Is regular denim dyed with direct dyes?

It's quite easy to dye, but it's generally dyed with sulfur dyes.

The conventional ones are vat dyes.

Direct dyes, acid dyes, cationic dyes, reactive dyes, insoluble azo dyes, disperse dyes, vat dyes, sulfur dyes, polycondensation dyes, fluorescent brighteners, in addition, oxidation dyes (such as aniline black) for textiles, solvent dyes, polypropylene dyes, and food coloring for food.

Direct dyes are mainly used for dyeing cellulose fibers, and can also be used for dyeing silk, paper, and leather. During dyeing, the dye is directly dyed on the fiber in the dyeing solution, and adsorbed on the fiber through van der Waals forces and hydrogen bonds.

Acid dyes are a class of water-soluble anionic dyes. The dye molecule contains sulfonic acid groups, carboxyl groups and other acidic groups, usually in the form of sodium salts, which can be combined with the amino groups in the protein fiber molecule in the acid dye bath with ionic bonds, so it is called acid dyes.

Cationic dyes are soluble in water and are in a cationic state, and early dye molecules have basic groups such as amino groups, often in the form of salts.

Rubia rubia cordifolia

One of the earliest red mordant dyes used by human beings, also known as: broken blood grass, red root grass, etc., there are mainly three kinds of Oriental Akane, Western Akane and Indian Akane. In ancient China, it was called Ru Zhi and earth blood, and it was already the main red dye as early as the Shang and Zhou dynasties.

Madder contains a large amount of alizarin, alizarin, pseudoalixin, etc., which can be obtained from light red to dark red after a series of complex processes such as adding mordant, extracting pigment, and dyeing. Among the large number of silk textile relics unearthed, madder dyeing accounts for a considerable proportion.

Grinding the roots of madder into powder can be dyed in various shades of red.

The raw material of the dye for dyeing cloth is a dye for textile dyeing. It is mostly plant extracts such as plant fruits and sap, and also contains extracts of natural chemicals such as coal tar. It is divided into natural dyes and synthetic dyes, and most of them are synthetic dyes on the market.

Textile dyes have good colorability, are not easy to fade, and are not easy to fade after washing. After the textile is colored, the feel does not change much, and there will be no hardening. However, compared with acrylic, the color is less vivid and saturated.

, acid dyes, mostly suitable for protein fibers, nylon fibers and silk, etc. It is characterized by bright color, but poor washing fastness and excellent dry cleaning fastness, and is widely used in natural dead dyeing.

, cationic dyes (basic dyes), suitable for acrylic, polyester, nylon, cellulose and protein fibers. It is characterized by its bright color, which is very suitable for man-made fibers, but the washing and lightfastness color fastness used for natural cellulose and protein fabrics are poor.

, direct dyes, suitable for cellulose fiber fabrics, washing fastness is relatively poor, light fastness is different, but the modified direct dye will be well improved in washing color fastness.

The principle of direct dyes:

1. The direct dye has a sulfonic acid group or a sulfonic acid group and other water-soluble groups, and the molecular structure of the aromatic ring is arranged in a straight line, and the aromatic ring structure is in the same plane;

2. Direct dyes have a large affinity for cellulose fibers, and can be dyed directly in neutral media, as long as the dye is dissolved in dry water, it can be dyed.

3. The dye is adsorbed to the surface by the fiber in the solution, and then continuously diffuses to the amorphous region of the fiber, forming hydrogen bonds and van der Waals force with the fiber macromolecules.

Dyes are substances that can color fibers and other materials, and are divided into two categories: natural and synthetic. Dyes are substances that are colored. But a substance that has color is not necessarily a dye.

Dye is a substance that can make a certain color adhere to the fiber, and it is not easy to fall off or change color. Dyes are usually soluble in water, and some dyes require mordants to make the dye stick to the fibers. Archaeological data show that dyeing has been used in India and the Middle East for more than 5,000 years.

At that time, dyes came from plants, animals, or minerals, and were rarely treated.

In 1856, Perkin invented the first synthetic dye, horsetail violet, which separated organic chemistry into a new discipline - dye chemistry. 50s of the 20th century. Pattee and Stephen discovered that dyes containing dichlorotriazine groups bonded to the hydroxyl groups on the fibers under alkaline conditions, marking the development of dyes to color fibers from physical to chemical processes, and ushering in the synthesis and application of reactive dyes.

Dyes are not limited to dyeing and printing of textiles, but are also used in many sectors such as paints, plastics, leather, optoelectronic communications, and food.

Generally, jeans are pure cotton, so they are basically dyed with reactive dyes. The jeans of the dark series are dyed with reactive dyes, and the light series are dyed with vat dyes (Shilin dyes). Shilin dye is more expensive, so it is generally only dyed in light color, and after dyeing with this dye, it will not fade!

Common dyes for jeans are:

1. Indigo dye.

Indigo, a blue, almost cyan vat dye with a history of more than 3,000 years. It is the most commonly used dye for denim, and is also commonly used for coloring food, branch stool medicine and daily cosmetics. Indigo dyes are also divided into natural indigo dyes and synthetic indigo dyes.

The natural indigo is extracted from the indigo grass.

2. Sulfur dyes.

Indigo has been the main dye used in the production of standard blue denim for a century, and the successful combination of sulfur dyes and indigo overdyes in the 80s of the last century has created a completely new dyeing effect and greatly increased the market demand for powdered sulfur dyes.

However, due to the shortcomings of the large amount of dust, pungent smell and industrial wastewater that is difficult to deal with due to the large amount of dust produced by powdered sulfur dyes, the liquid sulfur dyes have been further developed and gradually localized, becoming an ideal dye for cotton fabrics to dye dark colors.

3. Soluble azo dyes.

Insoluble azo dyes are also known as ice dyes. It is a class of water-insoluble azo dyes that are formed on fabrics under ice cooling. It was first invented in 1880 by the Englishman Holly.

Hello, kraft paper is usually a coarser kind of paper, its surface is less smooth, and it is more difficult to accept dyes. At the same time, kraft paper is also relatively poor in water absorption, and its absorption capacity for dyes is limited, so it may be difficult to use dyes directly for dyeing. If you want to dye kraft paper, it is advisable to treat it first, such as improving the smoothness and water absorption of its surface so that it can better accept the dye.

You can start by sanding the kraft paper or lightly sanding it with sand paper to make it smoother. In addition, you can use dyes or dye liquids that are specifically designed for paper dyeing burn-out sheds and follow their instructions for use for better dyeing results. In conclusion, dyeing kraft paper requires certain skills and experience, and it is recommended to make adequate preparation and experiments before dyeing to avoid wasting time and materials.

Hello, kraft paper dyeing can be dyed using direct dyes. Direct dyes are water-soluble dyes that can be combined directly with fiber molecules without the use of any mordants or laughing agents. Therefore, direct dyes are ideal for dyeing highly absorbent materials such as kraft paper.

The dyeing process of direct dyes is relatively simple, only need to dissolve the dye in water, soak the kraft paper in the dye solution, and then dry and set the color. The advantages of direct dyes are bright dyeing effect, high color fastness, fast dyeing speed, and suitable for mass production. Apart from direct dyes, there are other types of dyes such as acid dyes, basic dyes, vat dyes, etc.

Different types of dyes are suitable for different types of fibers and materials. When choosing a dye, it is necessary to choose the right dye according to the specific material and the effect of dyeing. In a word, kraft paper dyeing can be dyed using direct dyes, which have the advantages of bright dyeing effect, high color fastness and fast dyeing speed.

When choosing a dye, it is necessary to choose the right dye according to the specific material and dyeing effect.