Generally refers to the visible light in the range of strong absorption and radiation of fluorescent dyes. The application of fluorescent dyes in textiles mainly includes the following three aspects:
1. Fluorescent brightener;
2. Disperse fluorescent dyes;
The application of fluorescent dyes and the use and harm of fluorescent fabrics are introduced in detail in this paper.
Principle of fluorescence fabric generation:
Fluorescence is a phenomenon in which light gives off light. When ultraviolet light, or some kind of light, hits a fluorescent substance, it absorbs energy that's consistent with the frequency of its signature, jumping from the ground state to the higher excited state.
The molecules in the unstable excitation state will relax to the lowest vibrational energy level of the excited state for a short time, balance the excited state, and then fall back to the higher vibrational energy level of the ground state. In the process of falling down, the energy is attenuated in the form of fluorescence, and the fluorescence disappears when the irradiation is stopped.
Fluorescent whitening agents have been widely used in textile, paper, washing powder, soap, rubber, plastics, pigments and paints.
The dispersed fluorescence dyes are small in molecule, and do not contain water-soluble base in structure. After the dip - rolling dye immediately dry, then hot - melting treatment. Under the action of high temperature, the dye deposited on the fluorescence fabric can diffuse into the fiber in the form of a single molecule, and finish the dyeing of chemical fiber in a very short time.
Because the small molecules of fluorescent dyes fuse with the fibers, the fluorescence fabric has good color fastness to rubbing and washing, but poor color fastness to light.
Fluorescent paint is a kind of pulp material composed of fluorescent pigments, dispersants and wetting agents, which is insoluble in water and has no affinity to fibers, and cannot be dyed according to the conventional dyeing conditions.
2. The fluorescence pigment particles are large, so the color rate is low, the color light is dim, the color fastness is poor, and the color light is not easy to be accurate; The particle is small, then the chromaticity is high, the fastness is better, but the brilliance has the influence.
3. The fluorescent coating is dipped and then attached to the surface of the fiber, and the resin component of the adhesive is used to help the coating to stick on the surface of the fiber, so as to achieve a certain color fastness. Due to the influence of the resin contained in the binder, the fluorescence fabric feel will harden.