Sensing Temperature, Transmitting Information! There Are So Many Black Technology Applications Of Temperature Changing Ink!

With the emergence of new consumption scenarios, models, and formats, more and more users are pursuing personalized label products. Special inks, such as temperature sensitive inks, can greatly enhance the functionality and appearance of adhesive labels due to their unique properties. Therefore, more and more special inks are being applied to adhesive labels. In this article, the author focuses on sharing the working principle and application of temperature changing ink, hoping to bring some inspiration to readers.
01
The color changing principle of temperature changing ink
Thermochromic ink, also known as thermochromic ink, thermosensitive ink, or thermochromic ink. Thermochromic ink is a special type of ink that can change color according to temperature changes, meaning that when a specific temperature threshold is reached, the ink undergoes physical or chemical changes.
The color change principle of temperature sensitive ink is mainly based on its main component - thermosensitive microcapsule pigment. This pigment is composed of special dyes encapsulated in microcapsules. When the temperature reaches a specific threshold, the dyes inside the microcapsules undergo physical or chemical changes. For example, when the temperature rises, certain components in the ink may undergo phase transitions (such as solid to liquid) or structural changes. These changes lead to changes in the absorption and reflection characteristics of ink towards light, resulting in different colors appearing to the human eye.
02
Classification of Temperature Varying Ink
According to different color changing characteristics and thermodynamic properties, temperature changing inks are mainly divided into the following categories:
1. Classify according to the reversibility of the color changing process
According to the reversibility of the color changing process, thermal ink can be classified into two types: reversible and irreversible. Among them, reversible thermochromic ink is divided into three types: reversible thermochromic ink, reversible thermochromic ink, and reversible thermochromic ink.

(1) Reversible thermochromic ink. This ink displays a specific color at room temperature, and after heating, the color disappears and becomes colorless. It immediately returns to its original color after the temperature cools down. Due to the reversible process of its change, it is called reversible color changing ink.
(2) Reversible thermochromic ink. This ink appears colorless at room temperature, changes to another color after heating, and returns to its original colorless state after cooling. Due to the reversible process of its change, it is called reversible color changing ink.
(3) Reversible thermochromic ink. This ink displays one color at room temperature, changes to another color after heating, and returns to its original color after cooling. Due to its reversible process of change, it is called reversible temperature conversion ink.
Irreversible temperature change ink refers to a process in which the color changes during heating but cannot recover its original color after cooling. Due to its irreversible change process, it is called irreversible temperature change ink. Irreversible temperature change ink is often used in specific scenarios, such as some hospitals requiring high-temperature disinfection of medical supplies. In order to ensure that the relevant items have indeed undergone high-temperature treatment, high-temperature labels are needed. This type of label is printed with non reversible temperature changing ink. During high-temperature processing, the label will change from colorless to black, and it is irreversible. When the staff sees the label of the processed item changing color, they can determine that the item has undergone high-temperature disinfection treatment.
2. Classify by color changing temperature range and application scenarios
According to the range of color changing temperatures and application scenarios, temperature changing inks can be classified into low-temperature color developing inks, high-temperature color developing inks, motion sensing color fading/conversion inks, and three-stage color changing inks. Among them, low-temperature color developing ink refers to color developing below a specific temperature, and the color disappears after heating up. It is commonly used for applications that require low-temperature triggering of creativity or functionality; High temperature color developing ink refers to ink that needs to be heated to a higher temperature for color development, and then fades after cooling. This process requires an external heating source to trigger color change; Sensory fading/color changing ink refers to ink that changes color at a temperature close to human body temperature (31-35 ℃), changes color upon touch or heating, and recovers after cooling. This ink is suitable for interactive product displays; Three stage color changing ink refers to presenting three different color changes in different temperature ranges (such as 22-45 ℃), with customizable temperature nodes.
3. Classify according to pigment composition
According to the classification of pigment components, thermal ink can be further divided into inorganic reversible thermal ink, organic reversible thermal ink, and liquid crystal reversible thermal ink. Among them, inorganic reversible temperature ink is an ink developed based on inorganic thermosensitive materials. The ink has high stability, but some contain heavy metals, and it needs to comply with environmental standards when used; Organic reversible temperature change ink is a type of ink that uses organic compounds as color changing pigments. This ink has rich colors and good environmental friendliness; Liquid crystal reversible temperature change ink is an ink developed using the temperature response characteristics of liquid crystal materials. The ink has a delicate color change effect, but the cost is relatively high.
In short, the application range of temperature change ink is wide, covering food packaging, anti-counterfeiting, toys, medical and other fields. Its classification method can be flexibly selected according to specific needs.
03
Application of temperature changing ink

1. Changyu Paiger Brandy Wine: Feel the sweetness of the wine at any time
As shown in the picture, the pattern on the label of Changyu Paiger wine is printed with low-temperature color developing ink. Normally, the wine needs to be refrigerated at a temperature below 10 ℃. At this time, the color of the "horse" pattern on the label is white. When the optimal drinking temperature is reached, the color of the "horse" pattern on the label will change from white to red, reminding consumers that it is most suitable for consumption at this time.
Coors Light Beer: The Dual Magic of Sunshine and Temperature
Coors Light, a light beer under Molson Coors, has launched a label that changes color based on temperature and light. At the most suitable drinking temperature, the blue color on the can will be displayed; When consumers place the bottle in the sun, the yellow, orange, and red colors on the label will appear. It claims to be the world's first beer that can be activated by sunlight.
3. McDonald's x Coca Cola Co branded Cup: A Literary Style of Temperature Change
The joint cup launched by McDonald's and Coca Cola adopts the Morandi color scheme, which seems simple but hides "magic". As long as the appropriate temperature of water is poured in, the color of the cup will instantly change, restoring the brand's classic red and yellow colors.
3. South Korean dairy company Maeil Milk: Milk packaging with expiration reminder function
The word "milk" on the outer packaging of this milk will gradually change to "ill" over time, reminding us that drinking this box of milk after expiration will make us sick. This idea not only made the packaging more practical, but also earned the team the Red Dot Award in 2021.
3. Naked, a British skincare brand: cosmetics that can cause facial redness
This packaging, in terms of color and texture, is very similar to a girl's soft skin. When you touch it, the temperature of your fingers will immediately make the bottle body blush, like a shy girl. This interactive design not only provides topicality for the product, but also successfully stimulates consumers' curiosity, making them want to buy and try it out. Is it really that magical.
From food safety to anti-counterfeiting verification, temperature change ink is adding color to the label industry with "intelligent color change". Whether it's Coors Light's outdoor beer experience or McDonald's and Coca Cola's co branded cups, the application of thermal ink is bringing more surprises and interactive experiences to consumers. With technological iteration, it will enable every product to "sense temperature and transmit information"!