Temperature-sensitive ink is a type of ink that changes color with temperature fluctuations. It is commonly used in areas requiring high-temperature warnings, such as on boilers or equipment, to alert personnel to avoid contact or to visually indicate that the equipment is overheating and needs maintenance. Besides its warning function, temperature-sensitive ink is often used in creative products, such as color-changing mugs when hot water is added, or urinal deodorant balls that change color to help men aim better.
Reversible Thermochromic Ink
Reversible thermochromic ink usually has color at low temperatures and becomes transparent or colorless at high temperatures.
High-temperature transparent thermochromic ink is often used in "concealment" situations. A pattern is first printed on the substrate, followed by the thermochromic ink. When heated to a high temperature, the thermochromic ink turns transparent, revealing the hidden pattern below. In such scenarios, it is recommended to print with black or dark-colored thermochromic ink for better concealment.
Color change in response to body temperature is a popular theme among designers. It is recommended to use these products in air-conditioned environments to prevent them from changing color prematurely due to high ambient temperatures before they are touched.
Here's an example of a restaurant menu design. The menu printed with thermochromic ink is placed on a stove to heat up, revealing the menu content and enhancing the dining experience for customers.
Reversible thermochromic ink used in business card design examples.
Reversible thermochromic ink used in PVC card printing examples.
Irreversible Thermochromic Ink
Irreversible thermochromic ink usually appears white or light-colored at low temperatures and changes to a darker color at high temperatures. When the temperature returns to a low state, the color does not revert, hence it is called "irreversible." It is typically used for high-temperature warning purposes. For instance, during the logistics process, it can record temperature exposure.
Liquid Crystal Ink | Thermochromic Ink
Both liquid crystal ink and regular thermochromic ink change color due to temperature variations. The main difference between the two is that regular thermochromic ink has only two color changes (usually from colored to transparent or white), while liquid crystal ink can display 6-12 different colors depending on the temperature.
Liquid crystal ink can be classified into two types based on color changes:
12-Color Liquid Crystal Ink: Color changes from low to high temperature are black → red → green → blue → dark blue → purple → green → blue → dark blue → purple → dark purple.
6-Color Liquid Crystal Ink: Color changes from low to high temperature are black → red → green → blue → black.
Liquid crystal ink offers more precise color changes compared to regular thermochromic ink, making it suitable for "body temperature measurement strips." These can be roughly categorized based on accuracy into two types:
For decorative or fun purposes: Temperature difference range is about ±2.5°C.
Thermometer Use: Temperature difference range is about ±1 to 0.5°C.
The rich color variations of liquid crystal ink are also used in jewelry, toys, gifts, arts and crafts, and wine label designs.
