Thermochromic in-mold labels (temperature-sensitive IML) change color at a precise trigger temperature — fused permanently into PP cups. YZY supplies thermochromic IML from -15°C to 70°C, with 15+ base colors and the option to layer thermochromic + standard inks. Perfect for hot drink warnings, cold drink indicators, kids' products, limited editions, and interactive marketing.
❄️ A cold Pinkbox cup goes from black-and-white to vivid pink Plaza.
🔥 A 60°C orchid tea reveals "ORCHID" only at serving temperature.
👘 A Chinese beauty's hanfu shifts from pale pink to bright red as you hold it.
Thermochromic IML is a temperature-sensitive in-mold label. A microencapsulated dye — a leuco dye combined with a color developer and a temperature controller — is printed onto the IML film. Below the trigger temperature, the dye is colored. Above the trigger temperature, the dye becomes colorless (or shifts to a second color). The label is then fused into a PP or PE container during standard injection molding, exactly like a conventional IML.
The result: the cup, tub, or closure physically changes color or reveals hidden graphics when the contents cross a precise temperature threshold.
Figure 1: YZY thermochromic IML cup at 60°C trigger — the "ORCHID" graphic reveals in red as the drink reaches serving temperature. (Left: below trigger / Right: above trigger)
| Parameter | Specification |
|---|---|
| Operating temperature range | -15°C to 70°C |
| Trigger temperatures | Typically in 5°C increments (-15, -10, -5, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70°C) |
| Color behavior | "Low-temperature colored / high-temperature colorless" is the most common configuration |
| Base colors | 15 standard colors per trigger temperature (70°C formulation limited to black + deep blue only) |
| Color mixing | The 15 base colors can be intermixed to produce custom hues |
| Overprint | Thermochromic inks can be overprinted with standard CMYK inks for non-thermochromic elements |
| Response time | 1–3 seconds for full color transition at the trigger point |
Thermochromic ink also works on stickers, shrink sleeves, and surface-printed containers — but the format has major limitations:
· Stickers can be peeled and replaced (counterfeiting risk; also looks cheap on premium products)
· Shrink sleeves require a separate heat-shrink process and have visible seam lines
· Surface-printed containers expose the thermochromic ink to direct contact, accelerating wear
Thermochromic IML solves all of these issues:
· ✅ The label is fused into the container wall — cannot be peeled, removed, or transferred
· ✅ The thermochromic ink is printed on the inside of the label film and protected by the IML structure during normal use
· ✅ The container remains a mono-material PP product, fully recyclable in the #5 PP stream
· ✅ No secondary process — the IML is part of the same injection-molding cycle that produces the cup
· ✅ Printing resolution up to 200 LPI supports fine artwork, micro-text, and complex multi-color designs
3.1 Hot Drink Safety Warnings
A thermochromic IML that switches from "HOT! Careful!" (visible) to a clean brand design (hidden) at 50–60°C is a built-in safety label that disappears once the drink has cooled to a safe temperature. Restaurants, QSR chains, and coffee brands can integrate this into their standard cup design with no extra process step.
3.2 Cold Drink Indicators (the "Ice Melt" Effect)
The reverse configuration — a colored design that fades as the drink warms above 5–10°C — gives the consumer a real-time "is my drink still cold?" signal. Beer brands, RTD cocktail brands, and cold-brew coffee brands are actively piloting this concept in 2026.
3.3 Marketing Reveals & Limited Editions
A cup that reveals a hidden word, character, or graphic only when the consumer holds it (body heat crossing 28–32°C) is one of the highest-shareable unboxing experiences in beverage marketing. The Pinkbox Plaza and ICEE polar bear examples in this article are exactly this kind of design.
· 1. What is the trigger temperature for your application? Hot drink warnings typically use 50–60°C; cold drink indicators use 0–10°C; marketing reveals use 28–32°C (skin temperature).
· 2. What is the design intent? "Reveal" (hidden graphic appears at trigger), "Hide" (visible graphic disappears at trigger), or "Swap" (one color changes to a different color at trigger).
· 3. What is the use cycle? For single-use or short-cycle applications (QSR cups, festival cups, limited-edition SKUs), this is more than enough. For long-cycle reuse (reusable cups, food-storage containers), request a higher-grade formulation.
5. Thermochromic Material Data Sheet
| Parameter | Specification |
|---|---|
| Trigger temperature range | -15°C to 70°C (5°C increments) |
| Standard behavior | Low-temp colored / high-temp colorless |
| Base colors | 15 (limited to black + deep blue at 70°C) |
| Color mixing | Yes — 15 base colors can be blended |
| Overprint with standard ink | Yes — non-thermochromic elements can be added |
| Response time | 1–3 seconds |
| Container sizes | 8oz–24oz cups, 12oz–32oz bowls, 250ml–1L tubs |
| Materials | PP (standard), PE (optional) |
| Lead time | 12 days after design approval |
| Certifications | FDA 21 CFR, EU 10/2011, GB 4806.7 |
