What are Optical Brighteners?

Definition of the Optical Brightener

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 300-370 nm) of the electromagnetic spectrum, and re-emit light in the blue region (typically 420-470 nm) through the phenomenon of fluorescence. These additives are often used to enhance the appearance of color of fabric and paper, causing a “whitening” effect; they make intrinsically yellow/orange materials look less so, by compensating the deficit in blue and purple light reflected by the material, with the blue and purple optical emission of the fluorophore.

What are the synonyms?

There are many similar names for optical brighteners, and the most commonly used ones are listed below:

optical brightener / Fluorescent brightener / Fluorescent dye

Whitening additive / Optical brightening agent / Optical brightening compound

Fluorescent whitening agent / Optical bleaching agent / Fluorescent brightening agent

Fluorescent whitener / Brightening agent / Optical whitener / Optical bleach

Whitening agent / Fluorescent brightener / Optical bleach / Optical brightening dye

The trade names

World-famous manufacturers and their trade names.

^{Note: Due to mergers and acquisitions between companies, some brands may belong to different companies at different times.}

Dystar/Archroma/Bayer: Blankophor, Ultraphor, Hostalux

Ciba/BASF: Uvitex, Tinopal

Eastman: Eastobrite

NSK: Whitex

Clariant: Lecukophor

Hunstman: Uvitex

….

Work Principle of Optical Brighteners

Optical brighteners can absorb invisible ultraviolet light (wavelength of about 300-400nm), and remit blue or blue-violet (wavelength of about 400-500nm) visible light, offset the yellowish color on the substrate. This makes the substrate appear whiter, brighter, and more colorful. The whitening is a kind of physical optical whitening, which will not cause physical or chemical damage to the substrate.

What are the Main Features of optical brighteners?

The optical brighteners currently used in the industry are all synthetic organic compounds.
To work as a whitening agent, it must have some basic features:
1. The compound itself is nearly colorless or light colored
2. High fluorescence quantum yield
3. Good affinity and no chemical interaction with the substance/ substrate to be acted upon.
4. Good heat resistance and light stability.

Regulation, Health, and Safety.

FDA: CFR Title 21- Chapter I – Subchapter B – Part 178 – Subpart D
§178.3297. Colorants for polymers. In all polymers at levels not to exceed 0.015 percent by weight of the
polymer. The finished articles are to contact food only under conditions of use A through H described in Table 2 of §176.170(c).

Rohs, SVHC by SGS. OB OB-1 offered by Shandong Grand Chemical complies with the limits as set by Rohs directive (EU) 2015/863 and has passed SVHC screening for authorization by the European Chemicals Agency (ECHA) on and before June 5. 2020.

REACH registration: 10M-100MT of OB OB-1 to European Countries.

Common industry uses of Optical Brighteners

The application is extremely wide. It has been applied to various industrial areas and is closely related to people’s lives. The main purposes are as follows:

• Plastics / Polymers whitening
• Paints/coatings/inks whitening
• Textiles / Fibers whitening
• Detergent / Home Care / Personal Care
• Paper whitening

Classification of Optical Brighteners

• Classify by Application: Plastic/ Polymers, Paints/Coatings/Inks, Textile, Detergent, Paper etc.
• Classify by Ionicity: Cationic, Anionic, Non-ionic
• Classify by Using Method: Direct Dyeing, Dispersed Dyeing.
• Classify by Physical Form: Crystalline powder, fine powder, Liquid, Emulsion.
• viaClassify by Chemical Formula structure:
  • DSD acid fluorescent whitening agent
  • Stilbene-based fluorescent brighteners
  • Benzoxazole fluorescent brighteners
  • Benzimidazole-based fluorescent whiteners
  • Coumarin fluorescent whiteners
  • Naphthylimide fluorescent whiteners
  • Pyrazoline-based whitening agent
  • Polymerized fluorescent whitening agents
  • Others

Want to know more about the optical brighteners, please do not hesitate to contact us via: sales@obachemical.com or Whatsapp: +86 13173009832