Brighteners/whiteners

Hostalux . [Hoechst Celanese/Colorants Surf.] Benzoxazole tferiv. optical brightener, whitening agent fm polymer processing. 

Uses Opticai brightener, whitening agent in aii types of poiymer processing, piastic fiims, press moiding, and in], moiding materiai fibers and bristies, paints and iacquers... 

Hazardous Decomp. Prods. Heated to decomp., emits toxic fumes of NOx Uses Optical brightener, whitener for polyesters and blends... 

Dye Intermedia.tes, Dye intermediates are defined as those precursors to colorants that are manufactured within the dyes industry, and they are neady always colodess. Colored precursors are conveniendy termed color bases. As distinct from primaries they are only rarely manufactured in single-product units because of the comparatively low tonnages requited. Fluorescent brightening agents (FBAs) are neither intermediates nor tme colorants. Basic manufacturing processes for FBAs are described in Reference 18 (see Fluorescent whitening agents). 

Lawrence and Ducharme [489] have described a fast, simplified method for the detection of fluorescent whiteners in polymers, in which the polymer dissolution was applied directly to the thin layer. Also the separation of optical brighteners (Leucopur EGM, Azur 4, Azur 5, Hostalux ABC, Uvitex OB, Eastobrite OB) from plastics and migration into water and olive oil was studied by HPTLC on RP-18 silica using various mobile phase mixtures and UV detection [490]. 

A collection of UV spectra of plasticisers, fluorescent whitening agents (optical brighteners), UV absorbers, as well as of phenolic and aminic antioxidants was published by Hummel and Scholl [21]. UV absorbance data for isolated chromophores are listed elsewhere [22]. A general UV atlas of organic compounds is available [23]. 

Descriptive terms such as fluorescent whitening agents , optical brighteners and optical bleaches have all been used for the products described in this chapter as FBAs. Many of these terms have validity and the term fluorescent brightening agents is preferred here only because it has been adopted in the indexes of Chemical Abstracts. 

Fluorescent whitening agents (LD) Create a brightening effect Substantivity on fabrics Compatibility with other ingredients like bleaches Bistriazinyl derivatives of 4,4 -diamino-stilbene-2,2 -disulfonic acid 0.1-0.5%... 

Pyrazolo[3,4- [1,2,3]triazoles 85, when applied as fluorescent brighteners on polyester fibers have been found to give moderate whitening effects with a violet fluorescence, and they were categorized as grade one fluorescent brighteners <1992MI95>. 

Cyanuric chloride is also used for the synthesis of optical brighteners for the whitening of paper, textile finishing and brightening plastics and paints. Derivatives of flavic acid, e.g. 

Brightening - pLUORESCENT WHITENING AGENTS] (Volll) -of mechanical pulps pULP](Vol20)... 

Colourless molecules with blue fluorescence are optical brightening agents that are used as blue whiteners in paper production and washing powders (see Chapter 7). The two main classes are heterocylics such as pyrazolines and particularly stilbenes (1). 

Optical brighteners (fluorescent whitening agents, FWAs) are used primarily in the textile, detergent, and paper industries and are also added to plastics [118], The mode of application and performance requirements differ greatly from one substrate to another, but there are five common basic principles ... 

Whitening can be assessed either visually or instrumentally (by colorimetry). The quantities evaluated are the degree of whiteness and the tint. Special attention must be paid to the spectral distribution of the incident light in the UV and visible ranges, since this controls the fluorescent contribution of the brightener to the whiteness [171],... 

---