![Splendor Solis - Traité d'Alchimie - Femmes lavant le linge](https://upload.wikimedia.org/wikipedia/commons/2/22/Splendor_Solis_-_Trait%C3%A9_d%27Alchimie_-_Femmes_lavant_le_linge.jpg)
Scouring is a
preparatory treatment of certain
textile
Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, different fabric types, etc. At first, the word "textiles" only referred to woven fabrics. However, weaving is not the ...
materials. Scouring removes soluble and insoluble impurities found in textiles as natural, added and adventitious impurities, for example, oils, waxes, fats, vegetable matter, as well as dirt. Removing these contaminants through scouring prepares the textiles for
subsequent processes such as bleaching and
dyeing
Dyeing is the application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. Dyeing is normally done in a special solution containing dyes and particular ...
. Though a general term, "scouring" is most often used for
wool
Wool is the textile fibre obtained from sheep and other mammals, especially goats, rabbits, and camelids. The term may also refer to inorganic materials, such as mineral wool and glass wool, that have properties similar to animal wool.
As ...
. In
cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus ''Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor perce ...
, it is
synonymously called "boiling out," and in
silk
Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the coc ...
, and "boiling off."
Purpose of scouring
Scouring is an essential pre-treatment for the subsequent
finishing stages that include bleaching, dyeing, and printing. Raw and
unfinished textiles contain a significant amount of impurities, both natural and foreign. It is necessary to eliminate these impurities to make the products ready for later steps in
textile manufacturing
Textile Manufacturing or Textile Engineering is a major industry. It is largely based on the conversion of fibre into yarn, then yarn into fabric. These are then dyed or printed, fabricated into cloth which is then converted into useful goods ...
.
For instance, fatty substances and waxy matters are the major barriers in the
hydrophilicity
A hydrophile is a molecule or other molecular entity that is intermolecular force, attracted to water molecules and tends to be dissolution (chemistry), dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clar ...
of the
natural fiber
Natural fibers or natural fibres (see spelling differences) are fibers that are produced by geological processes, or from the bodies of plants or animals.
They can be used as a component of composite materials, where the orientation of fibers ...
s.
Absorbency helps the penetration of chemicals in the stages such as
dyeing
Dyeing is the application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. Dyeing is normally done in a special solution containing dyes and particular ...
and
printing
Printing is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The ea ...
or
finishing of the textiles. These fats and waxy substances are converted into soluble salts with the help of
alkali
In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...
.
This treatment is called
Saponification
Saponification is a process of converting esters into soaps and alcohols by the action of aqueous alkali (for example, aqueous sodium hydroxide solutions). Soaps are salts of fatty acids, which in turn are carboxylic acids with long carbon chains. ...
.
Impurities
Foreign matter in addition to
fiber
Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...
is known as impurities. Textile fibers contain many types of impurities. ''e.g.'':
* Natural impurities: Impurities gathered from the natural environment by the fibres. Natural impurities also include non-fibrous parts that are incorporated into the fiber during its growth. Notably, these are not present in synthetic fibres, which are manufactured artificially.
* Added: Oils and waxes during spinning or knitting or weaving.
* Accidental: dirt or mishandling, foreign contaminants.
Etymology, and history
![Waulking 18th century engraving](https://upload.wikimedia.org/wikipedia/commons/6/6d/Waulking_18th_century_engraving.jpg)
Etymology
The term "scouring" refers to the "act of cleaning with a rubbing action.
''
History
Textile manufacturing
Textile Manufacturing or Textile Engineering is a major industry. It is largely based on the conversion of fibre into yarn, then yarn into fabric. These are then dyed or printed, fabricated into cloth which is then converted into useful goods ...
was once an everyday household activity. Women were actively participating in manufacturing. They used to
spin
Spin or spinning most often refers to:
* Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning
* Spin, the rotation of an object around a central axis
* Spin (propaganda), an intentionally b ...
,
weave, process, and finish the products they needed at home.
Historically, in the pre-industrial era and even prior to that Scouring (wool scouring) was a part of the
Fulling
Fulling, also known as felting, tucking or walking ( Scots: ''waukin'', hence often spelled waulking in Scottish English), is a step in woollen clothmaking which involves the cleansing of woven or knitted cloth (particularly wool) to elimin ...
process of cloth making, in which the cloths were cleaned and milled ( a thickening process). Fulling used to be done by pounding the woolen cloth with a club, or by the fuller's feet or hands. This process was associated with
waulking song
Waulking songs ( gd, Òrain Luaidh) are Scottish folk songs, traditionally sung in the Gaelic language by women while fulling (waulking) cloth. This practice involved a group of women, who traditionally prepared cloth, rhythmically beating new ...
s, which were sung by women in the Scottish Gaelic tradition to set the pace.
,
Earliest scouring agents
Scouring agents are the
cleaning agents that remove the impurities from the textiles during the scouring process. While industry now employs
harmful chemicals, these were once actually natural;
Lant
Lant is aged urine. The term comes from Old English , which referred to urine. Collected urine was put aside to ferment until used for its chemical content in many pre-industrial processes, such as cleaning and production.
History
Because of ...
or stale urine and
Lixivium, a solution of
alkaline salts extracted from
wood ashes, were among the earliest scouring agents. Lant which contains
Ammonium carbonate
Ammonium carbonate is a salt with the chemical formula (NH4)2CO3. Since it readily degrades to gaseous ammonia and carbon dioxide upon heating, it is used as a leavening agent and also as smelling salt. It is also known as baker's ammonia and is ...
, was used to scour the wool.
Wool scouring
![CSIRO ScienceImage 11160 Siroscour](https://upload.wikimedia.org/wikipedia/commons/8/88/CSIRO_ScienceImage_11160_Siroscour.jpg)
The removal of lanolin, vegetable materials and other wool contaminants before use is an example of wool scouring. Wool scouring is the next process after
the
''The'' () is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the m ...
woollen fleece of a
sheep
Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus ''Ovis'', in everyday usage it almost always refers to domesticated s ...
is cut off. Raw wool is also known as
''Greasy wool.''
“Grease” or “yolk
'' is a combined form of dried sweat, oil and fatty matter.
Lanolin
Lanolin (from Latin 'wool', and 'oil'), also called wool yolk, wool wax, or wool grease, is a wax secreted by the sebaceous glands of wool-bearing animals. Lanolin used by humans comes from domestic sheep breeds that are raised specifically fo ...
is the major component (5-25%) of raw wool which is a waxy substance secreted by the
sebaceous gland
A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest number ...
s of wool-bearing animals. Greasy matter varies by breed.
Following the cleaning process, the wool fibers possess a chemical composition of
keratin
Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, ho ...
.
Impurities in wool
Process
Three steps comprise the complete cleaning process for wool: steeping, scouring, and rinsing.
Steeping
Potash and wool fat are two beneficial substances among the contaminants in wool, necessitating the development of specific cleaning techniques capable of recovering these compounds. Steeping is an alternative scouring process, In steeping system, scouring entails in parts. Wool steeping is carried out in stages such as immersing it in lukewarm water for many hours. When the wool includes only a little amount of yolk, the steeping method for recovering the yolk can be skipped.
Scouring treatment
Scouring is the process of cleaning wool that makes it free from grease, perspiration residue ( "suint"), dead skin and dirt and vegetable matter present as impurities in the wool. It may consist of a simple boiling of wool in water or an industrial process of treating wool with alkalis and detergents (or
soap
Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are use ...
and
Sodium carbonate
Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...
.)
Bath temperature is maintained (at 65 degree Celsius) to melt wool grease. (Lanolin melts at a temperature of 38-44 °C.)
The next treatment is
carbonization
Carbonization is the conversion of organic matters like plants and dead animal remains into carbon through destructive distillation.
Complexity in carbonization
Carbonization is a pyrolytic reaction, therefore, is considered a complex process ...
, a treatment with strong
acids
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...
that convert vegetable matter into
carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent
In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...
.
Rinsing
Rinsing is the process of thoroughly washing the cleaned wool.
Alternative method
The alternative method is solvent scouring.
Solvent method
Solvent scouring of wool replaces soap, detergent, and alkalies with a
solvent liquid such as
carbon tetrachloride
Carbon tetrachloride, also known by many other names (such as tetrachloromethane, also IUPAC nomenclature of inorganic chemistry, recognised by the IUPAC, carbon tet in the cleaning industry, Halon-104 in firefighting, and Refrigerant-10 in HVAC ...
,
ether
In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be c ...
,
petroleum naphtha
Petroleum naphtha is an intermediate hydrocarbon liquid stream derived from the refining of crude oil with CAS-no 64742-48-9. It is most usually desulfurized and then catalytically reformed, which rearranges or restructures the hydrocarbon mole ...
,
Chloroform
Chloroform, or trichloromethane, is an organic compound with chemical formula, formula Carbon, CHydrogen, HChlorine, Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to ...
,
benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, ...
, or
carbon disulfide
Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non ...
, etc. These liquids are capable of dissolving impurities but highly
volatile and
flammable
A combustible material is something that can burn (i.e., ''combust'') in air. A combustible material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort and a flammable mat ...
. Hence, they need extra care in handling.
Gallery
File:Sheep eating grass edit02.jpg, Australian
Australian(s) may refer to:
Australia
* Australia, a country
* Australians, citizens of the Commonwealth of Australia
** European Australians
** Anglo-Celtic Australians, Australians descended principally from British colonists
** Aboriginal Au ...
Merino sheep
The Merino is a breed or group of breeds of domestic sheep, characterised by very fine soft wool. It was established in Spain near the end of the Middle Ages, and was for several centuries kept as a strict Spanish monopoly; exports of the breed ...
File:Tom Roberts - Shearing the rams - Google Art Project.jpg, Sheep shearing
Sheep shearing is the process by which the woollen fleece of a sheep is cut off. The person who removes the sheep's wool is called a '' shearer''. Typically each adult sheep is shorn once each year (a sheep may be said to have been "shorn" or ...
File:CSIRO ScienceImage 2368 Wool Scouring.jpg, Unscoured wool
File:Wool washing (2377496505).jpg, Qashqhaï women (nomadic shepperds) washing the just harvested wool. Sarab-e Bahram, Area of Noorabad, Fars, Iran, April 2007
File:CSIRO ScienceImage 2801 Wool Scouring.jpg, Wool scouring in the machine
File:CSIRO ScienceImage 11503 Monitoring Wool Scouring.jpg, Wool scouring in the machine, technician monitoring wool scouring process
File:CSIRO ScienceImage 2850 Scoured Wool.jpg, Scoured wool
Cotton scouring
![EB1911 Bleaching - Fig](https://upload.wikimedia.org/wikipedia/commons/c/c4/EB1911_Bleaching_-_Fig._4._%E2%80%94High_Pressure_Blow-through_Kier.jpg)
In cotton, non-cellulosic substances such as waxes, lipids, pectic substances, organic acids contribute to around ten percent of the weight.
Cotton, in particular, has fewer impurities than wool.
Cotton scouring refers to removing impurities such as natural wax, pectins, and non-fibrous matter with a wetting agent and caustic soda.
In comparison, alkaline boiling has no effect on cellulose.
Impurities in cotton
Cotton Pectins, waxes, proteins, mineral compounds, and ash, etc.
Methods
Continuous scouring
A continuous method takes place in an arrangement of J box.
Discontinuous scouring
In discontinuous method certain machines are used such as dyeing vessels, winches, jiggers and Kier.
= Kier boiling
=
Kier is a large cylindrical vessel, upright, with egg shaped ends made of boilerplate that has a capacity of treating one to three tonnes of material at a time.
Kier boiling and
''Boiling off'' is the scouring process that involves boiling the materials with the
caustic
Caustic most commonly refers to:
* Causticity, a property of various corrosive substances
** Sodium hydroxide, sometimes called ''caustic soda''
** Potassium hydroxide, sometimes called ''caustic potash''
** Calcium oxide, sometimes called ''caus ...
solution in the Kier, which is an enclosed vessel, so that the fabric can boil under pressure. Open kiers were also used with temperatures below 100°C (at atmospheric pressure).
= Biotechnology
=
Biotechnology in textiles is the advanced way of processing, textiles, it contributes to numerous treatments of cellulosic materials such as
desizing
Desizing is the process of removing the size material from warp yarns after a textile fabric is woven.
Sizing agents
Sizing agents are selected on the basis of type of fabric, environmental friendliness, ease of removal, cost considerations, eff ...
, denim washing, biopolishing, and scouring, etc.
Scouring with enzymes
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s are helpful in bio-singeing, bio-scouring and removing impurities from cotton, which is more environmentally friendly. Biopolishing is an alternative method that is an
enzymetic treatment to clean the surface of cellulosic fabrics or yarns. It is also named
''Biosingeing.'' Pectinase
Pectinases are a group of enzymes that breaks down pectin, a polysaccharide found in plant cell walls, through hydrolysis, transelimination and deesterification reactions. Commonly referred to as pectic enzymes, they include pectolyase, pectozym ...
enzymes, breaks down
pectin
Pectin ( grc, πηκτικός ': "congealed" and "curdled") is a heteropolysaccharide, a structural acid contained in the primary lamella, in the middle lamella, and in the cell walls of terrestrial plants. The principal, chemical component of ...
, a
polysaccharide
Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wa ...
found in cellulosic materials such as cotton.
Gallery
File:Cotton bolls begin opening during the fall of 2010 crop year. (25090733866).jpg, cotton plant
File:Cotton - panoramio (1).jpg, Cotton farm
File:Cotton.JPG, Cotton boll
File:CottonModule.JPG, cotton ready to bale and transported to the mills
File:Ring spinning machine in the 1920s.jpg, Yarn
Yarn is a long continuous length of interlocked fibres, used in sewing, crocheting, knitting, weaving, embroidery, ropemaking, and the production of textiles. Thread is a type of yarn intended for sewing by hand or machine. Modern manufact ...
spinning
Spin or spinning most often refers to:
* Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning
* Spin, the rotation of an object around a central axis
* Spin (propaganda), an intentionally b ...
File:GF-08 b.JPG, Fabric manufacturing on loom
File:Circular knitting machine.jpg, Fabric manufacturing on knitting machine
File:EB1911 Bleaching - Fig. 7.—The Mather Kier, longitudinal section.jpg, The Mather Kier, longitudinal section (Kier, an old method of scouring)
File:Dyeing machines.jpg, Processing pretreatment and dyeing
Silk scouring
Silk is an
animal fiber
Animal fibers are natural fibers that consist largely of certain proteins. Examples include silk, hair/fur (including wool) and feathers. The animal fibers used most commonly both in the manufacturing world as well as by the hand spinners are w ...
it consists 70–80%
fibroin
Fibroin is an insoluble protein present in silk produced by numerous insects, such as the larvae of ''Bombyx mori'', and other moth genera such as ''Antheraea'', '' Cricula'', '' Samia'' and ''Gonometa''. Silk in its raw state consists of two ...
and 20–30%
sericin
Sericin is a protein created by ''Bombyx mori'' (silkworms) in the production of silk. Silk is a fibre produced by the silkworm in production of its Pupa#Cocoon, cocoon. It consists mainly of two proteins, fibroin and sericin. Silk consists of ...
(the gum coating the fibres). It carries impurities like dirt, oils, fats and
sericin
Sericin is a protein created by ''Bombyx mori'' (silkworms) in the production of silk. Silk is a fibre produced by the silkworm in production of its Pupa#Cocoon, cocoon. It consists mainly of two proteins, fibroin and sericin. Silk consists of ...
. The purpose of silk scouring is to remove the coloring matter and the gum that is a sticky substance which envelops the silk yarn. The process is also called
''degumming''. The gum contributes nearly 30 percent of the weight of unscoured silk threads. Silk is called ''boiled off'' when the gum is removed. The process includes the boiling the silk in a soap solution and rinsing it out.
Gallery
File:Silkworms3000px.jpg, Silk worms
The domestic silk moth (''Bombyx mori''), is an insect from the moth family Bombycidae. It is the closest relative of ''Bombyx mandarina'', the wild silk moth. The silkworm is the larva or caterpillar of a silk moth. It is an economically im ...
File:Bicho da seda.jpg, Silk worms forming cocoon
File:Azərbaycan kəlağayısının hazırlanması 1.JPG, Silk cocoon
File:Freixo de Espada à Cinta (744667341).jpg, Greige
The textile bleaching (or bleaching of textiles) is one of the steps in the textile manufacturing process. The objective of bleaching is to remove the natural color for the following steps such as dyeing or printing or to achieve full white. A ...
silk
File:Making silk from cocoon at Korean Folk Village.jpg, Silk extraction from cocoon
File:Silk making.jpg, Silk cocoons boiling in water while fibres are extracted
File:Silk raw 01.jpg, Silk hanks ready to process
File:Silk Yarn (3538527583).jpg, Dyed silk yarns
Manmade material Scouring
Oil and dirt are the impurities in
Synthetic materials Synthetic things are composed of multiple parts, often with the implication that they are artificial. In particular, 'synthetic' may refer to:
Science
* Synthetic chemical or compound, produced by the process of chemical synthesis
* Synthetic o ...
. Certain oils and waxes are applied as lubricants during spinning or fabric manufacturing stages such as knitting or weaving. Mild detergents can remove the impurities effectively.
Effluent of scouring
Effluent
Effluent is wastewater from sewers or industrial outfalls that flows directly into surface waters either untreated or after being treated at a facility. The term has slightly different meanings in certain contexts, and may contain various pollut ...
is waste water that is thrown away in the water bodies.
Industrial wastewater
Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sa ...
contaminated with scouring residues is heavily contaminated and extremely polluted.
See also
*
Grassing (textiles)
Grassing is one of the oldest methods of bleaching textile goods. The grassing method has been long been used in Europe to bleach linen and cotton based fabrics.
Method
The linens were laid out on the grass for over seven days after boiling w ...
*
Singeing (textiles)
Singeing is a preparation method of textiles; it is applied more commonly to woven textiles and cotton yarns where a clean surface is essential. Singeing in textiles is a mechanical treatment or finish to obtain a neat surface of the fabric or les ...
References
External link
*
*{{commonscatinline
Textiles
Textile techniques
Textile chemistry
Industrial processes