Acid Dyes
Hot-Selling Acid Dyes For Leather Coloring
Main Fiber Applications of Acid Dyes
Protein Fibers:
Bonded by ionic bonds.
Wool:
The primary application, used for yarn, woolen fabrics, carpets, etc.
Silk:
Used for silk fabrics, scarves, etc.
Polyamide Fibers (Nylon):
Nylon molecules have amino groups at the ends, allowing them to bond with acid dyes via ionic bonds, making them important dyes for clothing and socks.
Catonic Modified Polyester, etc.:
Can also be dyed with acid dyes after special treatment.
Classification of Acid Dyes
Based on molecular weight and affinity, acid dyes can be classified into three categories, which is crucial for practical dyeing processes:
| Type | Characteristics | Fastness | Applicable Scenarios |
|---|---|---|---|
| Strong Acid Dyes | Small molecular weight, excellent leveling properties, requires dyeing in a strong acid bath (pH 2~4) | Poor wet fastness | Dyeing wool where extremely high leveling properties are required |
| Weak Acid Dyes | Medium molecular weight, dyeing in a weak acid bath (pH 4~6) | Evenness and Fastness | Widely used for wool, silk, and nylon |
| Neutral / Acidic Dyes | Large molecular weight, suitable for dyeing in near-neutral baths (pH 6-7) | Good wet fastness, but poor levelness | Suitable for wool products requiring high wash and shrinkage fastness |
Dyeing Principle of Acid Dyes
Under acidic conditions, the amino groups (-NH₂) in fiber (e.g., wool) molecules protonate to form positively charged ammonium ions (-NH₃⁺). Dye molecules dissociate in water to form negatively charged pigment anions. The two bonds through ionic bonds (salt bonds) for dyeing.
Advantages and Disadvantages of Acid Dyes
+ Advantages
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Bright colors
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Relatively simple application method
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Comprehensive color spectrum
− Disadvantages
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Significant differences in wet fastness (e.g., wash and perspiration fastness) between different types.
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Usually, appropriate dye categories and post-treatment are required based on the final application.
In summary: If you need to dye wool, silk, or nylon and want vibrant colors, you'll need to look for acid dyes. When purchasing and using them, be sure to select the correct category of acid dye (strong acid, weak acid, or neutral) based on the fiber type and the colorfastness requirements of the final product.
