Vat dye

Vat dye

Vat dyes are an ancient class of dyes, based on the natural dye, indigo, which is now produced synthetically.

Overview

The process "vat dyeing" refers to dyeing in a bucket or fat. It can be performed whenever a liquid, even shade over the entire garment is desired. Almost any dye can be used, including fiber reactive dyes, direct dyes, and acid dyes. One alternative to vat dyeing is direct dye application, such as the process used for tie dyeing. "Vat dyes" are a special class of dyes that work with a special chemistry. Cotton, wool, and other fibers can be all dyed with vat dyes. Note that not all vat dyeing is done with vat dyes!

Most vat dyes are less suitable than fiber reactive dyes for the home dyers, as they are difficult to work with; they require a reducing agent to solubilize them. The dye is soluble only in its reduced (oxygen-free) form. The fiber is immersed repeatedly in this oxygen-free dyebath, then exposed to the air, whereupon the water-soluble reduced form changes color as oxygen turns it to the water-insoluble form. Indigo is an example of this dye class; it changes from yellow, in the dyebath, to green and then blue as the air hits it.

Light-oxidized Vat Dyes

Ink-o-dye is a type of vat dye which uses light rather than oxygen to 'fix' the dye, with an inspirationally wide variety of possible effects. These dyes, which are chemically similar to vat dyes, Inkodyes are developed by light instead of being applied in an oxygen-free bath and being developed in the fabric by exposure to oxygen. Ink-o-dyes are true dyes, not fabric paints. (A dye actually itself attaches to the fabric; fabric paint includes a glue-like binder, which imparts a stiffer feeling to the fabric.) The process is more difficult than the process of tie-dyeing with fiber reactive dyes. One retail source of Ink-o-dye is Dharma Trading Company.

Using vat dyes

PRO Chemical & Dye, which sells some vat dyes, provides instructions online for Immersion Dyeing using PRO Vat Dyes. The process requires the use of lye (sodium hydroxide), which must be used with due care, including the use of safety goggles.

Indigo is subject to major crocking (rubbing the dye off onto other items) unless it is applied carefully. This means use a weaker dyebath, and dipping many times, rather than a single strong dipping.

Application of vat Dyes:

Application of vat dyestuff is not so easy like direct or reactive dyes. The application involves a lot of chemistry - such as oxidation, reduction, pH control and so on.

Even the dissolution of the dyestuff involves a great technique of reduction using adequate quantities of caustic soda and sodium hydrosulphite.

There many several methods and machinery available for the application of vat dyes to yarn and fabric. A complete reference for all the technique and systems involeved cannot be explained fully over here. But anybody wants to know more they may refer to http://www.thesmarttime.com

References

"Imagery on Fabric" by Jean Ray Laury

"The Chemistry of Vat Dyes" by Dianne Epps

External links

* [http://www.dharmatrading.com/info/vat_dye.html Dharma Trading Company Vat Dye Instructions]
* [http://www.prochemical.com/directions.htm#Vat%20Dyes PRO Chemical & Dye - Vat Dye Instructions]


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Look at other dictionaries:

  • vat dye — n. a colorfast dye made soluble for application to cloth, then oxidized and thus rendered insoluble in the cloth vat dyed adj …   English World dictionary

  • vat dye — vat′ dye n. chem. any of a class of water insoluble dyes that are taken up by textile fibers and then fixed by oxidation • Etymology: 1900–05 …   From formal English to slang

  • vat dye — noun a water insoluble dye that is applied by reducing the dye to an alkaline form, applying the dye, then regenerating the insoluble dye by oxidation in the material; used for dyeing cotton • Syn: ↑vat color • Hypernyms: ↑dye, ↑dyestuff * * *… …   Useful english dictionary

  • vat dye — leukodažiklis statusas T sritis chemija apibrėžtis Bespalvė tirpi leukobazė, kuri oksiduojama ant dažomos medžiagos virsta spalvotu junginiu. atitikmenys: angl. leuco dye; vat dye rus. лейкокраситель …   Chemijos terminų aiškinamasis žodynas

  • vat dye — kubinis dažiklis statusas T sritis chemija apibrėžtis Vandenyje netirpstantis dažiklis, kurį prieš dažymą reikia redukuoti į tirpų leukojunginį. atitikmenys: angl. vat dye rus. кубовый краситель …   Chemijos terminų aiškinamasis žodynas

  • vat dye — Chem. any of the class of insoluble dyes impregnated into textile fibers by reduction into soluble leuco bases that regenerate the insoluble dye on oxidation. [1900 05] * * * ▪ chemical compound       any of a large class of water insoluble dyes …   Universalium

  • vat dye — noun Date: 1903 a water insoluble generally fast dye used in the form of a vat liquor called also vat color …   New Collegiate Dictionary

  • vat dye — /ˈvæt daɪ/ (say vat duy) noun any of a group of insoluble dyes which are applied to fabrics by first reducing them to alkali soluble leuco bases. After dyeing, the insoluble dye is regenerated in the fibres of the material by oxidisation …  

  • vat dye — noun Any of a type of dye, many based on indigo, in which a soluble form is used to impregnate a fibre or fabric and is then converted to an insoluble form …   Wiktionary

  • vat dye — noun an insoluble dye that is applied to a fabric in a reducing bath which converts it to a soluble form, the colour being obtained on subsequent oxidation …   English new terms dictionary

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