In PVC manufacturing, appearance quality is a critical factor that directly influences market competitiveness. Whether for rigid PVC pipes, sheets, transparent films, or soft PVC profiles, achieving high whiteness and brightness is essential. This is where the optical brightener for PVC becomes a key functional additive. By enhancing whiteness, improving visual appeal, and even contributing to better durability, optical brighteners play a vital role across PVC processing applications.
This article provides a structured, technical overview of optical brighteners used in PVC—covering mechanism, performance differences, and selection guidance—helping manufacturers choose the most suitable brightener for their product needs.
1. Working Mechanism of Optical Brighteners in PVC
An optical brightener for PVC is essentially a fluorescent dye that absorbs invisible ultraviolet (UV) radiation and re-emits it as blue–violet light. This blue–violet fluorescence counteracts the natural yellowish tint of PVC, producing a visually cleaner, purer white.
This whitening mechanism provides two major benefits:
✓ Enhanced Whiteness & Brightness
The emitted blue–violet fluorescence complements PVC’s yellow tone, delivering a brighter and more uniform white appearance.
✓ Improved UV Resistance & Anti-Aging
By absorbing UV radiation, optical brighteners help reduce UV-induced degradation. This contributes to better weatherability and extended service life of PVC products.
2. Common Types of Optical Brighteners for PVC
Although many optical brighteners exist—such as KSN, KCB, ER, OB-1, OB, and FP-127—only a few perform exceptionally well in PVC systems due to specific compatibility and processing demands.
The most widely used options in PVC include:
(1) Optical Brightener OB-1
Best for: Rigid PVC products (pipes, sheets, profiles)
- Advantages:
- Highly cost-effective
- Good thermal stability
- Provides moderate whitening performance
- Limitations:
- Weak compatibility in soft PVC
- Migration and discolouration may occur over time
OB-1 is widely used in rigid PVC applications where long-term flexibility and compatibility are less critical.
(2) Optical Brightener FP-127
Best for: Soft and semi-transparent PVC materials
- Advantages:
- Good whitening efficiency
- Better compatibility with flexible PVC
- Low migration tendency
- Limitations:
- Weather resistance is moderate
- Less suitable for outdoor products requiring long-term UV stability
FP-127 is commonly used in soft PVC films, transparent toys, soft profiles, and flexible packaging.
(3) Optical Brightener OB
Best for: High-end transparent or soft PVC products
- Advantages:
- Strongest whitening effect among the three
- Excellent compatibility and dispersion
- Outstanding weather and UV resistance
- Typical Applications:
- High-clarity PVC packaging
- Premium transparent or decorative soft PVC items
- PVC products requiring long-term stability
Although optical brightener OB is more expensive, it offers unmatched optical performance and durability, making it ideal for high-end PVC applications.
3. How to Select the Right Optical Brightener for PVC
Choosing the correct optical brightener for PVC depends on several key factors:
a. PVC Product Type
- Rigid PVC: OB-1 is typically sufficient and cost-effective.
- Soft or transparent PVC: FP-127 or OB works better due to superior compatibility.
- High-end transparent PVC: OB provides premium performance.
b. Final Appearance Requirements
- Moderate whitening → OB-1 or FP-127
- High-brightness, crystal-clear whiteness → OB
c. Environmental & UV Exposure
- Indoor products → FP-127 is usually suitable
- Outdoor or UV-exposed products → OB provides superior weather resistance
d. Processing Conditions
Some brighteners withstand high processing temperatures better than others. OB and OB-1 offer very good thermal stability for PVC extrusion and injection moulding.
e. Budget vs. Performance
- Tight budget: OB-1
- Balanced performance: FP-127
- Premium performance: OB
4. Conclusion
The selection of the right optical brightener for PVC directly impacts product whiteness, long-term stability, and market value. Each brightener—OB-1, FP-127, and OB—offers unique performance characteristics that suit different PVC applications. Manufacturers should evaluate performance requirements, optical targets, weatherability needs, and cost considerations to determine the optimal solution.
By choosing the proper optical brightener, PVC products can achieve superior aesthetics, enhanced durability, and a stronger competitive advantage in the market.
At Shandong Grand Chemical Co., Ltd., we specialise in producing and supplying a wide range of high-performance fluorescent brighteners for plastics, coatings, detergents, and textiles.
📩 Contact us for product data sheets, samples, or technical guidance:
Email: sales@obachemical.com
WhatsApp: +86 13173009832