Dyes can be defined as the different type of coloring particles which differ in each type from the. A vat pallet, listing with dyestuff suitability for the onephase and twophase procedure appears at the end of the bulletin. Colour fastness is a termused in the dyeing of textile materialsthat characterizes a materials colours resistance to fading or running. Their major disadvantage is that only synthetic fabrics can be used. They have excellent all round fastness, which includes washing, light. Cn101942219b dark blue vat dye with high fastness to. The vat dyes were one of the most significant textile dye inventions in the 20 th century.
Indanthrene blue was the first anthraquinone vat dye, synthesized by rene bohn at basf in germany in 1901. Pdf effect of oxidizing agents on the fastness properties of vat. Richard aspland 1997 color in the textile industries. Vat dyes provide textile material with the best color fastness of all the dyes in common use. Welcome to apex dyes industries dyes manufacturer, vat. Fastness properties of the dyes are excellent but its. Air oxidation fixes the dye strongly on the fiber, resulting in excellent wash fastness and light fastness. By definition dyes can be said to be coloured, ionizing and aromatic organic compounds which shows an affinity towards the substrate to which it is being applied.
They possess very high general fastness, especially to the light. The opposite of vat dyeing is direct dye application, for example, tie and dye. Vat dyes mainly belong to indigoid and anthra quinoid classes and are characterized by high fastness, specially anthraquinoids, most valuable for dyeing and printing cotton, wool and silk. Fastness properties of the dyes are excellent but its rubbing properties are not so good. Vat dyes are used for coloring cellulosic fiber specially cotton fiber. The invention relates to a dark blue vat dye with high fastness to chlorine bleaching and high fastness to hot pressing for tooling.
The research work deal on the comparative study of fastness properties of vat dye and reactive dye on cotton fabric. Sometimes, it causes different types of skin disease. Washing fastness, reactive dyes, cotton blended fabric. The dye comprises the following components in weight percentage. Dyeable by exhaustion and continuous dyeing with the excellent ability of light, solvent and chlorineresistance fastness. Vat dyeing process textile dyeing process with vat dye. Vat dyes are specially used for military uniforms owing to outstanding fastness properties, earth tone shade, and near infrared nir camouflage. Vat dyes are expensive because of the initial cost as well as the method of application. The original vat dye is indigo, once obtained from plants but now produced synthetically. Vat dyes are a class of dyes that are classified as such because of the method by which they are applied. It is selected by the manufacturer as a reference point to provide samples serving to establish the different fastnesses. Under these conditions, the dye is more soluble and the wettability of natural fibres is increased, improving the transport of dye molecules into the fabric. They are reduced by another chemical and converted to a soluble form. Vat dyes offer the best overall fastness on cellulosic fibers.
In many cases, the fabric is pretreated with metallic salts or mordants to improve the fastness and to vary the. Colorimetric and wash fastness data after repeated wash cycles of poly lactic acidpla fiber were examined with c. Filter dye dispersion and add to the circulating dyebath in which caustic soda was already added, add hydrosulphite and bring to. Pdf improving dyeability of cotton fabric for vat dyes. Cationization, cotton, vat dyes, cibafix wff, color strength, fastness. All the dyes we are producing are also available in the paste form. In what type of garments vat dyes are normally used. Vat dyes are an ancient class of dye, based on the original natural dye, indigo. Fastness property an overview sciencedirect topics. The discovery of vat dyes in the early 1900s was a major technological advance for the industry.
The dyes used for printing mostly include vat, reactive, naphthol and disperse colours which have good fastness properties venkataraman, 1978. Evaluation of wash and light fastness of some selected. Based on temperature, amount of caustic soda, hydrosulphite and salt, used in dyeing, vat dyes can be classified into four main groups. The dyes are insoluble within the fibre structure and therefore have good wash fastness and they also possess high light fastness. Pdf classifications, properties and applications of. Effect of oxidizing agents on the fastness properties of vat dyes on 100% cotton fabric dyeing in exhaust method. Direct dyes are so named because they were the first colourants that had affinity for cotton in the absence of a binding agent known as a mordant. Indanthren blue bc 3%, indanthren red fbb coll, indanthren brilliant green fbb coll, leva. Abstract the practical details of using vat dyes in both batch and continuous processes are covered in this second and final part of chapter 3. The crock fastness and wash fastness of the fabric decrease as dyes migrate to the fabric surface. In this study, 100 % metaaramid woven fabric was dyed with three vat dyes using an exhaustion method and their dyeing and fastness. Prints have excellent light and wash fastness and strong bright colours. The standard intensity represents the concentration of the dye with respect to the weight of fabric.
The name vat was drived from the large wooden vessel from which vat dyes were first applied. Direct, or substantive, dyes are applied to the fabric from a hot aqueous solution of the dye. Dye classification of dye according to application. The prepigmentation dyeing methods are simple processes in which a fine dispersion of the vat pigment is uniformly circulated through the goods that are then treated with alkaline hydros solution to cause reduction. List of americanmade dyes, 1952 technical manual and year book. Vat dye, any of a large class of waterinsoluble dyes, such as indigo and the anthraquinone derivatives, that are used particularly on cellulosic fibres. It is generally applied in a solution that is aqueous. Vat dyes cant be directly applied and required vatting because it is insoluble in water. Vat dyes have outstanding wash fastness and light fastness as a class exception indigo vat dyes the biggest disadvantage of vat dyes is their relatively high cost. The values of the dyed material gradually increased with.
Download pdf the chemistry of vat dyes book full free. The dyes are classified based on the fibers to which they can be applied and the chemical nature of each dye. Technical information basf auxiliaries for textile printing. Dyeing of cotton with vat dye part 01 textile study center. They are named so because of dyeing carried out in wooden vats. Gammacolor vat dyes, called gammanthren, are suitable for cellulosic fibers and are available in powder or liquid form. The vat dyes are naturally obtained coloring materials from the ancient time and kept into wooden vat and make soluble in vat by the process of fermentation so it is called vat dyes. Indigo sol vat dyes are the complex derivatives of anthraquinone and feature superior fastness properties when these are applied to cellulosic textiles. We have by far the broadest product range on the market, covering almost all fibres and quality specifications.
Apex dyes industries is leading vat dyes manufacturer, supplier and exporter in india. Indigo dye is the most used vat dye as it becomes the base for dyeing denim fabrics. Technologies of vat dyeing process their application. The shorter the incident wavelength, the higher the energy release on the coloured fabric surface and the higher the rate of fading. Vat dyes are like sulphur dyes in that they are pigments which must be. The first synthetic vat dye was an indigo created in 1879. The term is usually used in the context of clothes. Hot water dyes are available in both powder and liquid form. Dyes may also require a mordant to better the fastness of the dye on the material on which it is applied. Vat dyes are mainly used for coloring cellulosic fibers. The pigments, which are not truly dyes, are also used extensively for printing.
The vat dyes have high color fastness, which is uncommon in other dye classes. The colour yields of vat dyes on the envix were found to be dependent on dyeing. Color fastness to crocking improvement of indigo and. Vat dyes are most important dyes for dyeing and printing on cotton and cellulosic fibres. Vat dyes vat dyes are the fastest for cellulose fibres. Vatting process is needed for making the insoluble vat dyes into soluble form.
The dye is applied in a soluble, reduced form to impregnate the fibre and then oxidized in the fibre back to its original insoluble form. It is mainly suitable for cellulosic fibre for best overall fastness properties. Vat dyes, which include indigo and anthraquinonebased dyes, are. Dystar is the worlds leading supplier of textile dyes. Air oxidation fixes the dye strongly on the fiber, resulting in excellent washfastness and lightfastness. Anthraquinoid structures vat dyes show an excellent light fastness on cotton due to the compactness of the dye structure, which is not possible with other classes of dyes.
Types of dyes classification based on chemical structure. These colours are fixed to the fibre through resins that are very resistant to laundering or dry cleaning. Dyeing and fastness properties of vat dyes on metaaramid woven. But vat dyes fastness properties is good among the all dyes. Whats color fastness of dyed fabrics, how to test color. Dyes are complex unsaturated aromatic compounds fulfilling characteristics like intense color, solubility, substantiveness, and fastness. Sulfur dyes like vat dyes are applied to textiles cellulose, table 4 as a soluble anionic form and then oxidized into the insoluble form. However, their use is limited by their lack of good reds, their high cost and relative difficulty of application. The complex chemical structures provided a rainbow of shades and had remarkable lightfastness properties when applied to textiles. Recycling of vat and reactive dyed textile waste to new. Vat pigments, dissolved as leucovat dye anions, follow the. The reduction is carried out in an aqueous alkali medium using isomaltulose or a mixture containing isomaltulose as the reducing agent.
Vat dyes generally offer superior fastness properties. Pdf the chemistry of vat dyes download full pdf book. Natural indigo was extracted by fermenting indigofera tinctoria leaves. Auxiliary for dissolving acid, metal complex and direct dyes in the printing of pa, wool and silk. Because these dyes are watersoluble, many have low wet fastness. It can be done using almost any dye, including fiber reactive dyes, direct dyes, acid dyes, etc. For example, cellulosic fibers dyed with reactive or vat dyes will show good fastness properties. These dyes are available in 3 forms, crude dry powderrecommended for exhaust dying microdispersed formrecommended for continuous dying vat paste. Important considerations in dyeing with vat dyes vat dyes are the primary choice where the highest degree of fastness to industrial laundering, weathering and light are required.
The envix exhibited better dyeability than viscose rayon. That is to say compatibility of dye with the fiber is very important. Because of the popularity of blue jeans, indigo is still one of the most important dye in the world in the present time. Comparative study of washing fastness of vat and reactive dyed. Vat dyeing is a process that refers to dyeing that takes place in a bucket or vat. Vat dyes are a class of dyes that are classified as such because of the method by which they. Made available in powder form, it is preferred to be used in batch dyeing method where these provide fine.
The chemistry of vat dyes available for download and read online in other formats. Vat dyes have extremely good fastness properties on cellulose, and are used where fastness to washing and light are paramount, such as for awnings, upholstery, towels and shirting. Dye dissolving and fixing agent in textile printing with soluble dyes and with vat dyes. This invention concerns a process for reducing dyes of the group consisting of sulfur and vat dyes. Protein fibers dyed with acid mordant and reactive dyes will achieve good fastness properties and so on. Dyes designed for cellulosic polymers are direct, azoic, vat, sulfur, and reactive dyes.
The practical details of using vat dyes in both batch and. The pigment form, however, has no substantivity for cotton at all. The chemistry and manufacture of vat dyes by robert j. Vat dyeing process textile dyeing process with vat dye vat dyes. They are insoluble in water, therefore they need to be reduced with sodium hydrosulphite and caustic soda to allow dyeing. Vat dyes are different from r eactive dyes, disperse dyes, basic dyes, acid dyes or azoic color but its application process is near similar as sulphur dyes. While vat dyes are unable to achieve shades of extreme brightness, they do offer a wide range of shades and have innately good fastness. Fastness to light and washing of direct dyes for cellulosic textiles sity to daylight. Before dying they need to be reduced and solubilized by reductive agent in alkaline solution, then dyeing. Vat dyes are widely used for colouring cellulosic fibre, especially cotton fibre along with viscose rayon, leather and other fibres. It is widely used for run the dyeing process of cotton yarns which is used for producing jeans or denim product. Dye is printed or painted onto paper and heat pressed onto fabric.