Direct Blue 71

Direct Blue 71 alias direct light blue B2RL, direct light blue B2R. The appearance is generally blue gray uniform powder. Water soluble, soluble in water blue, slightly soluble in cellosolve, very slightly soluble in alcohol, Insoluble in other organic solvents. The dye is blue to grayish black in concentrated sulfuric acid, red-violet purple precipitate after dilution; dark brown in concentrated nitric acid; insoluble in concentrated sodium hydroxide; blue-violet in concentrated ammonia. The aqueous solution added with concentrated hydrochloric acid has a blue precipitate, and the concentrated sodium hydroxide has a red-violet purple precipitate. The copper and iron ion shades slightly change.

TRADE NAME:Direct Fast Blue B2RL,Direct Blue B2RL,Ambidirect Blue R,Bitafast Blue GLL,Blue 2-RL,Chrochem Direct Blue BRR,Direct Blue B2RL,Direct Blue FFC,Direct Blue GLL,Direct Light Blue FRL

Technical Specifications

• ‍CAS NO: 4399-55-7
• CI.NO: 34140
• Molecular Formula:C40H23N7Na4O13S4
• Molecular Weight: 1029.87
• Shade:dark blue‍

Application Features

Colour Fastness Test

Application:

Direct Blue 71 Widely used in viscose fiber dyeing, also used in viscose/PVA blends, cotton, and the carpet of dyeing and printing. Also used in leather, paper, soap, cheese, protein and formaldehyde resin color.

Use condition:

• ‍1. The dyed cotton or viscose fiber has a reddish-dark blue color. The dyeing rate is good, the transferability and levelness are poor. When dyeing, it is advisable to add salt to control the dyeing to obtain uniform color. After the dyeing stage, the dyeing solution should be naturally cooled to 80 ° C, which is beneficial to the dye exhaustion. After dyeing, the color light micro green is finished by urea-formaldehyde resin, and the color is brightly changed to green by the cyanoaldehyde resin; the red color is treated by copper sulfate, and then the resin is finished. , its sun fastness is not affected.
• 2. Used for dyeing rich fiber, the dyeing rate is very good, the color light is slightly darker than cotton. It can also be used for dyeing silk and its fabric, dyeing bath plus Yuanming powder and acetic acid. When dyeing vinyl fabric, dyeing The rate difference is lighter than blue. When cotton, viscose fiber and other fibers are dyed in the same bath, the wool is lighter than cotton and viscose fiber, the silk is lighter, the nylon is heavily stained, the second vinegar fiber, the three vinegar fiber, the polyester fiber. Acrylic fiber is almost non-staining.
• 3.Direct Blue 71 can be mixed with disperse dye in high temperature dyeing and blending fabric. The dyeing bath is heated to 120 °C under neutral conditions, or loaded with boiling dye. After the dye is dyed with polyester, the temperature is continued. After dyeing for half an hour, the cellulose fibers are fully colored, and the dye is exhausted, and the color light is substantially unchanged.
• 4. Used for continuous padding of cotton. After padding, it is treated with 10~25g/L yuan powder boiling bath, then steamed at 100~103°C for 1-3 minutes.
• 5. Used for direct printing of cotton or viscose fabric. When printing deep pattern, add urea and disodium hydrogen phosphate to prepare the printing paste.‍

FAQ

How does Direct Blue 71 behave in terms of fastness?

Direct Blue 71 offers good levelling and generally acceptable wash and light fastness for many end-uses. Fastness improves with proper fixation, rinsing and the use of recommended after-treatment agents; for high-performance textile applications additional finishing may be required.

What form does the product come in and how should it be stored?

Common commercial forms are fine powder or granules. Store in a cool, dry place, sealed against moisture and contamination. Keep away from strong oxidizers and direct sunlight to preserve color stability.

Are there common auxiliaries or process tips that improve results?

Salt or electrolyte control, proper liquor ratio and temperature management help achieve uniform shade. For printing and pad-dyeing, use recommended thickeners and fixation steps for improved penetration and reduced migration. Compatibility with specific auxiliaries should be trialed in small runs.

Is Direct Blue 71 suitable for printing and continuous processes?

Yes — its levelling properties make it suitable for both batch dyeing and printing. For continuous processes (pad-dry-steam or pad-batch), optimize paste viscosity and fixation conditions to minimize bleeding and migration.

What environmental or regulatory considerations apply?

As with all textile dyes, ensure effluent is treated to meet local discharge regulations. Follow recommended handling and waste-disposal procedures and consult SDS for details on safety, biodegradability and regulatory status.

How do I match or reproduce a specific shade with Direct Blue 71?

Shade matching requires lab trials: adjust recipe concentration, liquor ratio and process auxiliaries, and always produce lab-scale samples to evaluate wet- and post-wash shades. Use spectrophotometric measurement for accurate replication across batches.