How to Choose the Right Dye for Your Needs: A Comprehensive Guide

Dyestuff selection is an important link in process design. It not only affects dye quality, but also directly affects product cost and economic benefits. The choice of dye category should generally be based on factors such as fiber raw materials, color characteristics, fastness requirements, processing costs, equipment conditions, and environmental protection requirements. The dyeing process should be determined according to the dye type, production batch, equipment conditions, production cost and other factors, and combined with the actual situation of the factory.

The fiber raw materials that make up the fabric are the most basic basis for dye selection. Commonly used dyes for dyeing textile fibers are shown in the following table.

 

Commonly used dyes for dyeing textile fibers:

Fiber / Dye

Direct dyes

Reactive  dyes

Vat dyes

Sulfur dyes

Ice dye

indigosol dye

Coating

Disperse  dyes

Cationic  dyes

Acid dyes

Acid mordant

Acid complex

Neutral

Cotton

√

√

√

√

√

√

√

Flax

√

√

√

√

√

√

√

Viscose fiber

√

√

√

√

√

Silk

√

√

√

√

√

Wool

√

√

√

√

√

Polyester

√

√

√

Nylon

√

√

√

√

√

Acrylic

√

√

 

Blended or interwoven fabrics should choose appropriate dyes and processes according to the composition and content of the fibers, and try to choose the dyes that are compatible with the two fibers, so that the dyeing method and process are relatively simple.

 

If there is no suitable one, you can choose two types of dyes to dye two different fibers separately, but the process adaptability of the two types of dyes should be considered. For example, polyester-cotton blended products can be dyed with soluble vat dyes, coatings, etc., as well as disperse/reactive, disperse/ vat dyes.

 

Another example is the nylon/cotton interlaced fabric, which can be dyed with reactive dyes, or with disperse/reactive, weak acid/reactive dyes.

Incoming sample requirements generally include color difference, vividness, color fastness, product use, etc. For some fiber products, there are often many types of dyes applicable, but not all dyes can meet customer requirements.

 

For example, some dyes can only be dyed with a certain color; some dyes may be suitable for dyeing deep and dense colors, some dyes are only suitable for dyeing light and light colors; some dyes have good fastness, and some have poor fastness.

 

This requires us to have a sufficient understanding of the application properties of various dyes, including their chromatogram, brightness, color fastness, price, etc., and then choose the most suitable dye according to the customer's requirements for color and fastness. The application properties of commonly used dyes for cotton fabrics are shown in the following table.

 

Application performance of commonly used dyes on cotton fabrics

Performance Dye	Reactive dyes	Vat dyes	Sulfur dyes	Direct dyes	Ice dye	indigosol dye	Coating
Chromatography	Complete	Lack of scarlet	Incomplete	Complete	Lack of Green	Complete	Complete
Color Fastness	Bright	Bright	General	General	Rich Bright	Bright	Bright
Washing Fastness	Good	Good	Good	Poor	Good	Good	Good
Rubbing Fastness	Good	Good	General	Good	Poor	Good	General
Light Fastness	Good	Good	Good	General	General	Good	General
Level dyeing	Good	General	General	General	General	Good	General
Dyeing method	Simple	Simple	complex	Simple	complex	Simple	Simple
Cost	Low	litte high	Low	Low	Low	High	General
Disadvantage	Low fixing rate, not resistant to chlorine bleaching	Bad photosensitivity	Not resistant to chlorine bleaching, low wet rubbing fastness	Low wet fastness	Low wet rubbing fastness	Poor dyeing and poor photosensitivity	Low scrub fastness, poor hand feeling
Applicability	widely	widely	Deep concentration	widely	Deep concentration	Deep concentration	widely

 

If the customer needs to process a batch of bright green cotton products for washing garment fabrics, the optional dyes are reactive, reducing, coatings, etc., but considering the use and cost, there is no need to choose high fastness, expensive, and complex technology. Vat dyes, the first choice should be paint, followed by reactive dyes.

When the dye variety is selected, the dyeing process is basically determined.

 

Therefore, when selecting dyes, process designers must consider the implementation conditions of the process, such as the adaptability of the equipment to the process, the technical literacy of the operators and the production management level, etc., to ensure that the selected dyes and processes can be implemented smoothly.

 

For example, the continuous pad dyeing machine in some factories is not suitable for dyeing with sulfur dyes (the wet steaming for a long time after the padding solution), soluble vat dyes (the acid color padding tank needs to be corrosion resistant), and some factories do not have it. High-pressure closed equipment cannot implement high-temperature and high-pressure dyeing processes for disperse dyes.

The main factors affecting production costs are the raw material costs of dyes and auxiliaries, energy consumption in the dyeing process, and management costs. The principle of dye selection is to choose low-priced, low-energy, easy-to-operate and low-pollution dyes as much as possible on the premise of meeting customer requirements for product color and fastness, which will help reduce production costs.