Dye , substance used to impart colour to textiles , paper , leather , and other materials such that the colouring is not readily altered by washing, heat, light , or other factors to which the material is likely to be exposed. Dyes differ from pigments , which are finely ground solids dispersed in a liquid, such as paint or ink, or blended with other materials. Most dyes are organic compounds i. Pigments generally give brighter colours and may be dyes that are insoluble in the medium employed. Colour has always fascinated humankind, for both aesthetic and social reasons.
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WO1999007793A1 - Dye intermediate and method to manufacture dyes - Google PatentsVIDEO ON THE TOPIC: How Fabric is Dyed in a Massive and Eco-Friendly Way
Natural Science Vol. Color is the main attraction of any fabric. No matter how excellent its constitution, if unsuitably colored it is bound to be a failure as a commercial fabric. Manufacture and use of synthetic dyes for fabric dyeing has therefore become a massive industry today. In fact the art of applying color to fabric has been known to mankind since BC. WH Perkins in discovered the use of synthetic dyes. Synthetic dyes have provided a wide range of colorfast, bright hues.
However their toxic nature has become a cause of grave concern to environmentalists. Use of synthetic dyes has an adverse effect on all forms of life. Presence of sulphur, naphthol, vat dyes, nitrates, acetic acid, soaps, enzymes chromium compounds and heavy metals like copper, arsenic, lead, cadmium, mercury, nickel, and cobalt and certain auxiliary chemicals all collectively make the textile effluent highly toxic. Other harmful chemicals present in the water may be formaldehyde based dye fixing agents, chlorinated stain removers, hydro carbon based softeners, non bio degradable dyeing chemicals.
Many of these show allergic reactions. The colloidal matter present along with colors and oily scum increases the turbidity, gives the water a bad appearance and foul smell and prevents the penetration of sunlight necessary for the process of photosynthesis. This in turn interferes with the Oxygen transfer mechanism at air water interface which in turn interferes with marine life and self purification process of water.
If allowed to flow in drains and rivers it effects the quality of drinking water in hand pumps making it unfit for human consumption.
It is important to remove these pollutants from the waste waters before their final disposal. The art of color application to enhance our self appearance and the world around us has been known to man since time immemorial.
Historical records of the use of natural dyes extracted from vegetables, fruits, flowers, certain insects and fish dating back to BC have been found. No matter how excellent its constitution, if unsuitably colored it is bound to be a failure as a commercial product.
Fabric was earlier being dyed with natural dyes. These however gave a limited and a dull range of colors. Besides, they showed low color fastness when exposed to washing and sunlight. The discovery of synthetic dyes by W. Perkins in has provided a wide range of dyes that are color fast and come in a wider color range and brighter shades . However, due to the toxic nature and adverse effect of synthetic dyes on all forms of life the interest in natural dyes has revived throughout the world.
Nevertheless even the natural dyes are rarely low-impact, due to certain mordants that have to be used with them. They may be are very toxic and may have a high impact on the wastewater quality. Natural dyestuffs require large quantities of water for dyeing. About 80 percent of the dyestuffs stay on the fabric, while the rest go down the drain. Consequently natural dyes prepared from wild plants and lichens can have a very high impact on the environment.
The textile dyeing and finishing industry has created a huge pollution problem as it is one of the most chemically intensive industries on earth, and the No. More than individual textile dyes are being manufactured by the Industry today. The industry is using more than chemicals in various processes of textile manufacture including dyeing and printing. A fraction of these are listed in Table 1. Many of these chemicals are poisonous and damaging to human health directly or indirectly.
Large quantities of water are required for textile processing, dyeing and printing. The daily water consumption of an average sized textile mill having a production of about kg of fabric per day is about 1.
Specific water consumption for dyeing varies from 30 - 50 liters per kg of cloth depending on the type of dye used. The overall water consumption of yarn dyeing is about 60 liters per kg of yarn.
Water is also required for washing the dyed and printed fabric and yarn to achieve washing fastness and bright backgrounds. Washing agents like caustic soda based soaps; enzymes etc. This removes the surplus color and paste from the substrate.
Water is also needed for cleaning the printing machines to remove loose color paste from printing blankets, printing screens and dyeing vessels [3,4]. It takes about gallons of water to produce enough fabric to cover one sofa. The World Bank estimates that 17 to 20 percent of industrial water pollution comes from textile dyeing and finishing treatment given to fabric. Some 72 toxic chemicals have been identified in water solely from textile dyeing, 30 of which cannot be removed5.
This represents an appalling environmental problem for the clothing and textile manufacturers. Table 1. Major chemicals and dyes used in synthetic textile mills . Mills discharge millions of gallons of this effluent as hazardous toxic waste, full of color and organic chemicals from dyeing and finishing salts.
Presence of sulphur, naphthol, vat dyes, nitrates, acetic acid, soaps, chromium compounds and heavy metals like copper, arsenic, lead, cadmium, mercury, nickel, and cobalt and certain auxiliary chemicals all collectively make the effluent highly toxic. Other harmful chemicals present in the water may be formaldehyde based dye fixing agents, hydro carbon based softeners and non bio degradable dyeing chemicals. The mill effluent is also often of a high temperature and pH, both of which are extremely damaging.
The colloidal matter present along with colors and oily scum increases the turbidity and gives the water a bad appearance and foul smell. It prevents the penetration of sunlight necessary for the process of photosynthesis .
This interferes with the Oxygen transfer mechanism at air water interface. Depletion of dissolved Oxygen in water is the most serious effect of textile waste as dissolved oxygen is very essential for marine life.
This also hinders with self purification process of water. In addition when this effluent is allowed to flow in the fields it clogs the pores of the soil resulting in loss of soil productivity. The texture of soil gets hardened and penetration of roots is prevented. The waste water that flows in the drains corrodes and incrustates the sewerage pipes. It also leads to leakage in drains increasing their maintenance cost.
Such polluted water can be a breeding ground for bacteria and viruses. Impurities in water affect the textile processing in many ways. In scouring and bleaching they impart a yellow tinge to white fabric. In dyeing stage metallic ions present in water sometimes combine with the dyes causing dullness in shades Table 2.
Textile effluent is a cause of significant amount of environmental degradation and human illnesses. About 40 percent of globally used colorants contain organically bound chlorine a known carcinogen.
All the organic materials present in the wastewater from a textile industry are of great concern in water treatment because they react with many disinfectants especially chlorine. Chemicals evaporate into the air we breathe or are absorbed through our skin and show up as allergic reactions and may cause harm to children even before birth. Table 2. Characteristics of effluent from dyeing and printing unit of a textile mill.
The effect on crop irrigated with sludge can be observed through symptoms like plaque in teeth, joint pain and grey hair of villagers. The drain carries sludge of factories located in Barnala district. While crossing Bhatinda district the drain becomes almost dry as its water gets used in the fields. The official apathy is evident as farmers, pooling money, have installed motors along the banks of the drain to lift water to supply it via steel and cemented pipes buried in earth to irrigate their fields.
As a precaution, we sell whatever we produce and buy canal irrigated yield of crops for our consumption. Effluent treatment methods can be classified into physical, chemical and biological methods; Table 3. Exclusive treatment by one of these three methods has proved to be insufficient in removing color and other effluent from textile industry wastewater.
While some dyes are difficult to biodegrade few, particularly the hydrolyzed reactive and certain acidic dyes are not readily absorbed by active sludge; hence they escape treatment. The resulting effluent is usually high in color. A complimentary treatment process is needed to remove color and if possible residual impurities.
It requires large amounts of Chemicals and Water at every step of the textile manufacturing and finishing process. Water is needed to convey the chemicals into the fabric and to wash it at the beginning and end of every step. It becomes full of chemical additives and is then expelled as wastewater; which in turn pollutes the environment. Water: a finite resource is thus becoming scarce.
Water pollution is indeed a serious problem in most countries. The textile industry continues to search for an economical solution to decolorize the nearly billion liters of colored effluent produced annually. Nations, states, industries are spending billions in cash on research to reduce pollution and on construction of effluent treatment plants.
The public concern for industrial air and water pollution is leading to considerable restrictions on all industrial activities polluting the environment . Governments have proposed laws limiting the amount and kind of waste that can be dumped as such. Considering the adverse effect on environment and health of people due to the effluent being thrown out of the Textile Dye Industry we need to wake up to the serious problem and make every effort to reduce pollution and construct effluent treatment plants at the sites churning out billions of liters of waste water.
Calibration curves were plotted and the amount of dye adsorbed was calculated. The data was fitted to simple Polynomial, Langmuir and Freundlich isotherms for different.
Table 3. Effluent treatment methods . Constants were calculated from the slope and intercept values of the isotherms. Coefficient of co-relation R 2 and standard deviation SD were also noted.
The data was found to fit well to the isotherms.
The company Synthesia is a leading global manufacturer of organic pigments and dyes. Currently, the only producer of organic pigments and dyes in the Czech Republic. Products exported to over 50 countries worldwide. The Synthesia customers include major companies in the sector of plastics, paints and printing inks, textile, wood, leather factories and paper mills. Strong position results from a stable production base and the ability to offer individual solutions.
SBU Pigments and Dyes
Account Options Sign in. United States Tariff Commission. Selected pages Page Title Page.
dyes - Manufacturer producer - Italy
It is difficult if not impossible to determine when mankind first systematically applied color to a textile substrate. The first colored fabrics were probably nonwoven felts painted in imitation of animal skins. The first dyeings were probably actually little more than stains from the juice of berries. Ancient Greek writers described painted fabrics worn by the tribes of Asia Minor. But just where did the ancient craft have its origins? Was there one original birthplace or were there a number of simultaneous beginnings around the world? Unable to display preview.
Poland - Export
Dyes have applications in many technologies, both new and well established, which count amongst them textile dyeing, optical data storage media and various detection methods, for both chemical and biological use. Within these applications various properties of the dyes are exploited in their actual detection which may ultimately be traced back to absorption, reflectance and luminescence chemiluminescence, fluorescence and phosphorescence. However, a recurring theme of many applications is the need to form a relatively permanent link, in the form of a covalent bond, between the dye and the substrate of choice. The substrate may be inter alia: a relatively inert surface or probe possibly of insoluble polymeric origin; a macromolecule of biological origin e.
Account Options Sign in. Special occupational hazard review for benzidene-based dyes. National Institute for Occupational Safety and Health. Selected pages Title Page. Table of Contents. Common terms and phrases 4-amino biphenyl absorbance absorption acid addition administered amount analysis animals Appendix appropriate aqueous aromatic amines azo dyes bacteria benzidine benzidine-based dyes bladder cancer C. Direct cancer carcinogenic Chemical chloroform chromatography collected color concentration Congo Red considered containing demonstrated derivative detected determined developed diazonium salt Direct Black 38 Direct Blue Direct Brown 95 direct dyes Direct Orange Direct Red Direct Violet Dyeing of cotton effects employee excreted exposed exposure exposure to benzidine-based extracted female filters given Green handled Hazard humans Imported impurities industry Institute leather limit listed male manufacture material measured metabolism metabolites method mice NIOSH nylon observed Occupational potential prepared present procedure Publication range rats recommended reduction reference reported samples Service silk skin solution standard Structure substances substitutes textile tumors urine weeks wool workers. Bibliographic information.
These new textile dyeing methods could make fashion more sustainable
Bomberger, Julia E. Gwinn, and Robert L. Boughton A preliminary study of the manufac- ture of dyes and pigments was con- ducted to determine if process waste streams might contain hazardous mate- rial. The study first identifies the dyes and pigments that belong to the major segments of the industry, the amounts produced, and the known U. The chemistry of these dyes and pigments is discussed as well as the overall production process and waste treatment practices.
These new textile dyeing methods could make fashion more sustainable
Natural Science Vol. Color is the main attraction of any fabric. No matter how excellent its constitution, if unsuitably colored it is bound to be a failure as a commercial fabric. Manufacture and use of synthetic dyes for fabric dyeing has therefore become a massive industry today. In fact the art of applying color to fabric has been known to mankind since BC. WH Perkins in discovered the use of synthetic dyes. Synthetic dyes have provided a wide range of colorfast, bright hues. However their toxic nature has become a cause of grave concern to environmentalists. Use of synthetic dyes has an adverse effect on all forms of life.
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A dye is a coloured substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they colour.
Холодок этот был вызван не его личностью -- будь так, уж он смог бы все это правильно воспринять и преодолеть; нет, его породила обида на ничем не заслуженное невезенье, в силу которого из всех миллионов горожан именно им, Эристону с Итанией, по воле случая довелось первым повстречать Олвина, когда в тот памятный день -- двадцать лет назад -- он вышел из Зала Творения.