- Cotton gins are the factories that complete the first stage of cotton processing- separating the lint from the seed. Before gins were invented the lint was separated from the seed by hand – this would take approximately one day to process 0.5 kilos of lint. Today modern gins can process approx 230,000 kilos per day.
So how does this process work?
We start with Ginning
Moving to Seed, Lint and Trash
- Seed makes up approximately 55% of the seed cotton weight that comes from the farms, they have many uses such as oil, plastics, stock feed for cattle, cosmetics and margarine.
- Lint makes up approximately 35% of the seed cotton weight, once the lint has been separated it is compacted into bales for easier transporting, direct to the next stage of fibre processing.
- The remaining 10% of the seed cotton is classed as waste or trash, this is used in ethanol production or in products that clean up oil spills or even fertiliser.
Then onto Classing
- After the cotton is ginned, a sample is taken for classing or grading for its quality, which impacts greatly on the final selling price- the higher the class the greater the price. The classing comprises of colour grade, staple length, micronaire (fineness), strength and trash content.
Bale Breaking and Carding
- The bales of cotton are laid down in a row, opened and blended through a series of breaking machines, this ensures a consistent blend of fibres. The blend is then processed further to loosen the fibre tufts and remove any remaining vegetable matter.
- The cotton fibre is then fed into a carding machine, which is sometimes referred to the heart of the spinning mill. The carding machine, opens the fibre further, aligns the fibres in a parallel manner and pulls them into a single continuous rope called a sliver.
Roving ,Spinning and Weaving
- The cotton sliver is condensed into a finer sliver. This is called the roving, and is the final fibre preparation before the spinning process
- The cotton fibre then goes through the main spinning process. We currently use ring spinning, however, compact spinning is becoming more popular. The spinning frame draws out the sliver fibre even finer and inserts twist into the fibres by a rotating spindle, although production is slow and additional process are required to be able to use the final yarn.
- Once the cotton yarn is produced, the singles yarn is doubled to add strength and steam set to prevent spirality. The yarn can then be knitted direct from the greige state or yarn dyed.
The final stages - Yarn, Garment & Fabric Dyeing & Finishing
In the final stages, all of John Smedley’s Sea Island Cotton goes through the below processes, ensuring the highest quality finish in our iconic garments.
- Scour & bleach – we remove all oils, waxes & pectins
- Gassing – we remove all of the hairy fibre surface
- Mercerising – we swell the fibre to increase the surface diameter and make the fibre more absorbent, allowing darker shades with less dye.
- Dyeing – we add colour into the yarn itself or piece dye our iconic garments.
- Finally, we add all additional finishes, such as our bespoke treatment to make our iconic John Smedley’s Sea Island Cotton knitwear machine washable.