Mercerized cotton
Encyclopedia
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....
fabric and thread
Yarn
Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery and ropemaking. Thread is a type of yarn intended for sewing by hand or machine. Modern manufactured sewing threads may be finished with wax or...
that gives fabric or yarns a lustrous appearance and strengthens them. The process is applied to cellulosic materials like cotton or hemp
Hemp
Hemp is mostly used as a name for low tetrahydrocannabinol strains of the plant Cannabis sativa, of fiber and/or oilseed varieties. In modern times, hemp has been used for industrial purposes including paper, textiles, biodegradable plastics, construction, health food and fuel with modest...
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History
The process was devised in 1844 by John MercerJohn Mercer (scientist)
John Mercer was an English dye and fabric chemist and fabric printer born in Great Harwood, Lancashire. In 1844 he developed a process for treating cotton, mercerisation, that improves many of its qualities for use in fabrics.John Mercer never went to school, he learned basic reading and writing...
of Great Harwood
Great Harwood
Great Harwood is a small town in the Hyndburn district of Lancashire, England, north-east of Blackburn.-History:Great Harwood is a town with a industrial heritage. The Mercer Hall Leisure Centre in Queen Street and the town clock pay tribute to John Mercer , the 'father' of Great Harwood, who...
, Lancashire
Lancashire
Lancashire is a non-metropolitan county of historic origin in the North West of England. It takes its name from the city of Lancaster, and is sometimes known as the County of Lancaster. Although Lancaster is still considered to be the county town, Lancashire County Council is based in Preston...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, who treated cotton fibres with sodium hydroxide. The treatment caused the fibres to swell, which in Mercer's version of the process shrank the overall fabric size and made it stronger and easier to dye. The process did not become popular, however, until H. A. Lowe improved it into its modern form in 1890. By holding the cotton during treatment to prevent it from shrinking, Lowe found that the fibre gained a lustrous appearance.
Process
Mercerisation alters the chemical structure of the cotton fibre. The structure of the fibre inter-converts from alpha-cellulose to a thermodynamically more favourable beta-cellulose polymorph. Mercerising results in the swelling of the cell wall of the cotton fibre. This causes increases in the surface area and reflectance, and gives the fibre a softer feel. An optional last step in the process is passing the thread over an open flame; this incinerates stray fibers, improving the fabric's appearance. This is known as "gassing the thread" due to the gasNatural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
burner that is typically used.
Thread
The modern production method for mercerised cotton, also known as "pearl" or "pearle" cotton, gives cotton thread (or cotton-covered thread with a polyesterPolyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
core) a sodium hydroxide bath that is then neutralized with an acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
bath. This treatment increases lustre, strength, affinity to dye
Dye
A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber....
, resistance to mildew
Mildew
Mildew refers to certain kinds of molds or fungi.In Old English, it meant honeydew , and later came to mean mildew in the modern sense of mold or fungus....
, but also increases affinity to lint
Lint
Lint may mean:* Fibrous coat of thick hairs covering the seeds of the cotton plant* Lint , an accumulation of fluffy fibers that collect on fabric** Navel lint, an accumulation of fluffy fibres in one's navelLint may also refer to:...
. Cotton with long staple
Staple (textiles)
A Wool Staple is a naturally formed cluster or lock of wool fibres and not a single fibre. Very many staples together form a fleece.* Image of the staples on the sheep The cluster of wool fibres is made by a cluster of follicles...
fibre lengths responds best to mercerisation. Mercerised thread is commonly used to produce fine crochet
Crochet
Crochet is a process of creating fabric from yarn, thread, or other material strands using a crochet hook. The word is derived from the French word "crochet", meaning hook. Hooks can be made of materials such as metals, woods or plastic and are commercially manufactured as well as produced by...
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