KT-520 Satin Bronze Metal Luster Pearlescent Pigment — Natural Mica Iron Oxide

The KT-500 Series sits within Kolortek's Metal Luster family — pigments produced by depositing iron oxide (Fe₂O₃) at controlled thickness onto natural mica flakes. The color output is determined by that coating thickness: thinner layers yield gold tones, while progressively thicker coatings shift the hue through bronze and into deeper copper-red territories. KT-520 targets the satin bronze position in that range.

Unlike interference pearlescents that rely on thin-film optical effects to generate color, this series achieves its tone through the inherent absorption properties of ferric oxide. The result is a pigment with genuine concealing power — a characteristic that separates iron oxide mica grades from standard pearl pigments and makes them behave more like metallic pigments in application.

KT-520 is a recognized alternative to Merck Iriodin 520 Satin Bronze, offering comparable color position and particle size profile.

Product Series & Models

Two substrate options exist within the Metal Luster family. The KT-500 Series uses natural mica as the substrate; the KT-7500 Series uses synthetic mica (fluorphlogopite). Both are coated with iron oxide and follow the same color logic, but the synthetic mica base offers higher purity and improved whiteness in the substrate — relevant when color fidelity is critical or when formulating for cosmetic-grade applications with stricter raw material requirements.

Key Characteristics

• Warm metallic luster: The satin-finish bronze tone reads as metallic without the high-gloss flashiness of aluminum-based pigments. It integrates well in matte-to-satin coating systems.
• Strong concealing property: Iron oxide coating contributes genuine opacity. At sufficient loading, this pigment can mask the substrate without relying on additional opacifiers.
• Chemical and physical stability: Ferric oxide is inert across most formulation chemistries. KT-520 is stable in acidic and mild alkaline environments and does not react with common binder systems.
• Consistent particle morphology: The 5–25μm range (800 mesh) produces a smooth, satin surface texture — no coarse sparkle, no graininess in applied films.
• Broad compatibility: Performs in water-borne, solvent-borne, UV-cure, and resin-based systems. No surface treatment required for standard dispersion in most matrices.

Applications

KT-520 covers a wide application range. In practice, the same base pigment is used across industries with minimal reformulation — the primary variable is loading level and the binder system it's incorporated into.

Practical Considerations

Dispersion: KT-520 disperses readily by low-shear mixing. High-shear equipment is not recommended — it can fracture the mica platelets, reducing aspect ratio and degrading luster. Pre-wetting with a small amount of the carrier solvent or binder before adding to the bulk mix improves uniformity.

Loading levels: Typical use rates range from 2–15% depending on the system and desired opacity. In clear or translucent coatings, lower loadings maintain a depth effect. Higher loadings in pigmented systems build opacity without requiring additional iron oxide colorants in many cases.

Cosmetic use: The composition — natural mica and iron oxide — aligns with globally recognized cosmetic ingredient standards. That said, formulators should verify regulatory compliance against the specific regional requirements for their product category and intended use site (eye-area vs. general skin).

Coating systems: KT-520 is compatible with waterborne acrylics, solvent-borne alkyds, epoxy resins, polyurethanes, and UV-cure systems. In highly alkaline systems (e.g., cement-based or strongly basic epoxy hardeners), verify stability under your specific formulation conditions before scaling.

Worth noting: if your application demands a purer substrate — for ultra-high color accuracy or specific cosmetic grade requirements — the KT-7500 Series synthetic mica equivalent is the logical step up from KT-520.

KT-520 vs. Merck Iriodin 520 Satin Bronze

KT-520 is formulated as a functional alternative to Iriodin 520. Both share the same color designation (Satin Bronze), the same substrate type (natural mica), and the same active coating material (ferric oxide). The particle size range is equivalent. For formulators currently sourcing Iriodin 520, KT-520 can be evaluated as a drop-in replacement — batch-to-batch color consistency and particle distribution are controlled under ISO 9001-certified manufacturing processes. As with any pigment substitution, side-by-side drawdown testing under your specific formulation conditions is the appropriate validation step.

Frequently Asked Questions

Q: Is KT-520 suitable for cosmetic use?
Yes. The composition — natural mica and iron oxide — is listed within standard cosmetic ingredient inventories. It is used in cosmetics, nail products, and soap formulations. Formulators should confirm regional regulatory compliance (FDA, EU Cosmetics Regulation, etc.) for their specific product type and use zone.

Q: How does KT-520 differ from a standard gold pearlescent pigment?
Standard gold pearlescents achieve their color through thin-film interference — the color shifts with viewing angle and the pigment has limited opacity. KT-520's color comes from ferric oxide absorption, which gives it genuine hiding power and a more stable, angle-independent bronze tone. It reads as metallic rather than pearlescent in most applications.

Q: Can KT-520 be used in epoxy floor coatings?
Yes. Its chemical stability and strong concealing property make it a practical choice for cast epoxy floors and countertop systems. It holds up well under the alkaline conditions of standard epoxy resin systems, though testing under your specific hardener chemistry is always advisable.

Q: What is the difference between KT-520 (natural mica) and the KT-7500 Series (synthetic mica)?
The iron oxide coating and color logic are the same across both series. Synthetic mica (fluorphlogopite) offers a cleaner, higher-purity substrate with better whiteness — which can improve color brightness and is often preferred in cosmetic-grade applications. Natural mica is the standard industrial choice and is cost-effective for most coating and decorative applications.

Request Samples or Technical Data

If you are evaluating KT-520 as an Iriodin 520 alternative or incorporating it into a new formulation, sample quantities and full technical data sheets are available. Contact the technical team at contact@kolortek.com to specify your application, substrate system, and any regulatory requirements — this helps ensure the right grade is matched to your needs from the start.