The production of the corante directly on the substratum makes with that the tingimento is highly efficient, with good setting, resistance to the light and also to the humidity. The color is produced inside of the fiber, presents high solidity, does not need fixing, the gotten brightness is considered excellent, but it is a long process, with high cost and attacks the environment. The corantes daily pay-metallized use of pigments the oxide base wide used in the market for presenting high to be able of covering, easiness of use, raised opacity, possibility of products micronizados and low oil absorption. Already the reactive corantes contain a eletroflico group (reactive) that it forms covalentes linkings with molecules of staple fibres, for example, with hidroxilas of celulsicas staple fibres, or with amino, hidroxila and tiis of proteinic staple fibres or with groups still amino group of the poliamidas ones. They are economically intermediate, they do not need clamp, they present high solidity to the light and humid and the high reprodutividade. The restriction in the treatment with chlorine has as disadvantage and attacks the environment.
Differently of corantes or pigments fluorescent the optic or agent branqueadores of branqueamento are colorless organic composites or little colored that, in solution or applied to a substratum absorbs the light, in the region next to the ultraviolet one to the specter (340-380 nm), and re-emits most of the absorbed energy as violet-bluish fluorescent light, in the visible region between 400 and 500nm. The result is that the materials submitted to this treatment seem, by rough estimate human, less yellowish, more shining and whiter. Carrying through the dream of the man, or creating the optic illusion, to reproduce the pure white, of clouds and the snow, forgetting the yellowish appearance that the chemical pigments and alvejantes result in the conventional processes of tingimento in the white color. 2.3ESTRUTURA OF SOME MATERIALS the natural staple fibres of vegetal origin are composed basically of cellulose, a polymer of the carboidrato glucose.