Optical Brightener Masterbatch
Wash the yellow off your recyclate. Reclaim the white.
Optical Brightener Masterbatch (OB) makes plastic look whiter and brighter by cancelling out yellow tint. It absorbs invisible UV light and re-emits it as a faint blue glow, which the eye reads as a cleaner white. Used to lift whiteness in PE, PP, recycled polyolefins, white film and sheet.
A Fluorescent Whitening Agent masterbatch built around bisbenzoxazole and stilbene actives of the OB, OB-1 and KCB families, pre-dispersed in a polyolefin carrier. The active absorbs ambient UV and re-emits it as visible blue light. That extra blue luminance compensates the yellow undertone in recycled or aged polyolefins, lifts the apparent whiteness of white-pigment masterbatches and corrects yellowness drift (b* value) on transparent films.
Specifications
Grade-specific values and Certificate of Analysis are provided on confirmed dispatch. Contact us to confirm the right grade for your application.
- Appearance
- White cylindrical pellets
- Active chemistry
- Stilbene-based optical brightener
- Carrier resin
- LDPE / LLDPE / PP
- Recommended loading
- Varies by application; recommended dosage shared per grade
- Function
- Enhances perceived whiteness, removes yellow tinge
- Packaging
- 25 kg PE-lined paper sacks
Key benefits
Enhanced whiteness & brightness
Lifts the whiteness index of white-MB grades and corrects b* value on transparent film.
Restores brightness in recycled material
Compensates for the dulling effect of multiple heat histories in PCR and PIR streams.
Removes yellow tinge from regrind
UV-to-blue fluorescence cancels the natural yellow undertone of aged polyolefins.
Cost-effective vs more titanium dioxide
Lifts perceived whiteness at a fraction of the loading needed from titanium dioxide.
Applications
Frequently asked questions
What’s the recommended loading?
A very low dose of active fluorescent whitener is sufficient in the final compound. The required dose increases with the degree of yellowness in the feedstock. Above a threshold loading, the additive enters the quenching regime where more loading reduces, rather than improves, perceived whiteness. Contact us for the correct grade and loading for your application.
Which polymers and OB types do you stock?
Three actives are stocked: OB type bisbenzoxazole for PE, PP, PS; OB-1 for high-temperature PET, PA, PBT processing; KCB for transparent PVC and PMMA. Each is supplied at a low addition level on a polyolefin or polyester carrier matched to your host resin.
How does OB chemistry brighten the polymer?
Fluorescent whiteners absorb UV-A light (invisible to the eye) and re-emit the energy as visible blue light via fluorescence. The added blue compensates for the natural yellow tint of polymer chains (especially in recyclate, where chromophores from prior heat history absorb in the blue and shift the colour to yellow). The eye perceives the part as whiter and brighter, with a slight blue undertone.
OB vs OB-1 vs KCB, which should I use?
OB is benzoxazolyl thiophene, very high efficiency but more volatile at elevated processing temperatures. OB-1 is benzoxazolyl stilbene with higher thermal stability for engineering thermoplastics. KCB is a coumarin-type whitener tuned for PVC and clear PMMA where OB / OB-1 are insufficiently miscible. Selection depends on host-resin processing temperature and transparency requirement.
Can I get a trial sample?
Yes. We supply 1-2 kg trial samples. Share host resin, processing temperature, current Yellowness Index and target whiteness; we ship a matched grade with a Certificate of Analysis. Sample shipping is free within India; export samples available with freight at cost.
What’s the lead time?
Standard grades ship in 7-14 working days. Custom formulations for engineering polymers (PET, PA) or PVC-compatible grades take 3-4 weeks. We confirm an exact timeline at the quote stage.