
Product Name: Optical Brightener KCB / Fluorescent Brightener 367
Chemical Name: 2,2′-(1,4-Naphthalenediyl)bisbenzoxazole;1,4-Bis(benzoxazolyl-2-yl)naphthalene
Color Index: C.I. 367
CAS: 5089-22-5
Molecular Formula: C₂₄H₁₄N₂O₂
Formula Weight: 362.38 g/mol
Synonyms: Fluorescent Brightener 367; Fluorescent Whitening Agent KCB;
1,4-Bis(2-benzoxazolyl)naphthalene; FBA 367; 4,4-Bis(benzoxazolyl-2-yl)naphthalene; C.I. 367
Application:
Plastics (PVC, PE, PP, PS, ABS, EVA, TPU, TPR), EVA Foam (Sports Shoes, Slippers), Rubber Products, Synthetic Fibers (Polyester, Polyamide), Paints & Coatings, Printing Inks, Injection Molding Materials, Extrusion Molding Materials, Plastic Films
1.Product Description
Achieve Superior Whiteness with Optical Brightener KCB – The Premium Naphthalene-Based Brightener for Plastics and EVA Foam.
Optical Brightener KCB, internationally designated as Fluorescent Brightener 367 (C.I. 367), is a high-performance naphthalene-based bisbenzoxazole derivative that represents the pinnacle of optical brightening technology for plastic and foam applications . This sophisticated compound features a unique molecular architecture where a naphthalene core is symmetrically bonded to two benzoxazole rings, creating an extended conjugated system that delivers exceptional fluorescence efficiency and thermal stability .
The advanced molecular structure of KCB enables superior photophysical performance: it absorbs invisible ultraviolet radiation in the 370 nm range and re-emits it as brilliant blue-white visible light at approximately 434 nm, effectively neutralizing the yellowish cast inherent in many polymers and imparting a clean, "whiter-than-white" appearance . With a fluorescence quantum efficiency of 0.89, KCB delivers one of the highest whitening intensities available in its class .
What truly distinguishes Optical Brightener KCB from conventional brighteners such as OB and OB-1 is its exceptional performance in EVA foam applications and superior thermal stability. KCB is significantly stronger than OB and OB-1, imparting a more neutral white effect while maintaining excellent heat resistance during high-temperature processing . This makes it the preferred choice for demanding applications including:
EVA Foam Products: KCB is the industry standard for whitening sports shoe soles, slippers, yoga mats, and other EVA foam products, delivering uniform, brilliant whiteness with excellent dispersion characteristics .
High-Temperature Plastics: With a melting point of 210-212°C and stability at processing temperatures up to 300°C, KCB withstands the rigorous conditions of injection molding, extrusion, and foaming processes without degradation or sublimation .
Superior Color Neutralization: Unlike some brighteners that impart a blue or violet cast, KCB delivers a clean, neutral white effect that enhances the perceived quality of finished products .
Our Optical Brightener KCB is manufactured under strict quality controls in accordance with HG/T 5097-2016 standards, offering ≥98% to 99% purity with consistent batch-to-batch performance . The product exhibits excellent compatibility with a wide range of polymers, low volatility during processing, and outstanding lightfastness in end-use applications.
2.Product Specifications (Technical Data Sheet)
| Property | Specification | Insight |
| Product Name | Optical Brightener KCB (Fluorescent Brightener 367) | Premium naphthalene-based brightener for plastics and EVA foam |
| Appearance | Yellowish-green to light green uniform crystalline powder | Fine, free-flowing powder with excellent dispersion characteristics |
| CAS No. | 5089-22-5 | Verified chemical registry number |
| EINECS/EC No. | 225-803-5 | Listed in European inventory |
| Molecular Formula | C₂₄H₁₄N₂O₂ | Naphthalene-bridged bisbenzoxazole structure |
| Formula Weight | 362.38 g/mol | |
| Solubility | Insoluble in water; soluble in organic solvents (toluene, xylene, chlorobenzene, DMF, DMSO) | Hydrophobic nature ensures excellent polymer compatibility |
| Style | Bisbenzoxazole / Fluorescent Whitening Agent (FBA) | Non-ionic, heat-stable brightener for thermoplastics and elastomers |
| Maximum UV Absorption (λmax) | 370 nm | Efficient absorption of near-UV radiation |
| Fluorescence Emission (λmax) | 434 nm (blue-white light) | Characteristic fluorescence for optimal whitening effect; quantum efficiency 0.89 |
| Tinting Strength | High; significantly stronger than OB and OB-1 | Exceptional whitening efficacy with minimal dosage; 20-35% whiteness improvement in EVA foam |
| Purity | ≥ 98% - 99% (HPLC) | High purity ensures consistent performance and minimal impurities |
| Melting Point | 210-212°C | Excellent thermal stability for high-temperature processing |
| Density | 1.32 g/cm³ (25°C) | |
| Volatile Content | ≤ 0.5% | Low volatility during processing |
| Ash Content | ≤ 0.1% | High purity with minimal inorganic residues |
| Fineness | 100 mesh sieve pass rate ≥ 99.5% | Fine particle size ensures uniform dispersion |
| Packing | 10 kg, 20 kg, 25 kg fiber drums or cartons with PE inner liner; 500 kg jumbo bags; custom sizes available | Secure, moisture-proof packaging to maintain product integrity |
| Storage Conditions | Store in cool, dry, ventilated warehouse; avoid moisture, heat, and direct sunlight; protect from strong oxidizers; relative humidity ≤ 60% | Shelf life: 36 months under proper storage conditions |
| Application | EVA foam, PVC, PE, PP, PS, ABS, TPU, TPR, rubber, polyester fiber, polyamide fiber, paints, coatings, inks | Versatile across multiple industries |
3.Product Application
EVA Foam & Sports Shoe Industry – Primary Application:
Optical Brightener KCB is the undisputed industry leader for whitening EVA (ethylene-vinyl acetate) foam products, particularly in the sports footwear sector . Its exceptional performance in this application has made it the standard choice for major athletic shoe manufacturers worldwide.
| Application Type | Recommended Dosage | Performance Notes |
| EVA Foam (Sports Shoes, Slippers) | 0.01-0.05% (100-500 g per 1000 kg) | Delivers 20-35% whiteness improvement; uniform dispersion; neutral white effect |
| EVA Foam Sheets & Mats | 0.01-0.03% (100-300 g per 1000 kg) | Excellent for yoga mats, playground flooring, and industrial foam applications |
| TPU / TPR (Thermoplastic Rubber) | 0.01-0.05% (100-500 g per 1000 kg) | Ideal for shoe soles, automotive components, and consumer goods |
| PU Foam | 0.01-0.05% (100-500 g per 1000 kg) | Suitable for polyurethane foam applications |
Plastics & Thermoplastics:
KCB demonstrates exceptional whitening performance across a broad spectrum of thermoplastic polymers :
| Polymer Substrate | Application Type | Dosage (per 1000 kg) | Performance Notes |
| PVC (Polyvinyl Chloride) | Injection molding, extrusion, calendaring | 0.01-0.05% (100-500 g) | Excellent for rigid and flexible PVC; eliminates yellow cast |
| Polyethylene (PE) | Films, blow molding, injection molding | 0.005-0.03% (50-300 g) | Suitable for HDPE, LDPE, and LLDPE |
| Polypropylene (PP) | Injection molding, fibers, films | 0.005-0.03% (50-300 g) | Outstanding thermal stability for PP processing |
| Polystyrene (PS) | Injection molding, extrusion | 0.01-0.05% (100-500 g) | Effective for GPPS and HIPS |
| ABS | Engineering plastics, automotive components | 0.01-0.05% (100-500 g) | Excellent for high-performance engineering plastics |
| PET (Polyethylene Terephthalate) | Bottles, films, fibers | 0.01-0.05% (100-500 g) | Specially recommended for PET applications |
Plastic Films & Sheets:
For plastic film applications, KCB provides exceptional clarity enhancement and yellowing neutralization :
Agricultural Films: Improves light transmission and aesthetic appeal
Packaging Films: Enhances product presentation through brilliant whiteness
Shrink Films: Maintains optical properties through the shrink process
Protective Films: Improves visual clarity for surface protection applications
Synthetic Fibers:
Optical Brightener KCB is widely used in the production of man-made fibers, providing permanent whitening effects incorporated directly into the fiber during manufacturing :
Polyester Fibers: Delivers superior whitening with excellent lightfastness; can achieve whiteness values exceeding 150%
Polyamide (Nylon) Fibers: Effective for both textile-grade and engineering-grade nylon
Polypropylene Fibers: Suitable for non-woven fabrics, carpets, and technical textiles
Rubber Products:
KCB effectively whitens various rubber compounds :
Automotive Rubber Components: Enhances appearance of weather stripping, seals, and gaskets
Industrial Rubber Products: Improves aesthetic quality of conveyor belts, hoses, and mats
Consumer Rubber Goods: Ideal for footwear, sporting goods, and household products
Paints, Coatings & Printing Inks:
In surface coating applications, KCB provides superior whitening and fluorescence effects :
Industrial Coatings: Enhances whiteness and brightness; dosage 0.01-0.05%
Automotive Coatings: Improves depth and brilliance of white and light-colored finishes
Printing Inks: Used in security printing and anti-counterfeiting applications
Clear Lacquers: Masks yellowing in clear coatings over wood and other substrates
4.Storage
This product may be stored up to two years in a sealed container. Containers should be kept tightly closed when not in use and stored in a cool, dry place.
5.Packaging
Usually is 25Kg/drum or paper box or bag with inner double PE liner Or provide customized packaging according to customer requirements.
6.Our advantage
1) Provide free samples for testing or comparing the effect difference and cost performance.
2) Fast response speed, customers' questions at any time will be responded to in two hours.
3) Fast delivery: the fastest delivery can be made on the same day.
4)Different packaging solutions: provide various packaging options according to customer requirements.
5)Technical guidance: provide improved whitening and coloring formulas and guidance according to customer production materials.
6) Sample retention or sample mailing before bulk delivery.
7) Providing certificationes, such as Reach certification.
8) Different payment methods: TT LC, etc.
9) Providing door-to-door DDP service.