chemical fiber is a fiber with textile properties made from natural polymer compounds or synthetic polymer compounds as raw materials, through the preparation of spinning solution, spinning and subsequent processing.
chemical fibers are widely used in the manufacture of clothing fabrics, filter cloths, conveyor belts, hoses, ropes, fishing nets, electrically insulated wires, medical sutures, tire cord fabrics and parachutes. generally, the polymer compound can be made into a solution or melt, pressed out from the pores of the spinneret, and then solidified to form fibers. the product can be continuous filament, short fiber cut into a certain length or uncut tow, etc.
commercial names of chemical fibers: china temporarily stipulates that synthetic short fibers are all named “lun” (for example, nylon, polyester), cellulose short fibers are all named “fiber” (for example, viscose fiber, cuprammonium fiber), and filament is add the word “si” at the end, or change “lun” or “fibre” to “si”. among chemical fibers, the one we hear most about is polyester. today, lianda editor will take polyester as an example to talk about what kind of fluorescent whitening agent should be used for chemical fibers.
polyester itself has a certain degree of whiteness, but in order to meet specific whiteness and color requirements, it must be whitened with a fluorescent whitening agent. the structure and characteristics of polyester determine that it is difficult to whiten it. hydrophilic fluorescent whitening agents cannot be used for whitening. generally, non-water-resistant dispersed fluorescent whitening agents are used to make a stable dispersion, and then heated special methods such as melt dyeing, high temperature and high pressure dyeing or carrier dyeing allow the fluorescent whitening agent to diffuse into the fiber (relying on thermal movement to diffuse and sublimate into the fiber) and evenly distribute it to whiten it. sometimes when an intermittent process is used, it is often carried out in the same bath as bleaching. for the whitening of polyester puree, powdered products of dispersed fluorescent whitening agents can be used directly.
therefore, the fluorescent whitening agent used for polyester must have good thermal stability and high fastness to sublimation, light fastness and chlorine bleaching fastness. judging from the types of fluorescent whitening agents, there are azoles, coumarins, stilbenes, naphthalimides, triazinylpyrenes, etc.
the commonly used fluorescent whitening agents for polyester are: c.1. fluorescent whitening agents 135.179, 185, 199 and their isomers, 229, 236, 367, 368, 393, etc. among them, c.i. fluorescent whitening agent 199 and its derivatives, 236, 378, 393, 368 can be used to whiten the polyester fiber puree, and c.i. fluorescent whitening agent 199 and its derivatives can be used for polyester short fiber.
there are many varieties of fluorescent whitening agents. you can find the products you need according to the use of the products, solving your choice troubles.