Omnistab OB

Omnistab OB is a 2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole). It is a high molecular weight optical brightener / fluorescent whitening agent of the thiophenediyl benzoxazole class. Omnistab OB features excellent resistance to heat, exceptional whitening properties, good light fastness and low volatility. It has a brilliant bluish cast, is readily soluble in organic solvents and features good compatibility in various substrates. Suitable for the optical brightening of polymers at all stages of processing. It is highly effective in polymer substrates such as engineering plastics such as polyesters, polycarbonate, polyamides and acrylics, thermoplastic polyurethane, polyvinylchloride, styrene homo- and copolymers, polyolefins and other organic substrates. Main applications include synthetic leather, fibers, molded articles, films and sheets as well as packaging applications. The use levels of Omnistab OB range between 0.0005 – 0.0010 % in unpigmented polyolefins and 0.005 – 0.100 % in other plastics.

Product composition

  • CAS number(s): 7128-64-5
  • Chemical name(s): 2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole)
  • Molecular formula: C26H26N2O2S
  • Molecular weight (g/mol): 430.56
  • EU (EG-No (EINECS/ELINCS)): 230-426-4


  • Content (%): 99.00 min
  • Melting point/range (ºC): 196 - 205
  • Transmittance 450 nm (%): 97.00 min
  • Transmittance 500 nm (%): 98.00 min
  • Ash (%): 0.30 max
  • Volatiles (%): 0.50 max
  • Product form(s): Crystal powder, Powder
  • Packaging option(s): Fiber drum, Carton


In 2007 we decided to start ICG Specialty Chemicals selling specialty chemicals and additives under the tradename Omnistab.



Partners in Chemicals expanded its business in Middle East by setting up a branch office in Dubai in 2014.

Our Dubai office gives direct access to the Middle East and Africa. Having warehousing facility in the Dubai Free Zone makes it much easier to import, stock and re-export material to different destinations around the globe.




To serve the American market we have set up our Chicago branch office in 2009.



Deltachem (Qingdao) Co. Ltd. has been established in 2012 but general manager Mr. Mike Zou is already since 2007 a business partner for the Omnistab range.

Deltachem is the partner of Choice for Partners in Chemicals.

Besides being responsible for sourcing new products, supplychain and quality controle Deltachem is also managing the production facilities and handles the technical support.

Visit Deltachem