DYE PROCESS
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DYE THE FABRIC

ORGANIC DYES DYE LASER ACID DYES BASIC DYES  SUBESTANTIVE DYES 

MORDANT DYES   REACTIVE DYE TIE DYES

Dyeing is the process of importing color to a textile material in loose fibre, yarn, cloth or garment form by treatment with a dye.

DYE can generally be described as a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and may require a mordant to improve the fastness of the dye on the fiber.

 Direct application

The term direct dye application stems from some dyestuff having to be either fermented as in the case of some natural dye or chemically reduced as in the case of synthetic Vat and Sulphur dyes before being applied. This renders the dye soluble so that it can be absorbed by the fibre, the insoluble dye has very little substantively to the fibre. Direct dyes, a class of dyes largely for dying cotton, are water soluble and can be applied directly to the fibre from an aqueous solution. Most other classes of synthetic dye, other than vat and sulpur dyes, are also applIed in this way.

The term may also be applied to dyeing without the use of mordant to fix the dye once it is applied. Mordant were often required to alter the hue and intensity of natural dyes and improve their color fastness. Chromium salts were until recently extensively used in dying wool with synthetic mordant dyes. These were used for economical high color fastness dark shades such as Black and Navy. Environmental concern have now restricted their use and they have been replaced with reactive and metal complex dyes which need no mordant

Yarn dyeing

There are many forms of yarn dyeing. Common forms are -at package form & at honks form. Cotton yarns are mostly dyed at package form, and acrylic or wool yarn are dyed at hank form

The common dyeing process of cotton yarn with reactive dyes at package form is given below in short- firstly the raw yarn is winded on spring tube to achieve package suitable for dye penetration. then, these softened packages are loaded on a dyeing carrier's spindle one on other. Then, the packages are pressed up to a desired height to achieve suitable density of pkg. then, the carrier is loaded on dyeing machine and yarn is dyed. after dyeing, the packages are unloaded from the carrier in to a trolly. then, all the packages are hydro extracted to remove maximum amount of water. then, all the packages are dried to achieve the final dyed package. at last the dyed yarn packages are packed and delivered

Both dyes and pigments appear to be colored because they absorb some wavelengths of light preferentially. In contrast with a dye, a pigment generally is insoluble, and has no affinity for the substrate. Some dyes can be precipitated with an inert salt to produce a lake pigment.

Archaeological evidence shows that, particularly in India and the Middle East, dyeing has been carried out for over 5000 years. The dyes were obtained from animal, vegetable or mineral origin, with no or very little processing. By far the greatest source of dyes has been from the plant kingdom, notably roots, berries, bark, leaves and wood, but only a few have ever been used on a commercial scale.Color is the most important attribute to consumers . The colors in fabrics are infinite. They can be solids, multi-colored stripes, or other pattern effects such as floral and geometries. Dyeing of the material can be done at any stage of making the fiber, yarn, or fabric. The desired effect to be achieved will usually dictate the dyeing method.

For example, a multi-colored floral pattern requires the individual yarns to be pre-colored to as many different shades as there are in the desired pattern. The various colored yarns are then constructed into the floral pattern fabric.

 

By contrast a solid color can be achieved by constructing the fabric first and then dyeing the fabric. Another way to achieve a solid color or multi-color effect would be to use pre-dyed fiber, produce the colored yarn, and then construct the fabric. This assures consistently uniform color. Printing is localized coloration that also achieves multi-colored effects.

Finishing

We provide a wide range of finishing options, from scouring and prepare-for-print to a variety of soft to medium finishes to meet our customers' requirements. In addition, we also provide specialty finishes including soil resistant finishes, anti-microbial and water-repellent finishes.

Finishing follows coloration. This treatment can be mechanical, chemical, or both. The mechanical treatment is done at the textile mill or dye house. It can be one of various surface treatments. Brushing and sanding of fabrics, for example, can provide extra sheen and luster. 

Dye laser

A dye laser is a laser which uses an organic dye as the lasing medium, usually as a liquid solution. Compared to gases and most solid state lasing media, a dye can usually be used for a much wider range of wavelengths. The wide bandwidth makes them particularly suitable for tunable lasers and pulsed lasers. Moreover, the dye can be replaced by another type in order to generate different wavelengths with the same laser, although this usually requires replacing other optical components in the laser as well.

The long-wavelength absorption band of laser dyes is attributed to the transition from the electronic ground state S0 to the first excited singlet state S1. The transition moment for this process is typically very large, thus giving rise to an absorption band with an oscillator strength on the order of unity. The reverse process S1->S0 is responsible for the spontaneous emission known as fluorescence and for the stimulated emission in dye lasers.

Dye lasers are also used dermatologically, to make skin tone more

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Close-up of a table-top dye laser based on Rhodamine 6G, emitting at 580 nm (yellow-orange). The emitted laser beam is visible as faint yellow lines. The orange dye solution enters the laser from the left, and is pumped by a 514 nm (blue-green) beam from an argon laser. The dye jet is in the center of the image, behind the yellow window.

Organic Dyes

The first human-made (synthetic) organic dye, mauveine, was discovered by William Henry Perkin in 1856. Many thousands of synthetic dyes have since been preparedSynthetic dyes quickly replaced the traditional natural dyes. They cost less, they offered a vast range of new colors, and they imparted better properties upon the dyed materials. Dyes are now classified according to how they are used in the dyeing process.

Acid dyes

Acid dyes are water-soluble anionic dyes that are applied to fibers such as silk, wool, nylon and modified acrylic fibers using neutral to acid dyebaths. Attachment to the fiber is attributed, at least partly, to salt formation between anionic groups in the dyes and cationic groups in the fiber. Acid dyes are not substantive to cellulosic fibers.

Basic Dyes

Basic dyes are water-soluble cationic dyes that are mainly applied to acrylic fibers, but find some use for wool and silk. Usually acetic acid is added to the dyebath to help the uptake of the dye onto the fiber. Basic dyes are also used in the coloration of paper.

Substantive Dyeing

Direct or Substantive Dyeing is normally carried out in a neutral or slightly alkaline dyebath, at or near boiling point, with the addition of either sodium chloride (NaCl) or sodium sulfate (Na2SO4). Direct dyes are used on cotton, paper, leather, wool, silk and nylon. They are also used as pH indicators and as biological stains.

(Substantive Dyeing  is a dye used in a process in which dye molecules are attracted by physical forces at the molecular level to the textile. The amount of this attraction is known as "substantively": the higher the substantively the greater the attraction of the dye for the fiber).

Mordant Dyes

Mordant dyes require a mordant, which improves the fastness of the dye against water, light and perspiration. The choice of mordant is very important as different mordant can change the final color significantly. Most natural dyes are mordant dyes and there is therefore a large literature base describing dyeing techniques. The most important mordant dyes are the synthetic mordant dyes, or chrome dyes, used for wool; these comprise some 30% of dyes used for wool, and are especially useful for black and navy shades. The mordant, potassium dichromate, is applied as an after-treatment. It is important to note that many mordant, particularly those in the hard metal category, can be hazardous to health and extreme care must be taken in using them.

(A mordant is a substance used to set dyes on fabrics by forming an insoluble compound with the dye.)

Cellulose is an organic compound with the formula (C6H10O5)n.Cellulose in 3D

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Reactive dyes
Reactive dyes utilize a chromophore containing a substituent that is capable of directly reacting with the fibre substrate. The covalent bonds that attach reactive dye to natural fibers make it among the most permanent of dyes. "Cold" reactive dyes, such as Procion MX, Cibacron F, and Drimarene K, are very easy to use because the dye can be applied at room temperature. Reactive dyes are by far the best choice for dyeing cotton and other cellulose fibers at home or in the art studio.
 
In a reactive dye a chromophore contains a substituent that is activated and allowed to directly react to the surface of the substrate.
A chromophore is part (or moiety) of a molecule responsible for its color.
 
Sulfur dyes
Sulfur dyes are two part "developed" dyes used to dye cotton with dark colors. The initial bath imparts a yellow or pale chartreuse color. This is oxidized in place to produce the dark black we are familiar with in socks and the indigo blue of the common blue jeans.
 
Sulfur dyes are the biggest volume dyes manufactured for cotton.

Redox (shorthand for reduction/oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed.This can be either a simple redox process such as the oxidation of carbon to yield carbon dioxide, or the reduction of carbon by hydrogen to yield methane (CH4), or it can be a complex process such as the oxidation of sugar in the human body through a series of very complex electron transfer processes.The term redox comes from the two concepts of reduction and oxidation. It can be explained in simple terms:\\

Oxidation describes the loss of electrons by a molecule, atom or ion ,//

Reduction describes the gain of electrons by a molecule, atom or ion .Top of Page

However, these descriptions (though sufficient for many purposes) are not truly correct. Oxidation and reduction properly refer to a change in oxidation number the actual transfer of electrons may never occur. Thus, oxidation is better defined as an increase in oxidation number, and reduction as a decrease in oxidation number. In practice, the transfer of electrons will always cause a change in oxidation number, but there are many reactions which are classed as "redox" even though no electron transfer occurs (such as those involving covalent bonds).Non-redox reactions, which do not involve changes in formal charge, are known as metathesis reactions.

Tie-dye

 is typically brightly colored, patterned textile or clothing which is made from ordinary cloth, usually cotton, through a resist dyeing process known as tie-dyeing. This is the modern version of a traditional dyeing method.

Resist dyeing, resist-dyeing and variants is a term for a number of traditional methods of dyeing textiles with patterns. Methods are used to "resist" or prevent the dye from reaching all the cloth, thereby creating a pattern and ground. The most common forms use wax, some type of paste, or a mechanical resist that manipulates the cloth such as tying or stitching. Another form of resist involves using a chemical agent in a specific type of dye that will repel another type of dye printed over the top.

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