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Vat dyeVat dyeRinku ShemarVat dyes are insoluble in water but can be converted to soluble leuco compounds using reducing agents like sodium hydrosulphite and caustic soda. These leuco compounds are applied to cotton and oxidized back to insoluble dyes. Vat dyes are classified by application temperature and chemical requirements, with IK requiring the lowest temperatures and chemicals and IN-Special requiring the highest. The vat dyeing process involves vatting to solubilize the dye, dyeing to apply it to cotton, oxidation to fix it, and after treatment including soaping to improve fastness.Technical terms of textile dyeingTechnical terms of textile dyeingTanvir AhammedThis document provides definitions and explanations of various technical terms related to textile dyeing. It discusses terms like dye, substantivity, affinity, exhaustion, adsorption, absorption, desorption, diffusion, migration, fixation, reactivity, dye uptake, dyeing rate, dyeing equilibrium, heat of dyeing, compatibility, cloud point, depth of shade, anti-migration, dispersion, color fastness, fading, oligomers, level dyeing, reserving agents, OWB, OWF, and OWG. It explains the meaning and significance of each term in understanding dyeing processes and properties.Reactive Dye Reactive Dye Md. Mazadul Hasan ShishirThe document provides information about reactive dyes, including: - Reactive dyes form covalent bonds with fiber polymers through reactive groups, giving excellent wash and light fastness. - Important reactive groups include triazine, vinyl sulfone, and halogen groups. - Reactive dyes were invented in and became popular for their bright colors, low temperature dyeing, and simple process. - Common application methods are pad-batch and pad-dry processes at low temperatures. Proper pH, electrolyte, alkali, and time are required for effective dye fixation to the fiber.Reactive dyesReactive dyesMuhammad MudassirReactive dyes are organic dyes that form covalent bonds with cellulose fibers. They were first commercially produced in and have advantages like excellent color fastness and ease of washing. Reactive dyes contain three parts - a chromophore for color, a reactive group that bonds to fibers, and a bridging group connecting these. Dyeing involves exhaustion of dye onto fibers, fixation through alkaline conditions forming covalent bonds, and washing unfixed dye away. Reactive dyeing gives very colorfast results due to the strong covalent bonds formed.Dyeing of polyesterDyeing of polyesterAdane NegaThe document discusses various methods for dyeing polyester fibers, including: 1) Batch dyeing without carriers involves dyeing at a boil without additives to help penetration. 2) Carrier dyeing uses compounds to swell the fibers and allow deeper dye penetration. 3) High temperature, high pressure (HTHP) dyeing penetrates dye rapidly at over 120°C without carriers. 4) Continuous thermosol dyeing involves padding, drying, and fixing dye within fibers at 190-220°C.Direct dyeDirect dyeRinku ShemarDirect dyes are water-soluble aromatic compounds that have an affinity for cellulose fibers like cotton. They are applied as aqueous solutions and bond to fibers physically through hydrogen bonding and van der Waals forces. Direct dyes generally have poor fastness properties but these can be improved through after-treatments using metallic salts like copper or chromium compounds, or formaldehyde, which increase the dye's molecular weight and bonding strength to the fibers. Key factors that influence direct dye uptake include electrolyte concentration, temperature, liquor ratio, and dye class.Structure of fibre and dyeStructure of fibre and dyeMasum SheikhThis presentation discusses the functional groups present in various natural and synthetic fibers as well as different types of dyes. It begins by identifying the functional groups in common natural fibers like cotton, wool, and silk, which contain groups like hydroxyl, carboxylic acid, and amino groups. It then examines the functional groups in several synthetic fibers such as polyester, nylon, acrylic, polyurethane and Kevlar. The presentation also categorizes dyes based on their chemical structure and functional groups like nitro, azo, and anthraquinone groups. Finally, it describes different methods of dye application including reactive, direct, disperse, acid, basic, and vat dyes.Disperse dyeDisperse dyeNafiz AntuThis presentation provides an overview of disperse dyes. It was presented on November 27, at NUB by 4 students. Disperse dyes are organic compounds without ionizing groups that are insoluble in water but can be dispersed to dye synthetic fibers like polyester. The history and properties of disperse dyes are discussed. Disperse dyes are classified by chemical structure and fastness properties. Dispersing agents and carriers are used to aid disperse dyeing at high temperatures or through carrier methods. Examples of commercial disperse dyes and carriers are provided.Desizing in textileDesizing in textileKaramat Ali SaifDesizing removes starch sizing agents from warp yarns that were applied before weaving to improve the weaving process. The main objectives of desizing are to remove this non-water-soluble starch so the fabric can undergo further wet processing like dyeing. Common desizing methods include rot steeping, which uses microbes to hydrolyze starch over 24 hours; acidic desizing, which uses dilute acid to hydrolyze starch in 8-12 hours; and enzymatic desizing, the most widely used modern method harnessing enzymes. Oxidative desizing can work on a variety of unknown sizes but may damage fibers if not carefully applied. The type of size, fabric construction, and desizing methodSulphur dyeSulphur dyeRinku ShemarThis document discusses the properties, mechanisms, classification, and application of sulphur dyes. Sulphur dyes contain sulphur linkages, are insoluble in water but soluble in sodium sulphide. During dyeing, sodium sulphide converts the dye to soluble thiols which penetrate the fiber and are oxidized back to the insoluble dye. Sulphur dyes are classified as sulphur, leuco sulphur, or solubilized. Dyeing involves preparing a dye bath and dyeing cotton at a boil. Aftertreatment can improve fastness. Disadvantages include bronzing shades and tendering of sulphur black dyed goods over time.''Presentation On Disperse Dye''''Presentation On Disperse Dye''Khan. Ataur RahmanThis presentation discusses disperse dyes and their use for dyeing synthetic fibers like polyester and acetate. It provides details on the mechanism of disperse dyeing, including wandle wall forces and fiber affinity. It also outlines the structure, solubility, chargeability and environmental behavior of disperse dyes. Application methods like high temperature dyeing and thermosol processes are summarized, including dye bath recipes and temperature cycles. The presentation concludes with information on dye fastness properties and color ranges for disperse dyes.Vat Dye (Full PDF) | Vat DyeVat Dye (Full PDF) | Vat DyeMd Rakibul HassanVat dyes are insoluble natural or synthetic dyes that are converted to their soluble leuco form using a reducing agent like sodium hydrosulfite. This allows the dye to penetrate cellulose fibers during the dyeing process. After penetration, the fabric is oxidized, converting the dye back to its insoluble form within the fibers. Key steps are vatting to solubilize the dye, dyeing to allow penetration, and oxidation to fix the dye in the fibers. Vat dyes provide excellent washing fastness due to being locked inside the fibers. However, they are more difficult and costly to apply than other dyes.mass colarationmass colarationAmit kumarMass coloration, also known as solution dyeing or spun dyeing, involves adding pigments or insoluble dyes to the spinning solution or polymer melt before extrusion through a spinneret. This embeds the color within the fiber, resulting in fibers with excellent colorfastness to light, washing, rubbing, and other stresses. Mass coloration can be applied to both regenerated and synthetic fibers and is more economical and less wasteful than conventional dyeing processes. The most common mass coloration methods are addition during polymerization, chips coating, master batch addition, and injection into the extruder.Sulfur dye PresentationSulfur dye Presentationalaminmasum1This document provides information about sulfur dyeing. It discusses that sulfur dyes are inexpensive reaction mixtures that are chemically reduced prior to application and reoxidized after dyeing cotton or cellulose fibers. It also describes the two-stage dyeing process where the insoluble sulfur dye is converted to a water-soluble leuco form using sodium sulfide, which is absorbed by the fibers during dyeing and then reoxidized. The document provides details on the dyeing process and recipes used for cotton fabrics as well as some common faults and their remedies. It discusses the advantages of sulfur dyes being inexpensive while providing deep shades with good fastness properties.Introduction of vat dye /Some knowledge for Vat dyes.Introduction of vat dye /Some knowledge for Vat dyes.TonmoyMollickThe document discusses vat dyes, which are water-insoluble dyes that must be chemically modified before use. It provides details on: - The history and development of vat dyes, with the original being indigo obtained from plants. - The chemical process of reducing vat dyes with sodium dithionite to create water-soluble leuco compounds that can be applied to fabrics. - The dyeing process, which involves vatting, dyeing the fabric in alkaline conditions, oxidizing the dye, and soaping to improve fastness. - Examples of common vat dyes like indanthrones and flavanthrones and their properties. - The excellent fastness to lightScouringScouringMd. Mazadul Hasan ShishirThe document discusses the scouring process, which involves removing natural and added impurities from textile fibers. There are three main methods for removing impurities: saponification, emulsification, and solubilization. Saponification converts impurities like oils and fats into water-soluble soaps. Emulsification forms suspensions of non-saponifiable impurities. Solubilization dissolves substances like pectin and proteins into soluble salts. The scouring process aims to remove all impurities and leave the fibers highly absorbent without damage. Common scouring agents include alkaline solutions, surfactants, and sometimes organic solvents.Dyeing of cotton with reactive dyeDyeing of cotton with reactive dyeTanvir AhammedThe document provides information about dyeing cotton with reactive dyes, including: 1. Reactive dyes form covalent bonds with cotton fibers through reaction groups, making them very colorfast. 2. The dyeing process involves an exhaustion phase where the dye adsorbs to the fiber, and a fixation phase where the dye chemically reacts with and bonds to the fiber. 3. Key factors that affect dyeing include salt, soda, temperature, pH, time, and other assistants; the optimal time for fixation of reactive dyes to cotton is around 60 minutes.Reactive Dye (Full PDF)Reactive Dye (Full PDF)Md Rakibul HassanThe document provides an overview of reactive dyes: 1) Reactive dyes chemically bond to fibers through reactive groups that form covalent bonds with hydroxyl or amino groups on fibers like cotton, polyamide, and wool. 2) They were first invented in and provided brighter colors and better fastness than previous dyes. 3) Reactive dyes are now widely used for cellulosic fibers due to their brighter colors, good fastness properties, and simpler dyeing process compared to other dyes.Reactive dye,23.03.Reactive dye,23.03.Md. Abdul HannanThe document provides an extensive overview of reactive dyes used for dyeing cotton, including their chemical properties, classification, dyeing mechanisms, and factors affecting dye uptake. It details the manufacturing processes, dye structures, and practical applications in textile coloration, highlighting the significance of maintaining optimal conditions for successful dye fixation and minimizing dye hydrolysis. Additionally, different dyeing methods like pad-dry and continuous techniques, along with their merits and demerits, are discussed to guide effective dyeing practices.Dyeing in textilesDyeing in textilesAjinkya MuleThis document discusses dyeing in textiles, including different types of dyes, dye classification systems, dyeing parameters and calculations, auxochromes, chromophores, direct dyes, vat dyes, acidic dyes, basic dyes, dyeing faults, and dyeing remedies. It covers natural and synthetic dyes, factors that influence dyeing like temperature and pH, functional groups that increase dye absorption, chromophores that determine color, direct dye mechanisms and applications, vat dye mechanisms and applications, and remedies for uneven or inconsistent dyeing.Azoic Dye (Full PDF)Azoic Dye (Full PDF)Md Rakibul HassanAzoic dyes are produced by reacting a diazo-component or base salt with a coupling component like naphthol. This reaction forms an insoluble azo group that produces the dye within the fiber, resulting in excellent washing fastness. Azoic dyes can be used to dye cellulose fibers like cotton. The dyeing process involves three steps: naphtholation, diazotization, and coupling. Azoic dyes form an insoluble color product within the fabric, making them different from azo dyes which use a soluble azo group.DIRECT DYEDIRECT DYESayeed AhmedThis presentation discusses direct dyes, which are water-soluble dyes used to dye cellulosic materials like cotton directly. There are two major types of direct dyes: anionic direct dyes, which are used for paper coloring and shade correction, and cationic direct dyes. Direct dyes have properties like water solubility and being anionic in nature. They dye materials through weak hydrogen and van der Waals bonding in alkaline conditions. The dyeing process involves dissolving the dye in boiling water with electrolytes before applying it to materials and boiling for 30-45 minutes. Direct dyes provide duller colors than reactive dyes and have lower wash fastness. They are used for applications where high fastness isAzoic coloursAzoic colourssachinmanuAzoic dyes are formed by coupling naphthol compounds with diazotized bases, without use of an actual dye. Two key components are required - a naphthol (coupling component) and a base or salt (diazo component). Combinations of 34 naphthols and 50 bases/salts can produce around shades, though only a few are commonly used. Naphthols are dissolved in alkali solution and coupled with diazotized bases to form the dye directly on the fiber. Proper selection of naphthol and base determines the color produced.Vat DyesVat DyesKiran Qamar KayaniVat dyes are water-insoluble dyes that can be converted to a water-soluble form through chemical reduction. They were first developed in the s as synthetic dyes and include indigo dye. The vat dyeing process involves three steps - vatting to convert the dye to its soluble leuco form, oxidation to convert it back to insoluble form in the fiber, and after treatment. Vat dyes have high color fastness but more limited shades than other dyes and their application process is complex and time-consuming.Garment dyeing techniquesGarment dyeing techniquesPrabu KrishnarajGarment dyeing involves dyeing fully fashioned garments rather than constructing them from pre-dyed fabrics. It provides flexibility for fast changing fashion trends. The document discusses factors to consider for garment dyeing such as fabric selection, accessories, sewing threads and dyeing machinery. Paddle machines and rotary drums are commonly used dyeing machines. Paddle machines use paddles to gently move garments through the dye liquor while rotary drums rotate perforated drums of garments through a stationary dye bath. Proper fabric preparation, accessory selection, and dyeing parameters are required for optimal garment dyeing results.Textile DyeingTextile DyeingAhmadMostafa49This document provides an overview of different types of dyes used in textile dyeing, including their working principles and applications. It discusses vat dyes, reactive dyes, azoic dyes, acid dyes, sulphur dyes, metal complex dyes, basic dyes, disperse dyes, and direct dyes. For each dye type, it describes the general dyeing process, suitable fibers, advantages and limitations, and how the dye bonds to or reacts with the fiber on a molecular level. The document serves as an educational reference on the various classes of dyes and dyeing methods.Dyeing kinetics, (diffusion, pore model, free volume model)Dyeing kinetics, (diffusion, pore model, free volume model)Md. Abdul HannanThis document discusses dyeing kinetics and diffusion models for dye uptake in fibers. It describes the exhaustion curve which defines the rate of dyeing over time. The initial rate is called the strike. Diffusion occurs through three transport zones: flow, absorption, and diffusion into the fiber. Two main diffusion models are described: the pore model which considers diffusion through pores filled with dye liquor, and the free volume model which involves diffusion through amorphous, mobile regions of the polymer chain. The document contrasts these models and discusses how temperature affects dyeing rates.Chemicals and Auxiliaries used in Textile Wet ProcessingChemicals and Auxiliaries used in Textile Wet ProcessingMashrur WasityThis document discusses various chemicals and auxiliaries used in textile wet processing. It defines auxiliaries as chemicals that help processing operations like preparation, dyeing and printing work more efficiently. Some common auxiliaries mentioned include surfactants, wetting agents, sequestering agents, dispersing agents and emulsifiers. Basic chemicals used in wet processing like acids, bases, salts, oxidizing and reducing agents are also discussed. The roles and examples of various chemicals are provided in concise points.Disperse dyeing Disperse dyeing MajinthaThis document discusses disperse dyes, which are water-insoluble dyes used to dye synthetic fibers like polyester, acetate, and nylon. Disperse dyes penetrate fibers through weak Vander Waals forces and have a neutral charge. They require dispersing agents and high temperatures to dye polyester fabrics. The dyeing process involves an exhaust method where the dye bath is heated to 130°C to swell the polyester fibers and allow dye penetration. Disperse dyes have good fastness properties and provide a wide range of colors but are not environmentally friendly. The thermosol process is also described for dyeing mixed fabrics using a padding and heat fixation stage.