills, high-speed dispersers, or any equipment that generates significant shear on the flake particles. Adding KT-7511 toward the end of the formulation process, after other components are already dispersed, reduces total mechanical exposure and helps maintain the platelet integrity responsible for the metallic luster effect.

Request Samples or Technical Documentation

Samples of KT-7511 and related KT-7500 series grades are available for evaluation. TDS, MSDS, and COA can be provided on request. For application-specific technical questions or custom particle size requirements, contact the technical team directly at contact@kolortek.com.