The difference between dyes and pigments

Dyes and pigments have different roles in color applications:

Dyes are suitable for fields such as textiles, leather, and paper that require penetration coloring due to their small particles, transparency, and solubility.

Pigments are widely used in areas such as paints, coatings, and plastics that require surface coverage due to their large particles, opacity, and high covering power. Understanding the difference between these two can help choose the appropriate coloring agent to meet different application needs.

 

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Classification of Dyes - Classified by Chemical Structure

 

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Disperse Dyes - Main Applications and Characteristics

Purpose and Characteristics

1. Chemical fiber dyeing

1.1 Dyeing of Polyester Fiber (Polyester)

The main application areas of dispersed dyes. Polyester is a widely used synthetic fiber with strong water resistance, high crystallinity, and small fiber gaps, which are compatible with the characteristics of dispersed dyes. Polyester fabrics dyed with dispersed dyes have bright colors and excellent wash fastness, which can meet people's requirements for textile color and quality.

1.2 Dyeing of Acetate Fiber (Diacetate Fiber, Triacetate Fiber)
Acetate fiber is also one of the suitable fibers for dispersing dyes. Acetate fiber fabric processed by dispersed dye printing and dyeing has a soft touch, good glossiness, good drape and moisture absorption, and is commonly used in the production of high-end clothing and household items.

1.3 Dyeing of polyamide fiber (nylon)
Nylon fiber has the advantages of high strength and good wear resistance, and is widely used in the textile industry. Disperse dyes can dye nylon and impart rich colors to nylon fabrics, but their application in nylon dyeing is relatively limited.

1.4 Polyacrylonitrile (PAN) dyeing

There is a small application of acrylic fiber, which can make acrylic fabrics have good color fastness and vividness, but it is also not the main application field.
 

2. Printing and dyeing of blended fabrics

In synthetic fiber blended products, dispersed dyes usually need to be used in combination with other applicable dyes.
 

3. Plastic coloring

Disperse dyes can be used for coloring plastics, especially for plastic products that require high color requirements, light resistance, and heat resistance.
 

4. Transfer printing

After making dispersed dyes into printing ink, they are printed on fabrics and then subjected to high-temperature pressing and dyeing. This process, also known as non-aqueous printing, has the advantages of energy saving, time-saving, and convenience.

 

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Disperse dyes - dyeing mechanism and methods

1. Dye molecules dispersed in water (1-4 μ).

2. Under the dissociation of the dispersant, a portion of the dye decomposes into single molecules (2m μ) and diffuses in the dye bath.

3. Dyes adsorb onto the surface of fibers.

4. The dye penetrates and diffuses into the swollen part of the fiber, and attaches to the amorphous part of the fiber.

 

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Solvent Dyes - Overview of Solvent Dyes

Solvent dyes usually refer to dyes that are insoluble in water but soluble in organic solvents, so some countries refer to solvent dyes as organic solvent soluble dyes (such as Japan). As early as 1861, solvent dyes appeared, but they were only simple azo compounds, and industrial production was achieved in 1920, such as solvent yellow 1 # (commonly known as aniline yellow). The earliest solvent dye product brand was Zapon from BASF, and to this day, there are still 21 varieties of this brand available on the market. However, the production of solvent dyes in our country started relatively late, and it only took about ten years to truly calculate. There is great potential for the development of variety and quality, but there is still a certain gap compared to similar products abroad.

 

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Solvent dyes - Applications

The application of solvent dyes is very extensive and closely related to people's lives. It can be used as a fuel oil coloring agent, wood, candles, lubricating oil, leather oil, transparent paint, organic glass, plastic resin, film, vacuum coating, decorative material, textile fiber, etc. It can also be used in coatings, inks, liquid crystal displays, lasers, organic photoconductive materials, solar collectors, metal fluorescence detection, drug tracing, cosmetics, skincare products, etc. In addition, oil soluble dyes can also be used for coloring paints, inks, rubber, aluminum products, inks, furniture, leather jackets, and for coloring lightweight and daily chemical products.

 

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Application and main promotion direction of solvent dyes

1. Polyester spinning

Mainly the masterbatch factory, which is divided into long fibers and short fibers, such as plush toys, carpets, etc.

2. Plastic coloring

Mainly hard glue coloring, such as plastic toys, hard plastic products, various appliance shells, fruit baskets, etc.

3. Transfer ink (thermal transfer ink)

Ink factory, digital printing factory.