Food Grade Thermochromic Pigment Green 31°C BPA Free KTP-31-GBF

Custom activation temperatures and colors are available on request. Contact contact@kolortek.com for specification options.

What This Pigment Does

At ambient or cooler temperatures, KTP-31-GBF presents a saturated green color. Once the surface reaches 31°C — roughly skin or body contact temperature — the pigment transitions to colorless, exposing any base coat or graphics beneath. The change is fully reversible: the green returns as temperature drops.

This colored-to-colorless behavior makes the pigment particularly effective where a strong visual signal is needed at a defined threshold — indicating warmth, revealing a message, or creating an interactive cosmetic effect.

Worth noting: the 31°C activation point aligns closely with normal skin surface temperature, which is why this grade sees consistent demand in nail, hair, and cosmetic applications. The response is sharp enough to read clearly in use.

Applications

KTP-31-GBF is designed for systems where safety and regulatory compliance are non-negotiable. Suitable application areas include:

• Cosmetics & Personal Care: Nail polish, hair color formulations, body-contact products
• Food Contact Products: Cups, spoons, and similar items where surface temperature indication is functional — not for direct ingestion
• Textiles & Printing: Screen printing, heat-reactive ink systems for apparel or novelty textiles
• Craft & Art Products: Paints, coatings, DIY materials requiring a reversible green-to-clear effect
• Custom Paints & Coatings: Decorative or functional surface coatings — note: not suitable for automotive topcoats

In practice, this pigment has been incorporated into nail gel systems and hair color formulations where the green-to-clear shift adds a functional or aesthetic dimension tied to body temperature.

Key Characteristics

• BPA Free: Formulated without bisphenol A — critical for food contact and cosmetic compliance
• Food Grade Series: Positioned for skin contact and food contact surface use; not for direct consumption
• Colored to Colorless: Vivid green below threshold; fully transparent above 31°C
• Fine Particle Size (3–10μm): Disperses cleanly in most carrier systems without grit or settlement issues
• Reversible Color Change: Consistent cycle-to-cycle performance; the effect is repeatable under normal use conditions
• Batch-to-Batch Stability: Consistent activation point and color intensity across production runs

Formulation and Handling Considerations

Thermochromic pigments — including this food grade series — require some care during formulation. Avoid exposure to temperatures significantly above the activation point during processing, as sustained high heat can degrade the leuco dye system inside the microcapsule and affect long-term performance.

That said, KTP-31-GBF handles standard cosmetic and printing process conditions well. Dispersion in water-based systems is straightforward; in solvent-based carriers, pre-wetting the powder before addition helps achieve uniform distribution.

Do not grind or mill after incorporation — the microcapsule structure must remain intact for the thermochromic mechanism to function. Gentle mixing is the correct approach.

Recommended loading levels vary by application, but typically fall in the 3–8% range by weight for most printing and cosmetic systems. Higher concentrations produce deeper initial color and a more visible transition effect.

MSDS, TDS, and COA documentation are available upon request. Formulation support can be arranged through contact@kolortek.com.

Comparison: Standard vs. Food Grade Thermochromic Pigment

Frequently Asked Questions

Q: Is KTP-31-GBF safe for use in nail gel or nail polish formulations?
Yes. The BF (BPA Free) food grade designation makes this thermochromic powder appropriate for nail applications where skin contact occurs. It is formulated specifically for this type of use. That said, full regulatory review of your finished formulation remains the responsibility of the formulator.

Q: Can this pigment be used on cups or bottles that hold beverages?
KTP-31-GBF is suitable for food contact surfaces — meaning the exterior or surface of cups, spoons, or similar items. It is not intended for direct consumption or internal coating of food-contact surfaces where ingestion is likely. Verify end-use compliance with applicable local regulations.

Q: What happens if the pigment is processed above 31°C during manufacturing?
Brief exposure above 31°C during mixing will not permanently damage the pigment — the activation temperature refers to the reversible color change threshold, not a thermal degradation point. Sustained exposure to very high temperatures (typically above 80–90°C) during processing is what risks microcapsule integrity and should be avoided.

Q: Are other activation temperatures or colors available in the food grade series?
Yes. Kolortek's food grade thermochromic series covers a range of activation temperatures and colors beyond this specific 31°C green variant. Custom color and temperature specifications are available for sufficient order quantities. Reach out to contact@kolortek.com with your requirements.

Request Samples or Technical Documentation

Samples of KTP-31-GBF are available for evaluation. Technical data sheets, MSDS, and COA can be provided on request. For custom formulation support, volume pricing, or private labeling inquiries, contact the Kolortek technical team directly at contact@kolortek.com.