Frequently Asked Questions (FAQs) about Fluorescent Whitening Agent KCB
Time：2025-09-22Views：
1. What is Fluorescent Whitening Agent KCB?
Fluorescent Whitening Agent KCB belongs to the dibenzoxazolylnaphthalene compound family, with the chemical name 1,4-bis(benzoxazol-2-yl)naphthalene. It appears as a yellowish-green crystalline powder, with a melting point ranging from 210°C to 212°C.
It is a chemical substance that can absorb invisible ultraviolet (UV) light and convert it into visible light, thereby enhancing the whiteness and brightness of materials. It is widely used in industries such as plastics and synthetic fibers.
2. In which fields is Fluorescent Whitening Agent KCB mainly used?
1. Plastics Industry:
It is the preferred whitening agent for EVA (Ethylene-Vinyl Acetate) foam shoe materials. It can precisely control the quantity and size of bubbles during the foaming process, ensuring shoe material quality while improving whiteness and aesthetics.
It is also widely used in plastic films, extrusion-molded materials, and injection-molded materials made of PE (Polyethylene), PVC (Polyvinyl Chloride), PS (Polystyrene), ABS (Acrylonitrile-Butadiene-Styrene), etc. The recommended addition amount is usually 0.01% - 0.05% (based on the weight of the material) to effectively enhance the whiteness of plastic products.
2. Synthetic Fiber Industry:
It is used for whitening treatment of synthetic fibers such as polyester fibers. It can make fiber products brighter in color and higher in whiteness, bringing better visual effects to textile products.
3. What advantages does KCB have compared with other fluorescent whitening agents?
1. Temperature Resistance Compatibility:
The molding temperature of EVA materials is around 210°C, and KCB’s melting point (210°C - 212°C) perfectly matches the temperature requirements of EVA processing. Many other whitening agents cannot be used due to insufficient temperature resistance.
2. Color Tone Advantage:
It emits a bright blue light, which meets the preference of Asians for "bluish-white" (white with a slight blue tint). In contrast, fluorescent whitening agents like KSN and 127 emit a reddish light, making them unsuitable for domestic EVA foam shoe materials and similar products.
3. High Stability:
It does not react with additives such as foaming agents and cross-linking agents, maintaining good stability in plastic products. For example, although Fluorescent Whitening Agent OB-1 is cheaper and emits blue light, it has poor stability and is prone to migration and precipitation—leading to local yellowish-green discoloration of products. KCB avoids this problem entirely.
4. Good Process Adaptability:
EVA foaming has strict requirements for bubbles. Many other types of whitening agents interfere with the process, causing excessive bubbles during foaming (which makes shoe materials lose elasticity and become unusable). KCB prevents such issues and ensures product quality.
4. What precautions should be taken when using Fluorescent Whitening Agent KCB?
1. Control the Addition Amount:
The recommended addition amount is 0.005% - 0.05% (based on the weight of the treated material). Excessive addition may cause the product to turn bluish or precipitate, affecting product performance and appearance. For example, over-adding in plastics can lead to white powdery precipitation on the surface and a decrease in whiteness.
2. Ensure Uniform Dispersion:
The whitening agent must be thoroughly dispersed to ensure even distribution in the entire polymer. Using whitening agent masterbatches (concentrated pellets) achieves better dispersion—otherwise, the whitening effect may be inconsistent in different areas of the product.
3. Weather Resistance Consideration:
KCB may degrade due to UV exposure when used outdoors for a long time. If the product requires long-term outdoor use, it should be paired with UV stabilizers to extend the retention time of the whitening effect.
4. Storage Conditions:
It should be stored in a cool, dry, and light-proof environment with a relative humidity ≤ 60%. This prevents moisture, light, and other factors from affecting its performance. The shelf life of unopened products is approximately 48 months.
5. Regulatory Compliance:
If used in plastic products that come into contact with food (e.g., food packaging), select grades that comply with relevant regulations such as FDA (U.S. Food and Drug Administration) or EU 10/2011 to ensure product safety.
