Vat Blue 20

Vat Blue 20 appearance is blue-black powder. Insoluble in water, alcohol; slightly soluble in acetone, chloroform, o-chlorophenol, pyridine and toluene; soluble in tetralin, xylene (red with fluorescent solution). Violet black in concentrated sulfuric acid After dilution, there is a purple-black precipitate. The leuco body formed by the dye in the alkaline powder solution is dark purple, and the acid powder solution is dark red.

TRADE NAME:Vat Dark Blue BO,Vat Deep Blue BO,Cibanon Blue BOA-Ol

Key features

• Deep, intense blue shade with good shade consistency
• Excellent washfastness (minimal bleed and crock)
• High lightfastness compared with conventional direct dyes
• Good alkali and chemical resistance after oxidation
• Requires reduction to the leuco form for substantivity and fixation
• Suitable for pad-batch, exhaust and vat printing processes
• Reliable leveling on woven and knitted cotton fabrics
• Compatible with common reducing agents (e.g., sodium hydrosulfite) and alkaline buffers
• Low migration in blends when properly fixed and after post-treatments
• Stable storage under recommended conditions (cool, dry, sealed)

Technical Specifications

• ‍CAS NO: 116-71-2
• CI.NO: 59800
• Molecular Formula: C34H16O2
• Molecular Weight: 456.49
• Shade: Dark blue purple red to purplish blue‍

Application Features

Colour Fastness Test

Application:

Vat Blue 20 Used for cotton fiber dyeing, poor levelness. Widely used in dark blue fabric and polyester/cotton khaki dyeing. The leuco used for hosiery dyeing, in yarn-dyed mainly applied to dyeing yarn. Used for cotton fabric direct printing. Can dye viscose, silk and d/cotton goods. Can also be processed into organic pigment.

Use condition:

• ‍1.When used for cotton product dyeing or dip dyeing, it is most suitable to use the method of A. When the color matching is used, the method can be used. The drying time of the dry cylinder is 15min, the reduction temperature is 50~60°C, and the dry cylinder stabilization time is 30min.
• 2.Vat blue 20 leuco body has high affinity to cotton fiber, and the leveling property is general. The dyeing curve is shown in Figure 4-5-25. Because the dyeing rate is very fast, it is necessary to add appropriate amount of retarding agent to prevent color flowering during dyeing. The dosage is 0.5g/L. After dyeing, it is oxidized by watering and then boiled for about 10 minutes at high temperature to ensure sufficient color development. In addition to dyeing or dip dyeing, it is also suitable for suspension padding.
• 3.Vat blue 20(Vat dark blue BO) is rarely used in printing. It is suitable for direct printing. It should be added with white powder and urea to improve the color yield, and the color paste can be prepared with strong alkali. It is not suitable to use sodium perborate during oxidation. Dichromate, otherwise the color is dim. It is not suitable for discharge printing.
• 4.for viscose fiber dyeing, light color at low temperature, red light at high temperature. When dyeing cotton blend fabric, the viscose fiber component is darker and reddish. The fabric suspension is padded to obtain a more uniform dyeing effect. It is used for polyester/cotton blended (65/35) fabric dyeing, and has a slight stain on the polyester (red light). It can be hot melt dyed with the disperse dye in the same bath.
• 5.printing and dyeing fabric after finishing with urea-formaldehyde or cyanoaldehyde resin, the color light is significantly reddened.‍

Precautions

• ‍1.Vat blue 20 dyeing cloth is very sensitive to blanching and water staining, it will be reddish, so avoid excessive temperature when drying.
• 2.it should be stored in a dry, ventilated place to avoid moisture.‍

FAQ

How is Vat Blue 20 applied to cotton — does it require special equipment?

Vat Blue 20 is applied in its reduced (leuco) soluble form. Typical methods include pad-batch, exhaust (vat) dyeing and vat printing. Standard vat-reduction setups — alkaline buffer plus a reducing agent such as sodium hydrosulfite — are sufficient. Pad-batch gives consistent shade for continuous processing while exhaust vats are used for full-depth dyeing. No unusual equipment is required beyond standard vat-dye handling and oxidation facilities.

What are the recommended reduction and oxidation conditions?

Reduce Vat Blue 20 under alkaline conditions with a suitable reducing agent (e.g., sodium hydrosulfite) and a stabilizing buffer to maintain pH. Typical practice uses warm temperatures to speed reduction, followed by thorough oxidation on the fabric using either air oxidation or mild oxidizing baths (lime/chloride oxidizers are avoided unless specified). Exact concentrations and times depend on bath recipe, shade depth and equipment — run small lab trials to finalize process parameters.

How does Vat Blue 20 perform on blends (cotton/polyester) and mixed-fiber fabrics?

Vat Blue 20 has high substantivity for cellulose; on cotton/poly blends it will predominantly color the cellulose fraction. For blended fabrics, expect limited uptake on polyester unless combined with a disperse dye. Careful control of reduction and re-oxidation is essential to avoid migration and achieve even appearance; pre-scouring and appropriate auxiliaries improve levelness.

What fastness properties can customers expect after proper fixation?

When properly reduced, fixed and re-oxidized, Vat Blue 20 typically exhibits excellent washfastness and good-to-excellent lightfastness, along with strong rub/crock resistance and good chemical resistance under alkaline or neutral conditions. Final fastness depends on shade depth, dyeing recipe and post-treatments such as soaping and after-washes.

Are there environmental or safety considerations for Vat Blue 20 processing?

Vat dyeing uses reducing agents and alkaline baths; effluent management is important. Minimize residual reducing agents and neutralize baths before discharge. Follow local regulations for wastewater treatment and worker-safety procedures — provide appropriate PPE and ventilation during reduction and oxidation steps. Where possible, optimize recipes to reduce chemical consumption and improve rinse efficiency.

How should Vat Blue 20 be stored and handled?

Store in a cool, dry, well-sealed container away from direct sunlight and strong oxidizers. Avoid moisture ingress and sources of contamination. Handle with standard chemical-safety precautions: gloves, eye protection and avoid inhalation of dust; consult the product SDS for detailed guidance.

Can I achieve lighter shades and reliable shade matching with Vat Blue 20?

Yes — lighter shades are produced by lowering dye concentration or using appropriate leveling auxiliaries and process control. For precise shade matching, create a series of lab trials across recipe, liquor ratio and fixation conditions, and prepare standard lab-dip records. Controls for temperature, reduction strength and oxidation time are key to repeatable matches.