The reducible Vat Black 9(vat black RB) is a black powder, purple in concentrated sulfuric acid and black after dilution.
TRADE NAME:Vat Direct Black RB,Black RB,Dycosthren Black RB
Dyeing depth g/L | 60 |
Dyeing method | SP II |
Leuco color | Dark Blue |
Leveling property | ▲▲ |
Dead cotton | ▲ |
Light (Xenon test 1/12) | 6 |
Light (Xenon test 1/1) | 6-7 |
Light (Xenon test 2/1) | 7 |
Dyeing Method | Dyeing Tempreture(℃) | VAT Method | VAT Tempreture(℃) | Levelness | Others |
A method | 80,The Highest 90 | — | — | Good | — |
Sun fastness | Soaping(95℃) | Perspiration | Rubbing | Ironing | Bleach resistant | Mercerizing | |||||||
Standard Depth | 1/12 Depth | Sample change | White stained | Sample change | White stained | Dry | WEt | immediately | After 4h | Chlorine bleaching | Chlorine bleaching | sample change | White stained |
7~8 | — | 4~5 | 4~5 | 3~4 | 4~5 | 3~4 | 2 | 4~5 | 5 | 4~5 | 4~5 | 4~5 | 4~5 |
Mainly used in cotton fiber dyeing, suitable for suspension pad dyeing, can with other dye spell dye various grey. The main body of the leuco dye yarn. Also can be used for silk and Fiber/cotton blended dyeing, also used for polyester/cotton and polyester/viscose blended fabric dyed black and dark grey.
1.When reducing direct black RB is used for cotton products dyeing or dipping, it is suitable for methyl method, and the amount of caustic soda should be increased by 50% compared with ordinary methyl method.
2.The dyeing curve is shown in figure 4 -- 5 -- 42. It has covering power on dead cotton. Washing, air and hydrogen peroxide oxidation can be used during oxidation.
3.Reduced Vat Black 9(vat black RB) is suitable for printing.
4.A more uniform color can be obtained by reducing the direct black RB dyeing of vinylon cotton blended fabric. Its fine powder is often used for dyeing polyester/cotton and polyester/viscose blended fabric in black and dark grey. It is also used for dyeing polyester/cotton and polyester/viscose dyed fabric yarns.
5.The reduced direct black RB printed and dyed fabric was treated with cyanaldehyde resin and the color was light blue.
1.The reduced Vat Black 9(vat black RB) dyed products stained with concentrated sulfuric acid are black in the middle and bluish purple in the infiltration circle.
2.Reducing direct black RB should be stored in dry and ventilated place to avoid damp.
Typical application involves reducing the dye to its leuco form (common reducers: sodium hydrosulfite or thiourea dioxide) in an alkaline bath (e.g., NaOH). After exhaustion into the fiber, the fabric is re-oxidized (air or mild oxidant) to revert the dye to its insoluble form locked inside the fiber. Precise control of pH, temperature and reduction time is essential to avoid streaks and ensure even shade.
Vat Black 9 is chosen for high-performance fastness (typically excellent washfastness and strong rub fastness when correctly fixed). However, exact fastness values depend on substrate, recipe, and finishing; perform industry-standard tests (e.g., ISO wash and crocking tests) on pilot samples before scale-up.
Yes — it is compatible with pad-vat and vat printing workflows where the dye is applied as the leuco and then oxidized on the substrate. It is not a pigment and therefore requires the vat/chemical conversion step; binder-based pigment printing systems are not directly interchangeable.
Key concerns are the reducing agents and alkaline effluents used in the vat process. Treat wastewater to neutralize residual reducer and adjust pH before discharge. Follow local regulations and provide PPE for operators handling strong alkali and reducing chemicals.
