How much do you know about fiber materials that change color?
(1) Photosensitive color-changing materials
Photosensitive color-changing material is a functional dye that can change color under the irradiation of ultraviolet light or visible light, and can be reversed to the original color after the light disappears. Photosensitive color-changing materials mainly include silver chloride, silver bromide, stilbenes, spirocycles, norbornadiene, fulgid anhydride, triphenylmethane derivatives, salicylic aniline compounds, etc. At present, photosensitive color-changing materials have been developed to have four basic colors: purple, yellow, blue, and red. The initial structures of these four optically variable materials are all closed-loop, that is, there is no color when printed on the fabric, and they turn purple, yellow, blue, and red when exposed to ultraviolet light.
(2) Heat-sensitive color-changing material
The reason why heat-sensitive color-changing materials can change color is that the color-changing body can cause changes in the internal structure, resulting in a change in color. When the temperature drops, the color returns. Compared with photosensitive dyes, there are much more researches on thermosensitive dyes at home and abroad, especially in the aspect of textile printing, which has achieved certain results, and a series of thermosensitive printing products have come out.
For example, the RT series produced in our country are heat-sensitive discoloration products. During the wearing process, the fabrics show changeable colors with different seasons, regions, and indoor and outdoor temperatures. At present, the main countries that can produce color-changing coatings and master the processing technology are Britain, Japan, and Taiwan.
(3) Moisture-sensitive color-changing materials
The main reason for the discoloration of humidity-sensitive color-changing materials is that the humidity in the air causes the structural change of the dye itself, thereby changing the absorption spectrum of the visible part of sunlight, and the ambient humidity has a certain catalytic effect on the discoloration of the color-changing body. The main component of the moisture-sensitive color-changing dye color-changing printing paste is the color-changing cobalt double salt, and the color-changing body is firmly adhered to the fabric by an adhesive during application. In order to make the discoloration sensitive, a certain sensitizer needs to be added to help the discoloration body complete this process, and a certain color enhancer is also added to improve the vividness of the discoloration fabric.
If the color-changing paint is skillfully combined in the printing color paste, it can be used in towels, bath towels, handkerchiefs, swimwear, beach clothes, etc., to obtain unique printing patterns. It is white when dry, and becomes translucent when wet and the pattern disappears.
Manufacturing technology of color-changing materials
In the field of textiles, the manufacturing technology of color-changing materials mainly includes two parts: color-changing fibers and color-changing dyes:
The color-changing dyes used in textiles are mainly thermochromic dyes, photochromic dyes and moisture-sensitive color-changing dyes. However, due to the unsatisfactory rubbing fastness and washing fastness of these dyes, in the 1990s, people introduced microcapsule technology into the preparation of color-changing dyes, which made the application of color-changing dyes in textiles obtain a qualitative leap. Compared with printing and dyeing technology, color-changing fiber technology has obvious advantages: the fabric produced has good hand feeling, good washing resistance, and long-lasting color changing effect.
The development trend of color-changing materials
Color-changing fiber material is a high-tech functional fiber that has developed rapidly in recent years and is full of vitality. It has high added value and high benefit. With people's increasingly high-grade and individualized requirements for clothing and higher requirements for functional finishing fabrics, the development of new color-changing fiber materials and color-changing dyes will have good development prospects and broad application space.
