Mercerisation is a
textile finishing
In textile manufacturing, finishing refers to the processes that convert the woven or knitted cloth into a usable material and more specifically to any process performed after dyeing the yarn or fabric to improve the look, performance, or "hand" ...
treatment for
cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell w ...
fabric
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 th ...
and
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 manu ...
, mainly
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 pe ...
and
flax, which improves
dye uptake and
tear strength, reduces
fabric shrinkage, and imparts a
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 ...
-like
luster.
Development
The process was devised in 1844 by
John Mercer,
who treated cotton with solutions of20–30%
sodium hydroxide followed by washing. Mercer observed that the treatment shrank the fabric and increased its tensile strength and affinity for dyes. In the original process of Mercer, no tension was applied. The product was termed ''fulled cotton'', a nod to the process of
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 ...
in woven wool fabric. Mercer regarded the increased affinity for dyes as the most important technical aspect. Mercer also experimented with
sulfuric acid and
zinc chloride
Zinc chloride is the name of inorganic chemical compounds with the formula ZnCl2 and its hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white, and are highly soluble in water. This salt is hygroscopic and e ...
solutions and discovered the
parchmentising effect of sulfuric acid.
The silk-like lustre now commonly associated with mercerising is produced by tension and was discovered by
Horace Lowe in 1889.
[
]
Process
Treatment with sodium hydroxide destroys the spiral form of the cellulose with formation of alkali cellulose
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 ...
, which is changed to cellulose hydrate
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wa ...
on washing out the alkali. Caustic soda concentrations of 20–26% are used. Effective mercerization requires the use of wetting agent
Surfactants are chemical compounds that decrease the surface tension between two liquids, between a gas and a liquid, or interfacial tension between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming ...
s.
The improved lustre of mercerised cotton is due to the production of nearly circular cotton fibres under tension. Another characteristic feature is the untwisting (deconvolution) of the cotton hair.
In dry mercerization, the process is carried out while drying the fabric on a stenter.
References
External links
*
{{fabric
Fibers
Cotton
Textile treatments
1844 introductions