Temperature Changing Yellow Thermochromic Powder 32°C KTP-32-BY

KTP-32-BY is part of Kolortek's broader thermochromic pigment line. The 32°C activation temperature is available in two variants, and the full product family covers a range of transition behaviors beyond just colored-to-colorless.

Beyond the 32°C yellow series, the thermochromic line includes pigments that transition from one color to a different color — not just to colorless. Activation temperatures vary across the range to suit different end-use conditions.

Applications

The 32°C activation point sits close to normal skin surface temperature, which opens up a specific set of application categories where body heat is the intended trigger.

• Cosmetics & Nails: Color-shifting nail lacquers, body paints, and cosmetic formulations where skin contact drives the transition
• Textiles & Printing: Heat-reactive screen printing and textile coatings; fine particle size supports clean ink formulation
• Craft & Custom Paint: DIY and artisan products, novelty paints, educational kits
• Paints & Coatings: Specialty decorative coatings — not recommended for automotive coatings
• Hair Products: Compatible with food grade thermochromic formulations applicable to hair
• Food Contact Products (BPA Free series only): Temperature-indicating cups, spoons, and kitchenware — the pigment is not for direct consumption, only for product surface use

Worth noting: the standard KTP-32-BY is not cleared for food contact use. If your end product involves food or beverage contact, specify the KTP-32-BY F (BPA Free) variant.

Key Characteristics

• Activation at 32°C: Transitions from yellow to colorless at body-proximate temperature — consistent, repeatable response
• Colored to Colorless mechanism: Below 32°C, the yellow color is fully expressed; above 32°C, it fades to transparent, exposing whatever underlayer or substrate sits beneath
• Fine particle size (1–10μm): Compatible with most liquid systems — paints, inks, lacquers — without heavy formulation adjustment
• BPA Free option available: For applications requiring compliance with food contact or stricter safety standards
• Reversible transition: The color returns when temperature drops below activation point

Practical Considerations

In practice, the 32°C threshold means this pigment will respond to direct skin contact or warm ambient environments. If the application environment regularly exceeds 32°C — a product stored in direct sunlight, for example — the pigment will remain in its colorless state under those conditions. Design your color system accordingly: the base coat or substrate color becomes the visible color above activation temperature.

For printing applications, the 1–10μm range is fine enough for most gravure and screen printing setups, though very fine mesh screens benefit from the tighter 3–10μm distribution in the F (BPA Free) variant. Dispersion behavior is comparable to standard organic pigment powders — normal wetting and dispersion protocols apply.

That said, thermochromic pigments generally have lower heat and UV stability than conventional pigments. Processing temperatures above ~80°C (depending on exact formulation and exposure duration) can degrade performance over time. UV exposure is a similar concern — if outdoor durability is required, UV-protective overcoats should be considered in the system design.

For cosmetic and nail applications, the temperature changing powder format integrates well into solvent-based lacquer systems. Ensure full dispersion before evaluating color strength — undispersed agglomerates will reduce both color intensity and transition sharpness.

FAQ

Q: Can KTP-32-BY be used in products that contact food or beverages?
A: No — the standard KTP-32-BY is not suitable for food contact applications. The KTP-32-BY F (BPA Free) version is the correct choice for product-contact items like cups or spoons. Neither version is intended for direct ingestion.

Q: What color will the product appear above 32°C?
A: Above 32°C, the yellow pigment becomes colorless. The visible color at that point will be the base coat, substrate, or any non-thermochromic pigment present in the formulation. Planning the layering system is essential for predictable results.

Q: Is this pigment suitable for automotive coatings?
A: No. Thermochromic pigments in this series are not recommended for automotive coating systems due to the processing temperatures and long-term durability requirements involved.

Q: What is the difference between KTP-32-BY and KTP-32-BY F?
A: The core color and activation temperature are the same. The F variant is BPA Free and formulated to meet food grade requirements — it also has a slightly narrower particle size range (3–10μm vs. 1–10μm in the standard grade). Select the F variant when BPA-free compliance is required by your application or market.

Request Samples or Technical Data

Samples of KTP-32-BY and the BPA Free variant are available for formulation testing. If your application requires a different activation temperature, color, or transition type — colored to another color, alternative particle size, or custom specifications — contact the technical team directly to discuss what's available across the full thermochromic pigment range.

Contact: contact@kolortek.com