Vat dyes cant be directly applied and required vatting because it is insoluble in water. They are named so because of dyeing carried out in wooden vats. The dyes used for printing mostly include vat, reactive, naphthol and disperse colours which have good fastness properties venkataraman, 1978. All the dyes we are producing are also available in the paste form. 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 shorter the incident wavelength, the higher the energy release on the coloured fabric surface and the higher the rate of fading. Technical information basf auxiliaries for textile printing. 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. Vat dyeing properties of the envix were investigated and compared with those of regular viscose rayon. Recycling of vat and reactive dyed textile waste to new. Based on temperature, amount of caustic soda, hydrosulphite and salt, used in dyeing, vat dyes can be classified into four main groups.
Technologies of vat dyeing process their application. Sometimes, it causes different types of skin disease. Disperse dyes are widely used for heat transfer printing polysol. The reduction is carried out in an aqueous alkali medium using isomaltulose or a mixture containing isomaltulose as the reducing agent. The standard intensity represents the concentration of the dye with respect to the weight of fabric. Air oxidation fixes the dye strongly on the fiber, resulting in excellent wash fastness and light fastness.
Dyeing and fastness properties of vat dyes on metaaramid woven. The opposite of vat dyeing is direct dye application, for example, tie and dye. Vat dyeing is a process that refers to dyeing that takes place in a bucket or vat. Fastness to light and washing of direct dyes for cellulosic textiles sity to daylight. Vat dyes are most important dyes for dyeing and printing on cotton and cellulosic fibres. Cn101942219b dark blue vat dye with high fastness to. Dyeing of cotton with vat dye part 01 textile study center. 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. But vat dyes fastness properties is good among the all dyes. Filter dye dispersion and add to the circulating dyebath in which caustic soda was already added, add hydrosulphite and bring to. Vatting process is needed for making the insoluble vat dyes into soluble form.
The pigments, which are not truly dyes, are also used extensively for printing. Evaluation of wash and light fastness of some selected. They are insoluble in water, therefore they need to be reduced with sodium hydrosulphite and caustic soda to allow dyeing. However, their use is limited by their lack of good reds, and. Direct, or substantive, dyes are applied to the fabric from a hot aqueous solution of the dye. The original vat dye is indigo, once obtained from plants but now produced synthetically. Pdf improving dyeability of cotton fabric for vat dyes. The first synthetic vat dye was an indigo created in 1879. 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.
Indanthrene blue was the first anthraquinone vat dye, synthesized by rene bohn at basf in germany in 1901. Colorimetric and wash fastness data after repeated wash cycles of poly lactic acidpla fiber were examined with c. Vat dyes manufacturers, vat paste exporters in india. Vat dyes are widely used for colouring cellulosic fibre, especially cotton fibre along with viscose rayon, leather and other fibres. It can be done using almost any dye, including fiber reactive dyes, direct dyes, acid dyes, etc. Fastness property an overview sciencedirect topics. Vat dyes provide textile material with the best color fastness of all the dyes in common use. 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. Vat dyes are a class of dyes that are classified as such because of the method by which they.
Dyes can be defined as the different type of coloring particles which differ in each type from the. Dystar is the worlds leading supplier of textile dyes. That is to say compatibility of dye with the fiber is very important. However, their use is limited by their lack of good reds, their high cost and relative difficulty of application. The dyes are classified based on the fibers to which they can be applied and the chemical nature of each dye. Vat dyes are specially used for military uniforms owing to outstanding fastness properties, earth tone shade, and near infrared nir camouflage. Fastness properties of the dyes are excellent but its rubbing properties are not so good. Gammacolor vat dyes, called gammanthren, are suitable for cellulosic fibers and are available in powder or liquid form. Prints have excellent light and wash fastness and strong bright colours. Dyes are complex unsaturated aromatic compounds fulfilling characteristics like intense color, solubility, substantiveness, and fastness.
The research work deal on the comparative study of fastness properties of vat dye and reactive dye on cotton fabric. Auxiliary for dissolving acid, metal complex and direct dyes in the printing of pa, wool and silk. Indigo dye is the most used vat dye as it becomes the base for dyeing denim fabrics. Indigo sol vat dyes are the complex derivatives of anthraquinone and feature superior fastness properties when these are applied to cellulosic textiles. 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. 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.
They possess very high general fastness, especially to the light. The complex chemical structures provided a rainbow of shades and had remarkable lightfastness properties when applied to textiles. It is mainly suitable for cellulosic fibre for best overall fastness properties. Dye is printed or painted onto paper and heat pressed onto fabric. Comparative study of washing fastness of vat and reactive dyed. Vat dye, any of a large class of waterinsoluble dyes, such as indigo and the anthraquinone derivatives, that are used particularly on cellulosic fibres.
In many cases, the fabric is pretreated with metallic salts or mordants to improve the fastness and to vary the. Dyes designed for cellulosic polymers are direct, azoic, vat, sulfur, and reactive dyes. 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. Indanthren blue bc 3%, indanthren red fbb coll, indanthren brilliant green fbb coll, leva.
The name vat was drived from the large wooden vessel from which vat dyes were first applied. 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. The dyes are insoluble within the fibre structure and therefore have good wash fastness and they also possess high light fastness. Vat dyes are an ancient class of dye, based on the original natural dye, indigo. This invention concerns a process for reducing dyes of the group consisting of sulfur and vat dyes. The vat dyes were one of the most significant textile dye inventions in the 20 th century. Cationization, cotton, vat dyes, cibafix wff, color strength, fastness. Dyes may also require a mordant to better the fastness of the dye on the material on which it is applied. Vat dyes are like sulphur dyes in that they are pigments which must be. Washing fastness, reactive dyes, cotton blended fabric. Colour fastness is a termused in the dyeing of textile materialsthat characterizes a materials colours resistance to fading or running. Hot water dyes are available in both powder and liquid form. Whats color fastness of dyed fabrics, how to test color.
Download pdf the chemistry of vat dyes book full free. Pdf effect of oxidizing agents on the fastness properties of vat. They have excellent all round fastness, which includes washing, light. Vat dyes are expensive because of the initial cost as well as the method of application. Vat dyeing process textile dyeing process with vat dye vat dyes. It is widely used for run the dyeing process of cotton yarns which is used for producing jeans or denim product. Pdf classifications, properties and applications of. 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. Vat dyes vat dyes are the fastest for cellulose fibres. Dye classification of dye according to application. It is generally applied in a solution that is aqueous. It is selected by the manufacturer as a reference point to provide samples serving to establish the different fastnesses.
The chemistry and manufacture of vat dyes by robert j. The fastness of three vat dyes on pla fiber to repeated washing according to ks k 0430 a2 regulation increased with dyeing temperatures. The dye comprises the following components in weight percentage. 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. Before dying they need to be reduced and solubilized by reductive agent in alkaline solution, then dyeing. Dye dissolving and fixing agent in textile printing with soluble dyes and with vat dyes. List of americanmade dyes, 1952 technical manual and year book. In what type of garments vat dyes are normally used.
Vat pigments, dissolved as leucovat dye anions, follow the. Vat dyes offer the best overall fastness on cellulosic fibers. Dyeable by exhaustion and continuous dyeing with the excellent ability of light, solvent and chlorineresistance fastness. These dyes are available in 3 forms, crude dry powderrecommended for exhaust dying microdispersed formrecommended for continuous dying vat paste. Air oxidation fixes the dye strongly on the fiber, resulting in excellent washfastness and lightfastness. Because of the popularity of blue jeans, indigo is still one of the most important dye in the world in the present time. The values of the dyed material gradually increased with.
Comparative study of fastness properties of vat dye and. Because these dyes are watersoluble, many have low wet fastness. Vat dyes are a class of dyes that are classified as such because of the method by which they are applied. In this study, 100 % metaaramid woven fabric was dyed with three vat dyes using an exhaustion method and their dyeing and fastness. They are reduced by another chemical and converted to a soluble form. We have by far the broadest product range on the market, covering almost all fibres and quality specifications. These colours are fixed to the fibre through resins that are very resistant to laundering or dry cleaning. Effect of oxidizing agents on the fastness properties of vat dyes on 100% cotton fabric dyeing in exhaust method. Textile printing theoretical aspects of dyeing the measurement of colour fastness testing textile dyeing and coloration. 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. Vat dyeing process textile dyeing process with vat dye.
The term is usually used in the context of clothes. The vat dyes were one of the most significant textile dye inventions in the. The crock fastness and wash fastness of the fabric decrease as dyes migrate to the fabric surface. Us6093221a process for reducing sulfur and vat dyes. Pdf the chemistry of vat dyes download full pdf book. Natural indigo was extracted by fermenting indigofera tinctoria leaves. The vat dyes have high color fastness, which is uncommon in other dye classes. Richard aspland 1997 color in the textile industries. Their major disadvantage is that only synthetic fabrics can be used. A vat pallet, listing with dyestuff suitability for the onephase and twophase procedure appears at the end of the bulletin. The invention relates to a dark blue vat dye with high fastness to chlorine bleaching and high fastness to hot pressing for tooling. The practical details of using vat dyes in both batch and. Vat dyes are used for coloring cellulosic fiber specially cotton fiber. Sulfur dyes like vat dyes are applied to textiles cellulose, table 4 as a soluble anionic form and then oxidized into the insoluble form.
For example, cellulosic fibers dyed with reactive or vat dyes will show good fastness properties. Welcome to apex dyes industries dyes manufacturer, vat. 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. In general, clothing should be tested for colorfastness before using bleach or other cleaning products light fastness, wash fastness, and rub fastness are the main forms of colour fastness that are. 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 generally offer superior fastness properties. Fastness properties of the dyes are excellent but its. They are brilliant in shades, full range in colors and of good dyeing fastness properties on fibers. Protein fibers dyed with acid mordant and reactive dyes will achieve good fastness properties and so on. The discovery of vat dyes in the early 1900s was a major technological advance for the industry. The chemistry of vat dyes available for download and read online in other formats. Apex dyes industries is leading vat dyes manufacturer, supplier and exporter in india.