OBA Chemicals & How They Affect Paper

What is an OBA Chemical?

An OBA chemical, formally known as an “optical brightening agent” are chemical compounds that harvests a whitening effect in fabrics and paper. It is done so by a process that absorbs the light from violet and ultra-violet regions and emits it into the blue region. It typically gives off an effect that hides the yellow like fibers that are normally found in paper. In other words, it ultimately prevents that yellow like tint that bleaching gives and produces a white appearance like no other.

Types of OBA’S

There are three main subgroups based on sulfonic groups that optical brighteners are separated into.

Disulfonated OBA

Disulfonated OBA’S contain two sulphonic groups. They are hydrophobic (water fearing) with very low solubility. This is commonly used in wet end.

Tetrasulfonated OBA

Tetrasulfonated OBA’s contain four sulphonic groups with good solubility. This is the most common OBA used in the paper industry.

Hexasulfonated OBA

Hexasulfonated OBA’s contain six sulphonic groups with excellent solubility. This type is used mainly in higher brightness papers, such as photo paper.


Believe it or not, most known paper that has a nice white look to it, has some amount of OBA and other chemicals in them. It has become more common than not to have these agents included within your paper.

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