Textile chemicals

As textile chemicals or textile auxiliaries are all inorganic or organic chemicals referred to in the recovery and production of textile fibers on their processing, finishing , equipment and coloring to packing as well as the finished goods care of textiles can be used. A sharp distinction between textile auxiliaries and other chemicals used every day in the textile industry can at best be drawn between textile auxiliaries and dyes , since the former do not contribute directly to the coloring.

Chemicals used in the extraction or manufacture of textile fibers and textiles

In the production of textile fibers and the production of the textiles made from the fibers, these go through a large number of work steps in which a large number of chemicals can also be used.

Synthetic polymers, which are obtained as monomers from hydrocarbons through polycondensation , polyaddition and polymerisation , but also natural polymers from natural products such as cellulose , are used to manufacture man-made fibers . The best-known synthetic polymers for man-made fibers are polyester , polyamide , polyimide , polyethylene , polyurethane , aramid , well-known natural man-made fibers are viscose and lyocell .

Chemicals ( surfactants ) are used for washing in the manufacture of natural fibers .

The production of yarns from the textile fibers requires their preparation to improve the sliding and adhesion behavior. For example, emulsions made from nonionic, anionic or cationic surfactants (for example from fatty alcohol or fatty amine ethoxylates ) or sulfated vegetable oils, stearin soaps, ester and silicone oils are used. In the natural products such as wool are also lubricants to the lubrication of the fibers, such as emulsified mineral oils , organophosphate or olein (technical oleic acid) is necessary.

The resulting yarns require sizing (application of a protective film to smooth and make them more resistant to mechanical loads) and pretreatment for the production of textile surfaces. As sizing agents are starch (often in oxidatively more open form), starch ( carboxymethyl starch ), higher alcohols , polyvinyl alcohol , acrylic acid (also their salts, and polyacrylates ) or cellulose derivatives (eg. B. carboxymethyl cellulose ) are used. Emulsified white oils and paraffins are used as smoothing agents, which are intended to reduce the friction between the metal needles and the fiber during knitting and knitting . In the pretreatment, for example, when desizing , washing, singeing / gassing , bleaching, caustic treatment , carbonization and mercerizing are enzymes, surfactants (for. Example, fatty alcohol sulfate , alkyl sulfonate , alkyl benzene sulfonate , tetraalkylammonium chloride , alkyl polyglucoside ), alkalis in the form of sodium hydroxide solution (at Cotton) or soda (for wool), complexing agents to mask heavy metal ions (e.g. pentasodium triphosphate , sodium nitrilotriacetate , sodium citrate , DTPMP ), stabilizers to suppress side reactions during bleaching, dispersants and bleaching agents (e.g. hydrogen peroxide , peracids , sodium chlorite ) used.

Dyeing of fibers and textiles

In addition to the dyes themselves, dyeing auxiliaries are also used to dye fabrics . These include dye solvents and hydrotropes that help dissolve the dyes in the dyebath (water-soluble solvents such as alcohols or esters ), dispersants that keep dyes that are sparingly soluble and insoluble in water in suspension and form or stabilize dispersions (surfactants such as sulfited fatty acid esters and -amides , alkylarylsulfonates and fatty acid ethoxylates ), protective colloids that prevent the dispersions from flocculating (including lignosulfonates and water-soluble polymers such as polyacrylates), wetting agents that reduce the interfacial tension between the textile and the dye liquor (anionic surfactants used such as alkyl sulfates , alkanesulfonates and salts of sulfosuccinic acid and phosphoric acid), leveling agent for uniform coloring (fatty acid esters and amides, alkylamines and their ethoxylated variants, sodium sulfate), dyeing accelerator for polyester with disperse dyes and wool (poorly soluble ar omatic hydrocarbons and phthalic acid imides ) and post-treatment agents to improve the rub, wet or lightfastness of the colors ( quaternary ammonium compounds and cationic formaldehyde condensation products ). Thickening agents based on starch, guar , tamarind and their derivatives, alginates (the sodium salts of alginic acid), synthetic polymers such as polyacrylates, methacrylic acid derivatives , maleic acid derivatives and polyurethanes are also used for textile printing with printing pastes .

Since the fibers have different chemical and also different physical properties, it is not possible to dye all types of fiber with one dye. That is why different dyeing processes and dyes are used for each type of fiber, which are adapted to the later intended use and the desired color shade. Important dyes are vat dyes for dyeing cellulose-based textiles such as indigo , dyes for stain dyeing with a pretreatment with a solution of metal salts ( chromium salts ) and the dyes for development coloring .

The classification of the dyes is partly due to the content of a particular chromophore group (examples are azo dyes and anthraquinone dyes), partly due to the membership of a particular base class of compound or the natural origin (example are mushroom dyes such Arcyriafarbstoffe or Dermocybenfarbstoffe and the indigo dyes). In some cases, they are also named according to the behavior towards the fiber and the dyeing technique to be used (examples are basic or cationic dyes, mordant dyes, disperse dyes, developing dyes, vat dyes, reactive dyes , acid dyes , sulfur dyes, substantive dyes). Important dyes are so azo dyes , sulfur dyes , diphenylmethane dyes , thiazole dyes , triphenylmethane dyes , nitro dyes , anthraquinone dyes , nitroso , indigoid dyes, quinoline dyes , indigo Sole acridine , quinoneimine , cyanine ( azines , oxazines , thiazines ) and phthalocyanine dyes .

For cellulose fibers, cationic (basic) dyes, substantive dyes, come Diazotierungsfarbstoffe , sulfur dyes, Oxydationsfarbstoffe , mordant dyes , development dyes, vat dyes ( indanthrenes ), Indigo brine (Leukoküpenesterfarbstoffe), reactive dyes and pigment dyes are used. Cationic (basic) dyes, substantive dyes, anionic (acidic) dyes, chromium complex dyes , chromating dyes , wool vat dyes , indigosols (leuco vat ester dyes) or reactive dyes are used for protein and polyamide fibers, and disperse dyes for acetate fibers .

Other auxiliaries are also used in some dyeing processes. The addition of acid accelerates and the addition of salt delays the absorption of acid dyes. As acid it is the dyeing liquor dilute sulfuric acid , acetic acid , formic acid , tartaric acid to or sodium hydrogen sulfate, when added salt is sodium sulphate are used.

Finishing of fibers and textiles

Finishing (also called finishing ) refers to all processes in textile finishing that increase the usefulness and attractiveness of textiles. A number of chemicals are used when equipping with the aid of chemical processes. Softening is used to increase the suppleness of textile materials, using dispersions of fats , oils , waxes , paraffins , emulsions of silicone oils and polyethylene dispersions . Metal salts are used to weigh down fibers (e.g. silk) . Various strengths and special synthetic resins (which are also used for easy-care finishing) as well as magnesium sulphate , dextrin and albumin are used to fill and stiffen the textiles to influence the feel of the textiles ( e.g. petticoat ) . In the case of hydrophobing or impregnation , which makes the fabric water-repellent, oleophobing , which makes the fabric grease-repellent, and soil repellant, which makes the fabric dirt-repellent, fluorocarbon resins and metal salt-containing paraffin emulsions are used . The hydrophilization (used for example for women's stockings or corsetry) makes synthetic fibers more absorbent and is achieved through polyacrylates and polyamide derivatives . To improve the scratch and abrasion resistance (for example, bed and table linen and other heavy-duty textiles such. As carpets) are silicas and resins. Phosphoric acid esters , potassium salts and low molecular weight carboxylic acids (e.g. potassium formate ) are used for the antistatic treatment of synthetic fibers, especially carpets . In the felt-free finish, which makes textiles made of new wool or wool-rich mixtures machine washable, polyamide coatings and enzymes ( proteases ) are used. Triazinyl flavonates and stilbene derivatives are used to lighten the appearance and avoid yellowing or graying of sensitive textiles . Antimicrobial equipment prevents the multiplication of microorganisms, which is used, for example, in awnings or tent fabrics, is often achieved through tetraalkylammonium compounds . For protection against eating or repellants against moths (the wool seal, for example, requires moth- proof equipment) or carpet beetles , pyrethroids , for example , and fungicides against fungi . The easy- care finish changes cotton and cotton blends so that they are machine-washable or machine-washable, easy to iron, crease-resistant, dimensionally stable and dry quickly, for which purpose crosslinkers such as dimethyloldihydroxyethylene urea are used. The flame-retardant finish is the treatment with halogen or phosphorus-containing auxiliaries or mineral salts , the use of chlorine or bromine-containing flame retardants such as hexabromocyclododecane , decabromodiphenyl ether and chlorinated paraffins , but also agents based on red phosphorus and ammonium polyphosphates . If textiles are coated with cyclodextrins , odors can in turn be reduced. The anti- shrink finish (preventing from shrinking, shrinking or shrinking) is achieved in addition to mechanical and physical processes by incorporating synthetic resins and, earlier, also by chlorination for crosslinking.

Examples of textile chemicals

Inorganic textile chemicals

The following are used as textile chemicals:

• Sodium chloride , sodium hydrogen sulfate and sodium sulfate in dyeing
• Magnesium sulfate in the finish
• Sodium sulfide and sodium dithionite as reducing agents for vat dyes and sulfur dyes
• Aluminum salts for waterproofing equipment
• Sodium chlorite , sodium hypochlorite and hydrogen peroxide in the bleaching plant
• Ammonia , caustic soda and sulfuric acid in dyeing and finishing processes.

Indigo, of course

Indigo ( historical dye collection of the TU Dresden )

Organic textile chemicals

Organic acids such as formic acid and acetic acid are used in dyeing and finishing processes. Monopoly brilliant oil is a liquid organic textile auxiliary obtained from castor oil through sulphation and saponification . Most textile dyes are organic chemicals , e.g. B. from the group of triphenylmethane dyes. Other groups of dyes are:

• Indigoid dyes (e.g. indigo , a natural dye that can also be produced synthetically)
• Anthraquinone derivatives
• Anthrathrones, Pyranthrones and Violanthrones
• Perinons
• Perylenes
• Sulfur dyes
• Xanthene dyes
• Azine dyes (e.g. mauveine )

Health hazards

Around 8,000 chemicals are used in the production of textiles, some of which are toxic and carcinogenic. In some production facilities, a significantly increased exposure of employees to health hazards was also found.

Most textile auxiliaries are only used for the production of textiles and are washed off or washed out again during the manufacturing process. Ideally, only the finishing chemicals and the dyes remain in the end product, but remaining chemicals from the manufacturing process were found. Consumer advocates therefore advise against clothing whose care instructions contain sentences such as “Please wash separately” or “Color off”. Because then the garment loses color when it is worn, not just when it is washed.

In Germany, textiles are among the consumer goods whose manufacture, distribution and sale are regulated by the Consumer Goods Ordinance . It prohibits the manufacture, treatment or marketing of objects if they are harmful to health, for example if they contain toxicologically active substances. For textiles it is stated that they must not contain any azo dyes that can be broken down into carcinogenic aromatic amines. Of the approximately 3,000 azo dyes, around 120 are affected by this ban. Azo dyes can get into the body through the skin and are dangerous if they are split - this can produce carcinogenic aromatic amines ; you can neither smell nor see them. One consequence can be bladder cancer . Azo dyes that contain at least one carcinogenic amine are no longer used in the EU. Also imported goods, e.g. B. from China, may no longer be colored with these chemicals. Samples are designed to protect consumers.

Fat-soluble compounds such as dioxins or polychlorinated biphenyls (PCBs) are deposited in body fat and remain there for a long time. In tests, pentachlorophenol (PCP) was repeatedly found in clothing . This chlorinated hydrocarbon has been banned in Germany since 1989, but is used in India, China, France and the USA - among other things to protect items of clothing from mold on long transport routes . PCP can trigger so-called chloracne , damage nerves and cause cancer. Poisoning manifests itself with headache, dizziness and fever.

It should be noted that natural substances such as the silk bast protein sericin found in raw silk can in rare cases trigger allergic reactions in sensitized people.

Many previously used textile chemicals are now banned in industrialized countries; however, they are still used in developing and emerging countries. Greenpeace started the Detox campaign in July 2011 to dissuade textile suppliers from using such chemicals. Large companies such as Puma , Nike , Adidas , H&M and C&A have now signed voluntary commitments under pressure from the campaign to refrain from using hazardous substances by 2020.

Web links

• VCI ( Association of the Chemical Industry ): Information (2007, PDF, 64 pages)

• Federal Food Safety and Veterinary Office (Switzerland):
  • Textile chemicals
  • Chemicals in textiles
  • Textile chemicals database

See also

• Textile auxiliaries - additive
  • Cellulose ethers , cooking acids , sodium cyanate , manganese (II) acetate , cetostearyl alcohol
• Sensitization (medicine) , allergy
• Detox , a campaign launched by Greenpeace in July 2011 against residues of textile chemicals in clothing and against the poisoning of water by Chinese textile factories

Individual evidence

1. ↑ Entry on textile finishing. In: Römpp Online . Georg Thieme Verlag, accessed on July 16, 2014.
2. ↑ Entry on textile auxiliaries. In: Römpp Online . Georg Thieme Verlag, accessed on July 16, 2014.
3. ↑ ^{a b c d e} VCI: Textile Chemistry
4. ^ Brockhaus ABC Chemie , VEB FA Brockhaus Verlag Leipzig 1965, pp. 1244-1245.
5. ^ ^{A b c d} Hermann Rath: Textbook of textile chemistry: including textile-chemical technology . Springer-Verlag, 2013, ISBN 978-3-662-00064-9 , pp. 321 ( books.google.de ).
6. ↑ Entry on acid dyes. In: Römpp Online . Georg Thieme Verlag, accessed on September 23, 2017.
7. ^ W. Bernard: Finishing of the textiles: Mechanical and chemical technology of the finishing . Springer-Verlag, 2013, ISBN 978-3-642-92933-5 ( books.google.de ).
8. ^ Brockhaus ABC Chemie , VEB FA Brockhaus Verlag Leipzig 1965, p. 1391.
9. ^ Brockhaus ABC Chemie , VEB FA Brockhaus Verlag Leipzig 1965, p. 905.
10. ^ Winnacker, Küchler: Chemical Technology Volume 7, Organic Technology III 4th Edition (editors: Heinz Harnisch, Rudolf Steiner, Karl Winnacker), there Edwin Baier, Rudolf Dauter, Erwin Fleckenstein, Hermann Fuchs: Organic dyes and pigments , Carl Hanser Verlag München, Wien, 1986, pp. 1-83, see there pp. 22-49. ISBN 3-446-13186-8 .
11. ↑ Cotton processing. (No longer available online.) In: Umweltinstitut.org. Umweltinstitut München , archived from the original on June 3, 2016 ; accessed on June 3, 2016 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  
12. ↑ Rita Kant: Textile dyeing industry to environmental hazard . In: Natural Science . tape 04 , no. 01 , 2012, ISSN  2150-4091 , p. 22–26 , doi : 10.4236 / ns.2012.41004 ( scirp.org [accessed January 19, 2020]).
13. ↑ Franziska Heydebreck, Jianhui Tang, Zhiyong Xie, Ralf Ebinghaus: Emissions of Per- and Polyfluoroalkyl Substances in a Textile Manufacturing Plant in China and Their Relevance for Workers' Exposure . In: Environmental Science & Technology . tape 50 , no. 19 , October 4, 2016, ISSN  0013-936X , p. 10386-10396 , doi : 10.1021 / acs.est.6b03213 ( acs.org [accessed January 19, 2020]).
14. ↑ RB Chavan: Indian textile industry-Environmental issues . In: IJFTR Vol.26 (1-2) [March-June 2001] . March 2001 ( res.in [accessed January 19, 2020]).
15. ↑ Textile chemicals: Carcinogens from the closet
16. ↑ Werner Heppt, Harald Renz, Martin Röcken: Allergologie . Springer-Verlag, 2013, ISBN 978-3-662-05660-8 , pp. 98 ( books.google.de ).
17. ↑ Detox. In: greenpeace.org. Greenpeace International, accessed June 3, 2016 . 
18. ↑ Simone Miller: C&A also wants to detoxify. (No longer available online.) In: greenpeace.de. Greenpeace, November 22, 2011, archived from the original on June 3, 2016 ; accessed on June 3, 2016 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.