To dye

A traditional dye factory in Fez

During dyeing , textile material (fibers) is colored (“dyed”) by applying dyes in dyeing or printing processes .

Textiles made from natural fibers are bleached beforehand so that the natural color of the textile has as little effect on the hue and especially the brilliance as possible during the dyeing process . If, on the other hand, the dyeing of a textile is removed again, for example after a wrong dyeing, one speaks of peeling off the textile.

The dyeing industry has developed a millennia-old tradition and its own professional profile with numerous specializations. Today it is assigned to the chemical industry - unless it is done by hand .

The term “coloring” is also used to change the color of other materials .

Historical

A dyer in a 15th century house book

Kettle with yellow-greenish brew and wool.

Guild coat of arms of the dyers

The little knowledge about the dyes and dyeing methods of antiquity is mainly based on grave finds and records of Greek and Roman writers as well as their technological descriptions. For millennia one was dependent on natural dyes from minerals ( ocher , cinnabar ), from plants such as indigo or redwood (see also dye plants ) or from animals ( scale insect and purple snail ). From ancient Egypt there are finds of textiles dyed with madder . After the discovery of America, the dye works in Europe received a new boost from imported colored woods.

In the Middle Ages , the dyers were wage workers of the other cloth processing guilds . Dyer's guilds did not emerge until late. There has been a distinction between different dyes since the Middle Ages:

Black dyer , dyeing a deep black was considered a special art.
Canvas dyers , Bad dyers colored, the guild of dyers, the generally coarse fabrics.
Cloth dyers who specialized in dyeing wool .
Blue dyers , woad dyers who originally only used the local woad , later also the much more expensive imported indigo.
Whitening , a later term for the use of foreign dyes in application, especially on fine fabrics (this is where the metaphor “ whitewashing ” comes from .
Turkish red dyers who were specialized in dyeing a beautiful shade of red using an elaborate method.
Silk dyer
Smokers and sable dyers who dyed leather and hides ( tobacco goods )
Yarn dyer
Bogolan dyers in the African-Asian region

The specializations were named differently locally and temporally or were grouped into different professional groups or guilds.

Dyeing was considered a dirty business in the Middle Ages . Dyes were often considered unclean because they handled foul smelling substances (such as urine). With the Crusades , an increased interest in lavishly colored materials began in Europe. In the 13th century, the European market for dyed fabrics expanded and trained dyers were in great demand. So separate guilds and guilds were formed, which promoted the dyeing profession and protected its interests. One of the most famous dyers' guilds of the late Middle Ages was the "Arte di Calimala" in Florence , which placed such high demands on the products of their guild that they burned all cloths that were not dyed according to the quality standards and fined the dyers responsible. But dyeing also took place in nunneries as a handicraft activity, as can be seen from a little puchlet from the fifteenth century in Nuremberg about the klaidern, von auftrucken and glass making . The oldest German-language treatise on dyeing is a staining booklet that was probably created in Tyrol before 1320 , in which water-insoluble mineral colors are combined with water-soluble vegetable dyes .

The synthetic dyes developed in the 19th century have increasingly replaced natural dyes. Today the reactive dyes , followed by the disperse and direct dyes, have achieved the greatest importance. The dye solution is referred to as the “dye” or “dye liquor” or as the “dye bath”. “Textile printing” can be viewed as localized dyeing.

Dyeing process

Dyeing can be done almost anywhere in the textile processing chain.

Individual fibers or entire wool fleeces can be dyed before spinning.
Yarn that is already spun can be dyed.

A finished fabric or knitted fabric can be colored.

The earlier in the manufacturing process the dyeing, the better irregularities in the end product can be compensated. Dyed yarns are required to create patterns in weaving . Flat textiles are dyed in order to have a uniform surface (levelness) and to be able to produce individual colors in small quantities.

Dyeing is possible using three different technologies.

In the exhaust process ( discontinuous dyeing process ), the dyes are dissolved or dispersed in water . During a defined time / temperature curve as well as controlled movement of the material and / or the liquor, the dye draws evenly onto the material and is usually fixed on the fiber in the same dye bath - rarely in a second treatment bath . Depending on the substrate / dye system, textile aids can simplify the process by e.g. B. ensure better wettability of the substrate. It may also be necessary to add chemicals to the process in order to enable the dye to be fixed to the fiber or in the fiber (e.g. salt and soda for reactive dyes on cotton or hydrosulfite for vat dyes on cotton). The portion of the unfixed dye is removed in subsequent treatment baths.

In the continuous process , the dye solution is applied to the substrate by padding (also called padding ). The dye liquor is padded onto the textile material in the padder. The material is evenly wetted with dye liquor and squeezed evenly across the width of the fabric between usually two or three hard rubber rollers on a defined liquor pick-up. The dyes are then fixed on the fiber, which can be done either by treatment with steam (saturated steam at over 100 ° C ( PadSteam process) or superheated steam at around 180 ° C) or dry heat up to 220 ° C in a few seconds to minutes . This is followed by a wash-out process to remove the unfixed dye from the fiber and to obtain good fastness properties.

In the semi- continuous process, the impregnation of the fabric in the padder takes place continuously, the fixation of the dye at a later point in time also continuously or discontinuously. An example of the semicontinuous process is the so-called block-cold dwell process in which cotton is dyed with reactive dyes. After padding the cotton with the liquor, the textile is wound onto a drum and stored in a rotating manner for several hours at room temperature. The unfixed dye is then washed out on a wide washing machine or a tree apparatus.

With regard to the chemical and physical processes involved in dyeing, four types of dyeing process can be distinguished in modern textile dyeing.

Dye classes

Dyed wool

The appropriate class of dyes is primarily selected according to the substrate to be dyed and the required / necessary level of fastness (resistance of the dye to influences during further processing and use of the finished textile material).

Depending on the product, such as composition (mixture of fiber types or sheer fabric form), yarn type , mesh - or woven fabric , bonding of the dye on the fiber, request to the handle of the finished product, the decision is made whether a dyeing machine, a machine or a dyeing machine necessary is. The dye class determined by the fiber influences the conditions for the appropriate dyeing process.

For cellulosic fibers, dyes are used that are either bound to the fiber via physical forces (ionic or dispersion forces) or enter into a chemical bond with the fiber ( reactive dyes ).

Dyeing with vat dyes is a process in which the surface of the fibers is bound with water-insoluble dye molecules through adsorption. The advantage is the high color fastness. The best known vat dye is indigo .

When dyeing with developing dyes , the dye is first produced on the fibers (for example by azo coupling). The first water-soluble component is taken up with the fiber by adsorption , the second component then forms a water-insoluble azo dye . The color then adheres to the fiber through the formation of van der Waals forces and hydrogen bridges . In addition, forces act between polarized groups of molecules .

Dyeing with direct dyes (nouns dyes) is a process in which the dyes are absorbed directly from the dye liquor onto the fibers. It is mostly used for home-dyeing products.

Acid dyes are more suitable for wool and polyamide (such as nylon) with their basic amino groups. Basic dyes are suitable for polyacrylonitrile fibers (such as Dralon) and the like with their acid groups.

Since polyester fibers are largely non-polar, they are dyed using dispersion dyeing. A suspension is created in which the fiber is immersed. The dye diffuses into the fiber and remains there even after drying. However, the color fastness of such a dyeing is not too high, but can be improved with the so-called high temperature process ( HT process , temperature ≥ 130 ° C).

The poor rubbing fastness of indigo and vat dyes on cotton fibers due to the only superficial physical bond has become the hallmark of genuinely dyed "blue jeans" and must be achieved with modern dyes through post-treatment.

Dyeing machines / dyeing machines / dyeing systems

Washing of the cotton before dyeing in a factory in Myanmar

When dyeing according to the (discontinuous) exhaust process (the fiber draws the color from the liquor), a distinction is made between different types of dyeing machines, depending on the transport mechanism of the substrate and the liquor:

Dyeing machine: moving liquor, stationary goods; the liquor is pumped through the resting goods (e.g. dye tree, yarn dyeing machine)
Dyeing machine: moving goods, stationary liquor; the goods are moved by a stationary fleet (e.g. reel skid). With modern machines in use today, however, in addition to the movement of goods, there is also a specific fleet circulation.
Dyeing plant: for the (continuous) continuous process, the historical structure is irrelevant due to the changed technology.

The dyeing machines for the exhaust process are in turn divided into those for temperatures below 100 ° C. and those for high temperatures.

Natural fibers can usually be dyed at moderate temperatures; the dyeing takes place in (economically) inexpensive (open) machines under atmospheric pressure.
Synthetic fibers (especially polyester ) usually only absorb dyes at temperatures above 100 ° C. Since the water would evaporate at ambient pressure, the dyeing must take place under pressure. Temperatures of up to 135 ° C. with a static pressure of up to 4.0 bar are usual. This requires pressure-tight and therefore more expensive machines.
Dyeing fiber blends made from synthetic and natural fibers is particularly problematic. It is usually dyed with two different classes of dye, but the different fibers must be dyed the same color. ( Tone-on-tone coloring ).

Various machines are available for the different presentations.

In the jigger , the dyed material is guided through the dye liquor in a stretched and wrinkle-free state. This guarantees an even distribution of color across the entire width.

In the reel skid , the fabric is passed through the liquor without tension or in a strand, so that the goods are not warped.

The textile goods and the liquor are moved in the jet dyeing machine .

Environmental aspects

The dyeing of textiles has been done on an industrial scale since the 19th century . Additional chemicals (salts, acids, alkalis) and textile auxiliaries are added to the aqueous dye solutions or dye dispersions . If they get into the environment untreated, it can be heavily polluted. Previously, the residual liquor and waste water were fed directly into rivers, which were then also colored. Today this can be seen as solved in many parts of Europe and the USA through extensive investments in wastewater treatment plants and the use of modern dyes and the ban on problematic products. In many other parts of the world, such as in some Asian and Eastern European countries, this level of environmental protection has not yet been reached.

literature

Dorit Berger: Dyeing with natural colors. Dye plants, recipes, possible uses. Stuttgart 1998, ISBN 978-3-8001-7809-4 .

Franco Brunello: The Art of Dyeing in the history of mankind. Vicenza 1973 (translation of the Italian first edition from 1968).

Rita Buchanan: A weaver's garden: growing plants for natural dyes and fibers. Loveland (Colorado) 1987, reissued 1999, ISBN 0-486-40712-8 .

Color, dyer, color symbolism. In: Lexicon of the Middle Ages . Vol. IV, Munich and Zurich 1989, pp. 286–289.

Lydie Nencki: The art of dyeing with natural fabrics. History - Methods - Recipes. Haupt, Bern and Stuttgart 1984 (original title: La science des teintures animales et végétales. 1981), ISBN 978-3-258-03330-3 .

Carl Wilhelm Poerner: Instructions for the art of dyeing, especially to dye cloth and other items woven from wool. Weidmann and Reich, Leipzig 1785, digitized .

E. Max. Dingler: VITALIS plan of the dye works and the fabric printing. Cotta'sche Buchhandlung, Stuttgart and Tübingen, 1839, 2nd edition, Bavarian State Library, Munich, facsimile , limited preview in the Google book search.

Eberhard Prinz: Dye plants, instructions for dyeing, use in culture and medicine. Schweizerbart, Stuttgart 2009, ISBN 978-3-510-65258-7 .

H. Schweppe: Handbook of natural dyes. Occurrence, use, evidence. ecomed, Landsberg / Lech 1993, ISBN 978-3-609-65130-9 .

Emil Ernst Ploß: Studies on the German painter and dye books of the Middle Ages. A contribution to German antiquity and word research. Philosophical dissertation Munich 1952.

Emil [Ernst] Ploß: A book of old colors. Technology of textile colors in the Middle Ages with an outlook on solid colors. Heidelberg / Berlin 1962; Reprint (declared as 2nd edition) Munich 1967; 4th edition ibid 1977, ISBN 978-3-7879-0064-0 .

Emil Ernst Ploß: The dyeing in the Germanic housekeeping. In: Journal for German Philology . 75, 1956, pp. 1-22.

H. Grunfelder: The dyeing in Germany up to the year 1300. In: Quarterly journal for social and economic history . 16, Vol. H. 3/4, Freiburg i. B. 1922, JSTOR 20725214 .

Guido Ebner, Dieter Schelz: Textile dyeing and dyes. Springer, Berlin 1989, ISBN 978-3-642-70172-6 .

Simon Garfield: Purple - How one color changed the world. Siedler, Berlin 2001, ISBN 978-3-88680-719-2 .

Wilfred Kratzert, Rasmus Peichert: Dyes. Quelle & Meyer, Heidelberg 1981, ISBN 978-3-494-01021-2 .

Hans Wiswe: Medieval recipes for dyeing and for the production of colors and stain removers. In: Yearbook of the Association for Low German Language Research. Volume 81, 1958, pp. 49-58.

Web links

Commons : Coloring - Collection of images, videos and audio files

Wikisource: Coloring - Sources and Full Texts

Individual evidence

↑ Coloring entry . In: JG Krünitz: Oekonomische Encyklopädie , ( online , University of Trier),
^ Amy Butler Greenfield, A Perfect Red - Empire, Espionage and the Qest for the Color of Desire. HarperCollins Publisher, New York 2004, ISBN 0-06-052275-5 , p. 14.
^ Amy Butler Greenfield, A Perfect Red - Empire, Espionage and the Qest for the Color of Desire. HarperCollins Publisher, New York 2004, ISBN 0-06-052275-5 , p. 15.
^ Gundolf Keil : Nuremberg art book. In: Author's Lexicon . Volume VI, Col. 1257 f.
↑ Gundolf Keil: 'Bavarian coloring book'. In: Author's Lexicon . Volume I, Col. 582.

[1] Coloring entry . In: JG Krünitz: Oekonomische Encyklopädie , ( online , University of Trier),

[2] Amy Butler Greenfield, A Perfect Red - Empire, Espionage and the Qest for the Color of Desire. HarperCollins Publisher, New York 2004, ISBN 0-06-052275-5 , p. 14.

[3] Amy Butler Greenfield, A Perfect Red - Empire, Espionage and the Qest for the Color of Desire. HarperCollins Publisher, New York 2004, ISBN 0-06-052275-5 , p. 15.

[4] Gundolf Keil : Nuremberg art book. In: Author's Lexicon . Volume VI, Col. 1257 f.

[5] Gundolf Keil: 'Bavarian coloring book'. In: Author's Lexicon . Volume I, Col. 582.