Thermochromic Pigment Red 16°C Colored to Colorless KTP-16-BR

KTP-16-BR operates on a leuco dye mechanism. Below 16°C, the pigment presents a saturated red. As the substrate temperature crosses the activation threshold, the chromogenic system becomes colorless — exposing whatever base coat, print, or graphics sit beneath. The transition is reversible: cooling the substrate restores the original red.

In practice, this means the visual effect is entirely dependent on your base layer. A white substrate produces a clean disappearing red effect. A contrasting base coat — dark, printed, or patterned — creates a reveal effect that only becomes visible at temperature. This is worth planning at the formulation stage, not as an afterthought.

Product Specifications

Available Models — Colored to Colorless Series

KTP-16-BR sits within a broader range of activation temperatures and colors. The table below covers the standard colored-to-colorless lineup for cross-reference during formulation planning.

A BPA Free food-grade series is also available with activation temperatures at 30°C, 31°C, and 32°C, covering red, yellow, green, blue, violet, purple, and sapphire blue in a 3–10μm particle size range. These are intended for food contact applications such as cups and spoons — not for direct ingestion.

Applications

The 16°C activation point makes KTP-16-BR relevant for applications that need to respond to room-temperature or slightly chilled conditions. Typical use cases include:

• Textiles and screen printing: Temperature-reactive graphics on garments, athletic wear, or promotional items that change appearance in cool environments.
• Paints and decorative coatings: Interior or novelty coatings where surface color shifts with ambient temperature changes. Not recommended for automotive exterior use.
• Printing inks: Offset, flexo, or screen ink systems for packaging or label applications requiring a visual temperature cue.
• Nail and cosmetic formulations: Incorporated into gel or lacquer systems for color-shifting nail products.
• Craft and art applications: DIY and custom art projects where a reversible color effect adds functional interest.
• Custom paint: Mixed into base coats for object surfaces where a thermal reveal effect is the design intent.

Worth noting: KTP-16-BR is a standard-series pigment and is not cleared for food contact use. If the application involves direct contact with food or beverages, the BPA Free series is the appropriate choice.

Key Characteristics

• Reversible transition: The red-to-colorless shift is fully reversible across normal use cycles.
• Low activation threshold: At 16°C, this is among the lowest activation temperatures in the standard range — appropriate where cool ambient or refrigerated conditions are involved.
• Reveal-layer compatible: The colorless state exposes the layer beneath, which can be exploited as a design feature in layered print or coating systems.
• Fine particle distribution: The 1–10μm range supports smooth dispersion in most liquid carriers, including water-based, solvent-based, and UV-curable systems.
• Batch consistency: Consistent color response across production runs is maintained through controlled manufacturing.

Formulation Considerations

Thermochromic pigments based on leuco dye systems are sensitive to UV exposure and certain solvents. For outdoor or high-UV applications, a UV-protective topcoat is strongly recommended to preserve longevity of the color-change effect. Extended UV exposure without protection will degrade the chromogenic performance over time.

When dispersing KTP-16-BR, avoid prolonged high-shear mixing at elevated temperatures — sustained processing heat can partially activate or stress the microcapsule structure. Cold or ambient-temperature dispersion using low-shear mixing is the standard approach.

That said, compatibility with the carrier resin or medium should always be validated at lab scale before full production. Leuco-based thermochromic pigments can be sensitive to highly acidic or alkaline systems, and some solvent types can affect capsule integrity. TDS and MSDS documentation is available to support this evaluation.

For layered effects, design the base coat first. The colorless state of KTP-16-BR is transparent enough to reveal a well-designed underprint clearly — but base coat pigment strength and opacity need to be balanced against the thermochromic layer thickness to achieve a clean visual transition.

KTP-16-BR vs. Higher Activation Temperature Reds

Kolortek offers red-colored thermochromic pigments at three distinct activation points: 16°C (KTP-16-BR), 31°C (KTP-31-BR), and 45°C (KTP-45-BR). Choosing between them comes down entirely to the thermal conditions in the intended use environment.

At room temperature (typically 20–25°C), KTP-16-BR will already be in its colorless state unless the environment is actively cooled. This is a critical detail: if the application requires the red color to be visible under normal indoor conditions, a 31°C or higher activation point is more appropriate.

Frequently Asked Questions

Q: At standard room temperature (22°C), will KTP-16-BR appear red or colorless?
At 22°C — which is above the 16°C activation threshold — the pigment will be in its colorless state. To see the red color, the substrate needs to be cooled below 16°C. This is a common selection error: if red visibility at room temperature is required, consider KTP-31-BR or KTP-31-VP instead.

Q: Is KTP-16-BR suitable for food contact packaging or beverage cups?
No. KTP-16-BR is a standard-series pigment and is not certified for food contact use. For food contact applications — such as cups, spoons, or similar items — the BPA Free food-grade series (e.g., KTP-31-RBF) is the appropriate selection.

Q: Can this pigment be used in water-based ink systems?
Yes, the microencapsulated particle structure is compatible with water-based carriers. Dispersion should be carried out at ambient temperature with low-shear mixing to avoid mechanical stress on the capsules. Confirm compatibility with any specific binder or resin system at bench scale before scale-up.

Q: How durable is the color-change effect over repeated cycles?
Under normal indoor conditions with UV protection in place, the thermochromic effect is durable across a significant number of thermal cycles. UV exposure without a protective topcoat is the primary factor that degrades performance. Outdoor or high-UV applications require appropriate overcoat protection, and cycle durability should be evaluated under actual end-use conditions.

Request Samples or Technical Documentation

TDS, MSDS, and COA are available for KTP-16-BR. Sample quantities can be arranged for formulation testing. For technical questions about activation temperature selection, dispersion method, or substrate compatibility, contact the Kolortek technical team directly at contact@kolortek.com.