Heat Reactive Thermochromic Powder Malachite Green 17°C — KTP-17-MG

KTP-17-MG is a microencapsulated leuco-dye system processed to a fine powder, 1–10μm particle size, designed for wet and dry dispersion into a range of binders. At temperatures below 17°C, the pigment presents a saturated malachite green. As temperature rises above the activation point, the color fades to colorless — exposing whatever is beneath it, whether that's a white base, a printed graphic, or a contrasting color layer.

The transition is fully reversible. Cool the substrate back down and the green returns. That cycle can repeat many thousands of times in a properly formulated system with appropriate UV protection and thermal stability additives.

Worth noting: the activation temperature of 17°C places this product at a point where it responds to ambient room conditions, human touch, or mild heating. That's distinct from higher-temperature variants, which require sustained warmth to activate.

Product Series — KTP-17-MG

The broader KTP series includes variants that shift colored-to-colorless, colored-to-another-color, and food-grade BPA-free versions for direct-contact or sensitive applications. Activation temperatures range across the series to cover cold-chain, ambient, and high-heat use cases.

Applications

KTP-17-MG is formulated for use across several substrate categories. In practice, these are the most common integration points:

• Nail coatings: Disperses well in UV gel and lacquer systems; the 17°C activation responds to ambient temperature shifts during wear.
• Textile printing: Compatible with water-based binder systems for screen, digital, and heat-transfer printing. Color change is visible through normal temperature variation in garment use.
• Paints and coatings: Suitable for architectural, decorative, and novelty coating applications. Not recommended for automotive topcoats due to thermal cycling stress and clear-coat incompatibility.
• Printing inks: Works in offset, flexo, and screen systems where the base is formulated to maintain microencapsulation integrity during shear.
• Craft and art materials: Straightforward to use in low-shear, ambient-cure craft mediums — paints, resins, waxes.
• Cosmetics: Applicable in appropriate cosmetic matrices. For hair dye applications, the food-grade KT series is the correct specification.
• Custom paint projects: Color-reveal effects using layered base coats are a common design technique with this pigment.

Key Characteristics

A few points that affect formulation decisions:

• Low activation threshold: 17°C means the pigment can activate in cool ambient conditions — a design asset for touch-response applications, but a factor to manage in packaging and storage.
• Colored to colorless: The malachite green disappears above activation temperature. The visual result depends entirely on what's below — base coat color, substrate tone, or layered design.
• Fine particle distribution: The 1–10μm range supports smooth dispersion in most liquid systems without settling issues at typical formulation viscosities.
• Reversible cycle: The transition is thermally reversible under normal operating conditions. Long-term cycle stability depends on UV exposure management and binder compatibility.
• Microencapsulated structure: The capsule protects the leuco-dye core but requires care during high-shear mixing. Excessive mechanical stress can damage capsule walls and reduce color intensity or responsiveness.

Practical Considerations for Formulators

Dispersion method matters. KTP-17-MG should be incorporated using low-to-medium shear mixing. High-speed dispersers, bead mills, or three-roll mills are generally not appropriate — the mechanical energy damages the microcapsules and degrades performance. Stirring into a pre-wet binder or using a planetary mixer at controlled speed is the standard approach.

UV stability is a real limitation for outdoor use. Leuco-dye systems are inherently sensitive to UV degradation. For exterior applications, UV absorbers or UV-stable topcoats should be incorporated into the system design. Indoor or short-exposure applications have significantly fewer constraints.

Base coat color is a design variable, not an afterthought. Because the pigment becomes transparent above 17°C, the revealed color is whatever sits beneath it. A white base gives a neutral reveal; a colored base creates a complementary or contrasting shift. This is where most of the visual design work happens.

That said, loading rate affects both color saturation and the sharpness of the transition. Higher loads produce more intense color below activation; too high a load in thin films can create uneven distribution. Typical loading ranges vary by application — technical data sheets provide starting-point recommendations.

Storage: keep sealed, away from heat and direct light. The 17°C activation point means warehouse temperature is a real handling consideration — not just a spec footnote.

Colored-to-Colorless vs. Other Change Types

KTP-17-MG is a colored-to-colorless variant. This is the most common format for reveal-effect designs — the pigment disappears, exposing the layer below. It's the right choice when the design intent depends on a hidden graphic, text, or base color becoming visible.

Colored-to-colored variants shift from one hue to another. These are used where a continuous color presence is required and a full fade-to-clear isn't desirable. Food-grade BPA-free versions are available for sensitive contact applications. All variants operate on the same reversible temperature-response principle — only the color behavior and regulatory compliance differ.

FAQ

Q: Can KTP-17-MG be used in solvent-based systems?
Yes, it can be incorporated into solvent-based binders, but solvent selection matters. Strong solvents — particularly ketones and some esters — can attack the microcapsule shell over time. Aliphatics and mild aromatic systems are generally more compatible. Pre-dispersion testing in your specific solvent blend is recommended before scaling.

Q: Is this product suitable for food contact or cosmetic direct-skin applications?
KTP-17-MG is not designated food grade. For hair dye or direct food-contact applications, the KT Food Grade thermochromic series (BPA free) is the appropriate specification. For nail and general cosmetic applications, KTP-17-MG is applicable — but always verify compliance with your regional regulatory requirements.

Q: How sharp is the color transition at 17°C?
The transition zone typically spans a few degrees rather than being a single hard threshold. Color begins to fade as temperature approaches 17°C and completes the shift within a few degrees above. The perceived sharpness depends on film thickness, loading rate, and the contrast between the pigment color and the base coat beneath. Thicker films tend to show a more gradual transition; thinner films can appear sharper.

Q: What documentation is available for qualification or compliance work?
MSDS, TDS, and COA are available. Certifications include ISO 9001, REACH, and SGS. For procurement or regulatory qualification, contact contact@kolortek.com with your specific documentation requirements.

Request Samples or Technical Support

If you're evaluating KTP-17-MG for a specific application or need formulation guidance, samples and technical data sheets are available on request. Custom color development and activation temperature variants are also supported for projects with defined volume requirements. Reach out at contact@kolortek.com with your substrate, application type, and target performance criteria.