Description

HC Yellow 4 is a synthetic dye commonly used in hair coloring products. It is part of a group of azo dyes and is typically recognized by its vibrant yellow hue. This dye is often included in formulations for its ability to provide a bright, intense color, and is commonly used in products aimed at creating blonde, light brown, or vibrant yellow shades. HC Yellow 4 is generally considered safe for use in hair dyes, though, like many synthetic dyes, it may cause allergic reactions or skin irritation in sensitive individuals. The dye works by adhering to the hair shaft, penetrating the cuticle layer, and depositing color molecules, thus altering the natural pigment of the hair. It is often combined with other dyes and ingredients to achieve more complex, multidimensional hair colors.

Chemical Structure of HC Yellow 4

Appearance of HC Yellow 4

Uses

1. Hair Color Formulation

Packing

Export Worthy packing 5 Kg Drum, 25 Kg Drum, 50 Kg Drum.

Storage Conditions

Store in cool and dry place at room temperature, protect from direct sunlight.

Molecular Formula

CAS No.

IUPAC Name

Synonyms

Molecular Weight

Appearance

Solubility

Dye Content (Spectrophotometry)

C₁₀H₁₄N₂O₅

59820-43-8

2-[(2-(2-Hydroxyethoxy)-4-nitrophenyl)amino]ethanol

N,O-di(2-hydroxyethyl)-2-amino-5-nitrophenol)

242.23 g/mol

A bright / brilliant yellow solid / powder

98%

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HC Yellow 4 is widely utilized in the cosmetic industry, specifically in the formulation of hair dyes, because of its ability to deliver a bright, consistent yellow or golden hue. It is particularly common in products designed to lighten hair or enhance natural blondes. In combination with other dyes (such as reds, blues, or browns), HC Yellow 4 can contribute to the overall shade, giving the hair color a warm, rich base or highlighting certain undertones. It works well with oxidative hair dyes, which use a chemical developer (like hydrogen peroxide) to lift the hair’s natural pigment and allow the dye molecules to penetrate the hair shaft.

2. Blonde and Light Brown Shades

3. Dye Mix for Bright and Vivid Colors

In formulations where more vibrant or intense color is desired, such as in fashion colors (neon yellows, bright oranges, or other bold shades), HC Yellow 4 is a go-to ingredient. It can be used alone or mixed with other colorants to produce various shades of yellow, orange, and gold. This application is especially popular in semi-permanent or temporary hair dyes, which do not alter the hair’s structure as deeply as permanent color but still provide a noticeable change in hue.

Soluble in water

4. Colorant for Special Effects

Aside from its mainstream uses in blonde and brown hair dyes, HC Yellow 4 is sometimes included in formulations intended for special effects and creative colorants. These are often used for unique looks like pastel or pastel-enhanced colors, where the yellow dye complements other pigment layers (such as pinks or blues) to create pastel versions of the original colors. The versatility of HC Yellow 4 allows it to be part of a complex blend of pigments that gives the hair a multi-dimensional appearance.

HC Yellow 4 is a key ingredient in the creation of blonde and light brown hair dye shades. It is often added to formulations to counteract brassiness, a common concern when lightening hair. In these instances, it can help provide a warmer, golden undertone to blonde or brown shades, ensuring a natural, sun-kissed appearance. For lighter blonde shades, it imparts the desired yellow hue without overpowering the lighter tones.

Due to concerns about the safety of synthetic dyes, particularly azo dyes like HC Yellow 4, many countries regulate its use strictly in cosmetics and hair products. The European Union, for example, has specific regulations regarding the concentration of HC Yellow 4 in hair dye products, ensuring that the levels are safe for consumer use. While considered safe in the concentration levels commonly used in hair dyes, like many other synthetic dyes, HC Yellow 4 could cause allergic reactions in sensitive individuals. Patch tests are often recommended before applying it to the entire scalp or hair.

5. Blending with Other Colorants

In many professional salon hair dye formulations, HC Yellow 4 is rarely used in isolation. It is usually blended with other dyes to create specific color tones. For example, it may be combined with HC Red 3 (another synthetic dye) to produce warmer shades like auburn, or it could be blended with other yellow or orange-based pigments to create a unique golden color. These combinations allow for customized shades, which is particularly useful in the professional hair color industry, where bespoke color is often requested.

6. Use in Bleaching Systems

When combined with bleach or lightening agents, HC Yellow 4 can sometimes appear in hair lightening kits. While bleaching products typically work by stripping hair of its natural color, HC Yellow 4 can add some tonal control to the result, softening the transition from darker to lighter shades and avoiding the starkness or unevenness that can sometimes occur when using bleach. It’s not the primary active ingredient in these systems but acts as an auxiliary to enhance color after the lightening process is complete.

7. Temporary Hair Color Sprays and Chalks

In addition to permanent and semi-permanent hair dyes, HC Yellow 4 is also found in various temporary hair color products, such as color sprays, chalks, and powders. These products are typically applied for short-term color effects (lasting for a day or until washed out) and are often used for fashion, cosplay, or creative expression. The advantage of HC Yellow 4 in these temporary colorants is its stability, as it can retain its color for a few days even with repeated washing.

8. Staining or Highlighting Specific Areas

In some professional coloring techniques, like highlights or lowlights, HC Yellow 4 may be selectively applied to certain areas of the hair to create streaks of color or to enhance natural sun-kissed highlights. It can be used in streaking or balayage techniques, where it helps achieve lighter, more defined highlights without the need for full color processing.

9. Color Matching in Pigment Systems

In some hair color systems, the exact pigment makeup may need to be adjusted for clients with specific undertones in their natural hair. HC Yellow 4 can be added to correct or match certain shades, especially if a client’s hair has a naturally warm undertone (such as golden or reddish hues). This precision helps stylists tailor the hair color to better suit individual needs, making the dye more adaptable.

10. Color Matching in Pigment Systems