Optical Brightener Masterbatch — Recycled or Off-White Plastic Looks Yellow or Dull

1. Problem

Recycled resin or off-spec white looks yellow or gray on the finished part, and the customer wants a cleaner, whiter appearance without going to full white pigmentation.

2. Symptoms

• Yellow cast on recycled PET, PP, or PE
• Dull or gray tone in transparent parts
• Batch-to-batch color drift toward yellow
• Poor visual match to virgin resin

3. Investigation (Before Prescribing an Additive)

Before recommending any Masterbatch, work through these checks:

• Confirm the base color problem — yellowing (recyclate), thermal degradation, or contamination.
• Check whether the goal is neutralization (bluing) or actual brightening (fluorescence).
• Check whether the part is UV-exposed — some optical brighteners degrade quickly outdoors.
• Confirm food-contact and regulatory environment.

Not every symptom needs an additive — sometimes the correct answer is a resin change, a process change, or drying. Investigation prevents wasted spend on a Masterbatch that does not fix the true root cause.

4. Candidate Masterbatch Family

One family commonly evaluated is Optical Brightener Masterbatch — fluorescent whitening agents (typically stilbene- or benzoxazole-based) that absorb UV and re-emit blue-white light, visually neutralizing yellow tones. Often combined with a small amount of blue pigment ('bluing') for stable perceived whiteness.

This page does not prescribe a specific SKU. Grade selection depends on the RFQ Mini Technical Specification at the bottom.

5. Polymer Considerations

Compatible with most commodity and engineering resins at low loadings. Not a substitute for TiO2 when true opacity is needed — see Wave 5 Titanium Dioxide for opacity.

For polymer-specific carrier compatibility, see Wave 8 — Polymer × Masterbatch.

6. Application Examples

Common applications where this problem appears:

• Recycled PET sheet and bottle (Wave 10 Sheet / Bottle)
• Recycled polyolefin film (Wave 10 Film)
• White injection parts where TiO2 alone is not enough (Wave 10 Injection)

7. RFQ Mini Technical Specification (9 Fields)

Under Application-First Selling v1.0 and Problem-First Discovery v1.0, an RFQ from this page should include every field below so the supplier can respond without a clarifying round-trip:

1. Polymer — grade + MFI
2. Indoor / Outdoor service — service environment
3. UV exposure — region (kLy/year), hours/day, expected years
4. Processing method — film, injection, blow, pipe, sheet, raffia
5. Color target — color family + Pantone/RAL if applicable
6. Thickness / gauge / wall — µm or mm
7. Expected lifetime — months or years
8. Regulatory requirements — FDA, EU 10/2011, NSF-61, REACH, RoHS, UL, or industry-specific
9. Annual volume — kg or MT/year

Continue Your Path

• Understand the engineering → Wave 2 — Color Masterbatch Explained
• Match by polymer → Wave 8 — Polymer × Masterbatch
• Match by application → Wave 10 — Application × Masterbatch
• Prepare specifications → use the 9-field checklist above
• Submit RFQ → /quote

Allzone supplies industrial Masterbatch across North America. We do not publish inventory or lead-time claims on knowledge pages. Submit an RFQ with the 9 fields above for a technical response.