Optical Brighteners

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Brighteners, Optical

 

(also optical bleaches), colorless or slightly colored organic compounds that absorb ultraviolet rays of wavelengths between 300 and 400 millimicrons (mμ). They subsequently convert the ultraviolet rays into blue or violet light in the 400–500 mμ range, which compensates for an insufficiency of blue rays in the light that is reflected from the brightened material. Optical brighteners are used with many materials, including cotton, synthetic fibers, paper, wool, raw silk, leather, fur, and plastics. This process imparts a high degree of brightness to colorless materials and brightness and contrast to colored articles.

Most of the optical brighteners that are used with cellulose materials are stilbene-triazine derivatives of the general structural formula

where Rʹ and Rʺ are such groupings as NHR, NR2, NHC2H4-OH, N(C2H4OH)2, NHAr, OCH3, NHC6H4SO3Na, NH2, and OH (R being any alkyl radical and Ar being any aryl radical).

Optical brighteners are used during various stages in the preparation and processing of natural and synthetic materials. Optical brightening and dyeing are similar processes, especially the brightening and direct dyeing of cellulose materials. However, considerably less optical brightener than dye is needed to produce the desired effect. Optical brighteners that are insoluble in water may be used either in highly dispersed form or in solution with organic solvents.

References in periodicals archive ?
Rising demand in Asia-Pacific is the major growth driver for Optical Brightener market "
Also printed on pressure sensitive labels, the design is parallel, incorporating the intriguing eyes on the back label and including an optical brightener and foiling effects for on trade bottles.
The type of fluorophore (the compound that re-emits light when excited by UV light) used in the optical brightener can add to the inherent color of an object or stimulate color in another region," he explains.
To check for optical brightener, just observe the thermoplastic under a UV lamp.
Three tenders for the local supply of (a) 80 steel plates of special specs made of steel 316 L, (b) 200 tons optical brightener for delivery over several installments (a one ton sample need be delivered to Qous factories), & (c) 155 tons 210 gms.
The Ci64UV product is equipped with UV illumination to support the growing trend of adding optical brightener agents to materials
One of the models, C164vUV, uses UV illumination to support the trend of adding optical brightener agents to materials.
Optical brightener has been studied in relation to the effect of whitening properties of the polymer (18).
A representative continuous detector material may be an optical brightener.
5%, results that allow us to suggest the optical brightener presents a synergistic effect with the virus.
Optical brightener added to treated waste water, which is discharged into a dry creekbed, was detected at Reed Spring 1.
However, industrywide economic demands prompted a sheet ash increase along with optical brightener (OBA) use in the wet end.