Optical Brightener Agents
Optical brightening agents (OBAs), also known as fluorescent brightening agents (FBAs), are chemical compounds that give whitening effect to fabric. They do this by absorbing light in the ultraviolet and violet region and re-emit the light in the blue region.
This blue light reduces the yellow color of the substrate and give a brightened look. Unlike bleaching, it doesn’t leave a yellowish tinge and gives a much pleasing whiter-than-white appearance.
Types of Optical Brightening Agents
Based on the number of sulphonic groups, brightening agents can be categorized into three main types.
1) Disulfonated Optical Brightening Agents
These optical brighteners consist of two sulphonic groups. These agents are hydrophobic in nature because of their chemical composition. In simpler words, the solubility of these OBAs is quite low. Typically, they’re used in wet end.
2) Tetrasulfonated types
As the name suggests, these brighteners are made by four sulphonic groups. This type of brightening agents exhibits medium affinity and good solubility. Therefore, they’re an ideal solution in wet end as well as in dry end. These OBAs are most commonly used OBA type used in paper and paper board.
3) Hexasulfonated OBAs
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.
We offer neutral shade optical brightener for use in all applications, tetra and hexa sulphonated stilbene brightener which may be applied in the stock, at the size press or in a coating.
OBA liq is tetra sulphonated offers good substantivity to the bleached pulps and very good compatibility with the commercial size-press starches.
OBA Liquid is urea –free and therefore will not increase the nitrogen content of backwaters and effluent.