Optical Whiteners Fluorescers

White fabrics, such as cotton, tend to absorb an increased amount of blue light and begin to appear yellow. Historically, washing blue was added when washing clothes so that cotton fabrics naturally aging to a 

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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 ... 

The estimation of optical whiteners in substrate is really a difficult problem, but the qualitative and quantitative estimation of fluorescent brightener in solution by examination of absorption and/or emission spectra have been detailed [42-46], Since the brightener will differ in substantivity for a particular substrate with differences in their chemical structure, cost comparisons of performance can only be based upon evaluation of the treated substrates. Various techniques for such evaluation have been described [46-51]. 

Specific additives and minors Corrosion inhibitors (sodium silicate) Foam boosters (alkylolamides) Foam inhibitors (hydr. soap/silic. oils) Stabilizers/sequestrants Optical brighteners/fluorescent whitening agents Soil antiredepositioning agents (CMC, Bentonite) Enzymes (alcalase, protease) Minors (dyestuffs, perfume)... 

Chem. Descrip. 2,2 -(2,5-Thiophenediyl) bis (5-t-butylbenzoxazole) CAS 7128-64-5 EINECS/ELINCS 230-426-4 Uses Optical brightener, fluorescent whitener for plastics, coalings, printing inks, and fibers... 

In the early twentieth century, patents were taken out on certain bis-(acylamino)-stilbene disulfonic acids for use as fluorescers in stage lighting effects produced by UV light. Their optical whitening properties were not recognized at that time, and it was some time later that a patent was filed for the production, as UV absorbers, of optical whiteners from the series of 4,4 -bis-(triazinylamino)-stilbene-2,2 -disulfonic acids. " ... 

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. 

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). 

Triazoles and their benzo derivatives have attracted considerable attention because of their theoretical interest, and synthetic value, as well as for their numerous applications in industry and agriculture due to their extensive biological activities and their successful application as fluorescent whiteners, light stabilizers and optical brightening agents. 

Tinopal . [Ciba-Geigy] Fluorescent whitening agent, optical Mghtener for laundry det ents. 

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