Fluorescent Brightener 185, CAS 2866-43-5
Fluorescent Brightener 185 is a benzoxazole-based fluorescent whitening agent with the chemical name 2,5-Bis(2-benzoxazolyl)thiophene. It is also known as FBA 185, FBA185, Fluorescent Brightener EBF, Optical Brightener EBF, C.I. Fluorescent Brightener 172 and C.I. 515240.
Chemical Name: 2,5-Bis(2-benzoxazolyl)thiophene
Product Name: Fluorescent Brightener 185
CAS No.: 2866-43-5
Synonyms: FBA 185, FBA185, Fluorescent Brightener EBF, Optical Brightener EBF, Optical Brightener PB, Optical Brightener 185, C.I. Fluorescent Brightener 172, C.I. 515240, 2,5-Bis(benzoxazol-2-yl)thiophene, 2,2'-(2,5-Thiophenediyl)bisbenzoxazole, 2,2'-(Thiophene-2,5-diyl)bis(1,3-benzoxazole)
Molecular Formula: C18H10N2O2S
Molecular Weight: 318.35 g/mol
IUPAC Name: 2-[5-(1,3-benzoxazol-2-yl)thiophen-2-yl]-1,3-benzoxazole
Chemical Type: Benzoxazole Fluorescent Brightener
Main Function: Fluorescent Whitening Agent

Grade: EBF-L
Appearance: Ivory-white dispersion
Shade: Blue light
Ionicity: Anionic

Grade: EBF-powder
Appearance: Pale yellow crystalline powder
Content: ≥ 98.5 %
Melting point: 216-220℃
Ash content: ≤ 0.5%
Volatile matter: ≤ 0.5%

Performance characteristics
Suitable for whitening and brightening treatment of polyester and its blended fabrics. It is suitable for both exhaustion dyeing and pad dyeing processes. It has excellent light fastness properties, up to7 - 8 grades. It has good stability against acids/alkalis, hard water, peroxides and hypochlorite compounds. It is very suitable for alkaline discharge printing processing technology.
Applications of Fluorescent Brightener 185
Fluorescent Brightener 185 is used as a fluorescent whitening agent for synthetic fibers, textiles and polymer materials.
Fluorescent Brightener 185 can improve the apparent whiteness and brightness of suitable substrates by providing a fluorescent blue-white effect.
It is particularly suitable for synthetic fiber and textile applications where good whitening performance is required. Chemical reference information also describes its use for acetate, nylon, polyester, polypropylene, vinyl and blended fibers.
The recommended dosage depends on the substrate, formulation, processing method and required whitening performance. Application-specific compatibility and dosage should be evaluated before commercial production.
Usage method for Grade: EBF-L
1. High - temperature exhaustion dyeing process
Formula: Fluorescent whitening agentEBF - L 0.1 - 1.0% o.w.f Dispersant 0.5 - 1g/l Acetic acid to adjust PH = 4.5 - 5.5
Process:120 - 130℃ 20 - 40 minutes
2. Continuous pad dyeing process
Formula: Fluorescent whitening agentEBF - L 2 - 10g/l Other auxiliaries
Process:180 - 185℃ 30 seconds Padding rate: 60 - 100%
3. One - step resin finishing process
Formula: Fluorescent whitening agentEBF - L 1 - 10g/l Silicone softener 10 - 40g/l Resin, resin catalyst
Process: Drying 130℃ 1 minute Padding rate: 40 - 60% Fixation: 160 - 185℃ 2 - 3 minutes
Usage method for EBF-powder
Used for whitening and brightening polyester, acetate, and nylon fibers, polyester-cotton blends, as well as various polyolefin plastics, ABS engineering plastics, and acrylic (PMMA). Dosage: 0.01–0.05%.
25kg/drum or carton.
4800MT/year.
Precautions
1. This product must be fully stirred evenly before use to ensure the consistency of whiteness and shade of the processed fabric.
2. Fabrics bleached by oxygen must be thoroughly washed to remove the residual alkali on the fabric before whitening to ensure that the whitening agent can color fully and the shade is bright.
3. This product is a high - temperature type polyester fluorescent whitening agent. The dyeing temperature and setting temperature must meet the above process requirements to ensure the normal color development of the fluorescent whitening agent. If normal - temperature boiling is required, the carrier dyeing method can be used.
Store Fluorescent Brightener 185 in tightly sealed original containers in a cool, dry and well-ventilated area.
Protect the product from moisture, excessive heat and direct sunlight.
Keep containers properly closed when not in use.
Hosea Chem® supplies Fluorescent Brightener 185, CAS 2866-43-5, also known as FBA 185, Fluorescent Brightener EBF and 2,5-Bis(2-benzoxazolyl)thiophene, for polyester, synthetic fibers, textiles, plastics and other fluorescent whitening applications.