Vat Yellow 1

Vat Yellow 1 appearance is brown powder insoluble in water acetone alcohol chloroform and toluene are slightly soluble in o-chlorophenol pyridine is soluble in nitrobenzene (hot). It is diluted in dark orange in concentrated sulfuric acid to produce a yellow precipitate. The leuco body formed in the alkaline powder solution is green in the blue acid powder solution.

Vat Yellow 1 is Brown powder, Insoluble in water, ethanol, acetone, chloroform, toluene, slightly soluble in o-chlorophenol, Pyridine , soluble in hot the difficulties. In alkaline insurance powder also for blue ones; In the acidic insurance powder also in stock for green; The strong sulfuric acid for dark orange, yellow diluted produce precipitation. This product is crisp cloth varieties, for old yellow color Brightness as reduction golden, oxidation difficulties, after soaping color phenomenon.

TRADE NAME:Vat Yellow 5RC,Vat Yellow G,Yellow Brown D

Key features

• Solubility: insoluble in water in pigment form; soluble only as the reduced (leuco) form
• Fastness: excellent wash, light and weather fastness typical of vat dyes
• Durability: high chemical and chlorine resistance compared with many other dye classes
• Applications: cotton and cellulosic dyeing, PVA/cotton blends, direct printing, yarn dyeing; can also be processed into organic pigment
• Processing note: requires reducing agent (e.g. sodium dithionite) and controlled oxidation step
• Chemical data: formula C28H12N2O2; frequently sold as pigmentary/vat powder—handled as a pigment/dye intermediate

Technical Specifications

• ‍CAS NO: 475-71-8
• CI.NO: 70600
• Molecular Formula: C28H12N2O2
• Molecular Weight: 408.41
• Shade: Red light yellow‍

Application Features

Colour Fastness Test 

Application:

Vat Yellow 1 Mainly used for cotton cloth dyed and suspension of the volume of body knot dyeing, also can dip to cotton yarn, can be directly printing and the discharge, suitable for PVA, PVA/cotton blended fabric dyeing and printing. Can be processed into organic pigments.

Use condition:

• ‍1. When Vat yellow 1(Vat yellow G) for cotton product dyeing and dip dyeing, it is suitable to use method A or B. The reduction temperature is 50~60°C, the drying time of the dry cylinder is 40min (the fine powder is 15min). Because of the reduction of yellow G, there is no light brittleness. Therefore, it maintains a certain amount of demand in the printing and dyeing process of cotton fabrics, and can be used as a main color or color matching dye. In addition to being used for dyeing and dip dyeing, it can also be used for suspension padding.
• 2. It is easily reduced to leuco, and it is often used as a qualitative test to detect whether the powder in the dye liquor is sufficient. When the amount of the powder in the dye liquor is sufficient, the test paper changes from yellow to blue. Purple, if the transition is slow, it means that you need to add insurance powder.
• 3. The leuco body has good affinity to cotton fiber, good leveling property, and has a certain hiding power for dead cotton. The dyeing curve is shown in Figure 4-5. It has a slow oxidation rate and often requires an oxidizing agent. Oxidation. If it is oxidized with hydrogen peroxide or sodium perborate, the color is bright. If it is oxidized with sodium dichromate and acetic acid, the color is dim.
• 4. It can be used for direct printing and anti-discharge printing. The basic color paste is printed without pre-reduction method. Potassium carbonate or soda ash is used as an alkali agent, and the white block is added before use.
• 5. It can be used for dyeing or printing of vinylon and cotton blended fabrics, and can obtain a uniform color effect.
• 6. The dyed fabric is finished with BHES resin and the color is very dark.‍

Precautions

• ‍‍1.Vat yellow 1Printing and dyeing products have photochromism, which can be restored by air or mild soaping.
• 2.Vat of yellow 1dyeing cloth should avoid vigorous soaping to prevent color change.
• 3.Vat yellow 1should be stored in a cool, dry place to avoid moisture.

FAQ

What is the recommended reducing agent and typical vatting chemistry for Vat Yellow 1?

Use a standard alkaline vatting system with sodium dithionite (hydrosulfite) as the reducing agent and caustic soda to control pH; monitor reduction until the dye reaches the leuco (soluble) state, then apply and oxidize carefully to lock color. Controlled reduction/oxidation is essential to maximize fastness and avoid uneven shades.

Can Vat Yellow 1 be used for direct printing and reactive finishing on cotton?

Yes — Vat Yellow 1 is suitable for direct printing on cotton and PVA/cotton blends, but because it is a vat dye it must be applied using vat/printing paste formulations that include a reducing system or solubilised vat form. It is not a reactive dye and therefore behaves differently in post-treatments.

How does Vat Yellow 1 perform vs. reactive or disperse yellow dyes?

Compared with typical reactive or disperse yellows, Vat Yellow 1 provides markedly better wash and light fastness and higher chemical/chlorine resistance, but requires vatting chemistry (reduction + oxidation) and is less straightforward to apply in household conditions.

Is Vat Yellow 1 suitable for pigment processing and plastics?

Yes — Vat Yellow 1 can be converted to organic pigment grades and is used in plastics and coatings in specialist formulations; it shows good transparency and weather fastness when processed as a pigment. Thermal limits and masterbatch processing should be validated for each polymer system.

What safety and handling points should production teams follow?

Handle the powder with dust control and standard PPE (gloves, goggles, respirator as needed). Follow standard MSDS guidance for vat dyes and provide training for safe handling of caustic vats and reducing agents. Dispose of vatting bath wastes per local environmental regulations.

Which fibers and blends dye best with Vat Yellow 1?

Cellulosic fibers (cotton, viscose) and PVA/cotton blends are the primary targets. It can also be used in specialty applications such as polyacrylonitrile fiber pulp coloring and wood/art paints when converted appropriately.

What are common troubleshooting tips for uneven shade or poor penetration?

Ensure complete and uniform reduction of the dye to its leuco form, control bath temperature and pH, maintain oxygen-free conditions during reduction, and provide adequate after-soaping/oxidation cycles. Multiple short dips in a weaker bath often give better evenness than a single strong dip.