Talk:Mercerisation

Permission for including part of Tom Beaudet's mercerization article in the history section

On July 30, 2006 I emailed Tom Beaudet about permission:

<<if you would mind giving permission for part of your article on mercerized cotton to be included in the Wikipedia article>> Granted, with reference made to the full article for those that wish to pursue. Tom Beaudet

Note: I forgot to login to Wikipedia before I posted today's update to the main article.--Kaze0010 09:20, 31 July 2006 (UTC)

Some writing on mercerized cotton

FYI

 – Section heading added by Undead Shambles (talk) 05:29, 10 August 2021 (UTC)

Mercerized cotton is cotton which has been treated with sodium hydroxide to bring out certain properties first discovered by John Mercer in 1851. In 1890, Horace Lowe added an additional step to the process, and the British cotton industry began to take an interest in mercerized cotton, which is available today in a wide range of incarnations from thread to completed garments. When treated properly, mercerized cotton is stronger, smoother, and shinier than regular cotton. In addition, it takes dye more readily so that manufacturers can create rich color saturation in their cottons. The brilliant, lustrous hues of Mercerized cotton can be found in fabric stores, yarn shops, and department stores all over the world.

John Mercer discovered that immersing fibers such as cotton and linen in a caustic soda bath would increase their strength and also allow them to take dye more readily. He patented his fiber work, but the cotton industry did not express very much interest in it. It was Horace Lowe who popularized the process, by discovering that keeping the fibers under tension while they were soaked yielded a more lustrous thread. Mercer's name is presumably given to the process to recognize his important initial discovery, which paved the way to Lowe's refinement of the treatment.

Mercerization starts with gathering the cotton and spinning it normally. Because cottons with long fibers take better to mercerization, Pima, Egyptian, and Sea Island cotton are usually chosen for the process. The cotton thread is held under tension and submerged in a highly alkaline bath of sodium hydroxide in a percentage which ranges, but usually hovers around 22%. After treatment, the mercerized cotton is placed into an acidic bath to neutralize it. Once this process is complete, the cotton can be dyed and knitted, woven, or packed as stand-alone spools of thread.

The terms "pearl cotton" and "pearle cotton" are also used to refer to Mercerized cotton, because of the deeply lustrous appearance of the finished cotton thread. In addition to having rich color saturation and a shimmering appearance, mercerized cotton is also much stronger than conventional cotton thread. The process shrinks the cotton fibers, tightening and smoothing the grain of the thread. Because the cotton is preshrunk, mercerized cotton also tends not to shrink as much as regular cotton, so consumers can be more confident about the fit of mercerized garments. Mercerization is a treatment for cotton fabric and thread that gives cotton a lustrous appearance. The series of processes was devised by John Mercer of Great Harwood, Lancashire, in the middle of the 19th century, but did not become popular until improvements were made to the process in 1890. —Preceding unsigned comment added by 202.134.188.26 (talk) 13:34, 5 October 2007 (UTC)

Article inaccuracies

FYI

 – Section heading added by Undead Shambles (talk) 05:29, 10 August 2021 (UTC)

Bsmith0000 (talk) 17:51, 29 June 2010 (UTC) This article incorrectly states that "This treatment increases lustre, strength, affinity to dye, ...". This is false. Several papers from the 1920's and 1930's clearly show that direct dyes (e.g. Colour Index Direct Blue #1 and many others) have LESS AFFINITY for Mercerized cotton than for the same cotton prior to Mercerization. The darker visual color obtained when dyeing Mercerized cotton is completely due to optical effects, not due to increased dye sorption. In fact published dyeing isotherms clearly show that direct dyes have LESS (not MORE) affinity for Mercerized cotton. This article simply repeats the often-misstated myth. Bsmith0000 (talk) 17:51, 29 June 2010 (UTC) Bsmith0000 (talk) 17:51, 29 June 2010 (UTC)

The article still has significant problems ...

• 1 “treated cotton fibres with sodium hydroxide” … actually the fibers are treated at room temperature (that’s a very important part of the process that the article fails to mention) with a nominal 20% aqueous solution of sodium hydroxide. Also the process can be done with liquid ammonia, which is not described in the article. See USP 4051699 and scores of published papers on liquid ammonia mercerization.
• 2 “applied to cellulosic materials like cotton or hemp” ... I worked in literally thousands of mills all over the world, and have never encountered or heard of anyone mercerizing hemp (or any other bast fiber commercially. Mercerization is for cotton only. Period. There may have been some research lab investigations on the effect of mercerization of jute, hemp, etc with liquid ammonia, but I’ve never seen nor heard of any commercial mercerization process for hemp, jute, flax, ramie, etc.
• 3 “Converts cotton from the alpha to beta polymorph” … actually, caustic mercerization converts cotton from cellulose I to cellulose II, whereas liquid ammonia mercerization converts from cellulose I to cellulose III. These forms have different crystal structures due to trans/gauche changes in the orientation of the C6 hydroxyl group in the cellobiose polymer backbone. See the dissertation of Usa Sangwataranoj at NC State University, as well as many publications by John Cuculo.
• 4 “Increases surface area” … actually, the specific surface area (surface to volume ratio) of the fibers decreases. Cellulose II (caustic mercerized) and cellulose III (ammonia mercerized) forms are less dense than cellulose I, therefore the cellulose expands when mercerized, and the fiber cross-sectional shape changes from kidney shaped (original cell I) to round (mercerized cell II or cell III). The extent of expansion/swelling is limited by the fiber’s primary cell wall. The round cross section (cell II or cell III) has a smaller surface to volume ratio than the original form (cell I). See Clifford Preston “Dyeing of Cellulosic Fibers” (Dyers Publication Trust, UK).
• 5 “Increases affinity to dye” … actually, the affinity to dye is decreased by mercerization. The darker appearance of mercerized cellulose dyed with direct and fiber reactive dyes is purely an optical effect due to the educed specific volume (see above), which scatters less light at the surface. There are papers published on this in the 1930’s using mercerized and un-mercerized cellulose dyed with CI direct blue 1 and other dyes. This can be easily demonstrated by immersing a US dollar bill in liquid ammonia. After a while, the dollar shrinks to about ½ its original size, and the color darkens. Of course, the amount of dye in the dollar bill does not change – but its color darkens due to optical effects.
• 6 “An optional last step in the process is passing the thread over an open flame; this incinerates stray fibers, improving the fabric's appearance” … actually the statement implies that a thread is a fabric, which is not the case. Furthermore, the process with the flame is a completely separate process called “Singeing”. (See Wiki article on Singeing) — Preceding unsigned comment added by 71.23.80.95 (talk) 16:19, 14 May 2012 (UTC)

Perle cotton

FYI

 – Section heading added by Undead Shambles (talk) 05:29, 10 August 2021 (UTC)

Perle cotton, pearl cotton, or French coton perlé is an S-twisted, 2-ply thread with high sheen, sold in five sizes or weights (No. 3, 5, 8, 12 and 16 (Finca), with 3 being the heaviest and 16 the finest). 98.206.86.187 (talk) 15:43, 10 July 2013 (UTC)

"Fil d'Ecosse" listed at Redirects for discussion

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