Introduction
Dyes are coloured organic compounds that chemically bind to textile fibres, resulting in long-lasting colouration through solubility and affinity. Understanding the many types of dyes enables precise fabric selection, process optimisation, and high-quality production in textile manufacturing. This technical handbook emphasises the classifications, application procedures, and fabric interactions that are critical for industry experts and students.
Types of Textile Dyes: Classification, Uses & Examples
Types of Dyes
Dyes are classified primarily by application method, chemical structure, and fibre affinity, which determine colourfastness, dyeing conditions, and fabric appropriateness. Textile dyes range from water-soluble reactive dyes to dispersion-requiring synthetics, each optimised for a specific fibre, such as cotton, wool, polyester, or blends. Different colours strike a compromise between vibrancy, washability, and cost-effectiveness.
Also Read: https://tirumalaitextiles.com/yarn-manufacturing-process/
Classification of Dyes
1. Based on Application Method
- Direct Dyes: Water-soluble anionic dyes applied directly to cellulosic fibres (cotton and rayon). Excellent for khadi, with mild wet fastness. Examples are Congo Red and Direct Blue.
- Reactive dyes: Form covalent connections with cellulose, hydroxyl, or amino groups, resulting in the maximum colourfastness for cotton. Reactive dyes predominate in denim and sarees. Examples are Procion MX and Remazol.
- Acid Dyes: Anionic dyes for protein fibres (wool, silk, nylon) in acidic baths (pH 2-6). Brilliant colours with good light fastness. Examples include Acid Red and Coomassie Blue.
- Disperse Dyes: Non-ionic, water-insoluble dyes for hydrophobic synthetics (polyester, acetate). High-temperature dyeing (130°C). Example: Disperse Blue 56.
- Vat Dyes: Water-insoluble pigments are reduced to a soluble leuco form and subsequently oxidized. Premium cotton has excellent overall fastness; for instance, indigo used in jeans.
- Sulphur Dyes: A low-cost option for cellulose; used in an alkaline reduction bath. Examples include Sulphur Black (workwear).
2. Chemical Structure Classification
- Azo Dyes (60% production): The chromophore (-N=N-) produces the entire colour range. Versatile across fibres.
- Anthraquinone Dyes: Blues and greens with good light fastness.
- Phthalocyanine Dyes: Turquoise pigments for printing ink.
Dyeing Methods and Fiber-Specific Dyes Explained
Dyeing Methods Explained
- Exhaust Dyeing: Dye bath immersion (90%) is uniform for yarns and textiles.
- Continuous Dyeing: Pad-dry-cure for large production (denim, bed linens).
- Jet Dyeing: High-pressure liquid circulation for sensitive materials.
- Beam Dyeing: Wound yarn packages.
High-temperature dyeing (HT) at 130°C for polyester disperse dyes.
Also Read: https://tirumalaitextiles.com/difference-between-thread-and-yarn/
Examples of Dyes by Fiber Type
| Fiber Type | Recommended Dyes | Examples |
| Cotton | Reactive, Vat, Direct | Remazol Red, Indigo |
| Wool/Silk | Acid, Metal-complex | Lanaset Dyes |
| Polyester | Disperse | Terasil Dyes |
| Nylon | Acid, Disperse | Acidol Dyes |
| Acrylic | Basic | Astrazone dyes |
Industrial Uses of Dyes: Fabrics, Applications & Processes
Uses of Dyes in Industry
- Reactive Dyes: Fashion apparel, home textiles (80% cotton dyeing).
- Disperse Dyes: Sportswear, curtains (dominance of polyester).
- Acid Dyes: Used to create luxury suits and lingerie.
- Vat Dyes: Denim and uniforms (duration is important).
- Direct Dyes: canvas and handicrafts (with an emphasis on economy).
Chemical dyes for clothing enable mass customization, and digital printing uses pigment-reactive mixtures.
Effects of Dye on Different Types of Fabric
- Cellulosic (cotton): Reactive dyes penetrate deeply; direct dyes form surface bonds (crocking danger).
- Protein (wool): Acid dyes enter the cortex; alkalinity destroys the scales.
- Synthetic (Polyester): Disperse dyes sublimate into amorphous patches, whereas carriers accelerate at 110°C.
- Blends: Reactive cellulose is dyed first, followed by polyester (disperse).
colour yarn manufacturers in coimbatore specialise in creating melange effects with fiber-specific dye combinations.
Dyeing Process Parameters
Critical factors:
- pH: Reactive (10-11), Acid (3-5)
- Temperature: Cotton (60°C), Polyester (130°C)
- Time: Exhaust (60 min), Pad (2 min)
- Electrolyte: 50-80 gpl salt for exhaustion
- Fixation: Steam (101°C), Dry heat (160°C)
Dye Fastness, Sustainability & Selection: A Complete Guide
Fastness Properties Comparison
| Dye Type | Wash Fastness | Light Fastness | Rubbing Fastness |
| Reactive | 4-5 | 5-7 | 4-5 |
| Vat | 5 | 7-8 | 5 |
| Disperse | 4 | 5-6 | 3-4 |
| Direct | 2-3 | 4-5 | 2-3 |
Environmental & Technical Considerations
Modern Challenges:
- Azo dye prohibitions (carcinogenic amines)
- Salt-free reactive systems
- Low-temperature polyester dyeing.
- Bio-enzyme pretreatments
Sustainable dyes include natural indigo alternatives and low-impact reactive dyes.
Selection Criteria for Dyes
- Fiber compatibility.
- Required speed (end-use driven)
- Shade matching (computer colour matching)
- Cost per kg of fabric
- Ecological compliance
- Large-scale reproducibility
Quality Control Parameters
- Strength (ISO 105)
- Shade (ΔE<1.0)
- Fastness (AATCC standards)
- Fixation rate (>85% target)
Conclusion
Understanding different types of dyes improves production efficiency, quality consistency, and market competitiveness. Fiber-dye matching is guided by accurate classification, ranging from reactive dyes dominating cotton to dispersion dyes ruling synthetics. Scalability is determined by dyeing methods, which include exhaust and continuous.
Dyes are used in a variety of applications, including fashion and technical fabrics. To achieve long-term success, industry specialists use fastness data, dyeing parameters, and environmental compliance. Understanding the various types of dyes enables educated judgements throughout the textile value chain.
FAQs
- What are the two types of dyes?
Dyes are divided into two types: natural dyes (derived from plants, animals, or minerals) and synthetic dyes (chemically manufactured).
- What are the different types of dye?
Acid dyes, basic dyes, direct dyes, reactive dyes, vat dyes, disperse dyes, and sulphur dyes are all common types of dyes that are used for various fibres and purposes.
- What are the examples of basic dyes and direct dyes?
Examples of basic dyes are Methylene Blue, Crystal Violet, and Malachite Green.
Examples of direct dyes are Congo Red, Direct Blue, and Direct Black.
- What are synthetic dyes?
Synthetic dyes are artificial dyes generated by chemical processes, primarily from petroleum-based compounds, and are frequently used for their vibrant colours and durability.
- What is a dyeing technique?
Dyeing is the process of applying dye to fabrics or materials to achieve correct colour absorption, fixation, and consistency.
- What are the 7 synthetic dyes?
The seven commonly known classes of synthetic dyes are acid dyes, basic dyes, direct dyes, reactive dyes, vat dyes, disperse dyes, and sulfur dyes.
