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Textile bleaching

From Wikipedia, the free encyclopedia
Early method of bleaching cotton and linen goods on lawns
A bleach worker

Thetextile bleaching(orbleaching of textiles) isone of the stepsin thetextile manufacturingprocess.The objective of bleaching is to remove the natural color for the following steps such asdyeingorprintingor to achieve fullwhite.[1]All rawtextilematerials, when they are in natural form, are known as 'greige' material.They have their natural color, odor and impurities that are not suited to clothing materials. Not only the natural impurities will remain in the greige material, but also the add-ons that were made during its cultivation, growth and manufacture in the form ofpesticides,fungicides,worm killers,sizes,lubricants,etc. The removal of these natural coloring matters and add-ons during the previous state of manufacturing is called scouring and bleaching.[2]: 193 [3][4][5]

Acontinuous bleachingrange is a set of machines to carry out bleaching action. It consists of several compartments in which fabric moves from one side to another with the help of guide rollers and is treated with chemicals, heated, rinsed, and squeezed. Continuous bleaching is possible for the fabrics in open-width or rope form.[6][7]

History

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Bleaching can be dated back to at least 1000BC from an Egyptian list found in the tomb of Rekh-mi-re at Thebes, which mentioned both bleached and unbleached linen.[8]Mulrooney dates it back as far as 5000BC,[9]while Walton claims it was introduced to Egypt from Asia.[10]It’s plausible that it was discovered independently by different cultures. It’s generally assumed to have developed after noticing that garments are naturally bleached by sunlight and washing.[8][9]Wood ash(potash,or impurepotassium hydroxide) was an early form ofsoap,known to have been used in bleaching since at least 1AD.[10][11]This process of washing cloth in a solution of ashes (lye) and left in the sun, known asGrassing,is one of the oldest methods ofbleachingtextilegoods. To bleachlinenandcotton-based fabrics, the Grassing method has been used. Linen has long been bleached in Europe with Grassing method.[12]The linens were laid out on the grass for over seven days after boiling with the ''lyes of ashes and rinsing''.[13]Bleachfieldwas an open area to spread cloth, it was a field near watercourse used by a bleachery. Bleachfields were common in and around themill townsduring the British Industrial Revolution[14]

The Dutch were bleaching by about the 12th century and are credited with soaking the bleached cloth in a bath of soured milk for 5 – 8 days.[9][11][15]This softened and neutralised the harsh effects of the caustic lye.[9]By the 17th century the Dutch were renowned for their bleaching skills and much of their trade was for customers abroad.[16][15]Around 1756 an alternative to soured milk was proposed by the Scottish doctor,Francis Homeusing a weak solution of sulphuric acid.[17]This was made commercially viable byJohn Roebuck'smanufacture ofsulphuric acidand reduced the soaking time to 12 – 24 hours.[15]A final rinse and drying finished the bleaching process.

The English East India Company imported bleached, painted and printedcalicofrom India during the 17th century.[18]This disrupted the English silk and wool trades[19]and an act of parliament, theEncouragement of Manufactures Act 1698(11 Will. 3.c. 10), was passed that prohibited the wearing of printed calicos manufactured in China, India or Persia.[20]This inadvertently established a calico bleaching and printing industry using unbleached Indian calico. A second law in 1721 prohibited the use and wear of all printed, painted, stained or dyed calicoes[21]which stimulated demand forlinenandfustian.Thecalico actswere repealed in 1774 when cloth was made using imported cotton from America.[22]

Discovery of Chlorine

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After discoveringChlorinein the late 18th century, when chemical bleaching came into existence, the chemical bleaching rose above Grassing, as it was quicker and possible in indoors.[12][14][13]

The French chemistClaude Louis Bertholletfirst demonstrated the bleaching properties of chlorine and subsequently developed liquid bleaches around 1789.James Wattis credited with bringing it to Britain, and a fellow Scot,Charles Tennantpatented a more practical bleaching powder that made chlorine-based bleaching a commercial success.

Scouring

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Main article:Scouring (textiles)

Scouring is the first process carried out with or withoutchemicals,at room temperature or at suitable higher temperatures with the addition of suitablewetting agents,alkaliand so on. Scouring removes the impurities such aswaxes,pectinsand makes the textile materialhydrophilicor water absorbent.[23][24][25]: 78 Scouring is then followed by the bleaching process.[2]: 169 [2]: 193 

Bleaching

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The term "bleach" originates from a French word signifying "to whiten." In essence, the process of bleaching involves whitening by removing substances that impart color to the material undergoing the bleaching treatment.[26]Bleaching is the process of decolorizing the material after it has been scoured.[2]: 169 Bleaching textiles can be classified as oxidative bleaching and reductive bleaching which can be carried out with oxidizing and reductivebleaching agents.[27]: 161 Bleaching agents attack thechromophoresand alter the color absorbing properties of the objects.[28]

Oxidative bleaching

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Generally oxidative bleachings are carried out usingsodium hypochlorite,sodium chloriteorsulfuric acid.

Vegetable fibres,animal fibers,andmineral fibresare the three major types ofnatural fibers.Natural fibers such ascotton,ramie,jute,wool,and regenerated fibers such asbambooare all generally bleached with oxidative methods.[29]

Oxygen bleaching action

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It is theconjugated double bondsof the substrate that makes the substrate capable of absorbing visible light. Hence, it looks yellower and need bleaching. When bleaching action carries out with oxygen, it removes the chromophoric sites and makes the cloths whiter. Oxygen is a degrading bleaching agent. Its bleaching action is based on ''destroying the phenolic groups and the carbon–carbon double bonds.''.[30]The major source of chemical bleaching isHydrogen peroxideH
2O
2that contains asingle bond,(–O–O–). When this breaks down it gives rise to very reactive oxygen specie, which is the active agent of the bleach. Around sixty percent of the world Hydrogen peroxide is used in chemical bleaching of textiles and wood pulp.[31]

Reductive bleaching

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Reductive bleaching is done withsodium hydrosulphite,a powerful reducing agent. Fibres likepolyamides,polyacrylicsand polyacetates can be bleached using reductive bleaching technology.[29]

Textile whitening

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Main article:Optical brightener

Bleaching of textiles may include an additional application of optical brighteners (OBAs). Optical brightening agents are chemical compounds that absorblightin theultravioletand violet region (usually 340-370 nm) of theelectromagnetic spectrum,and re-emit light in the blue region (typically 420-470 nm) byfluorescence.After scouring and bleaching, optical brightening agents are applied to make the textile material appear a more brilliant white. These OBAs are available in different tints such asblue,violetandred.[32]

Whiteness

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Pope Francisat theVatican.Popes have traditionally worn white since 1566.

Whiteness incolorimetryis the degree to which a surface is white.[33]The term "whiteness" refers to the degree to which a surface resembles the properties of a perfect reflecting diffuser, i.e. an ideal reflecting surface that neither absorbs nor transmits light, but instead reflects it evenly in all directions.[34]

CIE Whiteness

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CIE Whiteness is a formula that measures the degree of whiteness.[34]The CIE Whiteness Index is a measure or methodology developed by the Commission on illumination.[35]

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  • Grassing, laying out linens to bleach in sunlight
    Grassing, laying out linens to bleach in sunlight
  • Linen Bleaching/ Grassing
    Linen Bleaching/ Grassing
  • Bleekveld in een dorp (Bleachfield in a village), circa 1650 (Jan Brueghel the Younger)
    Bleekveld in een dorp(Bleachfield in a village), circa 1650 (Jan Brueghel the Younger)
  • Market and washing place in Flanders
    Market and washing place in Flanders
  • Bleaching vats for cloth in the piece.
    Bleaching vats for cloth in the piece.
  • High Pressure Blow-through Kier
    High Pressure Blow-through Kier
  • Bleaching—Roller Washing Machine
    Bleaching—The Mather Kier, cross section
  • Bleaching—The Mather Kier, cross section
    Bleaching—The Mather Kier, cross section
  • Bleaching—The Mather Kier, longitudinal section
    Bleaching—The Mather Kier, longitudinal section
  • Bleaching—Mather & Platt’s Horizontal Drying Machine
    Bleaching—Mather & Platt’s Horizontal Drying Machine
  • Bleaching—Horizontal Drying Machine threaded with Cloth
    Bleaching—Horizontal Drying Machine threaded with Cloth

See also

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References

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  1. ^Hummel, J. J. (John James) (1898).The dyeing of textile fabrics.Harvard University. London [etc.] New York, Cassell and company, limited. p. 86.
  2. ^abcdHall, A. J. (Archibald John) (1969).The standard handbook of textiles.New York: Chemical Pub. Co.
  3. ^Clark, M. (2011-10-25).Handbook of Textile and Industrial Dyeing: Principles, Processes and Types of Dyes.Elsevier. pp. 65, 66.ISBN978-0-85709-397-4.
  4. ^The Cotton Year Book and Diary.Marsden and Company, Limited. 1919. p. 470.
  5. ^"Impurity - an overview | ScienceDirect Topics".www.sciencedirect.com.Retrieved2021-07-31.
  6. ^Code of Federal Regulations: Containing a Codification of Documents of General Applicability and Future Effect as of December 31, 1948, with Ancillaries and Index.Division of the Federal Register, the National Archives. 1992. p. 668.
  7. ^BLS Report.U.S. Department of Labor, Bureau of Labor Statistics. 1953. p. 147.
  8. ^abNicholson, Paul T.; Shaw, Ian (2000-03-23).Ancient Egyptian Materials and Technology.citing N Davies "The Tomb of Rekh-mi-re at Thebes" 1943, p.47. Cambridge University Press. p. 280.ISBN978-0-521-45257-1.
  9. ^abcdBach, Julie; Varatharajan, Jenenee."Bleach (Sodium Hypochlorite): History".whatisbleach.weebly.com.Archived fromthe originalon 11 March 2023.Retrieved2023-04-29.
  10. ^abWalton, Perry (1912).The story of textiles.University of California Libraries. Boston, Mass., J. S. Lawrence. pp. 111–115.
  11. ^abCrops in peace and war - The yearbook of agriculture 1950 - 1951.U.S. Government Printing Office. 1950. p. 410.
  12. ^abNystrom, Paul Henry (1916).Textiles.D. Appleton. p. 266.Grassing. — The oldest bleaching method is that of "grassing", still used to a certain extent in Europe for bleaching linens. The linen fabrics are laid on the grass or ground for weeks. The oxygen of the air and that given off by green plants
  13. ^abSansone, Antonio (1888).Dyeing: Comprising the Dyeing and Bleaching of Wool, Silk, Cotton, Flax, Hemp, China Grass &c.A. Heywood & son. p. 109.
  14. ^abAspin, C. (Christopher) (1981).The cotton industry.Aylesbury: Shire Publications Ltd. p. 24.ISBN978-0-85263-545-2.
  15. ^abcThe Encyclopaedia Britannica: A Dictionary of Arts, Sciences, and General Literature: Bleaching.Maxwell Sommerville. 1894. p. 704.
  16. ^Davids, Karel (2008-08-31).The Rise and Decline of Dutch Technological Leadership: Technology, Economy and Culture in the Netherlands, 1350-1800.Vol. 1. BRILL. p. 134.ISBN978-90-474-4332-2.
  17. ^Page, Frederick G (2002)."Francis Home and Joseph Black: the Chemistry and Testing of Alkaline Salts in the Early Bleaching and Alkali Trade".Bulletin for the History of Chemistry.27(2): 107–113 – via docslib.org.
  18. ^Chaudhuri, K. N. (1999).The English East India Company: The Study of an Early Joint-stock Company 1600-1640.Taylor & Francis. p. 199.ISBN978-0-415-19076-3.
  19. ^"House of Commons Journal Volume 11: 19 February 1696 | British History Online".www.british-history.ac.uk.Retrieved2023-04-29.
  20. ^Pickering, Danby (1762).Statutes at large 8 Gui III - 1 Ann (1696 - 1701).Vol. 10. University of Michigan. Great Britain: Cambridge [London]. pp. 328–331.
  21. ^Pickering, Danby (1765).The Statutes at Large 5 - 9 Geo 1 (1718 - 1721).Vol. 14. Cambridge: Joseph Bentham. pp. 318–321.
  22. ^Pickering, Danby (1762).Statutes at large 13 - 14 Geo 3 (1773 - 1774).Vol. 30. University of Michigan. Cambridge [London]: Charles Bathurst. p. 437.
  23. ^Faculty Of Engineering.p. 18.
  24. ^Horrocks, A. Richard; Anand, Subhash C. (2015-12-01).Handbook of Technical Textiles: Technical Textile Processes.Woodhead Publishing. p. 191.ISBN978-1-78242-481-9.
  25. ^Trotman, E. R. (Edward Russell) (1968).Textile scouring and bleaching.London: Griffin.ISBN978-0-85264-067-8.
  26. ^O'Neill, Charles; Fesquet, A. A. (1869).A dictionary of dyeing and calico printing: containing a brief account of dyeing and printing textile fabrics.University of California Libraries. Philadelphia: H.C. Baird.
  27. ^Karmakar, S. R. (1999-11-02).Chemical Technology in the Pre-Treatment Processes of Textiles.Elsevier.ISBN978-0-08-053947-8.
  28. ^"Bleaching Agent - an overview | ScienceDirect Topics".www.sciencedirect.com.Retrieved2021-08-01.
  29. ^abThe Indian Textile Journal.Indian Textile Journal Limited. 2012. p. 113.
  30. ^"Bleaching Agent - an overview | ScienceDirect Topics".www.sciencedirect.com.Retrieved2021-07-27.
  31. ^Hage, Ronald; Lienke, Achim (2006)."Applications of Transition-Metal Catalysts to Textile and Wood-Pulp Bleaching".Angewandte Chemie International Edition.45(2): 206–222.doi:10.1002/anie.200500525.ISSN1521-3773.PMID16342123.
  32. ^Smulders, Eduard; Rybinski, Wolfgang von; Sung, Eric; Rähse, Wilfried; Steber, Josef; Wiebel, Frederike; Nordskog, Anette (2007),"Laundry Detergents",Ullmann's Encyclopedia of Industrial Chemistry,American Cancer Society,doi:10.1002/14356007.a08_315.pub2,ISBN978-3-527-30673-2,retrieved2021-08-01
  33. ^Colorimetry: understanding the CIE system.János Schanda, International Commission on Illumination. Vienna, Austria: CIE/Commission internationale de l'eclairage. 2007.ISBN978-0-470-17563-7.OCLC181346337.{{cite book}}:CS1 maint: others (link)
  34. ^abWestland, Stephen (2014),"CIE Whiteness",in Luo, Ronnier (ed.),Encyclopedia of Color Science and Technology,Berlin, Heidelberg: Springer, pp. 1–5,doi:10.1007/978-3-642-27851-8_5-1,ISBN978-3-642-27851-8,retrieved2021-08-01
  35. ^Amutha, K. (2016-04-05).A Practical Guide to Textile Testing.CRC Press. p. 105.ISBN978-93-85059-62-9.
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Wikisourcehas the text of the1911Encyclopædia Britannicaarticle "Bleaching".
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