Description

Fluorescent Brightening Agent 91 (CAS NO 51811-43-9) is a high-performance stilbene-based optical brightener designed to impart a brilliant white appearance to various substrates. This agent functions by absorbing ultraviolet light and re-emitting it as visible blue light, effectively compensating for yellowish tints and enhancing perceived whiteness and brightness. It is an essential component for manufacturers in the detergent, paper, textile, and plastics industries seeking to improve the visual appeal and marketability of their finished products.

Application

• Laundry Detergents & Fabric Softeners: Primary application for whitening and brightening cotton, polyester, and blended fabrics, providing a superior visual effect in household and industrial laundry.
• Paper & Pulp Industry: Used in coating formulations and mass coloration to achieve high-grade brightness in printing papers, tissues, and board, reducing the need for costly blueing agents.
• Textile & Fiber Treatment: Applied in the finishing process for synthetic fibers like polyester and nylon, as well as in spin finishes, to enhance the whiteness of textiles.
• Plastics and Polymers: Incorporated into polymers such as PVC, polyethylene, and polystyrene to correct inherent yellowness and improve the aesthetic quality of molded articles and films.
• Soaps and Personal Care: Utilized in bar soaps, liquid soaps, and cosmetic formulations to boost whiteness and create a clean, premium product impression.
• Coatings and Inks: Added to specific coating systems and inks to increase luminosity and achieve optical brightening effects on surfaces.

Basic Information

Product Name	Fluorescent Brightening Agent 91
CAS No.	51811-43-9
Molecular Formula	C₄₀H₄₂N₁₂O₆S₂
Molecular Weight	843.0 g/mol
Synonyms	FBA 91; Optical Brightener 91; OB-1; 2,2'-(1,2-Ethenediyl)bis[5-[4-[bis(2-hydroxyethyl)amino]-6-(phenylamino)-1,3,5-triazin-2-yl]amino]benzenesulfonic acid disodium salt; 4,4'-Bis[(4-anilino-6-bis(2-hydroxyethyl)amino-1,3,5-triazin-2-yl)amino]stilbene-2,2'-disulfonic acid disodium salt; Tinopal UNPA-GX; Blankophor BBH
EINECS	257-418-0

Quality Control

Our Fluorescent Brightening Agent 91 is manufactured under a stringent quality management system. Every batch undergoes comprehensive analytical testing to ensure consistent purity, performance, and batch-to-batch uniformity. We provide Certificates of Analysis (COA) with key parameters including assay, absorbance, and hue. Our production adheres to relevant ISO quality standards, and we support compliance with global regulatory frameworks such as REACH.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, and well-ventilated area at room temperature (15-25°C). Keep away from heat sources and incompatible materials. The product is light-sensitive (store away from light).

Specification

Item	Specification
Appearance	Yellowish-green powder or granules
Identification (IR)	Conforms to standard
Assay (HPLC)	≥ 98.0%
Absorbance (in water)	Conforms
Volatile Matter	≤ 1.0%
pH (1% aqueous solution)	7.0 - 9.0
Whiteness Degree (on fabric)	Standard sample comparison

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.