What is the principle of mug discoloration?

Feb. 19, 2020

People often used to call ceramic cups with handles like mugs. There is a ceramic mug that looks black, red, green, or other colors, but when you pour hot water into the cup, the original color of the cup will gradually fade away and a special pattern will appear. After a few minutes, the pattern became clear. If the water in the cup is cold, the pattern on the cup will gradually disappear, revealing the original color of the cup. This is how it happened? Ceramic coffee mug supplier shares with you.

Ceramic Mug

It turns out that this color-changing mug has a layer of thermosensitive coating made of heat-sensitive material than ordinary mugs. The thermosensitive material is also called thermochromic material. Its color will change from colored to colorless, or from colorless to colored, and it can also change from one color to another according to the change of temperature. Common thermochromic materials are composed of an electron donor (chromogen), an electron acceptor (chromogen), and a solvent. The developer receives the electrons provided by the color former to produce a color reaction, and the solvent determines the color-changing temperature of the material. The color-developing agents include triarylmethane phenols and fluorane compounds. The color-developing agents are mainly phenolic hydroxy compounds and their derivatives, and most of the solvents are alcohols (such as n-hexadecanol). When the temperature rises, the electrons in the atom transfer, causing the molecular structure of the organic substance to change, thereby achieving a color change. This reaction is reversible. When the original temperature is restored, the structure of the material molecule is also restored to its original state, and its color is restored to its original color.

Making color mugs is easy. The thermochromic material is ground into 3 to 10-micron powder particles, adjusted to a water-based paint, coated on an ordinary ceramic cup, and then placed in an oven and baked at a high temperature of about 320 ° C to remove moisture and adhesives, so that The thermochromic material is cured on a ceramic cup. Then enter the pictures or photos to be "printed" on the cup into the computer, and then use a special "printer" to print on a piece of thermal transfer paper. Thermal transfer can print the pattern on various materials. The specific production method is to print the pattern on special transfer paper with special transfer ink, then paste it on the thermochromic coating on the outer surface of the cup and put it in the oven The heat transfer process is performed at a temperature of about 220 ° C. After a few minutes, the picture or photo on the transfer paper is printed on the cup, and a special color-changing mug is made. When hot water is added to the cup, the thermochromic coating becomes colorless and transparent, and exquisite pictures appear.

Temperature-sensitive materials were first extracted from plants. In order to obtain more kinds of colors and higher yields, scientists artificially synthesized a large number of temperature-sensitive materials. Different temperature-sensitive materials have different temperature sensitivity ranges, so the color of the color-changing cups made of different materials varies with temperature.