Why are optical brightening agents used in textile materials?
In the application of OBAs, it is possible to replace the light lost through absorption, thereby attaining a neutral, complete white. Further, through the use of excess whitener, still more UV radiation can be converted into visible light, so that the whitest white is made more sparkling.
What is meant by optical brightening agent?
Optical brighteners, optical brightening agents (OBAs), fluorescent brightening agents (FBAs), or fluorescent whitening agents (FWAs), are chemical compounds that absorb light in the ultraviolet and violet region (usually 340-370 nm) of the electromagnetic spectrum, and re-emit light in the blue region (typically 420- …
What is the function of optical brightener?
Optical brighteners are used to mask the inherent yellowness of plastics and are used to improve colors and make plastic look whiter and brighter. These are generally added to enhance the esthetics and consumer appeal as shown in Fig. 4.7.
What is an optical brightener and how does it work?
Optical brighteners transform UV (ultraviolet) light waves to enhance blue light and minimize the amount of yellow light to make things appear whiter. So, they don’t get your clothes any cleaner, but make them appear whiter and brighter.
Which chemical is used as optical whitener in textile?
Hexasulfonated OBAs are the kind of OBAs that are made of six sulphonic groups. As a result, these OBAs display a remarkable solubility and they’re used in dry end coating. They’re mostly used in areas where high brightness is required.
What is optical whitening?
Optical brightening, or optical bleaches, are finishes giving the effect of great whiteness and brightness because of the way in which they reflect light. These compounds contain fluorescent colourless dyes, causing more blue light to be reflected.
Is optical brightener harmful?
Optical brighteners have also been shown to cause mutations in bacteria. Unfortunately, Optical Brighteners are just one of the many potentially harmful ingredients in a number of laundry detergent brands.
Is optical brightener bad for the environment?
Optical brighteners can irritate peoples skin, but it’s also believed they bioaccumulate in our water ways causing eutrophication – out of control algae growth and suffocate fish! They’re also so tiny, that they may pass through our water treatment facilities – not very eco-friendly!
What is fluorescent brightening agents?
Other names of FBA Optical brighteners, optical brightening agents (OBAs), fluorescent brightening agents (FBAs) or fluorescent whitening agents (FWAs) are dyes that absorb light in the UV and violet region (usually 340-370 nm) of the EM spectrum and re-emit light in the blue region (typically 420-470 nm).
What is optical brightener made of?
Optical brighteners also called fluorescent whitening agents (FWAs) are hydrophilic water-soluble compounds used in laundry detergents. They are mainly anionic diamino stilbene (DAS) or distyryl biphenyl (DSBP) derivatives displaying a low aquatic toxicity.
What chemicals are in optical brighteners?
Is optical brightener bad?
Detergents that use optical brighteners make the fabric stiffer, can be irritating to your skin, are bad for the environment, and do not even make your clothes any cleaner. Your eyes may think your clothes are cleaner, but it’s just an optical illusion.
What is the role of brightening agents in textile processing?
The operation of whitening, ie, bleaching or brightening, is concerned with the preparation of fabrics whose commercial value is dependent on the highest possible whiteness. In bleaching, textile process houses are concerned with the removal of colored impurities or their conversion into colorless substances.
How are optical brightener agents used in laundry?
Optical brightening agents are used to obtain white textiles. Due to their environmental properties, the Nordic Ecolabel excludes them from use in detergents and other laundry chemicals in leas- ing laundries certified with the Nordic Ecolabel to avoid leaching of OBAs to the environments with the washing water.
How are optical brighteners applied to polyester fibers?
In case of polyester fibers brighteners are applied in the form of fine aqueous dispersions. The brightener particles penetrate into the fiber in a state of molecular dispersion and they are held in the fiber by Vanderwaals forces. A part of finely dispersed particle forms a molecular solution in the dye-bath.
Which is the largest use of optical brighteners?
1) Detergent Industry: The biggest requirement of OBAs is in whitening the clothes and therefore, it’s no surprise that the detergent industry is the largest user of the fluorescent brighteners. As we all have experienced, clothes lose their natural whiteness over the course of time.