Vat Blue 4, also known as vat Blue RSN, Brilliant Blue RSN, vat Brilliant Blue 5RL, etc., is a widely used vat dye.

In the printing and dyeing process of cotton and linen textiles, vat blue 4 plays an important role.

Physical properties
Vat Blue 4 is a blue black powder that is insoluble in water, acetic acid, pyridine, toluene, xylene, acetone, and ethanol, but slightly soluble in hot chloroform, o-chlorophenol, and quinoline. This dye appears blue in alkaline sodium hydroxide reducing solution and red blue in acidic solution.

Application

1. Dyeing application: Vat Blue 4 is widely used for latent dyeing of yarns, and its ultrafine powder can be used for suspension pad dyeing of cotton fabrics and polyester/cotton. In addition, it can also be used for immersion dyeing of cotton knitted fabrics, as well as direct printing and anti dyeing printing of cotton fabrics (but not for dip dyeing).

2. Blended fabric dyeing: Vat Blue 4 can also be used for two bath dyeing of blended fabrics made of wool, polyester, and cotton, demonstrating its flexibility and adaptability in complex textile dyeing.

3. Color matching: This dye can be used to match with restored deep blue VB, FSHB and other varieties to create richer color effects. At the same time, it can also be combined with vat  brown BR and olive green B to dye dark gray, providing more choices for textile dyeing.